5-Methyl-3-vinyl-2-oxazolidinone-Investigations of a New Monomer for Kinetic Hydrate Inhibitor Polymers

Kinetic hydrate inhibitors (KHIs) are polymers used in a chemical method to prevent gas hydrate plugging of oil and gas production flow lines. The main ingredient in a KHI formulation is one or more water-soluble amphiphilic polymers. Several classes of KHI polymers contain pendant heterocyclic 5rings including poly(N-vinylpyrrolidone) (PVP) and poly(2-isopropenyl-2-oxazoline) (PiPOx). Here, we present a KHI performance study on polymers based on the 5-ring vinylic monomer 5-methyl-3-vinyl-2-oxazolidinone (VMOX), which has only recently been manufactured in large quantities. Low molecular weight PVMOX homopolymers were produced in quantitative yield using radical polymerization, with or without a chain transfer agent. For example, PVMOX-2.4k (Mn = 2400 g/mol) had a cloud point at 2500 ppm of 73 degrees C in deionized water. The polymers were screened for KHI performance using slow constant cooling tests (1.0 degrees C/h) in high-pressure rocking cells with a synthetic natural gas blend. At 2500 ppm, PVMOX-2.4k gave a better performance than PVP or PiPOx at a similar molecular weight but not as good as poly(N-vinylcaprolactam) (PVCap). Isobutyl glycol ether was shown to enhance the KHI performance of PVMOX. PVMOX gave improved performance with increasing concentration but not as steep of an improvement as some of the best amide-based KHI polymers. A 1:1 copolymer of VMOX with N-vinylcaprolactam gave improved performance compared to the PVMOX homopolymer.

Automated summary

Kinetic hydrate inhibitors (KHIs) are polymers used to prevent gas hydrate plugging of oil and gas production flow lines. In this study, the KHI performance of polymers based on the vinylic monomer VMOX was investigated. PVMOX-2.4k showed better performance than PVP or PiPOx, but not as good as PVCap. Isobutyl glycol ether enhanced the KHI performance of PVMOX, and increasing concentration improved the performance but not as much as some of the best amide-based KHI polymers. A copolymer of VMOX with N-vinylcaprolactam performed better than the PVMOX homopolymer.