A vitrinite concentrate prepared from the Liddell Seam (high volatile bituminous coal, NSW, Australia) has been hydrogenated in an unstirred 50 cm 3, batch autoclave at reaction temperatures between 200 and 480°C in the presence of metal halides (SnCl 1 or ZnCl 1) and/or alumina (α-Al 1O 3). A vehicle was not used. The influence of reaction temperature, metal halide and alumina on the composition of the products was studied by gas chromatography (GC), gel permeation chromatography (gpc), 1H solution and 13C solid-state cross polarization (CP) nuclear magnetic resonance (nmr) spectroscopy and optical microscopy. The metal halides lower the temperature at which softening and agglomeration of vitrinite takes place. The resultant plastic isotropic material forms mesophase at temperatures above 400°C unless an inert diluent, i.e. alumina, is added. The alumina inhibits reactions involved in the formation of mesophase which would otherwise compete with hydrogenation reactions that yield hexane soluble material (oil). Above 400°C carbon monoxide, carbon dioxide and C 1-C 5 alkanes are the principal gaseous products. At lower temperatures, in the presence of alumina, ethylene is formed in the catalysed experiments; the ethylene is converted to ethane at higher temperatures. The structure of the hexane soluble products derived from vitrinite is also temperature dependent. Above 420°C much of the aliphatic component decomposes to yield further quantities of hydrocarbon gases. Tin(II) chloride and zinc chloride produce hexane soluble products of similar molecular composition, which suggests that they operate through a similar mechanism. The addition of alumina to the reaction mixture results in a more aromatic liquid product with shorter aliphatic carbon chains. Whether or not alumina is present, the aromaticity of the solid residues increases with increase in hydrogenation temperature. Thus the increased aromaticity of the liquid products is not caused by the extraction of a greater proportion of aromatic material from the coal with increase in the hydrogenation temperature. It follows that with increase in hydrogenation temperature an increasing proportion of the aliphatic material becomes transformed into aromatic compounds and/or gas. In summary, the results show that over a wide range of temperatures (200–480°C) the structure of the hexane soluble product depends on the thermal stability of the products and the degree of competition from reactions leading to mesophase formation, and not on the nature of the halide catalyst.