The destructive hydrogenation of carbonaceous materials such as coals and other solid carbonaceous materials, oils, tars &c. and also similar reactions in which carbonaceous materials or organic compounds are treated with hydrogenating gases under pressure and at temperatures of 250--700 DEG C., are carried out in the presence of an active carbon from which ash constituents have been wholly or in part removed. The active carbon may act as the catalyst or as the carrier for the catalyst, or as an agent to assist in the dispersion of the reacting materials. The ash constituents comprise mineral matter contained in the carbonaceous material from which the active carbon has been made and also such inorganic substances as may be introduced during the process of activation; and their removal is effected by lixiviation with water, acids or alkalies. When treating solid carbonaceous materials, the active carbon is simply mixed with them; in the case of liquid phase reactions, it may be suspended in the liquid preferably in the form of an easily filterable powder, or it may be used as a packing or other rigid form; for gas phase reactions, the active carbon may be in the form of grains, balls, cubes or rings. Other catalytic materials especially such as are immune from sulphur-poisoning may be employed in conjunction with the active carbon, particularly when the latter serves as the catalyst carrier. In the latter case, the catalytic metal or metal compound is brought while in the colloidal state of dispersion on to the active carbon. Suitable catalysts are the heavy metals of the sixth periodic group especially molybdenum and tungsten, and also chromium, uranium, tin, rhenium, manganese, zinc, cadmium, aluminium and cobalt, and their compounds such as oxides, hydroxides and sulphides. The hydrogenating gases may be hydrogen alone or mixed with nitrogen, carbon monoxide, carbon dioxide, sulphuretted hydrogen, water vapour, or methane or other hydrocarbons; and the hydrogen may be generated in the reaction chamber by interaction of water and coal, carbon monoxide or hydrocarbons. Carbonaceous material may be supplied continuously to the reaction vessel, and the reaction products removed continuously therefrom, and a number of reaction vessels in which different pressures and temperatures are maintained and in which different catalysts are employed, may be arranged in series. When it is desired to obtain low boiling products, the process may be so arranged that cracking also occurs. In an example, active carbon is boiled in dilute hydrochloric acid, and then washed by boiling with ammoniacal water and rinsing with water; the de-ashed carbon is then added to ammonium molybdate solution, and sulphuretted hydrogen passed through the solution which is at the same time evaporated to dryness; sulphuretted hydrogen is then passed over the dried material first at normal temperature and then at 100 DEG C., and the catalyst is finally reduced in hydrogen; with the resulting catalyst, naphthalene is reduced to give a mixture of tetra- and deca-hydronaphthalene by hydrogen under 100 atmospheres pressure and at 430 DEG C. The method is also applicable to the removal of oxygen- and sulphur-containing impurities and nitrogen compounds from crude benzol, motor and lubricating oils, etc.; the conversion of oxygen- and sulphur-containing organic compounds to hydrocarbons, for example, phenols and cresols to cyclic hydrocarbons; and also the hydrogenation of unsaturated compounds to saturated compounds and of aromatic compounds to hydro-aromatic compounds.ALSO:Reactions in which organic compounds are treated with hydrogenating gases under pressure and at temperatures of 250--700 DEG C., are carried out in the presence of an active carbon from which ash constituents have been wholly or in part removed. The active carbon may act as the catalyst or as the carrier for the catalyst, or as an agent to assist in the dispersion of the reacting materials. The ash constituents comprise mineral matter contained in the carbonaceous material from which the active carbon has been made and also such inorganic substances as may be introduced during the process of activation; their removal is effected by lixiviation with water, acids or alkalies. In liquid phase reactions, the carbon may be suspended in the liquid, preferably in the form of an easily filterable powder, or it may be used as a packing or other rigid form; in gas phase reactions, the carbon may be in the form of grains, balls, cubes or rings. Other catalytic materials especially such as are immune from sulphur-poisoning may be employed in conjunction with the carbon, particularly when the latter serves as the catalyst carrier. In the latter case, the catalytic metal or metal compound is brought while in colloidal dispersion on to the carbon. Suitable catalysts are the heavy metals of the sixth periodic group especially molybdenum and tungsten, and also chromium, uranium, tin, rhenium, manganese, zinc, cadmium, aluminium and cobalt, and their compounds such as oxides, hydroxides and sulphides. The hydrogenating gases may be hydrogen alone or mixed with nitrogen, carbon monoxide, carbon dioxide, sulphuretted hydrogen, water vapour, or methane or other hydrocarbons; the hydrogen may be generated in the reaction chamber by interaction of water and coal, carbon monoxide or hydrocarbons. The compound to be treated may be supplied continuously to the reaction vessel and the reaction products removed continuously therefrom, and a number of reaction vessels in which different pressures and temperatures are maintained and in which different catalysts are employed, may be arranged in series. In an example, active carbon is boiled in dilute hydrochloric acid, and then washed by boiling with ammoniacal water and rinsing with water; the de-ashed carbon is then added to ammonium molybdate solution, and sulphuretted hydrogen passed through the solution which is at the same time evaporated to dryness; sulphuretted hydrogen is then passed over the dried material first at normal temperature and then at 100 DEG C., and the catalyst is finally reduced in hydrogen; the resulting catalyst is applicable in the conversion of oxygen- and sulphur-containing organic compounds to hydrocarbons, for example, phenols and cresols to cyclic hydrocarbons.