Methylation of kukersite kerogen – estimation of the content of free hydroxyl groups

Derivatization of the kerogen backbone changes its chemical reactivity profile. In this study, kukersite kerogen was methylated with dimethyl carbonate. The substance was analyzed before and after processing by Fourier transform infrared spectroscopy, 13C cross-polarization/magic angle spinning nuclear magnetic resonance spectroscopy, and elemental analysis. It was observed that kukersite kerogen can be readily methylated with dimethyl carbonate. Based on mass balance and the Lille-Blokker model, an average of 19 methyl groups were added to the kerogen unit. It was concluded that about half of the hydroxyl groups in Estonian kukersite kerogen are “free” and accessible to methylation.