Title of Invention

"AN IMPROVED PROCESS FOR THE PREPARATION OF ALKANE SULFONATES"

Abstract

The present invention relates to an improved process for the preparation of alkane sulfonates. The sulfonates are produced from unsaturated hydrocarbons as feedstock obtained from thermal cracking processes. Typically such feedstocks contains olefins, paraffins and aromatics. The feedstock is introduced into the reactor gradually or at one time and by maintaining a concentration of the alcohol having C1-C4 carbon atom and water varying from the range 0-100% such that an excess of alcohol is not used or an insufficient amount of water is used for dissolving the bisulfite, a two-layer or two- phase rather than a three-phase system is provided. By agitating the two-phase system at ambient to 120°C and 1-5 atmospheric pressure, a turbid appearing dispersion of the phases is maintained and shortly before the reaction is completed, two clear phases results, and separate these layers. The upper layer contains paraffin, unreacted olefins and others. The products of the instant invention encompass this clear solution, or a semi-solid material resulting from the evaporation or distillation of the alcohol from the

Full Text

Present invention relates to an improved process for the preparation of alkane sulfonates. The present invention is particularly related to the production of such sulfonates from unsaturated hydrocarbons by reacting them with bisulfite in a solvent reaction media. More particularly this invention relates to the preparation of alkane sulfonates using the addition of bisulfite ions to olefins without using a free radical initiator/ The alkane sulfonates are effective as detergents. These detergents provide outstanding detergency, high compatibility with water, and good wetting and foaming properties. Alpha olefin sulfonates are free of skin irritants and sensitizers, and a great impdrtance is their high degree of biodegradability. They are used in high quality shampoos, light-duty detergents, bubble baths and heavy-duty liquid and powder detergents. The product obtained by the present invention can be utilized by detergent industry specially used in personal care products. The addition of sodium bisulfite to unsaturated organic compounds has long been known. One of the early patents in which this reaction was used is Patent No. 2,028,091, which described the addition of sodium bisulfite to esters of maleic acid. The reaction is carried out by heating an aqueous alcoholic solution of sodium bisulfite and the maleic acid ester in a closed vessel. Several patents e.g. U.S. pat. Nos. 4,171,291; 3,356,717; 3,168,535; 3,349,122; 4,070,396 describe the above mentioned reaction with olefin(s) in presence of peroxide initiators to form alkane sulfonates. It has long been further, known that the above mentioned reaction is feasible with alpha olefins, olefins with pendant or internal unsaturation. The pendant or internal olefins react at slower rate than alpha olefin and the rate of reaction is decreased with increase in the molecular weight of olefin. Such observations are reported in open literature (Chemical Reviews, 37, pp-351; Industrial and Engineering Chemistry, Product Research and Development, No.1, March 1964, pp-3). Most of the work on the preparation of olefin sulfonates has been done in United States and in Britain, which is covered by numerous patents e.g. 2, 653, 970; 3,084,186 and 3,168,555 and British Patent No. 995, 376. However, to our knowledge, no process for production of organic sulfonates by reaction of the unsaturated hydrocarbons with inorganic bisulfites has been found sufficiently economic to be practiced on a commercial scale. All of the above cited patents need a emphasis precise control of the pH. Various ranges of pH have been found to be beneficial to the reaction forming organic sulfonates. The process disclosed in U.S. patent no. 2,653,970 requires about from 16 to 40 hours for obtaining reasonable yields of sodium alkyl sulfonate. German patent No. 1,098,936, French Patent No. 1,222,105 and U.S. patent no. 3,084,186 claim the use of peroxide compounds as promoters to reduce the reaction time. Patent No. 3, 479, 397 discloses the use of nitrates as promoters. U. S. Patent. No. 3,541,140 describes the preparation of alkane sulfonates wherein the process is accomplished by pre-reacting the olefin with an oxygen containing gas in presence of AIBN as free radical initiator and then reacting a non-interfering bisulfite with the pre-reacted olefin. The use of nitrates as promoters give rise to alkyl sulfonates containing nitrogen in an amount of about 1 g per alkyl chain and on a prior oxygenation of olefins gives rise to recycle products, which are no longer reactive with respect to bisulfite. French Patent Na 1,453,398 and U.S. Patent No. 3,450,749 claims the use of gamma or UV radiations, which do not give good yields and show some technological difficulties. Similarly, U. S. Patent. No. 3,558,693 discloses the separation of alkane sulfonate product from the reaction mixture by maintaining a critical alcohol to water ratio and a critical temperature range. The U. S. Patent No. 2,504,411 discloses the necessity of maintaining certain molar ratios of bisulfite ions to olefins and of olefins to organic peroxide initiators and the importance of controlling the reaction temperature in rather narrow limits and pairing up the initiators with a specific solvent to obtain good yields of alpha olefin sulfonates. The U. S. Patent No. 3,084,186 describes the addition of bisulfites to olefins in a system to maintain fixed concentration of bisulfite. This also requires regular analysis of the bisulfite ion during the course of reaction, which makes this process difficult and impractical. The important drawbacks associated with hitherto known processes can be summarized as: (i) Economically viable production of organic sulfonates has not been achieved so far. (ii) Reaction time is generally very high ranging from 16-40 hrs (U.S. Patent No. 2,653,970). (iii) Reasonably high yield of product is not obtained. (iv) The high cost and non-availability of raw materials are other interfering factors for the large-scale production. (v) Sometimes very controlled reaction parameters (e.g. addition of bisulfite) make the process more tedious (vi) Some of the process utilized nitrates as the initiators. The product thus obtained is associated with nitrogen, which makes the recycle of unreacted product more difficult. (vii) For rapid completion of the reaction controlled and gradual introduction of the bisulfite compound, which is usually a salt like ammonium or sodium bisulfite is necessary. It being stated that without such controlled introduction, long reaction times are required, extending upto 100 hours. These efforts, in turn, involved a careful supervision over the bisulfite concentration. Also, in order to check the rate of addition, aliquot portions of the reaction mixture were periodically withdrawn and tested as a pre requisite to the maintenance of the bisulfite concentration within desired limits. Such periodic tests were done as often as every 10 minutes. From the prior processes it may be seen that they are marked by tedious techniques, which result in increasing the cost of the product and prolong the reaction well beyond desired times. According to the present invention, it is proposed to eliminate completely the need for such careful control, including both the gradual addition of bisulfite and the periodic testing of the reaction mixture. All the reactants are mixed in a single addition, there being no gradual or stepwise addition of reactants. All of the prior art processes also use a free radical initiator to accomplish the addition of bisulfite ion in presence of a lower alcohol as solvent. We also instead to eliminate the use of free radical initiator. The main object of the present invention is to provide an improved process for the preparation of alkane sulfonates which obviates the drawbacks as detailed above. Another object of the present invention is the addition of bisulfite ions to an alkene having at least 10 carbon atoms per molecule to form an alpha olefin sulfonates without the use of free radical initiator. Still another object of the present invention to generate the free radical to initiate the reaction in the 1st step by contacting a source of oxygen (air or O2) with the feed at elevated temperature. Yet another object of the present invention is to use cracked distillates from thermal cracking processes containing alpha olefins without purification as a cheap and easily available source of olefins, e.g. mixed streams such as alpha olefins, paraffin mixture obtained from kerosene/gas oil distillate fraction from thermal coking/visbreaking operations in a refinery which goes as a low value fuel component and typically such mixed alpha olefins contain about 25-30% olefins, 70-75% paraffins and about 0.1-0.5% aromatics. For reasons of economics, we prefer to use sodium bisulfite in our process, but other water-soluble bisulfites, for example ammonium bisulfite or aliphatic amines or pyridine bisulfite may be used. Sodium bisulfite, while in general less reactive and more difficult to remove firm the reaction products, is advantageous in the manner that the sodium alkane sulfonates formed are generally more effective as detergents. Further in the process, according to the present invention the manner in which feed containing olefins and bisulfite are mixed is not critical or complicated. Further the use of peroxides for free radical initiation has been eliminated. Accordingly the present invention provides an improved process for the preparation of alkane sulfonates which comprises reacting the hydrocarbon feed selected from olefins or a mixture of olefins and paraffins obtained from the thermally cracked hydrocarbon distillate having 10 to 18 carbon atoms at a temperature in the range of 70-15 0°C in the presence of oxygen containing gas mixture wherein the O2 concentration in the gas mixture is in the range of 4-100% or air to obtain mixture of peroxides having peroxide value in the range of 100-300, reacting the above said treated hydrocarbon feed with an alkali metal bisulfite in aqueous or non aqueous saturated monohybrid alcohol having one to four carbon atoms at a temperature of 20-25°C to obtain two phases disperse system, agitating the above said reaction mixture and slowly raising the temperature to 60-150°C over a period of 1 to 2 hours and further maintaining the said elevated temperature for a period of 2 to 16 hours till the reaction mixture turns clear and water white to obtain the alkane sulfonates. In an embodiment of the present invention the mixture of olefins and paraffins used is obtained from the thermally cracked hydrocarbon distillate. In another embodiment of the present invention the O2 concentration in the gas mixture is in the range of 4-100% preferentially in the range of 15-25%. In yet another embodiment of the present invention value of the in-situ peroxide obtained having the value in the range of 10-300 preferably 100-200. In still another embodiment of the present invention the bisulfite used is of the general formula MHSO3 where M is an alkali metal or an ammonium ion. In still another embodiment of the present invention the bisulfite used is selected from the group consisting of sodium bisulfite, ammonium bisulfite and sodium Meta bisulfite. In still another embodiment of the present invention the olefin is single or a mixture of olefins having carbon atoms in the range of C10-C18. In still another embodiment of the present invention the ratio of olefins to paraffins in the mixture is in the range of 1:9 to 1:1. In still another embodiment of the present invention the thermally cracked distillate used is consisting of olefins, saturated hydrocarbons and aromatics. In still another embodiment of the present invention bisulfite reaction with feed is carried out at temperatures in the range of 60°C to 150°C preferably at 70°C tol00°C at 1-5 atmospheric pressure. In still another embodiment of the present invention the reaction is carried out preferably for a period 8-12 hrs. In still another embodiment of the present invention the molar ratio of olefins in olefins -paraffins mixture to bisulfite used is in the range of 1:1 to 1:5. In still another embodiment of the present invention said monohybrid alcohol is selected from the group consisting of methanol, ethanol, isopropanol and tertiary butanol. In still another embodiment of the present invention said solution contains a low molecular weight alcohol from Ci-C4 range of carbon such as methanol, ethanol, isopropanol or tertiary butanol. The reaction is carried out by agitating an aqueous solution of the bisulfite with an alcoholic solution of the pretreated olefin at a temperature in the range from 25 - 100°C preferably somewhat less than the boiling point of the solvent and for a time sufficient to complete the bisulfite addition without a free radical-forming initiating catalyst. The temperature, order of addition of the reactants and their ratio are not critical. The free radicals are produced prior to the addition to bisulfite solution, by heating the olefins or olefin containing hydrocarbon feed in presence of oxygen containing gas mixture. 02 concentration may very from 4-100% preferentially in the range of 15-25% at temperatures in the range of 80 - 200 °C. The alcoholic solution of feed was treated with aqueous solution of bisulfite wherein the bisulfite is of the general formula MHSO3 in which M is an alkali metal, alkaline earth metal or an ammonium. Preferably sodium bisulfite or ammonium bisulfite or sodium meta bisulfite. The mole ratio of bisulfite used varies from 0.5 - 5 mol % on the basis of olefin present in the feed. All the reactants can be introduced into the reactor gradually or at one time and by maintaining a concentration of the alcohol having Ci - 64 carbon atom and water varying from in the range 0-100% such that an excess of alcohol is not used or an insufficient amount of water is used for dissolving the bisulfite, a two-layer or two- phase rather than a three-phase system is provided. By agitating the two-phase system at ambient to 120°C and 1-5 atmospheric pressure, a turbid appearing dispersion of the phases is maintained and shortly before the reaction is completed, two clear phase results, and separate these layers. The upper layer contain paraffin, unreacted olefins and others. The products of the instant invention encompass this clear solution, or a semi-solid material resulting from the evaporation or distillation of the alcohol from the clear solution or a semi-solid material resulting from the removal of both the alcohol and the water. The reaction can be carried out at normal temperatures, it is accelerated at increased temperatures. The temperatures preferred are those approaching the boiling point of the olefin solvent employed, which in the case of the above mentioned alcohols is in the range of about 70-82°C. A reflux condenser can be associated with the reaction vessel if it is anticipated that the temperature will possibly exceed the boiling point the solvent. After the reaction is complete, the reaction mixture can be subjected to separate saturated hydrocarbons followed by an evaporation step wherein water and organic solvent are separated from the product alpha olefin sulfonate. AOS yields of 20-95 percent are obtained by the inventive process. The "yield" as the term is here in employed is the weight percent of olefin feed charged to the reaction zone converted to the alpha olefin sulfonate. In order to more fully illustrate the process of this invention and manner of practicising the same, the following examples are presented. The examples are provided for illustrative purposes and not to limit the invention as defined by the claims. The examples also demonstrate that the alpha olefins mixture containing Ci0-Ci8 carbon atoms can also be reacted to prepare alpha olefin sulfonates using the present invention. The examples further demonstrate that the process of the present invention can also be used to prepare alpha olefin sulfonates by reaction alpha olefins-paraffin mixture obtained from thermally cracked petroleum streams obtained from coker operations and having Ci0-Ci8 carbon atoms. In such a case only alpha olefins present in the cracked stream reacts to form sulfonates. The following examples are given by way of illustration and therefore should not be construed to limit the scope of the present invention. Example-1 Into a 500 ml three-necked flask equipped with a reflux condenser, a Teflon - bladed glass agitator and a thermometer, 29.7 g of sodium bisulfite, previously dissolved in 56 ml of water, was charged. There was then added 75.0 g of olefin - paraffin mixture (30% : 70%, C-H product) having peroxide value ~ 10 (peroxides generated by passing air at 150°C for 1/2 hr) in 113 ml isopropyl alcohol. The agitation was started and the temperature was gradually raised from 25°C to 78°C with vigorous stirring over a period of 2 hrs, temperature was maintained an additional for period of 10 hrs with stirring. The alcohol was distilled off from the reaction mixture and the two layers obtained were separated. On evaporation of water a light yellow, soap-like, water -soluble semi-solid product resulted. The conversion, basis consumed olefin, is found to be 20%. Example-2 The same procedure and ratio of ingredients were carried out as in Example-1. Oiefin -paraffin mixture (30% : 70%, C14 product) having peroxide value - 170 (peroxides generated by passing air at 150°C for ~2 hr). The product obtained was similar to that obtained in Example-1. The conversion, basis consumed olefin, is found to be 95+%. Example-3 The procedure of example-1 was carried out with about 1.5 moles of bisulfite and olefin - paraffin mixture (30% : 70%, CM product) having peroxide value ~ 278 (peroxides generated by passing air at 150°C for ~2 hr). The product obtained was similar toJhat obtained in Example-1. The conversion, basis consumed olefin, is found to be 83%. Example-4 The procedure of example-1 was carried out with about 2.5 moles of bisulfite except Ci4-Cie mixture from cracked hydrocarbons having peroxide value - 277 (peroxides generated by passing air at 150°C for -2 hr) was used. The product obtained was similar to that obtained in Example-1. The conversion, basis consumed olefin, is found to be 87+%. Almost total olefins can be made to react with bisulfite in the presence of other hydrocarbons. No prior separation of olefins from a mixture of saturated and unsaturated hydrocarbons is necessary. In the process of the invention an olefin having a carbon chain length of from 10 to 18, preferably an alpha-olefin, is reacted with bisulfite ions in a liquid medium, comprising the steps of: (ij Heating of olefin at a temperature in the range of 80 - 150°C while bubbling air the system to obtain a mixture of peroxides (peroxide value = 100-300) and olefins and cooling the mixture. (ii) Forming a mixture of olefin and a co-solvent consisting of water and a short chain alcohol containing from 1 to 4 carbon atoms, the preferred alcohol is isopropyl alcohol, wherein the alcohol present is about 58% to about 70% by weight of the co-solvent and the alcohol is present in an amount of from about 50% to about 100% by weight of the olefin, (iii) Adding an aqueous solution of bisulfite ions, containing 1-3 mols of bisulfite ion per mol of olefin and the alcohol is present in an amount from about 16% to about 19% by weight in the final reaction mixture, and (iv) Maintaining the reaction zone, preferably at a temperature of from 70°C to 100°C for 5-15 hrs. Although this invention has been primarily described in conjunction with examples and by reference to embodiments thereof, it is evident that many alternatives, modifications, and variants will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intented to embrace within the invention all such alternatives, modifications, and variations that fall within the spirit and scope of the appended claims. The main advantages of the present invention are: 1. It has been found that the present process can be carried out efficiently and high yields can be obtained by charging all of the ingredients into the reaction vessel at the same time without undue regard for solvent selection, solvent concentration, time or temperature. Contrary to U. S. Patent No. 3, 084, 186 in which the rate of addition of the bisulfite to the olefin is strictly controlled and to U. S. Patent No. 2, 504, 411 in which many factors are controlled, among them the temperature within narrow limits and the ratios of initiators solvents, and olefins. 2. The present invention provides a process wherein the terminal olefins can be made to react almost quantitatively with bisulfite under the experimental conditions to produce alpha olefin sulfonates by using water-soluble bisulfites and olefins (obtained from coker distillates) containing from 10 to 18 carbon atoms. 3. Thus, the invention provides a simplified process which can be carried out at temperatures in the range suitable for atmospheric pressure operation without an initiating catalyst and with proper agitation to maintain a disperse system of the two- phases during the course of the reaction, which generally runs from 2 to 20 hours. 4. The process is free from the use of free radical initiator. The free radicals are generated prior to the reaction with bisulfite by contacting oxygen containing gas at elevated temperature. Excellent yields of the sulfonates above 80% are obtained compare to the processes wherein the various free radical initiators were used. 5. The main achievement of this process is the utilization of alpha olefins from cracked hydrocarbons i.e. alpha olefin-paraffin mixture, which is available in large quantities in refineries at a very cheaper rate and so far has not been utilized. 6. The other usefulness of this process lies in the conversion of alpha olefins present in the alpha olefin-paraffin mixture into high marketability product i.e. alpha olefm sulfonates, a potential detergent type. No prior separation of alpha olefins from coker distillate is required. We Claim: 1. An improved process for the preparation of alkane sulfonates which comprises reacting the hydrocarbon feed selected from olefins or a mixture of olefins and paraffins obtained from the thermally cracked hydrocarbon distillate having 10 to 18 carbon atoms at a temperature in the range of 70-150°C in the presence of oxygen containing gas mixture wherein the O2 concentration in the gas mixture is in the range of 4 - 100% or air to obtain mixture of peroxides having peroxide value in the range of 100-300, reacting the above said treated hydrocarbon feed with an alkali metal bisulfite in aqueous or non aqueous saturated monohybrid alcohol having one to four carbon atoms at a temperature of 20-25°C to obtain two phases disperse system, agitating the above said reaction mixture and slowly raising the temperature to 60-150°C over a period of 1 to 2 hours and further maintaining the said elevated temperature for a period of 2 to 16 hours till the reaction mixture turns clear and water white to obtain the alkane sulfonates. 2. An improved process as claimed in claim 1 wherein oxygen concentration in the mixture preferentially in the range of 15-25%. 3. An improved process as claimed in claims 1-2, wherein peroxide value of the mixture of peroxides is preferably 100-200. 4. An improved process as claimed in claims 1-3 wherein the bisulfite used is of the general formula MHSO3 wherein M is an alkali metal or alkaline earth metal or an ammonium ion. 5. An improved process as claimed in claims 1-4, wherein the bisulfite used is selected from the group consisting of sodium bisulfite, ammonium bisulfite and sodium meta bisulfite. 6. An improved process as claimed in claims 1-5, wherein the ratio of olefins to paraffins in the mixture is in the range of 1:9 to 1:1. 7. An improved process as claimed in claims 1-6, wherein the thermally cracked distillate used is consisting of olefins, saturated hydrocarbons and aromatics. 8. An improved process as claimed in claims 1-7, wherein bisulfite reaction with feed is carried out at temperatures preferably in the range of 70°C to l00°C. 9. An improved process as claimed in claims 1-8, wherein the reaction is carried out preferably for a period of 8-12 hours. 10. An improved process as claimed in claims 1-9, wherein the molar ratio of olefins in the olefin-paraffins mixture to bisulfite used is in the range of 1:1 to 1:5. 11. A process as claimed in claims 1 to 10, wherein said monohybrid alcohol selected from the group consisting of methanol, ethanol, isopropanol and tertiary butanol. 12. An improved process as claimed in claims 1-11, wherein said solution contains a low molecular weight alcohol from C1-C4 range of carbon such as methanol, ethanol, isopropanol or tertiary butanol. 13. An improved process for the preparation of alkane sulfonates substantially as herein described with reference to the examples accompanying this specification.

Documents:

410-DEL-2002-Abstract-(04-08-2008).pdf

410-del-2002-abstract.pdf

410-DEL-2002-Claims-(04-08-2008).pdf

410-del-2002-claims.pdf

410-DEL-2002-Correspondence-Others-(04-08-2008).pdf

410-del-2002-correspondence-others.pdf

410-del-2002-correspondence-po.pdf

410-del-2002-description (complete)-04-08-2008.pdf

410-del-2002-description (complete).pdf

410-del-2002-form-1.pdf

410-del-2002-form-18.pdf

410-del-2002-form-2.pdf

410-DEL-2002-Form-3-(04-08-2008).pdf

410-del-2002-form-3.pdf