Patent GB-379335-A (GB)
Title: Improvements in carrying out catalytic reactions
IPC: B01J37/20
Filed: 1931-05-26
Abstract: Catalysts suitable for use in reactions involving carbonaceous materials, especially destructive hydrogenation, comprise metal sulphides other than iron sulphide which are prepared from metals or their compounds, especially from groups 5 and 6 of the periodic system, under vigorously sulphidizing conditions, i.e. by treatment with liquid or vaporous sulphur or volatile compounds containing divalent sulphur under conditions allowing an intensive reaction or by the thermal decomposition of thio salts, and preferably with the exclusion of substances having an oxidizing effect during and after the preparation.  The treatment with sulphur or its compounds is carried out at temperatures between 150-700 DEG  C. and in the absence of oxygen.  Small amounts of hydrogen, e.g. up to 10 per cent, may be added to the sulphidizing substances.  Examples of suitable sulphidizing agents include hydrogen sulphide, mercaptan, thiophenol, carbon disulphide and thioacetic acid.  When sulphides, e.g. commercial sulphides such as those of zinc, cadmium magnesium, titanium, chromium, molybdenum, tungsten, uranium, vanadium, manganese, cobalt, nickel or aluminium, if desired admixed with boron sulphide, are treated by this process, the reaction may be carried out under ordinary or increased pressure.  Metals and compounds other than sulphides, e.g. oxides, hydroxides, carbonates, nitrates, chlorides, nitrides or phosphides, are treated at elevated temperature preferably above 300 DEG  C. and at least for some time under elevated pressure, e.g. from 3 to 15 atmospheres. The heavy metals of the 4th to the 7th groups, e.g. titanium, zirconium, vanadium, chromium, molybdenum, tungsten, manganese or rhenium, and also zinc, cadmium, cobalt and nickel or their compounds, e.g. vanadium nitride, are particularly suitable for the preparation of these catalysts.  Those of the above elements, the oxides or hydroxides of which are capable of forming salts with ammonia or other basic substances may be employed in the form of such salts, e.g. ammonium vanadate.  The catalysts mentioned may be used alone or admixed with each other or with other additions such as copper, silver, aluminium, titanium and tin. Gas mixtures which yield sulphur or divalent sulphur compounds under the conditions of operation may be employed as sulphidizing agents, e.g. a mixture of sulphur dioxide and hydrogen.  If sulphur is used as the reagent, a succeeding treatment with volatile divalent sulphur compounds, especially hydrogen sulphide, may be used.  The material treated may be finely ground, or in the form of plates, sticks, nets, cubes, rings, or star-shaped bodies or in the form of frothy structures obtained by adding substances which evolve gases, such as ammonium carbonate or nitrite, during the preparation of the catalyst.  During the treatment the temperature and/or pressure is preferably varied, for example the material may be treated at rising temperatures at ordinary pressure and then further treated under increased or increasing pressure.  In general, treatment under increased pressure results in catalysts of greater activity.  Pressures up to 1000 atmospheres may be used.  The metals or their compounds may be pretreated with hydrogen at 250-400 DEG  C. under atmospheric pressure or pressures up to 200 atmospheres.  The catalysts thus obtained may be mixed with other substances which act as catalysts or carriers or both, and which do not split off oxygen under working conditions, particularly sulphides obtained in a manner different from that described above.  Other substances may be added before the sulphidizing treatment, e.g. difficulty reducible metallic oxides, such as zinc oxide, titanium oxide, silicic acid, kaolin, alumina, chromium oxide or magnesia; magnesite, active carbon, active silica, bentonite, Florida earth, and pumice.  The catalysts may also be mixed with metals, preferably finely divided, such as aluminium, magnesium, silicon, tungsten or molybdenum, e.g. a suitable catalyst consists of 80 parts of tungsten sulphide and 20 parts of aluminium powder.  The catalysts may also be prepared by the thermal decomposition of thio salts with the exclusion of oxidizing agents. Metals of the 5th and 6th groups of the periodic system, such as tungsten, molybdenum, chromium or vanadium or other metals such as copper or rhenium, are suitable for this method of preparation.  The thio salts are obtained by passing hydrogen sulphide through or adding soluble sulphides especially ammonium sulphide to aqueous salt solutions, e.g. ammonium tungstate and they are then converted into sulphides by heating at temperatures between 200 and 500 DEG  C. in a current of hydrogen, nitrogen, ammonia or carbon dioxide.  If oxy salts are formed during the preparation of the thio salts, oxy sulphides are formed on decomposition and these are converted into sulphides by treatment with sulphur or volatile sulphur compounds as previously described.  The formation of the oxy sulphides may be avoided by adding sulphur or volatile sulphur compounds to the above gases before the decomposition of the thio salts, or the production of the thio salts is carried out under conditions in which hydrolysis is suppressed, e.g. by employing a high concentration of ammonium sulphide or hydrogen sulphide and working under increased pressure, e.g. 3 atmospheres.  The temperature should also be kept low.  For example, ammonium thiotungstate free from oxy salts may be obtained by spraying a solution of ammonium tungstate into a container filled with hydrogen sulphide, under pressure if desired.  The exhausted gas is replenished and the salt allowed to crystallize in an atmosphere of hydrogen sulphide.  Alternatively ammonium tungstate may be treated with hydrogen sulphide in countercurrent. The catalysts prepared in this manner may be mixed with other catalysts and carriers as described above.  When working with materials containing oxygen, such as phenols, it is preferable to add sulphur or divalent sulphur compounds to the hydrogenation gas or to mix sulphur with the initial materials.  Reactions in which the above catalysts may be used include the destructive hydrogenation of coals, tars, mineral oils, &c., the cracking of liquid carbonaceous materials, the purification of gases by treatment with hydrogen, the preparation of methanol or hydrocarbons from carbon monoxide and hydrogen, the purification, especially desulphurization, of carbonaceous materials with hydrogen, the preparation of hydrogen sulphide from its elements, the hydrogenation and dehydrogenation of hydrocarbons and the preparation of hydrogen or polymerization products from the waste gases from destructive hydrogenation or cracking processes. Specifications 348,690, 354,181, and 365,276 are referred to.ALSO:Catalysts suitable for use in reactions involving carbonaceous materials, e.g. the production of methanol and hydrocarbons from carbon monoxide and hydrogen, the desulphurization of carbonaceous materials with hydrogen, and the preparation of polymerization products from the waste gases from destructive hydrogenation and cracking processes comprise metal sulphides other than iron sulphide which are prepared from metals or their compounds, especially from groups 5 and 6 of the periodic system, under vigorously sulphidizing conditions, i.e. by treatment with liquid or vaporous sulphur or volatile compounds containing divalent sulphur under conditions allowing an intensive reaction or by the thermal decomposition of thio salts, and preferably with the exclusion of substances having an oxidizing effect during and after the preparation.  The treatment with sulphur or its compounds is carried out at temperatures between 150 DEG  and 700 DEG  C. and in the absence of oxygen.  Small amounts of hydrogen, e.g. up to 10 per cent, may be added to the sulphidizing substances. Examples of suitable sulphidizing agents include hydrogen sulphide, mercaptan, thiophenol, carbon disulphide and thioacetic acid.  When sulphides, e.g. commercial sulphides such as those of zinc, cadmium, magnesium, titanium, chromium, molybdenum, tungsten, uranium, vanadium, manganese, cobalt, nickel or aluminium, if desired admixed with boron sulphide, are treated by this process, the reaction may be carried out under ordinary or increased pressure.  Metals and compounds other than sulphides, e.g. oxides, hydroxides, carbonates, nitrates, chlorides, nitrides, or phosphides, are treated at elevated temperature preferably above 300 DEG  C. and at least for some time under elevated pressure, e.g. from 3 to 15 atmospheres.  The heavy metals of the 4th to the 7th groups, e.g. titanium, zirconium, vanadium, chromium, molybdenum, tungsten, manganese or rhenium and also zinc, cadmium, cobalt, and nickel or their compounds, e.g. vanadium nitride, are particularly suitable for the preparation of these catalysts.  Those of the above elements, the oxides or hydroxides of which are capable of forming salts with ammonia or other basic substances may be employed in the form of such salts, e.g. ammonium vanadate.  The catalysts mentioned may be used alone or admixed with each other or with other additions such as copper, silver, aluminium, titanium, and tin.  Gas mixtures which yield sulphur or divalent sulphur compounds under the conditions of operation may be employed as sulphidizing agents, e.g. a mixture of sulphur dioxide and hydrogen.  If sulphur is used as the reagent, a succeeding treatment with volatile divalent sulphur compounds, especially hydrogen sulphide, may be used.  The material treated may be finely ground, or in the form of plates, sticks, nets, cubes, rings, or star-shaped bodies or in the form of frothy structures obtained by adding substances which evolve gases, such as ammonium carbonate or nitrate, during the preparation of the catalyst.  During the treatment the temperature and/or pressure is p