NITROGEN-BASED COPOLYMERS AS WAX DISPERSANTS FOR PARAFFINIC GAS OILS

n-Alkyl acrylates and n-alkyl methacrylates were prepared by esterific ation of acrylic and methacrylic acids with two linear long chain alco hol blends NAFOL 1822 and NAFOL 1822C. The four synthesized monomers w ere characterized and copolymerized with maleic anhydride in 1:1 molar ratio individually. The prepared copolymers were subjected to partial amidation with n-hexadecylamine. The amidated copolymers were purifie d, characterized, and then evaluated as wax dispersant flow improvers (WDFIs) for improving the cold flow properties of a highly paraffinic gas oil G1 through cloud point (CP), cold filter plugging point (CFPP) and pour point (PP) tests. NAFOL 1822C methacrylate-n-hexadecylamine maleamic acid copolymer has achieved the highest CFPP and PP depressio n. Consequently, NAFOL 1822C methacrylate monomer was selected for fur ther copolymerization with maleic anhydride in a molar ratio 1.4, resp ectively. The prepared copolymers were then submitted to partial and c omplete amidation with n-hexadecylamine, ditallowamine (ARMEEN 2HT), t etraethylenepentamine (TEPA) and morpholine successively. In addition, combined esterification and amidation of the copolymer with NAFOL 182 2C and morpholine, respectively, was carried out. Evaluation of the sy nthesized products as WDFIs in a less paraffinic gas oil G2 revealed t hat nitrogen and/or oxygen based functional groups of the copolymers a re controlling parameters judging their dispersing effect and that NAF OL 1822C methacrylate-n-morpholine amide of NAFOL 1822C maleate copoly mer has attained the optimum performance. Results also showed that no correlation is found between gas oil flowability improvements (Delta P P) and filterability amelioration (Delta CFPP). Stability of performan ce of the prepared additives as wax dispersants lasted for four weeks while for two weeks only as flow improvers. (C) 1998 Elsevier Science Ltd. All rights reserved.