Autoxidation in Coal Chemistry and Petroleum Chemistry

Abstract

The autoxidation reaction of coal was reviewed from the petrochemical point of view. The first step in the oxidation of coal in alkaline aqueous solution is the formation of water insoluble acids by the dissolution of coal and the second step the base-catalyzed autoxidation of water insoluble acids to water soluble aromatic acids such as benzene polycarboxylic acids. At the optimum conditions the yield of water soluble aromatic acids was about 60% from a Japanese bituminous coal, when sodium carbonate was used bleeding carbon dioxide from the reactor. It was confirmed that the side chains of benzene ring, naphthalene nucleus and phenolic compounds were easily decomposed to form benzene carboxylic acids, but anthracene, anthraquinone and diphenyl compounds relatively stable against oxidative decomposition. Properties and utilization of produced aromatic acids along with the application of coal oxidation process were discussed.