Enhancement of benzene-methanol extraction (low molecular weight products) of coal in depolymerization reactions

Depolymerization of coals is an important reaction for the study of coal structure. Coal is depolymerized by using p-toluenesulphonic acid in phenol. Depolymerization takes place mainly through the cleavage of C-C and C = bonds and subsequent phenolation, whereas C-O-C linkages of coal are not affected by this treatment. In the present work, reactions, such as, reduction of coal through Li in ethylene-diamine, alkaline-degradation and dry HCl gas, which are known to cleave C-O-C linkages in coal selectively, have been coupled (as a pre-treatment) with depolymerization reactions. This could enhance the yields of low molecular weight products from coal as revealed by the enhancement in the benzene-methanol (7/3 vol/vol) extractability of depolymerized coals. The use of Ce(IV) salt, benzoyl peroxide, lead tetra-acetate and potassium persulphate, promotes the depolymerization reaction to low molecular weight products. These studies help in understanding the mechanism of generation of asphaltenes and, thereby, might help in the studies of liquefaction of coal.