PROCESS FOR PREPARING LOW SULFUR DISPERSANT POLYMERS Russian patent published in 2018 - IPC C08F265/06 C10L1/196 C10L1/236 

FIELD: biochemistry.

SUBSTANCE: invention relates to a process for the preparation of grafted polyalkyl(meth)acrylates and their use. Process for the preparation of graft copolymers of polyalkyl(meth)acrylate (A) comprises the preparation of a polymer backbone, chain contains monomeric units (A1)-(A4), whose structure and quantities are defined, as in the claims, the monomer (A5) is grafted onto the chain in an amount of 0.5 % to 10 % by weight, based on the total weight of the components (A1) – (A5). Monomer, that is grafted onto the polymer backbone consists of at least one N-dispersing monomer selected from the group, consisting of N-vinylimidazole, N-vinylpyrrolidone (N-VP), morpholinoethyl methacrylate, N-vinylcaprolactam, N, N-dimethylaminoethyl methacrylate (DMAEM), tert-butylaminoethyl methacrylate, N, N-dimethylaminopropyl methacrylamide (DMAPMam), dimethylaminopropyl acrylamide and dimethylaminoethyl acrylamide, the process comprising the steps of: (a) charging a mineral oil having a sulfur content of less than 50 ppm to a reaction vessel; (b) obtaining a monomer mixture from the monomeric units (A1) – (A4) and the first reaction initiator; (c) adding the mixture obtained at the stage (b) to the mineral oil of the stage (a), preferably for 1 to 5 hours; (d) polymerizing the mixture obtained at the stage (c) in the absence of any degree of polymerization regulator; (e) optionally recovering the polymer obtained at the stage (d); (f) adding monomer units (A5); (g) adding a second reaction initiator; (h) polymerizing the mixture obtained at the stage (g); (i) optionally recovering the graft copolymer of the polyalkyl (meth) acrylate (A) obtained at the stage (h); and/or (j) diluting the mixture of the graft copolymer polyalkyl (meth) acrylate (A), (h) or an isolated graft copolymer of the polyalkyl (meth) acrylate (A) obtained at the stage (i), a mineral oil having a sulfur content of less than 50 ppm to achieve the desired polymer concentration in oil, wherein the graft copolymer of the polyalkyl (meth) acrylate (A) has a number of average molecular weight M_n from 3,000 to 150,000 g/mol.

EFFECT: technical result is the provision of a method for obtaining a substantially sulfur-free stabilizer for fuels and oils.

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