Design of a rigid side chain for poly(N‐vinylamide) derivatives bearing an alkenyl group and evaluation of their ability to inhibit tetrahydrofuran hydrate crystal growth

Abstract

AbstractKinetic hydrate inhibitors (KHIs) are water‐soluble polymers that are used to prevent gas hydrate formation in flow lines during upstream oil and gas production. All commercial polymers have pendant hydrophobic moieties with saturated carbon–carbon bonds. In our previous studies, poly(N‐vinylamide) derivatives bearing alkyl groups and ethylene glycol groups were synthesized and investigated as KHIs. For comparison, we have now synthesized poly(N‐vinylamide) derivatives in which an alkenyl group has been introduced at the N‐position to improve the rigidity and steric hindrance of the side chain. The KHI performances of synthesized polymers were evaluated by the method of tetrahydrofuran (THF) hydrate crystal growth. The molecular weight of the synthesized polymers affected their ability to inhibit THF hydrate crystal growth. Higher molecular weight polymers, above 4,000 g/mol, tended to show higher inhibition efficiencies compared with lower molecular weight polymers of around 1,000 g/mol. However, the KHI performance of poly(N‐vinylamide) derivatives bearing alkenyl groups was generally lower than the polymers in the previous studies. This indicates that the side chain rigidity and/or steric hindrance do not significantly influence the KHI performance.