Model Compound Studies of Coal Liquefaction with Zinc–Butyl Iodide under Mild Conditions

Abstract

Abstract A number of model compounds having representative coal structures were treated with zinc–butyl iodide under mild conditions. Gas chromatography and gas chromatography/mass spectrometry were used to identify the reaction products. Polynuclear aromatic compounds gave the butyl-substituted and butyl-addition products. In a reaction of anthracene, its aromatic backbone was cleaved. Alkoxynaphthalene and dibenzyl ether were butylated along with cleavage of ether linkage, while diphenyl ether gave only the butyl-substituted products without cleavage. Butylation and cleavage also took place in the reactions of diphenylmethane and bibenzyl. In the cases of substitution reaction, some butyl groups were rearranged to s-butyl. Because the formation of the most reaction products is interpreted by a similar mechanism to that of Friedel–Crafts alkylation and the formation of some butyl-addition products of polynuclear aromatic compounds is explained by assuming a radical reaction mechanism, it is suggested that both alkyl cation reaction and alkyl radical reaction occur competitively.