Synthesis of copolymers based on maleic anhydride and α-olefins and modification with primary amines as pour point depressant (PPD) for waxy crude oils

Polymeric PPDs that reduce the pour point of crude oil are one of the most important chemicals utilized in the petroleum industry, especially when transporting waxy oil. The regulation of the structure of such polymers with different hydrophobic-hydrophilic balance makes it possible to select an effective PPD to improve the low-temperature properties of crude oil. On this basis, the current work presents a series of syntheses of copolymers based on α-olefins and maleic anhydride and their modification by the amidation reaction with primary amines: butylamine, hexylamine, hexadecylamine, octadecylamine, and benzylamine. The structure of the copolymers was determined through FTIR spectroscopy and 1H and 13C NMR spectroscopy. The molecular weight of the copolymers was identified by the method of light scattering. The study of the effect of modified copolymers on rheological behavior and lowering the pour point was performed for waxy crude oil from the Akshabulak field (Kazakhstan). Rheological tests have shown that the synthesized copolymers improve the fluidity of oil and reduce the values ​of the yield stress of oil. Optical micrograph showed that the modified copolymers form fine crystals of paraffins and exhibit dispersing properties.