Amidation of Polyethylene-Acrylic Acid Copolymer as Pour Point Depressants for Waxy Crude Oils

Abstract

The present work aims to provide amine-modified polyethylene-acrylic acid (PEAA) copolymers as a pour point depressant (PPD) that will be evaluated for lower pour point of crude oil. For this, PEAA was amidated with butylamine and octadecylamine in the presence of xylene as a solvent at 150 °C for 10 hours to obtain copolymers PEAA/ODA and PEAA/BA. The copolymers were modified by amidation using the carboxyl groups of an ethylene-acrylic acid copolymer as reaction sites in reactions with RNH2. The resulting copolymers were purified and analyzed by FTIR spectroscopy. The modified PEAA copolymers were evaluated for their effectiveness as depressants for crude oils by pour point measurements at 50 ppm, 100 ppm and 200 ppm and rheological measurements at 100 ppm. The pour point measurements of the crude oil showed that octadecylamine-modified PEAA copolymer performed better than butylamine-modified and unmodified PEAA copolymer. The effectiveness of the modified copolymers compared to unmodified PEAA can be explained by the polarity of the monoalkylamide groups in the peripheral substituents along the copolymer backbone, which plays a crucial role in preventing the agglomeration of wax crystals in crude oil.