Indian Patents. 242041:"POLYMERIZATION PROCESS INVOLVING DIACYL PEROXIDES"

Title of Invention	"POLYMERIZATION PROCESS INVOLVING DIACYL PEROXIDES"
Abstract	The invention relates to a process to make and use specific diacyl peroxides in polymerization reactions. The peroxides are produced and used in a polymerization process within a short timeframe in order to overcome stability issues associated with them.

Full Text	ACD 2S25 R POLYMERIZATION PROCESS INVOLVING DIACYL PEROXIDES The present invention relates to a polymerization process wherein at least one I diacyl ceroxide of formula (I) is used as a source of free radicals. Such crccesses are known from, for instance, WO 00/17245, where diisobutanoyi peroxide is used to polymerize vinyl chloride by means cf the radicals that are formed curing the thermal decomposition of the peroxide. However, the use of diacyl peroxides of formula (I) can be cumbersome. More particular?/, the peroxides of formula (!) are very thermally labile, as a result of which they show significant decomposition during storage at temperatures as low as -5"C. In order to ensure the quality and assay of the product, it is typically produced at temperatures of 0°C or lower and kept at temperatures of -20°C during its storage and handling. However, even at such low temperatures, a noticeable reduction of the assay of the material is noted. Furthermore, it is necessary to phlegmatize the peroxides of formula (I), particularly the products wherein R1f R2, R3, and R4 contain less than 20 carbon atoms in total, using a water-immiscible, hydrophobic solvent, such as isododecane, because the peroxides cannot be handled in the pure form for safety reasons. Such solvents will end up in the polymer made in the polymerization process, which for a variety of wei!-kr,own reasons (undesired plasticizing of the polymer, exudation from finished polymer articles, which may lead to fogging, and the like), is typically undesired. There fere, there is need for a process wherein peroxides of formula (I) can be used wiihout undesired refrigeration and solvents being obligatory. Preferably, the process also allows the use of water to reduce the safer/ hazards associated with the clacyl peroxides, so that they can be handled safeiy during processing and handling/metering to the polymerization reactor. Surprisingly, we have found that the use of a specific process for making and using the diacyl peroxides of formula (I) fulfills this need. The process according to the invention is characterized in that - an aqueous mixture comprising a peroxide of formula (I) is produced in a peroxidation step wherein i) ere or more acid halides of formula (II) are reacted with ii) MOOH/M2O2 and/or one or more peracids (or their salts) of formula (111) , in an aqueous phase, in which peroxidation step the acid halide, or mixture of acid halides, is essentially only brought into contact with water containing MOOH/M2O2 and/or one or more peracids (or their M salts), to give an aqueous mixture, and iii) optionally one or more colloids and/or surfactants are combined with said aqueous mixture before, during, or after the peroxidation step and - the resulting aqueous mixture is used in a polymerization process. It is noted that the term MOOH/M202 stands for the product that is formed from H202 sr.d a suitable source of metal (M) ions. The product typically is not a discrete product M202] but the equilibrium comprising H2O2, MOOH and M202. From a~ Industrial point of view it is preferred that the s:ar~:ng material from which the diacy1 peroxides of formula (I) are prepared, i.e. the ore or more acid halides of formula (II, ~. J the one or more peracids (or their M salts) of formula !!l) are easily available or obtainable. Most preferably, these compounds are commercially available. The process of this invention is pre-eminently suitable for diacyl peroxides that are liquid at the process temperature, since these diacyl peroxides have a lower hydrolytic and thermal stability than diacy! peroxides that are solid at the process temperature In a preferred embodiment, the aqueous mixture comprising diacyl peroxide of formula (I) is used in the polymerization process within a period of 168, more preferably 102, even more preferably 48, more preferably still 24, yet more preferably 12, yet more preferably still 2 hours after the peroxidation step. In a most preferred embodiment the reactor wherein the peroxidation step is conducted is directly linked by means of piping and optional further holding or processing tanks to the reactor in which the polymerization process is conducted. In another preferred embodiment, the diacyl peroxide is stored and handled in this process at temperatures up to 5°C, since it was observed that, depending on the hydrolytic and thermal stability of the diacyl peroxide, it can be acceptable in the process according to the invention to store and handle the diacyl peroxide up to temperatures of ~5°C, preferably 0°C or more preferably 5°C. In the process of the present invention it is necessary to prevent just water and acid ha::de of formula (II) from being combined at any given time, since otherwise the ac;c halide would hydrolyze, resulting in low yieics of peroxide and causing contamination of the aqueous mixture. Also, a mixture cf just water and acid halide was found to be very corrosive, which would require the use of more expensive process equipment. Hence, when it is stated that in the process the acid halide is essentially only brought into contact with water containing MOOH/M2O2 and/or one or more peracids, what is meant is that water and just acid halide are contacted for a period of at most 1 minute, preferably at most 20 seconds, more preferably at most !C seconds, even more preferably at most 5 seconds, most preferably at most "i second. Therefore, the only viable ways to make diacyl peroxide are: i) to pre-charge water, MOOH/M202 (or, optionally, to make the MOOH/M202 from H202 and a source of M) and dose acid halide thereto, ii) to pre-charge water and H2O2 and dose both the source of M and acid halide, iii) to pre-charge water and dose both MCOH/M2O2 (optionally H202 together with a source of M) and acid halide, and iv) to pre-charge water and a source of M and dose both H202 and acid halide. If a peracid is used in the present process, the same viable ways are available (substituting the peracid for H202, and substituting the M salt of the peracid for MOOH/M202). In order to optimize the yield of peroxide, using one of the four viable ways is preferred. It is noted that US 3,923,766 discloses a so-called "in-situ" process where a diacyl peroxide of formula (I) is used that is produced from an anhydride and a peracid. The "in-situ" process is characterized in that the diacyl peroxide is produced in the polymerization reactor in the presence of the monomer, which is not a process according to the invention. Such "in-situ" processes are undesired, since they do not ailcv/ a flexible mode of operation. More particularly, most of the peroxide is formed r.ear the start of the process, preventing a constant polymerization rate, and thus resulting in a heat output that is not constant. Such a variation in heat outpu: ;s undesired, since polymerization reactors are run most cost-effectiveiy under renditions where cooling is at the maximum rate. To overcome this problem, it is suggested in U-S 3,923,766 to use a second (conventional) more stable initiator.-However, such more stable initiators will partially end up in the final polymer, which is undesired for polymer stability reasens (the remaining initiator will leac to premature decomposition of the resin during heat treatment, such as moulding operations). US 3.925,506 discloses a method of preparing asymmetrical a-halogen substituted diacyl peroxides of formula (I) wherein R2 is chloride or bromide, R4 is hydrogen, and each of R1 and R3 is a long chain alkyl radical having about 10 to about 16 carben atoms, it is noted that these a-halogen substituted diacyl peroxides of US 3,936.5C6 are not of interest for the present invention, since the starting materials from which these diacyl peroxides are to be prepared are not easily available or obtainable. From an industrial point of view this is an undesirable situation. It is furthermore noted that WO 01/32613 discloses a process where peroxydicarbonates are produced ex-situ. However, it is desired to offer alternative processes allowing the production of a broader range of peroxides. More specifically, the peroxydicarbonates of WO 01/32613 all have a half-life of 1 hour at a temperature of about 64°C. This means a rather limited freedom when it comes to selecting the polymerization temperature. Also, the chloroformate used to make the peroxydicarbonates is much more hydrolytically stable than the acid halides that are used to make the diacyl peroxides of the present invention. At lower temperatures (say about 50°C) the peroxydicarbonates will not decompose fast enough to give efficient polymerization times and lead to an unacceptably high residuai peroxide content in the final polymer, which adversely affects the thermal stability of the formed polymer. At higher polymerization temperatures (say about 60°C) the peroxydicarbonates will decompose too quickly, leading to inefficient use and tec slow polymerization rates towards the end of the polymerization. Surprisingly, it was found that, after further modification, the concept of WO 01/32513 could be extended to diacyl peroxides of formula (1). The modification needed !sT inter alia, to make sure that the acid halide is no: just substituted for the chlorcfermate, but that it is brought into contact with water only when an inorganic peroxide or peracid (salt) is present in the aqueous phase. Detailed description of the invention The present invention relates to a process comprising the steps of: - producing an aqueous mixture comprising a diacyl peroxide of formula (1) wherein R1-R4 are independently selected from the croup consisting of hydrogen, halogen, and saturated or unsaturated, linear or branched alkyl, alkaryl, and aralkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R2 are hydrogen, then R3 and/or R4 are not hydrogen and, vice-versa, that if R3 and/or R4 are hydrogen, then R1 and/or R2 are not hydrogen, in which process R1-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R1, or one of R1-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, by reacting, in a so-called peroxidation step, one or more acid halides of formula , wherein X is halide, preferably chloride or bromide, most preferably chloride, with i) MOOH/M202J wherein M is any metal or ammonium-containing group that will react with H202 to form MOOH/M2O2 with cut decomposing one or more of the peroxides present in the process, preferably M is selected from the group consisting cf ammonium, sodium, pc:assium, magnesium, calcium, and lithium, and/or ii) zne or more peracids of formula !!!) preferably the M salts thereof, in an aqueous phase, in which process the acid halide, or mixture of acid halides, is essentially only brought into contact with water containing MOOH/M2O2 and/or one or more peracids (or their peracid salts), preferably M2O2 or the M salt of the peracid, - optionally introducing one or more solvents for the acid halide in any part of the process, - opiicnally introducing one or more salts in any part of the process, - optionally introducing one or more colloids and/or surfactants, before, during, or after :he peroxidation step, - optionally purifying the aqueous mixture in one or more purification steps, - optionally homogenizing the aqueous mixture in one or more homogenization steps, - transferring the product from the previous steps that comprises the diacyl peroxide of formula (I) to a polymerization reactor, and - thermally decomposing said diacyl peroxide, to generate organic free radicals, in the presence of one or more ethylenically unsaturated monomers, to polymerize said monomers in said polymerization reactor. In a preferred embodiment, the aqueous mixture comprising said diacyl peroxide is used in said polymerization process within a period of 168, more preferably 102, even mere preferably 48, more preferably still 24, yet mere preferably 12, yet more preferably still 2 hours after said peroxidation step. In a most preferred embodiment, the reactor wherein the peroxidation step is conducted is directly linked by means of piping and optional further holding or processing tanks to the reader in which the polymerization process is conducted. Preferably, the diacyi peroxice-containing mixture is prepared just prior to when it is needed in the polymerization step. Should the dispersion be stored for any period of time, then it is preferred, from a safety point of view, to keep the dispersion in motion to prevent phase separation. Any conventional agitation can be used, such as a shaft with blades, a system to bubble inert gas through the dispersion, and/or a recirculation pump, if one or more of the optional colloids and/or surfactants are used in the process, then the diacyi peroxide-containing mixture typically is less prone to phase separation, increasing safety margins. In another preferred embodiment, the diacyi peroxide is stored and handled in this process at temperatures up to 5aC, since it was observed that, depending on the hydrolytic and thermal stability of the peroxide, it can be acceptable to store and handle the peroxide in the process according to the invention up to temperatures of -5°CT preferably 0°C or more preferably 5°C. In a further preferred embodiment, the process involves diacyi peroxides of formula (1) , wherein R1-R4 are independently selected from the group consisting of hydrogen, halogen, and saturated or unsaturated, linear or branched alkyl, alkaryl, and araikyl moieties optionally substituted with one or more halogen atoms, provided that if R and/or R are hydrogen, then R3 and/or R4 are not hydrogen and, vice-versa, that if R and/or R are hydrogen, then R1 and/or R2 are not hydrogen, in which process R -C-R and/or Rs-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen croups R , or one of R -C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, with the further proviso that diacyi peroxides of fcrmula (!) wherein R is halogen and R4 is hydrogen, and both R1 and R3 are ;ong chain alky! groups having aoout 10 to about 16 carbon atoms, are excludec from this invention. In yet another preferred embodiment, the process involves diacyl peroxides of R4 P4 formula (I) v , wherein R'-R are independently selectee from the group consisting of hydrogen, halogen, and saturated or unsaturated, linear or branched alkyi, alkaryl, and araikyl moieties optionally substi:-j:ed with one or more halogen atoms, providec that if R1 and/or R2 are hydrogen, then R and/or R are not hydrogen and, vice-versa, that if R and/or R are hydrogen, then R1 and/or R2 are not hydrogen, in which process R1-C-R2 and/or R°-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R1, or one of R1-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, with the further proviso that if R2 is halogen and R4 is hydrogen, and both R1 and R3 are alkyl groups, then each of these alkyi groups has up to about 6 carbon atoms. In yet another preferred embodiment, the process involves diacyl peroxides of I3 formula (I) ■ wherein R1-R4 are independently selected from the group consisting of hydrogen and saturated or unsaturated, linear or branched alkyi, alkaryl, and araikyl moieties optionally substituted with one cr nore halogen atoms, provided that if R . and/or R are hydrogen, then R and/cr R4 are not hydrogen and, vice-versa, that if R3 and/or R4 are hydrogen, then R1 and/cr R2 are not hydrogen; in which process R^C-R2' and/or R3-C-R4 can be part cf a ring structure that can be saturated or unsaturated and substituted with one cr r~>ore independently chosen croups R1, or one of R-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure. In yet another preferred embodiment of this invention, :he diacyl peroxide of formula M), when transferred to the polymerization reactor, is always transferred from :r.e previous step in the aqueous phase, with the diacyl peroxide being represented by formula (I) " '% wherein R1-R4 are indepencently selected from the group consisting of hydrogen, halogen, and saturaiec or unsaturated, linear or branched alky!, alkar/l, and aralkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R" are hydrogen, then R and/or R are not hydrogen and, vice-versa, that if R and/or R4 are hydrogen, then R1 and/or R2 are not hydrogen, in which process R1-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R , or one of R1-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure. In one still more preferred embodiment only one reactor is used to produce the diacyl peroxide. Most preferably, only one reactor is used to react both the source of M and H202 and to carry out the peroxidation step to make the diacyl peroxide. The amount of diacyl peroxide (which acts as an initiator) to be used as a source of free radicals in the polymerization step according to the invention is within the range conventionally used in polymerization processes. Typically, from 0.005 to 2% by weight (r/ow/w) of initiator, preferably 0.01-1 %w/w, more preferably 0.01-0.5 %w/w, based cr\ the weight of the ethylenically unsaturated moncmer(s) to be polymerized, is used, it is noted that the diacyl peroxide initiator of the present invention may be used ir. combination with other initiators. Preferably, the acid halide of formula (II) is derived from Ci-C30 carboxyiic acids, preferably from isobutanoic acid; 2-methyibutanoic acid, 2-methylpentanoic acid, 2-metr.y;hexanoic acid, 2-methylheptanoic acid, octancic acid, 2-methyloctanoic acid, decanoic acid, 2-methyinonanoic acid, tetradecancic acid, hexadecanoic acid, cctadecanoic acid, lauric acid, 2-ethylbutanoic acid. 2-ethylpentanoic acid, 2-ethylhexanoic acid, 2-ethylheptanoic acid, 2-ethylnonanoic acid, 2-propylcapryIic acid, 2-cropylheptanoic acid, 2-propylhexanoic acid, 2-propyloctanoic acid, 2-propylpentanoic acid, 2-propyl-4-pentanoic acid, 2-butyIcaproic acid, 2-butyl-heptar.cic acid, 2-butyioctanoic acid, (substituted) cyciohexane carboxyiic acid, chlcrcacetic acid, 2-chloropropionic acid, 2-chlorobutancic acid, 2-chlorohexanoic acid, cichloroacetic acid, propanoyi-Ci6 acid, and aromatic acids such as benzoic acid, 2-chlorobenzoic acid, 3-chlorobenzoic acid, 2-methylbenzoic acid, 3-methyl-benzoic acid, 4-methylbenzoic acid, naphtoic acid, and toluic acid. More preferably, at least one of the acid halides is selected from isobutanoyl halide, 2-ethylbutanoyl halide, 2-ethylhexanoyl halide, 2-chloropropanoyl halide, dichloroacetic acid halide, lauroyl halide, cyciohexane carbonyl halide, 3-methylcyclohexane carbonyl halide, 2,3 dihalocyclohexane carbonyl halide, benzoyl halide, 2-methylbenzoyl halide, and 2-chlorobenzoyl halide. If so desired, also the acid halides of polycarboxylic acids, with two or more acid moieties, can be used, such as (cyclo) hexy! dicarboxylic acid, phthalic acid (any isomer), maleic acid, fumaric acid, 1,2,4-butanetricarboxyIic acid, (oligomeric) polyacrylic acid, and copolymers with maleic anhydride derivable acid groups. Suitably, a mixture of any of these acid halides is used, typically resulting in a mixture of three or more diacyl peroxides of formula (l), as is known in the art. If the add halide of formula (II) is reacted with a peracid of formula (III), or the salt of such a peracid, wherein R3 and R4 are not hydrogen, then also acid halides of formula II) can be used wherein R1 and/or R2 are hydrogen. Examples of such acid haildes include chloroacetic acid halide, chloroprcpionic acid halides (ali isomers . acetyl chloride, propionyi chloride, butanoyi chloride, pentanoyl or valercy: chloride, decanoyl chloride, lauroyl chloride, malonyl chloride, succinoyl chloride, glutaroyl chloride, adipoyl chloride, azeloyl chloride, sebacoyl chloride. Most preferably, the diacyl peroxide produced is diisobutancyi peroxide. The M-O2 is preferably prepared by combining hydrogen peroxide and NaOH, KOH, K-CO3, and/or Na2C03. The M202 can be prepared separately or in a reacticr, step of the present process. Any peracid used can be prepared in a conventional way. Preferably, a C2-C20 peracic Is used. It is noted that when a peracid is reacted with acid halide, typically an asymmetrical diacyl peroxide is obtained, meaning that R1 and R2 are not the same as R3 and R4, whereas if a mixture of two different acid haiides is reacted with MCOH/M202, a statistical mixture of two symmetrical and one asymmetrical diacyl peroxides is obtained. The use of a peracid allows better control of the polymerization rate, since just one product with a dedicated half-life time is formed. •a Furthermore, it is noted that if asymmetrical diacyl peroxide is desired of which R or R4 is hydrogen, the use of a mixture of acid halides will partially result in the formation of diacyl peroxide that shows no branching on the two a-carbons (relative to the diacyl peroxide function). Such a-carbon unbranched diacyl peroxides are quite stable and part of them will end up in the final polymer, typically resulting in a lower than desired heat stability of the polymer. Hence, it is preferred to use a peracid if it is desired that R3 and/or R4 are hydrogen. More preferably, the peracid is selected from the group consisting of peracetic acid, perprcpicnic acid, perisobutanoic acid, perhexanoic acid, perbenzoic acid, 3-chlorocerbenzoic acid, and perlauric acid, the use of perpropionic acid and perlauric acid being most preferred. the process is conducted such that it is essentially free of solvent, since Such solvents are not desired in the final polymer. For the purpose of this specification,, essentially solvent-free means that less than 20 %w/w of solvent, based en the weight of the diacyl peroxide, is present. Preferably less than 10 %w/v/. nore preferably less than 5 %w/w, most preferably less than 2 %w/w of solver: :s present, all based on the weight of the diacyl peroxide. However, if the use cf certain solvents, such as conventional plasticizers fcr PVC or phlegmatizers for the peroxide, is acceptable in the polymer obtained in the polymerization step, it may be advantageous to use such solvents. Conventional plasticizers include epoxicized soybean oil, dialkyl esters, such as alkyl esters of aliphatic carboxylic acids with two or more carboxylic acid moieties, and less desired phthalate esters. Conventional phlegmatizers include hydrocarbons, such as isododecane. Preferably, the peroxidation step of the process is.conducted without a salt being addec to the reaction mixture. However, if so desired, a salt may be added, for instance to increase the yield of diacyl peroxide. If used, the salt is preferably selected from alkali and/or alkaline-earth metals. Preferably, they are salts of strong acids that do not react with H2O2, peracid, or a salt thereof. More preferably, the salt is selected from NaCl, KCI, Na2S04, K2S04, and NH4CI. If used, the colloids are advantageously selected from the group consisting of hydrofyzed polyvinyl acetate, alkyl cellulose, hydroxyalkyl alkyl cellulose, gelatin, polyvinyl pyrrolidone, polyoxyethylene sorbitan monolaurate,and polyacrylic acid. Preferably, said dispersant is a non-ionic compound. Most preferably, it is a mixture of one or more hydrolyzed polyvinyl acetates (PVA). Suitably, the degree of hydrolysis of the PVA ranges from 50 up to 95%, preferably up to 90%. Preferably, the degree of hydrolysis is at least 55%, more preferably at least 60%, so that :he PVA is soluble in the diacyl peroxide-containing mixture. In order to increase the solubility of the PVA, it can be advantageous to add a C1-C4 alcohol, preferably methanol, ethanolr and/or isopropanoi. All conventional surfactants can be used. However, in order not to disturb the dispersion of the polymerization reaction and not to adversely affect the properties of the final polymer, the surfactant preferably is a (biodegradable) cationic compcund, such as preferred quaternary ammonium compounds, or a non-ionic surfactant Preferred conventional non-ionic surfactants include, but are not limited to, aikcxylated (fatty) alcohols and alkoxylated sugars. The aqueous mixture that results from the peroxidation.step can be transferred to the pciymerization reactor "as is". Hcwever, in order to enhance the safety of handling of the diacyl peroxide, it is preferred to add at least one surfactant and/or colloid, so that a physically stable dispersion of the diacyl peroxide in the aqueous mixture, or a dispersion of the aqueous phase in the diacyl peroxide, is obtained. If need ce: the size of the dispersed phase (droplet or particle size) can be reduced in an optional further homogenization step. However, such a step is only a prerequisite when the dispersion as obtained is not safe. Suitably, this is detected by heating a 100 g sample of the dispersion up to a temperature where the diacyl peroxide decomposes. If a certain phase separation is observed, the safety characteristics of the least safe phase are decisive. However, it may also be desired to obtain a very finely dispersed phase, for instance to enhance an even distribution of the diacyl peroxide over the monomer(s) in the polymerization reactor (e.g. to reduce the fish-eye level in PVC that is produced by a suspension polymerization process). If such fine dispersions (with the average size by volume of the dispersed phase being less than 10 μ m, preferably less than 5 μ m, most preferably less than 2 jam) are of interest, then also an extra homogenization step can be advantageously introduced. The homogenization step can be performed using any suitable (high) shear mixer, such as rotor/sta:or homogenizers, colloid mills, ultrasonic devices, and the like. In a preferred embodiment, the diacyl peroxides of this invention are prepared in a feed lire, such as a pipe, that is directly connected to the polymerization reactor. The desired (raw) materials for the peroxidation step are then fed into the pipe at suitable points. Optionally, an in-line mixer is then used to homogenize the resulting product of the peroxidation step before it is used in the polymerization step, if so desired, part of the product of the peroxidation step may be recycled in such a set-up to increase the yield of diacyl peroxide. If so desired, the line may be flushed clean with water after the peroxidation step. However, it can also be switched to another polymerization reactor, such that the peroxidation can be an essentially continuous operation. The product resulting from the peroxidation step typically contains by-products and residual raw materials. Particularly when the diacyl peroxide is prepared using MOOH/M2O2, a substantial quantity of a salt (MX) is formed. The by-products must not be a hindrance in the polymerization reaction. However, it is known that salts adversely affect the stability of the emulsion of the diacyl peroxide, which is a safety concern, while salts may also adversely affect the electrical properties of the final polymer. Hence, it may be preferred to include a purification step. Depending on safety considerations, it can be acceptable to conduct the peroxidation step without any surfactants and/or colloids being used and then to separate and discard (part of) the water layer, after which the diacyl peroxide-rich organic layer may be dispersed and/or diluted, if so desired, using the appropriate media and/or solvents. If an aqueous diacyl peroxide dispersion is to be achieved, conventional surfactants and/or colloids can be used in the dispersion step. Alternatively, (part of) the salt may be removed using conventional techniques, such as (reverse) osmesis, nanofiltration, ion-exchange, precipitation, and the like. A less preferred piuuc-ss would involve a step wherein a conventional solvent for the diacyl peroxlze is added to extract the diacyl peroxide from the mixture. The process according to the invention is pre-eminently suited to polymerize one or more ethylenically unsaturated monomers, including (rr.eth)acrylic acid (esters), styrer.e, vinyl acetate, acrylonitriie, vinyl chloride moncmer (VCM), and the like. Preferably, the process according to the invention involves the polymerization of monor-.er mixtures comprising at least 50 %w/w of VCM. based on the weight of all monorr.er(s). In this preferred process, preferred comoncmers for use are of the conventional type and include vinylidene chloride, vinyl acetate, ethylene, propylene, acrylor.itrile, styrene, and (meth)acrylates. More preferably, at least 80 %w/w of the monorr.er(s) being polymerized is made up of VCM, while in the most preferred process the monomer consists essentially of VCM. As is known in the art, the polymerization temperature of such processes determines to a large extent the molecular weight of the final polymer. The polymerization process can be conducted as a mass process where the reaction mixture is predominantly monomer(s) or as a suspension process where the reaction mixture typically is a suspension of monomer(s) in water, or as an emulsion or micro-emulsion process where the monomer(s) typically is/are emulsified in water. In these processes the usual additives will have to be used. For example, if the monomer(s) is/are present in the form of a suspension in water, the usual additives such as surfactant(s), protective colloid(s), anti-fouling agent(s), pH-buffer(s), etc. may be present. Depending on the type of polymer desired, each of the above-mentioned processes may be preferred. The process according to the invention is especially suited for mass and suspension processes. In the aqueous suspension process to produce PVC from VCM, the polymerization is usually conducted at a temperature in the range of about 0°C to 10Q°C, However, for the process of the present invention it is preferred to employ polymerization temperatures of about 4LTC tc about 70°C, since this is the temperature at which VCM is polymerized efficiency. The polymerization reaction time may vary from about 1 to about 15 hours, and is preferably from 2 to 6 hours. The aqueous suspension VCM polymerization process in addition to the VCM typically contains water, dispersants, free racical initiator, and optional further ingredients, such as buffers, short stop agents, ore-stabilizers, and the like. After :ns polymerization, the resulting (co)polymer (or resin) will be worked up as is usual in the art. Polymers obtained by a suspension polymerization according to the invention, for example, will be submitted to the usual drying and screening steps. The respiting resin preferably is characterized in that it contains less than 50 ppm of residual diacyl peroxide, more preferably less than 40 ppm, and most preferably less than 25 ppm of diacyl peroxide, immediately after drying for 1 hour at 60°C and screening. The resin was found to exhibit excellent heat stability, as measured with a Metrastat® PSD260 testing oven in accordance with ISO 182-2 (1990E). The improved heat stability proved that the resin hardly discoloured when submitted to melt-prccessing steps, e.g., to form shaped articles. The prccess according to the present invention is pre-eminently suited for combination with polymerization processes as disclosed in WO00/17245. Accordingly, a preferred embodiment of the present invention relates to a process of claim 1 wherein at least part of the diacyl peroxide is dosed to the polymerization mixture at the reaction temperature. More preferably, essentially all of the organic initiator, i.e. diacyl peroxides andt if used, other conventional initiators, dosed in the polymerization process has a half-life of from 0.0001 hour to 1.0 hour at the polymerization temperature, preferably from 0.001 to 0.8 hour, more preferably from 0.002 to 0.5 hour at the polymerization temperature. If the one or more diacyl peroxides are dosed together with other initiators, it is preferred that the diacyl peroxide'5) as well as all other initiators fulfill these half-life requirements. It is noted that ha--lives are determined in conventional thermal decomposition studies in monocriorobenzene, as is well-known in the art (see fcr instance the brochure "Initiators for high polymers'1 with code 10737 obtainable from Akzo Nobel). The dosing of the extremely fast initiators to the polymeriza:ion reaction mixture can be internittent or continuous over a period of time wherein at least 20%, preferably at leas: 40%, more preferably at least 50% of all monomer used in the process is polymerized. If an intermittent operation is selected, there are at least 2, preferably at least 4, more preferably at least 10, and most preferably at least 20 moments at the polymerization temperature at which the initiator is dosed. If so desired, the intermir:ent and continuous operations may be combined, such that the initiator is dosed intermittently for certain (longer or shorter) periods of time. Most preferably, the diacyl peroxide is dosed continuously and/or intermittently after at least 5%,' preferably at least 10%, more preferably at least 20%, most preferably at least 30% of the rr.onomer(s) has already been polymerized and while during the dosing period at least 10%, preferably at least 20%, more preferably at least 30%, and most preferably at least 50% of all monomer used in the process is polymerized. Preferably, the diacyl peroxide is dosed in a concentration of 0.1 to 60 %w/w, more preferably 0.5 to 25 %w/w, and most preferably 2 to 15 %w/w, based on the weight of the diacyl peroxide-containing mixture, in order to facilitate the even distribution of the diacyl peroxide over the monomer. The dosing can be effected at any suitable entry point to the reactor. If water is added in the course of the polymerization process, for example to compensate for the shrinkage of the reactor content due to the polymerization reaction, it may be advantageous to use the line through which this water is dosed to also dose the initiator. In a most preferred' embodiment, the diacyl peroxide has also been produced in said line. Experimental The fc "lowing chemicals were used in the process to manufacture diacyl peroxides. It is noted that all experiments were performed taking sufficient safety measures. In this respect it is also noted that pure diisobutanoyl peroxide is a detonatabie explosive. Commercially available aqueous H2O? with an assay of 69.97% was used. NaOK solution (NaOH-25 and NaOH-33) containing 25 %w/w and 33 %w/w, respectively, of NaOH was produced from Baker-grade NaOH and distilled water. NaCI solution (NaCI-15 and NaCI-25) containing 15 %w/w and 25 %w/w, respectively, of NaCI was produced from Baker-grade NaCI and distilled water. Na2CO: solution containing 10 %w/w of Na2C03 was produced from Baker-grade Na-COo and distilled water. HCI solution containing 18 %w/w of HCI was produced from Baker-grade HCI and distilled water. Isobu:ar.oyl chloride (99.3%) was supplied by BASF Laurcyl chloride (98%) was supplied by Acros. A fresh PVA solution, 5 %w/w Alcotex® 72.5 ex Harco in demineralized water was prepared fresh, 1 day prior to use. Example 1 For the preparation of isobutanoyl-Iauroyl peroxide, a reactor was charged at 0°C with 35 g deionized water, 286 g NaCI-25 solution, 110 g of Na2C03 solution, 39 g NaOH-25 solution, and 32.5 g H202 solution. Then, within 50 minutes 103.0 g isobutanoyl chloride were dosed while maintaining a pH-value of 11.0 with the aid of NaOH-25 solution. The temperature was maintained at 0°C, and meanwhile the contents of the reactor were homogenised. After addition of the total amount of isobutanoyl chloride, the reaction mixture was stirred for another 15 minutes at pH 11.0. Then, the pH was lowered to 10.0 with HCI solution and the temperature was broucht to 5°C. Next, 70.5 g lauroyl chloride were dosed over a period of 10 minutes, while maintaining the pH on 10.0 with the aid c NaOH-25 solution. After adciilc-i of the total amount of lauroyl chloride, stirring was continued for another 15 mir.'jtes. The reaction mixture was set aside for 30 minutes in orcer to allow the two-phase system .to separate. The aqueous layer was removed '713 g) and the organic peroxide layer was washed with 300 g NaCI-15 solution. Again, the aqueous layer and the organic layer were allowed to separate, in order to facilitate the isolation of the peroxide layer (Isolated yield: 145.0 g). Analysis of the isolated peroxide layer: 35% ciisobutanoyl peroxide 64% is-butanoyl-iauroyl peroxide Examcie 2 and Comparative Examples A-D In Example A, the procedure of WO 01/32613 was repeated. First, a solution of Na202 was prepared by combining 108.3 g of demineralized water, 18.5 g of NaOH-33 solution, and 37 g of the aqueous H2O2. A second reactor was charged with 33.3 g of demineralized water, 277 g of the PVA solution, and 16.3 g of isobutanoyl chloride while controlling the temperature between 5-10°C. Next, the Na202 solution was dosed while the system was homogenized. No diisobutanoyl peroxide was obtained and only an aqueous phase formed. In Example B, the same procedure was followed as in Example A, except that 2- ethyibutyroyl chloride was used instead of the isobutanoyl chloride. Again, no diacyl peroxide was obtained. In Example CT the same procedure was followed as in Example A, except that 2- ethylhexanoyl chloride was used instead of the isobutanoyl chloride. Again, no diacy! ceroxide was obtained. The resulting mixture was milky white, probably because a lot of 2-ethylhexanoic acid was formed which did not all dissolve in the water. In Example D, the procedure of Example A was modified ;n that the second reactor was charged with all the water, PVA solution, isobutyrcyi chloride, and aqueous H:0:. and the NaOH-33 solution was then dosed to it at a temperature of 5-1 G°C. The yield of diisobutanyl peroxide is expected to be less than 20 %w/w. In Example 2, a single reactor was charged with 141.5 g of demineralized water, 13.5 g of NaOH-33 solution, 27.7 g cf PVA solution, and 3.7 g of the aqueous H?0:. after which 16.3 g of isobutanoyl chloride were dosed to the contents of the reacicr. while maintaining a temperature of 5-10°C and while homogenizing the contents of the reactor. An emulsion resulted. The yield cf diisobutanoyi peroxide was 32 %w/w. It is expected that if the emulsion is used within 43 hours in a polymerization reaction, it will show the same polymerization rates for VCM as were observed when using the same amount of a conventional 30 %w/w diisobutanoyi peroxide solution in isododecane. Example 3 The product of Example 2 was stored for 1.5 hours at 5°C without being stirred. The active oxygen content (a measure of the amount of diacyl peroxide of formula (I)) of the emulsion was reduced by 2.5% and a little phase separation occurred. In Example 3, a reactor was charged with 175 g of demineralized water, 16.4 g of NaOH-33 solution, 43.8 g of NaCI-25 solution, 250.5 g of Na2C03 solution, and 4.8 g of the aqueous H202. Then 23.1 g of isobutanoyl chloride was dosed to the contents of the reactor, while maintaining a temperature of 5-10°C and homogenizing the contents of the reactor. At the end of the reaction the mixture was neLftralized to pH=7. Taking sufficient safety measures, the two-phase system was allowed to separate and about 70% by volume of the aqueous phase was retrieved. To the organic layer and the remainder of the water layer were added 207.2 a of demineralized water, 109.3 a of PVA solution, 13.7 g of methanol, and 21.9 g zf an aqueous 0.2%w/w Bercl© 08 (non-ionic emulsifier ex Akzo Nobel) solutlcr. A dispersion resulted which was stable for rr.zre than 2.5 hours and shov/ec good performance in the polymerization process of VCM. The yield of diiscbu:~noyl peroxide was 86% on iscbutanoyl chloride ar.d 93% on H2O2. Claim . Prccess comprising the steps of; producing an aqueous mixture comprising a peroxide of formula (I) wherein R1-R~ are independently selected -rom the group consisting of hydrogen, halogen, and saturated or unsaturated, linear or branched alkyi, alkaryl, and aralkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R2 are hydrogen, then R3 and/or RA are not hydrogen and, vice-versa, that if R3 and/or R4 are hydrogen, then R1 and/or R: are not hydrogen, in which process R1-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R\ or one of R1-C(R:)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, with the further proviso that ciacyl peroxides of formula (i) wherein R2 is halogen and R4 is hydrogen, and both R1 and R3 are long chain alkyl groups having about 10 to about 16 carbon atoms, are excluded, by reacting, in a so-called peroxidation step, one or more acid haiides of formula [\\) , wnerein X is halide, preferably chloride or bromide, most preferably chloride, with i) MOOH/M202, wherein M is any metal or ammonium-containing group that will react with H202 to form MOOH/M202 without decomposing one or more of the peroxides present in the process, preferably M is selected from the croup consisting of ammonium, sodium, potassium, magnesium, calcium, and lithium, and/or ii) one or more peracids of formula (III) or the salts thereof, an aqueous phase, in Which process the acid halide, or mixture of ac:c halides, is essentially only Drought into contact with water containing MOCH. M202 and/or one or more eracids or peracid salts, preferably M202 or the M salt of the peracid, optionally introducing one or more solvents for the acid halide in any part of The process, optionally introducing one or more salts in any par, of the process, optionally introducing one or more colloids and/or surfactants, before, during, or after the peroxidation step, optionally purifying the aqueous mixture in one or more purification steps, optionally homogenizing the aqueous mixture in one or more nomogenization steps, transferring the product from the previous steps that comprises the diacyl oeroxide of formula (I) to a polymerization reactor, and - thermally decomposing said diacyl peroxide, tc generate organic free radicals, in the presence of one or more ethylenicaliy unsaturated monomers, to polymerize said monomers in said polymerization reactor. 2. Process comprising the steps of: - producing an aqueous mixture comprising a diacyl peroxide of formula (I) wherein R1-R4 are independently selected -fom the group consisting of hydrogen, halogen, and saturated or ■unsaturated, linear or branched alky!, aikaryl, and a^alkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R2 are hydrogen, then R3 and/or R4 are not hydrogen and, vice-versa, that if R3 and/or R4 are hydrogen, then R1 and/or R2 are not hydrogen, in which 2-rocess R'-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with cne or more independently chosen groups R\ or ore of R1-C(R2)H and R:-C(R4)H represents an, cptionaily substituted, aromatic ring structure, with the further proviso that if R2 is halogen and R4 is hydrogen, and both R1 and R3 are alkyl groups, then each of these alkyl groups has up to about 6 carbon atoms, by reacting, in a so-called peroxidation step, one or more acid haiides of" formula (li) wherein X is halide, preferably chloride or bromide, most preferably chloride, with i) MOOH/M202, wherein M is any metal or ammonium-containing group that will react with H:02 to form MOOH/M202 without decomposing one or more of the peroxides present in the process, preferably M is selected from the group consisting of ammonium, sodium, potassium, magnesium, calcium, and lithium, and/or ii) one or more peracids of formula (m; , or the M salts thereof, in an aqueous phase, in which process the acid halide, or mixture of acid haiides, is essentially only brought into contact with water containing MOOH/M202 and/or one or more peracids or peracid salts, preferably M202 or the M salt of the peracid, - optionally introducing one or more solvents for the acid halide in any part of the process, c ptionally introducing one or more salts in any part of the process, - cotionally introducing one or more colloids and/cr surfactants, before, curing, or after the peroxidation step, - cotionaiiy purifying the aqueous mixture in one or more purification steps, optionally homogenizing the aqueous mixture in one or more homogenization steps, transferring the product from the previous steps that comprises the diacyi peroxide of formula (I) to a polymerization reactor, and thermally decomposing said diacy! peroxide, :o generate organic free V radicals, in the presence of one or more ethylenically unsaturated monomers, to polymerize said monomers in said polymerization reactor. 3. Process comprising the steps of: producing an aqueous mixture comprising a diacyi peroxide of formula (1) , wherein R'-R4 are independently seloAed from the group consisting of hydrogen and saturated or unsaturated, linear or branched aikyi, alkaryl, and aralkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R2 are hydrogen, then R3 and/or R4 are not hydrogen and, vice-versa, that if R3 and/or R4 are hydrogen, then R1 and/or R2 are not hydrogen, in which process R'-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R\ or one of R1-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, by reacting, in a so-called peroxidation step, one or more acid halides of formula wherein herein X is halide, preferably chloride or bromide, most preferably chloride, with i) 'vlOOH/M202, wherein M is any metal or ammonium-containing group that will react with H202 to form MOOH/M202 without decomposing one or more of the peroxides present in the process, preferably M is selected from the group consisting of ammonium, sodium, potassium, magnesium, calcium, and lithium, and/or ii) one or more peracids of formula (III) or the M salts thereof, in an aqueous phase, in T which process the acid haiide, or mixture of acid halides, is essentially only orought into contact with water containing MOOK M202 and/or one or more peracids or peracid salts, preferably M202 or the M salt of the peracid, optionally introducing one or more solvents for the acid haiide in any part of :he process, optionally introducing one or more salts in any part of the process, optionally introducing one or more colloids and!or surfactants, before, during, or after the peroxidation step, optionally purifying the aqueous mixture in one or imore purification steps, optionally homogenizing the aqueous mixture in one or more homogenization steps, - transferring the product from the previous steps that comprises the diacyl peroxide of formula (I) to a polymerization reactor, and - thermally decomposing said diacyl peroxide, to generate organic free radicals, in the presence of one or more ethylenically unsaturated monomers, to polymerize said monomers in said polymerization reactor. 4. A process according to any one of the preceding claims wherein the diacyl peroxide obtained in the peroxidation step is used in the polymerization process within a period of 168 hours after said peroxidation step. 5. A process according to any one of the preceding claims wherein the diacyl peroxide is stored and handled in this process at temperatures up to 5°C. 6. A process according to any one of the preceding claims wherein one and the sane reactor is used to make the MOOH/M202 from a source of M and H20: and to carry out the peroxidation srep. 7. A process according to any one of the preceding cairns wherein 0.005 to 2 'w of the diacyl peroxide is used in the polymerization step, based on the weight of the ethylenicaily unsaturated monomer(s). 8. A process according to any one of the preceding claims wherein the e;hylenicaily unsaturated monomer(s) comprise(s) vinyl chloride monomer. 9. A process according to any one of the preceding claims wherein at least one azlc halide is used that is selected from the group consisting of lauroyl halide, isobutanoyl halide, 2-ethylbutanoyl halide, 2-ethylhexanoyl halide, 2-cnlcropropanoyl halide, cyclohexane carbonyl halide, 3-methylcyclohexane carbonyl halide, and 2,3-dihalocyclohexane carbonyl halide. 10. A process according to any one of the preceding claims wherein at least one resulting diacyl peroxide is asymmetrical. 11. A process according to claim 10 wherein a peracid is used in the peroxidation step. 12. A process according to any one of the preceding claims that is essentially solvent-free. 13.A process according to any one of the preceding claims wherein the diacyl peroxide is dosed to the polymerization reaction mixture at the reaction temperature. 14. A process comprising the steps substantially as herein described and exemplified.

Full Text

ACD 2S25 R
POLYMERIZATION PROCESS INVOLVING DIACYL PEROXIDES
The present invention relates to a polymerization process wherein at least one
I
diacyl ceroxide of formula (I) is used as a source of
free radicals.
Such crccesses are known from, for instance, WO 00/17245, where diisobutanoyi peroxide is used to polymerize vinyl chloride by means cf the radicals that are formed curing the thermal decomposition of the peroxide.
However, the use of diacyl peroxides of formula (I) can be cumbersome. More particular?/, the peroxides of formula (!) are very thermally labile, as a result of which they show significant decomposition during storage at temperatures as low as -5"C. In order to ensure the quality and assay of the product, it is typically produced at temperatures of 0°C or lower and kept at temperatures of -20°C during its storage and handling. However, even at such low temperatures, a noticeable reduction of the assay of the material is noted. Furthermore, it is necessary to phlegmatize the peroxides of formula (I), particularly the products wherein R1f R2, R3, and R4 contain less than 20 carbon atoms in total, using a water-immiscible, hydrophobic solvent, such as isododecane, because the peroxides cannot be handled in the pure form for safety reasons. Such solvents will end up in the polymer made in the polymerization process, which for a variety of wei!-kr,own reasons (undesired plasticizing of the polymer, exudation from finished polymer articles, which may lead to fogging, and the like), is typically undesired.

There fere, there is need for a process wherein peroxides of formula (I) can be used wiihout undesired refrigeration and solvents being obligatory. Preferably, the process also allows the use of water to reduce the safer/ hazards associated with the clacyl peroxides, so that they can be handled safeiy during processing and handling/metering to the polymerization reactor.
Surprisingly, we have found that the use of a specific process for making and using the diacyl peroxides of formula (I) fulfills this need.
The process according to the invention is characterized in that
- an aqueous mixture comprising a peroxide of formula (I) is produced in a
peroxidation step wherein
i) ere or more acid halides of formula (II) are reacted with
ii) MOOH/M2O2 and/or one or more peracids (or their salts) of formula (111)
, in an aqueous phase, in which peroxidation step the acid halide, or mixture of acid halides, is essentially only brought into contact with water containing MOOH/M2O2 and/or one or more peracids (or their M salts), to give an aqueous mixture, and iii) optionally one or more colloids and/or surfactants are combined with said aqueous mixture before, during, or after the peroxidation step and
- the resulting aqueous mixture is used in a polymerization process.
It is noted that the term MOOH/M202 stands for the product that is formed from H202 sr.d a suitable source of metal (M) ions. The product typically is not a discrete product M202] but the equilibrium comprising H2O2, MOOH and M202.

From a~ Industrial point of view it is preferred that the s:ar~:ng material from which the diacy1 peroxides of formula (I) are prepared, i.e. the ore or more acid halides
of formula (II, ~. J the one or more peracids (or their M salts) of
formula !!l) are easily available or obtainable. Most
preferably, these compounds are commercially available.
The process of this invention is pre-eminently suitable for diacyl peroxides that are liquid at the process temperature, since these diacyl peroxides have a lower hydrolytic and thermal stability than diacy! peroxides that are solid at the process temperature
In a preferred embodiment, the aqueous mixture comprising diacyl peroxide of formula (I) is used in the polymerization process within a period of 168, more preferably 102, even more preferably 48, more preferably still 24, yet more preferably 12, yet more preferably still 2 hours after the peroxidation step. In a most preferred embodiment the reactor wherein the peroxidation step is conducted is directly linked by means of piping and optional further holding or processing tanks to the reactor in which the polymerization process is conducted.
In another preferred embodiment, the diacyl peroxide is stored and handled in this process at temperatures up to 5°C, since it was observed that, depending on the hydrolytic and thermal stability of the diacyl peroxide, it can be acceptable in the process according to the invention to store and handle the diacyl peroxide up to temperatures of ~5°C, preferably 0°C or more preferably 5°C.

In the process of the present invention it is necessary to prevent just water and acid ha::de of formula (II) from being combined at any given time, since otherwise the ac;c halide would hydrolyze, resulting in low yieics of peroxide and causing contamination of the aqueous mixture. Also, a mixture cf just water and acid halide was found to be very corrosive, which would require the use of more expensive process equipment. Hence, when it is stated that in the process the acid halide is essentially only brought into contact with water containing MOOH/M2O2 and/or one or more peracids, what is meant is that water and just acid halide are contacted for a period of at most 1 minute, preferably at most 20 seconds, more preferably at most !C seconds, even more preferably at most 5 seconds, most preferably at most "i second. Therefore, the only viable ways to make diacyl peroxide are: i) to pre-charge water, MOOH/M202 (or, optionally, to make the MOOH/M202 from H202 and a source of M) and dose acid halide thereto, ii) to pre-charge water and H2O2 and dose both the source of M and acid halide, iii) to pre-charge water and dose both MCOH/M2O2 (optionally H202 together with a source of M) and acid halide, and iv) to pre-charge water and a source of M and dose both H202 and acid halide. If a peracid is used in the present process, the same viable ways are available (substituting the peracid for H202, and substituting the M salt of the peracid for MOOH/M202). In order to optimize the yield of peroxide, using one of the four viable ways is preferred.
It is noted that US 3,923,766 discloses a so-called "in-situ" process where a diacyl peroxide of formula (I) is used that is produced from an anhydride and a peracid. The "in-situ" process is characterized in that the diacyl peroxide is produced in the polymerization reactor in the presence of the monomer, which is not a process according to the invention. Such "in-situ" processes are undesired, since they do not ailcv/ a flexible mode of operation. More particularly, most of the peroxide is formed r.ear the start of the process, preventing a constant polymerization rate,

and thus resulting in a heat output that is not constant. Such a variation in heat outpu: ;s undesired, since polymerization reactors are run most cost-effectiveiy under renditions where cooling is at the maximum rate. To overcome this problem, it is suggested in U-S 3,923,766 to use a second (conventional) more stable initiator.-However, such more stable initiators will partially end up in the final polymer, which is undesired for polymer stability reasens (the remaining initiator will leac to premature decomposition of the resin during heat treatment, such as moulding operations).
US 3.925,506 discloses a method of preparing asymmetrical a-halogen substituted diacyl peroxides of formula (I) wherein R2 is chloride or bromide, R4 is hydrogen, and each of R1 and R3 is a long chain alkyl radical having about 10 to about 16 carben atoms, it is noted that these a-halogen substituted diacyl peroxides of US 3,936.5C6 are not of interest for the present invention, since the starting materials from which these diacyl peroxides are to be prepared are not easily available or obtainable. From an industrial point of view this is an undesirable situation.
It is furthermore noted that WO 01/32613 discloses a process where peroxydicarbonates are produced ex-situ. However, it is desired to offer alternative processes allowing the production of a broader range of peroxides. More specifically, the peroxydicarbonates of WO 01/32613 all have a half-life of 1 hour at a temperature of about 64°C. This means a rather limited freedom when it comes to selecting the polymerization temperature. Also, the chloroformate used to make the peroxydicarbonates is much more hydrolytically stable than the acid halides that are used to make the diacyl peroxides of the present invention. At lower temperatures (say about 50°C) the peroxydicarbonates will not decompose fast enough to give efficient polymerization times and lead to an unacceptably high residuai peroxide content in the final polymer, which adversely affects the thermal stability of the formed polymer. At higher polymerization temperatures (say about

60°C) the peroxydicarbonates will decompose too quickly, leading to inefficient use and tec slow polymerization rates towards the end of the polymerization. Surprisingly, it was found that, after further modification, the concept of WO 01/32513 could be extended to diacyl peroxides of formula (1). The modification needed !sT inter alia, to make sure that the acid halide is no: just substituted for the chlorcfermate, but that it is brought into contact with water only when an inorganic peroxide or peracid (salt) is present in the aqueous phase.
Detailed description of the invention
The present invention relates to a process comprising the steps of:
- producing an aqueous mixture comprising a diacyl peroxide of formula (1)
wherein R1-R4 are independently selected from the croup consisting of hydrogen, halogen, and saturated or unsaturated, linear or branched alkyl, alkaryl, and aralkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R2 are hydrogen, then R3 and/or R4 are not hydrogen and, vice-versa, that if R3 and/or R4 are hydrogen, then R1 and/or R2 are not hydrogen, in which process R1-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R1, or one of R1-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, by reacting, in a so-called peroxidation step, one or more acid halides
of formula , wherein X is halide, preferably chloride or
bromide, most preferably chloride, with i) MOOH/M202J wherein M is any metal or ammonium-containing group that will react with H202 to form MOOH/M2O2 with cut decomposing one or more of the peroxides present in the process,

preferably M is selected from the group consisting cf ammonium, sodium, pc:assium, magnesium, calcium, and lithium, and/or ii) zne or more peracids of
formula !!!) preferably the M salts thereof, in an
aqueous phase, in which process the acid halide, or mixture of acid halides, is essentially only brought into contact with water containing MOOH/M2O2 and/or one or more peracids (or their peracid salts), preferably M2O2 or the M salt of the peracid,
- optionally introducing one or more solvents for the acid halide in any part of the process,
- opiicnally introducing one or more salts in any part of the process,
- optionally introducing one or more colloids and/or surfactants, before, during, or after :he peroxidation step,
- optionally purifying the aqueous mixture in one or more purification steps,
- optionally homogenizing the aqueous mixture in one or more homogenization steps,
- transferring the product from the previous steps that comprises the diacyl peroxide of formula (I) to a polymerization reactor, and
- thermally decomposing said diacyl peroxide, to generate organic free radicals, in the presence of one or more ethylenically unsaturated monomers, to polymerize said monomers in said polymerization reactor.
In a preferred embodiment, the aqueous mixture comprising said diacyl peroxide is used in said polymerization process within a period of 168, more preferably 102,
even mere preferably 48, more preferably still 24, yet mere preferably 12, yet more preferably still 2 hours after said peroxidation step. In a most preferred embodiment, the reactor wherein the peroxidation step is conducted is directly linked by means of piping and optional further holding or processing tanks to the

reader in which the polymerization process is conducted. Preferably, the diacyi peroxice-containing mixture is prepared just prior to when it is needed in the polymerization step. Should the dispersion be stored for any period of time, then it is preferred, from a safety point of view, to keep the dispersion in motion to prevent phase separation. Any conventional agitation can be used, such as a shaft with blades, a system to bubble inert gas through the dispersion, and/or a recirculation pump, if one or more of the optional colloids and/or surfactants are used in the process, then the diacyi peroxide-containing mixture typically is less prone to phase separation, increasing safety margins.
In another preferred embodiment, the diacyi peroxide is stored and handled in this process at temperatures up to 5aC, since it was observed that, depending on the hydrolytic and thermal stability of the peroxide, it can be acceptable to store and handle the peroxide in the process according to the invention up to temperatures of -5°CT preferably 0°C or more preferably 5°C.
In a further preferred embodiment, the process involves diacyi peroxides of
formula (1) , wherein R1-R4 are independently
selected from the group consisting of hydrogen, halogen, and saturated or unsaturated, linear or branched alkyl, alkaryl, and araikyl moieties optionally substituted with one or more halogen atoms, provided that if R and/or R are hydrogen, then R3 and/or R4 are not hydrogen and, vice-versa, that if R and/or R are hydrogen, then R1 and/or R2 are not hydrogen, in which process R -C-R and/or Rs-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen croups R , or one of R -C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, with the further proviso that diacyi peroxides of fcrmula (!) wherein R is

halogen and R4 is hydrogen, and both R1 and R3 are ;ong chain alky! groups having aoout 10 to about 16 carbon atoms, are excludec from this invention.
In yet another preferred embodiment, the process involves diacyl peroxides of
R4 P4 formula (I) v , wherein R'-R are independently
selectee from the group consisting of hydrogen, halogen, and saturated or unsaturated, linear or branched alkyi, alkaryl, and araikyl moieties optionally substi:-j:ed with one or more halogen atoms, providec that if R1 and/or R2 are hydrogen, then R and/or R are not hydrogen and, vice-versa, that if R and/or R are hydrogen, then R1 and/or R2 are not hydrogen, in which process R1-C-R2 and/or R°-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R1, or one of R1-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, with the further proviso that if R2 is halogen and R4 is hydrogen, and both R1 and R3 are alkyl groups, then each of these alkyi groups has up to about 6 carbon atoms.
In yet another preferred embodiment, the process involves diacyl peroxides of
I3
formula (I) ■ wherein R1-R4 are independently
selected from the group consisting of hydrogen and saturated or unsaturated, linear or branched alkyi, alkaryl, and araikyl moieties optionally substituted with one cr nore halogen atoms, provided that if R . and/or R are hydrogen, then R and/cr R4 are not hydrogen and, vice-versa, that if R3 and/or R4 are hydrogen, then R1 and/cr R2 are not hydrogen; in which process R^C-R2' and/or R3-C-R4 can be part cf a ring structure that can be saturated or unsaturated and substituted with

one cr r~>ore independently chosen croups R1, or one of R*-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure.
In yet another preferred embodiment of this invention, :he diacyl peroxide of formula M), when transferred to the polymerization reactor, is always transferred from :r.e previous step in the aqueous phase, with the diacyl peroxide being
represented by formula (I) " '% wherein R1-R4 are
indepencently selected from the group consisting of hydrogen, halogen, and saturaiec or unsaturated, linear or branched alky!, alkar/l, and aralkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R" are hydrogen, then R and/or R are not hydrogen and, vice-versa, that if R and/or R4 are hydrogen, then R1 and/or R2 are not hydrogen, in which process R1-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R , or one of R1-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure.
In one still more preferred embodiment only one reactor is used to produce the diacyl peroxide. Most preferably, only one reactor is used to react both the source of M and H202 and to carry out the peroxidation step to make the diacyl peroxide.
The amount of diacyl peroxide (which acts as an initiator) to be used as a source of free radicals in the polymerization step according to the invention is within the range conventionally used in polymerization processes. Typically, from 0.005 to 2% by weight (r/ow/w) of initiator, preferably 0.01-1 %w/w, more preferably 0.01-0.5 %w/w, based cr\ the weight of the ethylenically unsaturated moncmer(s) to be polymerized, is used, it is noted that the diacyl peroxide initiator of the present invention may be

used ir. combination with other initiators.
Preferably, the acid halide of formula (II) is derived from Ci-C30 carboxyiic acids, preferably from isobutanoic acid; 2-methyibutanoic acid, 2-methylpentanoic acid, 2-metr.y;hexanoic acid, 2-methylheptanoic acid, octancic acid, 2-methyloctanoic acid, decanoic acid, 2-methyinonanoic acid, tetradecancic acid, hexadecanoic acid, cctadecanoic acid, lauric acid, 2-ethylbutanoic acid. 2-ethylpentanoic acid, 2-ethylhexanoic acid, 2-ethylheptanoic acid, 2-ethylnonanoic acid, 2-propylcapryIic acid, 2-cropylheptanoic acid, 2-propylhexanoic acid, 2-propyloctanoic acid, 2-propylpentanoic acid, 2-propyl-4-pentanoic acid, 2-butyIcaproic acid, 2-butyl-heptar.cic acid, 2-butyioctanoic acid, (substituted) cyciohexane carboxyiic acid, chlcrcacetic acid, 2-chloropropionic acid, 2-chlorobutancic acid, 2-chlorohexanoic acid, cichloroacetic acid, propanoyi-Ci6 acid, and aromatic acids such as benzoic acid, 2-chlorobenzoic acid, 3-chlorobenzoic acid, 2-methylbenzoic acid, 3-methyl-benzoic acid, 4-methylbenzoic acid, naphtoic acid, and toluic acid. More preferably, at least one of the acid halides is selected from isobutanoyl halide, 2-ethylbutanoyl halide, 2-ethylhexanoyl halide, 2-chloropropanoyl halide, dichloroacetic acid halide, lauroyl halide, cyciohexane carbonyl halide, 3-methylcyclohexane carbonyl halide, 2,3 dihalocyclohexane carbonyl halide, benzoyl halide, 2-methylbenzoyl halide, and 2-chlorobenzoyl halide. If so desired, also the acid halides of polycarboxylic acids, with two or more acid moieties, can be used, such as (cyclo) hexy! dicarboxylic acid, phthalic acid (any isomer), maleic acid, fumaric acid, 1,2,4-butanetricarboxyIic acid, (oligomeric) polyacrylic acid, and copolymers with maleic anhydride derivable acid groups. Suitably, a mixture of any of these acid halides is used, typically resulting in a mixture of three or more diacyl peroxides of formula (l), as is known in the art.
If the add halide of formula (II) is reacted with a peracid of formula (III), or the salt of such a peracid, wherein R3 and R4 are not hydrogen, then also acid halides of formula II) can be used wherein R1 and/or R2 are hydrogen. Examples of such

acid haildes include chloroacetic acid halide, chloroprcpionic acid halides (ali isomers . acetyl chloride, propionyi chloride, butanoyi chloride, pentanoyl or valercy: chloride, decanoyl chloride, lauroyl chloride, malonyl chloride, succinoyl chloride, glutaroyl chloride, adipoyl chloride, azeloyl chloride, sebacoyl chloride. Most preferably, the diacyl peroxide produced is diisobutancyi peroxide.
The M-O2 is preferably prepared by combining hydrogen peroxide and NaOH, KOH, K-CO3, and/or Na2C03. The M202 can be prepared separately or in a reacticr, step of the present process.
Any peracid used can be prepared in a conventional way. Preferably, a C2-C20 peracic Is used. It is noted that when a peracid is reacted with acid halide, typically an asymmetrical diacyl peroxide is obtained, meaning that R1 and R2 are not the same as R3 and R4, whereas if a mixture of two different acid haiides is reacted with MCOH/M202, a statistical mixture of two symmetrical and one asymmetrical diacyl peroxides is obtained. The use of a peracid allows better control of the polymerization rate, since just one product with a dedicated half-life time is formed.
•a
Furthermore, it is noted that if asymmetrical diacyl peroxide is desired of which R or R4 is hydrogen, the use of a mixture of acid halides will partially result in the formation of diacyl peroxide that shows no branching on the two a-carbons (relative to the diacyl peroxide function). Such a-carbon unbranched diacyl peroxides are quite stable and part of them will end up in the final polymer, typically resulting in a lower than desired heat stability of the polymer. Hence, it is preferred to use a peracid if it is desired that R3 and/or R4 are hydrogen. More preferably, the peracid is selected from the group consisting of peracetic acid, perprcpicnic acid, perisobutanoic acid, perhexanoic acid, perbenzoic acid, 3-chlorocerbenzoic acid, and perlauric acid, the use of perpropionic acid and perlauric acid being most preferred.

the process is conducted such that it is essentially free of solvent, since Such solvents are not desired in the final polymer. For the purpose of this specification,, essentially solvent-free means that less than 20 %w/w of solvent, based en the weight of the diacyl peroxide, is present. Preferably less than 10 %w/v/. nore preferably less than 5 %w/w, most preferably less than 2 %w/w of solver: :s present, all based on the weight of the diacyl peroxide. However, if the use cf certain solvents, such as conventional plasticizers fcr PVC or phlegmatizers for the peroxide, is acceptable in the polymer obtained in the polymerization step, it may be advantageous to use such solvents. Conventional plasticizers include epoxicized soybean oil, dialkyl esters, such as alkyl esters of aliphatic carboxylic acids with two or more carboxylic acid moieties, and less desired phthalate esters. Conventional phlegmatizers include hydrocarbons, such as isododecane.
Preferably, the peroxidation step of the process is.conducted without a salt being addec to the reaction mixture. However, if so desired, a salt may be added, for instance to increase the yield of diacyl peroxide. If used, the salt is preferably selected from alkali and/or alkaline-earth metals. Preferably, they are salts of strong acids that do not react with H2O2, peracid, or a salt thereof. More preferably, the salt is selected from NaCl, KCI, Na2S04, K2S04, and NH4CI.
If used, the colloids are advantageously selected from the group consisting of hydrofyzed polyvinyl acetate, alkyl cellulose, hydroxyalkyl alkyl cellulose, gelatin, polyvinyl pyrrolidone, polyoxyethylene sorbitan monolaurate,and polyacrylic acid. Preferably, said dispersant is a non-ionic compound. Most preferably, it is a mixture of one or more hydrolyzed polyvinyl acetates (PVA). Suitably, the degree of hydrolysis of the PVA ranges from 50 up to 95%, preferably up to 90%. Preferably, the degree of hydrolysis is at least 55%, more preferably at least 60%, so that :he PVA is soluble in the diacyl peroxide-containing mixture. In order to

increase the solubility of the PVA, it can be advantageous to add a C1-C4 alcohol, preferably methanol, ethanolr and/or isopropanoi.
All conventional surfactants can be used. However, in order not to disturb the dispersion of the polymerization reaction and not to adversely affect the properties of the final polymer, the surfactant preferably is a (biodegradable) cationic compcund, such as preferred quaternary ammonium compounds, or a non-ionic surfactant Preferred conventional non-ionic surfactants include, but are not limited to, aikcxylated (fatty) alcohols and alkoxylated sugars.
The aqueous mixture that results from the peroxidation.step can be transferred to the pciymerization reactor "as is". Hcwever, in order to enhance the safety of handling of the diacyl peroxide, it is preferred to add at least one surfactant and/or colloid, so that a physically stable dispersion of the diacyl peroxide in the aqueous mixture, or a dispersion of the aqueous phase in the diacyl peroxide, is obtained. If need ce: the size of the dispersed phase (droplet or particle size) can be reduced in an optional further homogenization step. However, such a step is only a prerequisite when the dispersion as obtained is not safe. Suitably, this is detected by heating a 100 g sample of the dispersion up to a temperature where the diacyl peroxide decomposes. If a certain phase separation is observed, the safety characteristics of the least safe phase are decisive. However, it may also be desired to obtain a very finely dispersed phase, for instance to enhance an even distribution of the diacyl peroxide over the monomer(s) in the polymerization reactor (e.g. to reduce the fish-eye level in PVC that is produced by a suspension polymerization process). If such fine dispersions (with the average size by volume of the dispersed phase being less than 10 μ m, preferably less than 5 μ m, most preferably less than 2 jam) are of interest, then also an extra homogenization step can be advantageously introduced. The homogenization step can be performed

using any suitable (high) shear mixer, such as rotor/sta:or homogenizers, colloid mills, ultrasonic devices, and the like.
In a preferred embodiment, the diacyl peroxides of this invention are prepared in a feed lire, such as a pipe, that is directly connected to the polymerization reactor. The desired (raw) materials for the peroxidation step are then fed into the pipe at suitable points. Optionally, an in-line mixer is then used to homogenize the resulting product of the peroxidation step before it is used in the polymerization step, if so desired, part of the product of the peroxidation step may be recycled in such a set-up to increase the yield of diacyl peroxide. If so desired, the line may be flushed clean with water after the peroxidation step. However, it can also be switched to another polymerization reactor, such that the peroxidation can be an essentially continuous operation.
The product resulting from the peroxidation step typically contains by-products and residual raw materials. Particularly when the diacyl peroxide is prepared using MOOH/M2O2, a substantial quantity of a salt (MX) is formed. The by-products must not be a hindrance in the polymerization reaction. However, it is known that salts adversely affect the stability of the emulsion of the diacyl peroxide, which is a safety concern, while salts may also adversely affect the electrical properties of the final polymer. Hence, it may be preferred to include a purification step. Depending on safety considerations, it can be acceptable to conduct the peroxidation step without any surfactants and/or colloids being used and then to separate and discard (part of) the water layer, after which the diacyl peroxide-rich organic layer may be dispersed and/or diluted, if so desired, using the appropriate media and/or solvents. If an aqueous diacyl peroxide dispersion is to be achieved, conventional surfactants and/or colloids can be used in the dispersion step. Alternatively, (part of) the salt may be removed using conventional techniques, such as (reverse) osmesis, nanofiltration, ion-exchange, precipitation, and the like. A less preferred

piuuc-ss would involve a step wherein a conventional solvent for the diacyl peroxlze is added to extract the diacyl peroxide from the mixture.
The process according to the invention is pre-eminently suited to polymerize one or more ethylenically unsaturated monomers, including (rr.eth)acrylic acid (esters), styrer.e, vinyl acetate, acrylonitriie, vinyl chloride moncmer (VCM), and the like. Preferably, the process according to the invention involves the polymerization of monor-.er mixtures comprising at least 50 %w/w of VCM. based on the weight of all monorr.er(s). In this preferred process, preferred comoncmers for use are of the conventional type and include vinylidene chloride, vinyl acetate, ethylene, propylene, acrylor.itrile, styrene, and (meth)acrylates. More preferably, at least 80 %w/w of the monorr.er(s) being polymerized is made up of VCM, while in the most preferred process the monomer consists essentially of VCM. As is known in the art, the polymerization temperature of such processes determines to a large extent the molecular weight of the final polymer.
The polymerization process can be conducted as a mass process where the reaction mixture is predominantly monomer(s) or as a suspension process where the reaction mixture typically is a suspension of monomer(s) in water, or as an emulsion or micro-emulsion process where the monomer(s) typically is/are emulsified in water. In these processes the usual additives will have to be used. For example, if the monomer(s) is/are present in the form of a suspension in water, the usual additives such as surfactant(s), protective colloid(s), anti-fouling agent(s), pH-buffer(s), etc. may be present. Depending on the type of polymer desired, each of the above-mentioned processes may be preferred. The process according to the invention is especially suited for mass and suspension processes. In the aqueous suspension process to produce PVC from VCM, the polymerization is usually conducted at a temperature in the range of about 0°C to 10Q°C, However, for the process of the present invention it is preferred to employ polymerization temperatures of about

4LTC tc about 70°C, since this is the temperature at which VCM is polymerized efficiency. The polymerization reaction time may vary from about 1 to about 15 hours, and is preferably from 2 to 6 hours. The aqueous suspension VCM polymerization process in addition to the VCM typically contains water, dispersants, free racical initiator, and optional further ingredients, such as buffers, short stop agents, ore-stabilizers, and the like.
After :ns polymerization, the resulting (co)polymer (or resin) will be worked up as is usual in the art. Polymers obtained by a suspension polymerization according to the invention, for example, will be submitted to the usual drying and screening steps. The respiting resin preferably is characterized in that it contains less than 50 ppm of residual diacyl peroxide, more preferably less than 40 ppm, and most preferably less than 25 ppm of diacyl peroxide, immediately after drying for 1 hour at 60°C and screening. The resin was found to exhibit excellent heat stability, as measured with a Metrastat® PSD260 testing oven in accordance with ISO 182-2 (1990E). The improved heat stability proved that the resin hardly discoloured when submitted to melt-prccessing steps, e.g., to form shaped articles.
The prccess according to the present invention is pre-eminently suited for combination with polymerization processes as disclosed in WO00/17245. Accordingly, a preferred embodiment of the present invention relates to a process of claim 1 wherein at least part of the diacyl peroxide is dosed to the polymerization mixture at the reaction temperature. More preferably, essentially all of the organic initiator, i.e. diacyl peroxides andt if used, other conventional initiators, dosed in the polymerization process has a half-life of from 0.0001 hour to 1.0 hour at the polymerization temperature, preferably from 0.001 to 0.8 hour, more preferably from 0.002 to 0.5 hour at the polymerization temperature. If the one or more diacyl peroxides are dosed together with other initiators, it is preferred that the diacyl peroxide'5) as well as all other initiators fulfill these half-life requirements. It is noted

that ha--lives are determined in conventional thermal decomposition studies in monocriorobenzene, as is well-known in the art (see fcr instance the brochure "Initiators for high polymers'1 with code 10737 obtainable from Akzo Nobel).
The dosing of the extremely fast initiators to the polymeriza:ion reaction mixture can be internittent or continuous over a period of time wherein at least 20%, preferably at leas: 40%, more preferably at least 50% of all monomer used in the process is polymerized. If an intermittent operation is selected, there are at least 2, preferably at least 4, more preferably at least 10, and most preferably at least 20 moments at the polymerization temperature at which the initiator is dosed. If so desired, the intermir:ent and continuous operations may be combined, such that the initiator is dosed intermittently for certain (longer or shorter) periods of time. Most preferably, the diacyl peroxide is dosed continuously and/or intermittently after at least 5%,' preferably at least 10%, more preferably at least 20%, most preferably at least 30% of the rr.onomer(s) has already been polymerized and while during the dosing period at least 10%, preferably at least 20%, more preferably at least 30%, and most preferably at least 50% of all monomer used in the process is polymerized. Preferably, the diacyl peroxide is dosed in a concentration of 0.1 to 60 %w/w, more preferably 0.5 to 25 %w/w, and most preferably 2 to 15 %w/w, based on the weight of the diacyl peroxide-containing mixture, in order to facilitate the even distribution of the diacyl peroxide over the monomer.
The dosing can be effected at any suitable entry point to the reactor. If water is added in the course of the polymerization process, for example to compensate for the shrinkage of the reactor content due to the polymerization reaction, it may be advantageous to use the line through which this water is dosed to also dose the initiator. In a most preferred' embodiment, the diacyl peroxide has also been produced in said line.

Experimental
The fc "lowing chemicals were used in the process to manufacture diacyl peroxides. It
is noted that all experiments were performed taking sufficient safety measures. In
this respect it is also noted that pure diisobutanoyl peroxide is a detonatabie
explosive.
Commercially available aqueous H2O? with an assay of 69.97% was used.
NaOK solution (NaOH-25 and NaOH-33) containing 25 %w/w and 33 %w/w,
respectively, of NaOH was produced from Baker-grade NaOH and distilled water.
NaCI solution (NaCI-15 and NaCI-25) containing 15 %w/w and 25 %w/w,
respectively, of NaCI was produced from Baker-grade NaCI and distilled water.
Na2CO: solution containing 10 %w/w of Na2C03 was produced from Baker-grade
Na-COo and distilled water.
HCI solution containing 18 %w/w of HCI was produced from Baker-grade HCI and
distilled water.
Isobu:ar.oyl chloride (99.3%) was supplied by BASF
Laurcyl chloride (98%) was supplied by Acros.
A fresh PVA solution, 5 %w/w Alcotex® 72.5 ex Harco in demineralized water was
prepared fresh, 1 day prior to use.
Example 1
For the preparation of isobutanoyl-Iauroyl peroxide, a reactor was charged at 0°C with 35 g deionized water, 286 g NaCI-25 solution, 110 g of Na2C03 solution, 39 g NaOH-25 solution, and 32.5 g H202 solution. Then, within 50 minutes 103.0 g isobutanoyl chloride were dosed while maintaining a pH-value of 11.0 with the aid of NaOH-25 solution. The temperature was maintained at 0°C, and meanwhile the contents of the reactor were homogenised. After addition of the total amount of isobutanoyl chloride, the reaction mixture was stirred for another 15 minutes at pH 11.0. Then, the pH was lowered to 10.0 with HCI solution and the temperature was broucht to 5°C. Next, 70.5 g lauroyl chloride were dosed over a period of 10

minutes, while maintaining the pH on 10.0 with the aid c* NaOH-25 solution. After adciilc-i of the total amount of lauroyl chloride, stirring was continued for another 15 mir.'jtes.
The reaction mixture was set aside for 30 minutes in orcer to allow the two-phase system .to separate. The aqueous layer was removed '713 g) and the organic peroxide layer was washed with 300 g NaCI-15 solution. Again, the aqueous layer and the organic layer were allowed to separate, in order to facilitate the isolation of the peroxide layer (Isolated yield: 145.0 g).
Analysis of the isolated peroxide layer: 35% ciisobutanoyl peroxide 64% is-butanoyl-iauroyl peroxide Examcie 2 and Comparative Examples A-D
In Example A, the procedure of WO 01/32613 was repeated. First, a solution of
Na202 was prepared by combining 108.3 g of demineralized water, 18.5 g of
NaOH-33 solution, and 37 g of the aqueous H2O2. A second reactor was charged
with 33.3 g of demineralized water, 277 g of the PVA solution, and 16.3 g of
isobutanoyl chloride while controlling the temperature between 5-10°C. Next, the
Na202 solution was dosed while the system was homogenized. No diisobutanoyl
peroxide was obtained and only an aqueous phase formed.
In Example B, the same procedure was followed as in Example A, except that 2-
ethyibutyroyl chloride was used instead of the isobutanoyl chloride. Again, no
diacyl peroxide was obtained.
In Example CT the same procedure was followed as in Example A, except that 2-
ethylhexanoyl chloride was used instead of the isobutanoyl chloride. Again, no
diacy! ceroxide was obtained. The resulting mixture was milky white, probably

because a lot of 2-ethylhexanoic acid was formed which did not all dissolve in the water.
In Example D, the procedure of Example A was modified ;n that the second reactor was charged with all the water, PVA solution, isobutyrcyi chloride, and aqueous H:0:. and the NaOH-33 solution was then dosed to it at a temperature of 5-1 G°C. The yield of diisobutanyl peroxide is expected to be less than 20 %w/w. In Example 2, a single reactor was charged with 141.5 g of demineralized water, 13.5 g of NaOH-33 solution, 27.7 g cf PVA solution, and 3.7 g of the aqueous H?0:. after which 16.3 g of isobutanoyl chloride were dosed to the contents of the reacicr. while maintaining a temperature of 5-10°C and while homogenizing the contents of the reactor. An emulsion resulted. The yield cf diisobutanoyi peroxide was 32 %w/w. It is expected that if the emulsion is used within 43 hours in a polymerization reaction, it will show the same polymerization rates for VCM as were observed when using the same amount of a conventional 30 %w/w diisobutanoyi peroxide solution in isododecane.
Example 3
The product of Example 2 was stored for 1.5 hours at 5°C without being stirred. The active oxygen content (a measure of the amount of diacyl peroxide of formula (I)) of the emulsion was reduced by 2.5% and a little phase separation occurred. In Example 3, a reactor was charged with 175 g of demineralized water, 16.4 g of NaOH-33 solution, 43.8 g of NaCI-25 solution, 250.5 g of Na2C03 solution, and 4.8 g of the aqueous H202. Then 23.1 g of isobutanoyl chloride was dosed to the contents of the reactor, while maintaining a temperature of 5-10°C and homogenizing the contents of the reactor. At the end of the reaction the mixture was neLftralized to pH=7. Taking sufficient safety measures, the two-phase system was allowed to separate and about 70% by volume of the aqueous phase was retrieved. To the organic layer and the remainder of the water layer were added 207.2 a of demineralized water, 109.3 a of PVA solution, 13.7 g of methanol, and

21.9 g zf an aqueous 0.2%w/w Bercl© 08 (non-ionic emulsifier ex Akzo Nobel) solutlcr. A dispersion resulted which was stable for rr.zre than 2.5 hours and shov/ec good performance in the polymerization process of VCM. The yield of diiscbu:~noyl peroxide was 86% on iscbutanoyl chloride ar.d 93% on H2O2.

Claim
. Prccess comprising the steps of;
producing an aqueous mixture comprising a peroxide of formula (I)
wherein R1-R~ are independently selected -rom the group consisting of hydrogen, halogen, and saturated or unsaturated, linear or branched alkyi, alkaryl, and aralkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R2 are hydrogen, then R3 and/or RA are not hydrogen and, vice-versa, that if R3 and/or R4 are hydrogen, then R1 and/or R: are not hydrogen, in which process R1-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R\ or one of R1-C(R:)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, with the further proviso that ciacyl peroxides of formula (i) wherein R2 is halogen and R4 is hydrogen, and both R1 and R3 are long chain alkyl groups having about 10 to about 16 carbon atoms, are excluded, by reacting, in a so-called peroxidation step,
one or more acid haiides of formula [\\) , wnerein X is halide,
preferably chloride or bromide, most preferably chloride, with i) MOOH/M202, wherein M is any metal or ammonium-containing group that will react with H202 to form MOOH/M202 without decomposing one or more of the peroxides present in the process, preferably M is selected from the croup consisting of ammonium, sodium, potassium, magnesium, calcium, and lithium, and/or ii) one or more peracids of formula (III)

or the salts thereof, an aqueous phase, in Which process the acid halide, or mixture of ac:c halides, is essentially only Drought into contact with water containing MOCH. M202 and/or one or more eracids or peracid salts, preferably M202 or the M salt of the peracid, optionally introducing one or more solvents for the acid halide in any part of The process,
optionally introducing one or more salts in any par, of the process, optionally introducing one or more colloids and/or surfactants, before, during, or after the peroxidation step,
optionally purifying the aqueous mixture in one or more purification steps, optionally homogenizing the aqueous mixture in one or more nomogenization steps,
transferring the product from the previous steps that comprises the diacyl oeroxide of formula (I) to a polymerization reactor, and - thermally decomposing said diacyl peroxide, tc generate organic free radicals, in the presence of one or more ethylenicaliy unsaturated monomers, to polymerize said monomers in said polymerization reactor.
2. Process comprising the steps of:
- producing an aqueous mixture comprising a diacyl peroxide of formula (I)
wherein R1-R4 are independently selected -fom the group consisting of hydrogen, halogen, and saturated or ■unsaturated, linear or branched alky!, aikaryl, and a^alkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R2 are hydrogen, then R3 and/or R4 are not hydrogen and, vice-versa, that if R3

and/or R4 are hydrogen, then R1 and/or R2 are not hydrogen, in which 2-rocess R'-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with cne or more independently chosen groups R\ or ore of R1-C(R2)H and R:-C(R4)H represents an, cptionaily substituted, aromatic ring structure, with the further proviso that if R2 is halogen and R4 is hydrogen, and both R1 and R3 are alkyl groups, then each of these alkyl groups has up to about 6 carbon atoms, by reacting, in a so-called peroxidation step, one or more acid haiides of" formula (li)
wherein X is halide, preferably chloride or bromide, most preferably chloride, with i) MOOH/M202, wherein M is any metal or ammonium-containing group that will react with H:02 to form MOOH/M202 without decomposing one or more of the peroxides present in the process, preferably M is selected from the group consisting of ammonium, sodium, potassium, magnesium, calcium, and lithium, and/or ii) one or more
peracids of formula (m; , or the M salts thereof, in an
aqueous phase, in which process the acid halide, or mixture of acid haiides, is essentially only brought into contact with water containing MOOH/M202 and/or one or more peracids or peracid salts, preferably M202 or the M salt of the peracid,
- optionally introducing one or more solvents for the acid halide in any part of
the process,
c ptionally introducing one or more salts in any part of the process,
- cotionally introducing one or more colloids and/cr surfactants, before,
curing, or after the peroxidation step,
- cotionaiiy purifying the aqueous mixture in one or more purification steps,

optionally homogenizing the aqueous mixture in one or more
homogenization steps,
transferring the product from the previous steps that comprises the diacyi
peroxide of formula (I) to a polymerization reactor, and
thermally decomposing said diacy! peroxide, :o generate organic free
V
radicals, in the presence of one or more ethylenically unsaturated monomers, to polymerize said monomers in said polymerization reactor.
3. Process comprising the steps of:
producing an aqueous mixture comprising a diacyi peroxide of formula (1)
, wherein R'-R4 are independently seloAed from the group consisting of hydrogen and saturated or unsaturated, linear or branched aikyi, alkaryl, and aralkyl moieties optionally substituted with one or more halogen atoms, provided that if R1 and/or R2 are hydrogen, then R3 and/or R4 are not hydrogen and, vice-versa, that if R3 and/or R4 are hydrogen, then R1 and/or R2 are not hydrogen, in which process R'-C-R2 and/or R3-C-R4 can be part of a ring structure that can be saturated or unsaturated and substituted with one or more independently chosen groups R\ or one of R1-C(R2)H and R3-C(R4)H represents an, optionally substituted, aromatic ring structure, by reacting, in a so-called peroxidation step, one or
more acid halides of formula wherein herein X is halide,
preferably chloride or bromide, most preferably chloride, with i) 'vlOOH/M202, wherein M is any metal or ammonium-containing group that will react with H202 to form MOOH/M202 without decomposing one or more of the peroxides present in the process, preferably M is selected from the

group consisting of ammonium, sodium, potassium, magnesium, calcium, and lithium, and/or ii) one or more peracids of formula (III)
or the M salts thereof, in an aqueous phase, in
T
which process the acid haiide, or mixture of acid halides, is essentially only
orought into contact with water containing MOOK M202 and/or one or more
peracids or peracid salts, preferably M202 or the M salt of the peracid,
optionally introducing one or more solvents for the acid haiide in any part of
:he process,
optionally introducing one or more salts in any part of the process,
optionally introducing one or more colloids and!or surfactants, before,
during, or after the peroxidation step,
optionally purifying the aqueous mixture in one or imore purification steps,
optionally homogenizing the aqueous mixture in one or more
homogenization steps,
- transferring the product from the previous steps that comprises the diacyl peroxide of formula (I) to a polymerization reactor, and
- thermally decomposing said diacyl peroxide, to generate organic free radicals, in the presence of one or more ethylenically unsaturated monomers, to polymerize said monomers in said polymerization reactor.

4. A process according to any one of the preceding claims wherein the diacyl peroxide obtained in the peroxidation step is used in the polymerization process within a period of 168 hours after said peroxidation step.
5. A process according to any one of the preceding claims wherein the diacyl peroxide is stored and handled in this process at temperatures up to 5°C.

6. A process according to any one of the preceding claims wherein one and the sane reactor is used to make the MOOH/M202 from a source of M and H20: and to carry out the peroxidation srep.
7. A process according to any one of the preceding cairns wherein 0.005 to 2 'w of the diacyl peroxide is used in the polymerization step, based on the weight of the ethylenicaily unsaturated monomer(s).
8. A process according to any one of the preceding claims wherein the e;hylenicaily unsaturated monomer(s) comprise(s) vinyl chloride monomer.
9. A process according to any one of the preceding claims wherein at least one azlc halide is used that is selected from the group consisting of lauroyl halide, isobutanoyl halide, 2-ethylbutanoyl halide, 2-ethylhexanoyl halide, 2-cnlcropropanoyl halide, cyclohexane carbonyl halide, 3-methylcyclohexane carbonyl halide, and 2,3-dihalocyclohexane carbonyl halide.
10. A process according to any one of the preceding claims wherein at least one resulting diacyl peroxide is asymmetrical.
11. A process according to claim 10 wherein a peracid is used in the peroxidation step.
12. A process according to any one of the preceding claims that is essentially solvent-free.
13.A process according to any one of the preceding claims wherein the diacyl peroxide is dosed to the polymerization reaction mixture at the reaction temperature.

14. A process comprising the steps substantially as herein described and exemplified.

Documents:

1919-CHENP-2004 AMANDED PAGES OF SPECIFICATION 22-1-2010.pdf

1919-CHENP-2004 FORM-1 22-1-2010.pdf

1919-CHENP-2004 FORM-3 22-1-2010.pdf

1919-CHENP-2004 OTHER PATENT DOCUMENT 22-1-2010.pdf

1919-CHENP-2004 AMANDED CLAIMS 22-1-2010.pdf

1919-CHENP-2004 CORRESPONDENCE OTHERS 22-1-2010.pdf

1919-CHENP-2004 FORM-13 10-08-2009.pdf

1919-chenp-2004-claims.pdf

1919-chenp-2004-correspondnece-others.pdf

1919-chenp-2004-correspondnece-po.pdf

1919-chenp-2004-description(complete).pdf

1919-chenp-2004-form 1.pdf

1919-chenp-2004-form 26.pdf

1919-chenp-2004-form 3.pdf

1919-chenp-2004-form 5.pdf

1919-chenp-2004-pct.pdf

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Patent Number

242041

Indian Patent Application Number

1919/CHENP/2004

PG Journal Number

33/2010

Publication Date

13-Aug-2010

Grant Date

06-Aug-2010

Date of Filing

27-Aug-2004

Name of Patentee

AKZO NOBEL N.V

Applicant Address

VELPERWEG 76 NL -6824 BM ARNHEM THE NETHERLANDS.

Inventors:

#	Inventor's Name	Inventor's Address
1	TAMMER MARINUS ,CATHARINUS,	UMBROVEVELAAN 7 NL-7431 ZA DIEPENVEEN THE NETHERLANDS.
2	DE,JONG,JOHANNES,JACOBUS ,THEODRUS,	DE HAM 13, NL-6932 BR WESTERVOORT, THE NETHERLANDS
3	OVERKAMP,JOHANNES,WILLBRORDUS,ANTONIUS	AAKSTAAT16, NL-8152 CB LEMERVELD , THE NETHERLANDS

PCT International Classification Number

C08F4/34

PCT International Application Number

PCT/EP03/01746

PCT International Filing date

2003-02-20

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	02075882.7	2002-03-01	EUROPEAN UNION