Title of Invention

"A PROCESS FOR THE PREPARATION OF HIGH MELTING POINT (95-100˚C) MICROCRYSTALLINE WAX"

Abstract

A process for the preparation of high melting point (95-100° tC) microcrystalline wax which comprises. a), dissolving distillates of Assam mix crude vacuum residue with toluene at about 80 ° C by varying distillate/toluene ratio 1:1, 1:4, 1:5, 1:10, 1:12 and 1:15 b) cooling to room temperature followed by precipitation of waxes with either (i) acetone in toluene/acetone ratio of 1:2, 1:2.5, 1:3, 1:4, 1:5, 1:6, 1:6.5, 1:7 & 1:9 or (ii) methyl ethyl ketone (MEK) in toluene/MEK ratio of 1:3 & 1 :15 or (iii) MEK acetone mixture in the toluene / MEK/ toluene ratio of 1:5:10, 1: 5:15 and 1: 5:20 c) stirring the above mixture mechanically, d) keeping the stirred mixture undisturbed, e) separating the precipitated wax by filtration followed by washings with solvents such as toluene-acetone or toluene - MEK -acetone, in order to remove the entrapped oil. f) Recovering the solvent from dew axed oil by distillation for reuse in the process g) Further deoiling of the precipitated wax by again dissolving the latter in minimum amount of toluene followed by reprecipitation with solvents such as acetone or MEK or a mixture thereof, h)f Stirring the above mixture magnetically fro 5 to 10 minutes ifollowed by filtration to remove the precipitated wax after heaping it undisturbed for a time ranging from half hour to 2 hrs., i) Washing the precipitated wax thoroughly until it is free frormany trapped oiled and drying to get a mixture of head, high melting point and soft, flexible microcrystalline wax. j) Dissolving the separated precipitated wax in hexane (petroleum grade) along with heating, cooling to room temperature in order to precipitate the wax, separating it by filtration followed by washings with hexane to remove the trapped soft microcrystalline wax from the precipitated wax and then drying the wax at 60 to 70 degree C to get hard, high melting microcrystalline wax k) Recovering the excess of solvent by distillation and the traces by evaporation or vacuum in order to separate the soluble soft flexible microcrystalline wax.

Full Text

This invention relates to the process for producing hard microcryetalline waxes melting in the range of 95 -100 C from the distillates of vacuum'residue of Assam mix crude obtained by short path distillation under different distillation conditions. The process involves precipitation of the wax from the distillate using polar organic solvents ( like toluene, acetone, ethyl methyl ketone ) and the precipitated, wax separate into two fractions based upon the solubility in a nonpolar organic solvent ie. hexane. The hexane insoluble ones give hard microcrystalline wax of high melting point and are predominantly composed of saturated alkanes of larger carbon number.The entire prooeaw io being carried oub at room temperature, thus reducing the expenditure on employing low temperature extractive crystallization. Micro-crystalline waxes are extensively used in various industrial applications such as in the manufacture of polishes, petroleum jellies, Pharmaceuticals, cosmetics, candles, cable filling, casting waxes, PVC pipes, hot melt adhesives for paper coating, textiles, tyres and other rubber goods and in miscellaneous uses such as manufacture of calibrated glass wares, batteries, printing inks etc. These waxes are generally used directly or indirectly as speciality wax blends. These blends contain microcrystalline waxes, paraffin waxes, ethylene - vinyl acetate polymers, resins, additives and other compounding agents depending upon the end uses. Such formulations are mostly of proprietory nature as they are based on development work carried out for different applications. The microczystalline wax is generally marketed in three grades:- (a) Soft flexibe grade ( melting point 60- 70°C) (b) medium melting grade (melting point 75- 80°C) (c) hard high melting grade (melting point 85 C and above) Microcryatalline waxes are usually obtained from three sources (1) tank bottoms (2) sucker rods and (3) vacuum residues. The usual process involves the precipitation of these waxe« uoiiig polar oolvontn liko methyl ethyl kotone -aromatic mix, methyl isobutyl ketone - aromatic mix. etc. at a low temperature, separation of the precipitated wax by filtration /centrifugation , recrystallization of wax cake at low temperature and solvent recovery by distillation. The wax cake is then treated with some decolouring agent such as charcoal, clay, fuller's earth etc. to get requisite specifications. [ Pol. PL 151,667 (C1.C10G73/32) 28 Sep. 1990, Pol. PL 135,300 (Cl.C10G73/38) 30 Apr.1986, Indian J. Technol. 31(9),619,1993.] . In the conventional process, the separation of wax is carried out at low temperatures (-10 to -40 c), and the obtained waxes consist of both low melting and high melting waxes, thus giving higher yield in which the former being at a greater proportion. The conventional processes use the extractive crystallization of the wax and de-oiling of the wax by solvent recrystallization at low temperatures, by which the investment as well as operating costs are very high .[ Ger. (EAST) DD 234,437(Cl. C10G73/32) 02 Apr.1986, Can. CA 1,262,881 (Cl.10G73/04) 14Nov.l989] The recent patent literature indicates that all the processes of dewaxing are on the dewaxing of wax from mineral oils especially lubricating oils, slack wax from deasphalted o.ils and froom middle distillates. So far no process has been patented for the dewaxing of distillates obtained above 530+ C. C Ger.(East) DD 300,445 (Cl.C10G73/08) 11 June 1992, U.S. US 5,190,673 (Cl.210-772; C10G73/06) 02 Mar.1993.] Keeping in mind the above disadvantages of the conventional processes for the separation of inicrocryatalline wax, a new process has been developed by the applicants for the separation of hard, high melting microcrystalline wax, at a reasonable yield without low temperature facility from the distillates (530 - 700 ° C) of vacuum residue of Assam mix crude . In this invention , the raw material from which hard microcrystalline wax separated, are two types of distillates of Assam mix crude, obtained by short path distillation of its vacuum residue under different distillation conditions. The main objective of the present invention is to develop a process for isolation of hard, high melting microcrystalline wax melting in the range of 95 -100 from vacuum distillates of Assam mix crude at room temperatures. Other objectives of this invention are :- (1) to develop a process for the separation of hard, high melting microcrystalline waxes as well as soft flexible waxes using cheaper solvents. (2) to carry out subsequent washings and de-oiling of the precipitated wax at room temperature, thus eliminating refrigeration equipments leading to high installation cost. (3) to separate precipitated wax (M.pt.84°-96°C) and dewaxed oil - solvent mixture by filtration aid at room temperature. (4) to separate hard, high melting and soft flexible microcrystalline wax from the precipitated wax by using nonpolar organic solvent i.e. hexane (petroleum grade) at or above room temperature. The hexane - insoluble ones give hard high melting microcrystalline wax and hexane - soluble ones give soft flexile microcrystalline wax of melting point 65° - 70°C. (5) to recover solvent by distillation for reuse in this process. (6) to obtain hard, high melting microcrystalline wax meltihg in the range of 95°-100°C/ which is a very valuable product in the world market as its prices are directly related to the melting points and is being produced by few countries only. In India, at present microcrystalline waxes are being produced from crude tank bottoms of O.N.G.C.L. at Ankleshwar and the remaining requirements are being met! through imports. Accordingly , the present invention provides a process for the separation of hard, high melting microcrystalline wax and soft flexible microcrystjalline wax from the vacuum distillates of Assam mix crude vacuum at room temperature . A large number of experiments are carried out at room temperature by varying feedstock to solvent ratio, stirring time and contact time in order to achieve a process which provides greater yield of microcrystalline wax by utilizing minimum amount of solvent and minimum man hours. Accordingly, the present invention provides a process for the preparation of high melting point (95-100° C) microcrystalline wax which comprises. a) dissolving distillates of Assam mix crude vacuum residue with toluene at about 80 ° C by varying distillate/toluene ratio 1:1, 1:4, 1:5, 1:10,1:12 and 1:15 b) cooling to room temperature followed by precipitation of waxes with either (i) acetone in toluene/acetone ratio of 1:2, 1:2.5, 1:3, 1:4, 1:5, 1:6, 1:6.5, 1:7 & 1:9 or (ii) methyl ethyl ketone (MEK) in toluene/MEK ratio of 1:3 & 1 :15 or (iii) MEK acetone mixture in the toluene / MEK/ toluene ratio of 1:5:10, 1: 5:15 and 1: 5:20 c) stirring the above mixture mechanically, d) keeping the stirred mixture undisturbed, e) separating the precipitated wax by filtration followed by washings with solvents such as toluene-acetone or toluene - MEK -acetone, in order to remove the entrapped oil. f) Recovering the solvent from dew axed oil by distillation for reuse in the process g) Further deoiling of the precipitated wax by again dissolving the latter in minimum amount of toluene followed by reprecipitation with solvents such as acetone or MEK or a mixture thereof, h) Stirring the above mixture magnetically fro 5 to 10 minutes followed by filtration to remove the precipitated wax after heaping it undisturbed for a time ranging from half hour to 2 hrs., i) Washing the precipitated wax thoroughly until it isi free from any trapped oiled and drying to get a mixture of head, high melting point and soft, flexible microcrystalline wax. j) Dissolving the separated precipitated wax in hexane (petroleum grade) along with heating, cooling to room temperature in order to precipitate the wax, separating it by filtration followed by washings with hexane to remove the trapped soft microcrystalline wax from the precipitated wax and then drying the wax at 60 to 70 degree C to get hard, high melting rpnicrocrystalline wax k) Recovering the excess of solvent by distillation andithe traces by evaporation or vacuum in order to separate the soluble soft flexible!microcrystalline wax. The percentages of precipitated wax separated from the vacuum distillates (type 1 and type 2) of Assam mix crude by this new process at room temperature along with varying conditions i.e. feedstock / solvent ratio, stirring time, contact time etc. employed in various experiments, are given in Table 1. (Table Removed) The results of this Table indicate that in type 1 distillate, the total yield of precipitated wax is 18 - 20 % and 14 - 18 % , when acetone and a mixture of MEK - acetone is used as a precipitating agent respectively. In type - 2 distillate , the total yield of precipitated wax is 12 -13 %, IS - 21 % and 16 - 17 % when MEK alone , acetone alone and a mixture of MEK -acetone is used as a precipitating agent respectively. These results of present invention reveal that acetone is a better precipitating agent compared to either MEK or a mixture of MEK -acetone for the precipitation of microcrystalline wax at room temperature , from the vacuum distillate of Assam mix crude , obtained by short path distillation of its vacuum residue. These waxes are then dissolved in hexans , cooled and filtered to separate hard, high melting microcrystalline wax melting in the ranso of 95 -100 C and soft flexible microcrystalline wax of melting point 65° - 70°C. The yield of hard , high melting microcryetalline wax is 25 % on the basis of total separated wax from the distillate. From the experience and results of all the above experiments carried out by this new invention, using different conditions for the separation of hard high melting wax at room temperature from the vacuum distllates of Assam mix crude , efforts have been made to standardise the conditions for efficient precipitation and separation of microcrystalline wax at room temperature. Accordingly, this process involves dissolution of distillate in toluene at about 70 - 80°C in the feedstock / .solvent ratio of 1:5. After cooling to room temperature, acetone is added as a precipitating agent in the toluene / acetone ratio of 1:6 to 1:7. Stir it magnetically for 1 hr. and after keeping it undisturbed for 3 hr., filter it to separate the precipitated wax followed by thorough washings with a mixture of toluene -acetone in the ratio of 1:2 to 1:4. Excess of solvent is recovered from the dewaxed oil by distillation for reusing in this process. Reprecipitate the precipitated wax by dissolving the latter in minimum amount of toluene by slight heating followed by precipitation with acetone in the toluene /acetone ratio of 1 : 6 to 1:7. Stir it for 5-10 minutes and filter it after keeping undisturbed for 1 hr. to separate the reprecipibated wax, followed by washings with toluene -acetone mixture and final washings with acetone to remove the trapped oil. Dissolve the precipitated wax in hexane (petroleum grade) by slight heating , cool to room temperature for the precipitation of hard high melting microcrystalline wax. Filter, wash and dry the hard high melting microcrystalline wax. Excess of hexane is recovered from the filtrate and last traces by vacuum to recover the soft flexible microcrystalline wax malting in the range of 65° - 70°C. The melting point of separated hard high melting microcrystalline wax is about 95°-100°C and is a very valuable product in the world market. We Claim: 1. A process for the preparation of high melting point (95-100° C) microcrystalline wax which comprises. a) dissolving distillates of Assam mix crude vacuum residue with toluene at about 80 ° C by varying distillate/toluene ratio 1:1, 1:4, 1:5, 1:10, 1:12 and 1:15 b) cooling to room temperature followed by precipitation of waxes with either (i) acetone in toluene/acetone ratio of 1:2, 1:2.5, 1:3, 1:4, 1:5, 1:6, 1:6.5, 1:7 & 1:9 or (ii) methyl ethyl ketone (MEK) in toluene/MEK ratio of 1:3 & 1 :15 or (iii) MEK acetone mixture in the toluene / MEK/ toluene ratio of 1:5:10, 1: 5:15 and 1: 5:20 c) stirring the above mixture mechanically, d) keeping the stirred mixture undisturbed, e) separating the precipitated wax by filtration followed by washings with solvents such as toluene-acetone or toluene - MEK -acetone, in order to remove the entrapped oil. f) Recovering the solvent from dew axed oil by distillation for reuse in the process g) Further deoiling of the precipitated wax by again dissolving the latter in minimum amount of toluene followed by reprecipitation with solvents such as acetone or MEK or a mixture thereof, h) Stirring the above mixture magnetically fro 5 to 10 ij minutes followed by filtration to remove the precipitated wax after heaping it undisturbed for a time ranging from half hour to 2 hrs., i) Washing the precipitated wax thoroughly until it is free from any trapped oiled and drying to get a mixture of head, high melting point and soft, flexible microcrystalline wax. j) Dissolving the separated precipitated wax in hexane (petroleum grade) along with heating, cooling to room temperature in order to precipitate the wax, separating it by filtration followed by washings iwith hexane to remove the trapped soft microcrystalline wax from the precipitated wax and then drying the wax at 60 to 70 degree C to get hard, high melting microcrystalline wax k) Recovering the excess of solvent by distillation and the traces by evaporation or vacuum in order to separate the soluble soft flexible microcrystalline wax. 2, A process for the preparation of high melting point microcrystalline wax substantially as herein described with reference to the Table given in the specification.

Documents:

669-del-1996-abstract.pdf

669-del-1996-claims.pdf

669-del-1996-complete specification (granted).pdf

669-del-1996-correspondence-others.pdf

669-del-1996-correspondence-po.pdf

669-del-1996-description (complete).pdf

669-del-1996-form-1.pdf

669-del-1996-form-2.pdf

669-del-1996-form-3.pdf

669-del-1996-form-4.pdf