Improved filtration process for dewaxing mineral oils, and compositions for facilitating such filtration

摘要

A composition suitable as a filtering aid in the dewaxing (e.g by chilling) of mineral oils (see Group III) comprises 5-95 per cent by weight of (A) a Friedel-Crafts condensation product of a halogenated aliphatic compound with an aromatic compound containing a maximum of three substituent groups and/or condensed rings, and 95-5 per cent by weight of (B) a polymeric compound of a specified type. The halogenated aliphatic compound used in preparing component A may be a chlorinated paraffin wax, an acid chloride containing at least 10 carbon atoms in the molecule, a chlorinated alcohol, a chlorinated ether or a chlorinated ester. The aromatic compound used in preparing component A may be naphthalene, phenanthrene, anthracene, a hydroxy compound (e.g. phenol, cresol or xylenol) or an amine (e.g. aniline). Component B is a polymeric compound formed by polymerizing (i) a compound of formula FORM:0758421/IV(a)/1 wherein R is hydrogen or an alkyl radicle, R1 is hydrogen or a halogen atom, R11 is hydrogen, a halogen atom or an alkyl radicle, and R111 is an alkyl, aralkyl or alicyclic radicle, or (ii) esters of a ,b -unsaturated dicarboxylic acids with either vinyl acetate or styrene, or (iii) a compound of formula FORM:0758421/IV(a)/2 wherein Y is hydrogen or methyl, m is zero or one, and R1 and R11 are alkyl groups. In the examples, compositions are described consisting of (A) the Friedel-Crafts condensation product of chlorinated paraffin wax and naphthalene, and (B) either a polymer of methyl methacrylate or a copolymer of vinyl acetate and fumarates of a mixture of hydrogenated alcohols obtained from coconut oil. Specifications 511,207 and 562,714 [both in Group IV], are referred to.ALSO:In a process for dewaxing mineral oils, which involves filtering the solid wax from the liquid mineral oil the tendency of the wax crystals to block the filters is inhibited by dissolving in the mineral oilwax mixture before filtration a composition comprising 5-95 per cent by weight of (A) a Friedel-Crafts condensation product of a halogenated aliphatic compound with an aromatic compound containing a maximum of three substituent groups and/or condensed rings, and 95-5 per cent by weight of (B) a polymeric compound of a specified type. The halogenated aliphatic compound used is preferably component A may be a chlorinated paraffin wax, an acid chloride containing at least 10 carbon atoms in the molecule, a chlorinated alcohol, or chlorinated ether or a chlorinated ester. The aromatic compound used in preparing component A may be naphthalene, phenanthene, anthracene, a hydroxy compound (e.g. phenol, cresol or xylenol) or an amine (e.g. aniline). Component B is a polymeric compound formed by polymerizing (i) a compound of formula FORM:0758421/III/1 wherein R is hydrogen or an alkyl radicle, R1 is hydrogen or a halogen atom, R11 is hydrogen, a halogen atom or an alkyl radicle, and R111 is an alkyl, aralkyl or alicyclic radicle, or (ii) esters of a , BETAunsaturated dicarboxylic acids with either vinyl acetate or styrene or (iii) a compound of formula FORM:0758421/III/2 wherein Y is hydrogen or methyl, m is zero or one, and R1 and R11 are alkyl groups. Dewaxing may be effected by chilling the mineral oil and filtering off the wax which is precipitated. Solvents, which dissolve the oil and precipitate the wax, may be added to the oil to reduce its viscosity, and facilitate the filtration. Solvents which may be used include liquid paraffins of low boiling point such as propane, butane, pentane, hexane and light petroleum oils mixtures of ketones and aromatic hydrocarbons such as mixtures of methyl ethyl ketone and benzene or toluene, and chlorinated hydrocarbons such as dichlorethane and trichlorethylene. In the examples, petroleum bright stock is dewaxed by heating it to 55 DEG C. with a paraffinic petroleum solvent boiling between 60 and 80 DEG C. and with components A and B, cooling the mixture to precipitate the wax and filtering. Component A is the Friedal-Crafts condensation product of chlorinated paraffin wax and naphthalene, while component B is either a polymer of methyl methacrylate or a copolymer of vinyl acetate and fumarates of a mixture of hydrogenated alcohols obtained from coconut oil. For comparison purposes, the effect of the omission of component A or B on the dewaxing is described. Specifications 511,207 and 562,714 are referred to.