Cleavage of methylene and ether linkages between aromatic nuclei in coal-related structures catalyzed by zinc halides

It is well known that zinc halides are effective catalysts for the liquefaction of coal and it has been suggested that this may be due, in part, to their ability to promote the cleavage of ether and aliphatic linkages between aromatic centers. The purpose of the present study was to investigate the effects of catalyst composition and the structure of the aromatic groups attached to the linkages on the kinetics of linkage cleavage. Model compounds, containing structural elements similar to those present in coal, were used to facilitate identification of reaction pathways. A list of the model compounds used is given.