Geochemical origin of long chain alkyl aromatics in coal: 2. Model reaction of lignin with alcohol

The reaction of lignin with n-C 14 alcohol (as a model of hydrolysate of lipid) at 120–180 °C using active clay as catalyst was studied. The n-hexane insoluble product and lignin itself were then hydrogenated under mild conditions. The benzene soluble fractions of reacted product contained n-C 14 substituted phenols and C 1 -C 3 substituted phenols. The latter have also been found in the hydrogenation product of lignin itself. Therefore alcohol could link to the benzene nuclei of lignin. As long alkyl chain substituted phenols are found abundantly in coal liquids, pyrolysates or extracts and are regarded as the main constituent of coal, it is suggested that the early diagenesis process includes the reaction between lignin and alcohol (or fatty acid) which may be the hydrolysation product of lipids widely occurring in nature.