DOUBLE-ACTION ADDITIVE, ADDITIVE COMPOSITION, AND FUEL Russian patent published in 2000 - IPC

FIELD: petroleum processing and petrochemistry. SUBSTANCE: double-action additive, limiting and preventing precipitation of paraffins in middle distillates boiling away within 150-450 C, and also providing dispersing of paraffin crystals, consists of at least one modified copolymer with weight-average molecular weight 500 to 5000. Additive is prepared by copolymerization of first carboxylic acid with alkyl ester of second carboxylic acid, identical to the first or not, followed by amidation at 100 to 200 C of carboxylic groups in resulting copolymer with polyamide having general formula (RR′N-[-(CH₂)_n-NH-]-H_m), in which n and m are within a range between 1 and 8 and R and R' are preferably alkyl groups. EFFECT: optimized preparation procedure. 12 cl, 3 tbl