Patent GB-369613-A (GB)
Title: Improvements in the manufacture and production of condensation products from aromatic hydrocarbons
IPC: C07C2/76
Filed: 1930-12-17
Abstract: Aromatic hydrocarbons in which any aliphatic side-chain present contains only one carbon atom are condensed with themselves by passing their vapour at 500-800 DEG  C. over catalysts comprising one or more difficultly reducible but fusible metal oxides, or compounds which decompose into said oxides under the reaction conditions, mounted upon a carrier.  Catalysts mentioned are the oxides of alkali metals fixed on such carriers as pumice, silica, chamotte or pieces of electrode carbon.  Difficultly fusible metal oxides may also be present and can be regarded as carriers; cobalt oxide, which is easily reducible, may be added in small quantities as an activator. The catalysts may be subjected to a pretreatment with aliphatic or other easily decomposed hydrocarbons, at temperatures of about 700 DEG  C. in order to form a coating thereon of lustrous or crystalline carbon.  It is advantageous to employ a velocity of flow of the hydrocarbon vapours such that only 10-15 per cent is condensed; the remaining vapours serve as a diluent, but other diluents such as nitrogen, methane, water vapour or carbon dioxide may be present. The product is condensed and the unconverted hydrocarbon preferably recirculated.  According to the examples, (1) diphenyl together with some diphenylbenzene is obtained by passing benzene vapour over a catalyst consisting of a mixture of potash, thoria and cobalt oxide deposited on pumice; (2) carbon dioxide saturated with benzene vapour is circulated over a mixture of magnesium and lithium carbonate which has been pressed into granules; diphenyl and diphenylbenzene separate out on cooling the reaction product; (3) carbon dioxide saturated with toluene vapour is conducted over a catalyst prepared by soaking pumice with an aqueous solution of potash, thorium nitrate, and cobalt nitrate in equimolecular proportions and heating; a hydrocarbon mixture is obtained which contains small quantities of diphenylmethane and anthracene; (4) vapours of xylene are passed over pumice impregnated with potassium hydroxide, yielding a mixture of solid and liquid hydrocarbons.ALSO:Aromatic hydrocarbons in which any aliphatic side-chain present contains only one carbon atom are condensed with themselves by passing their vapour at 500-800 DEG  C. over catalysts comprising one or more difficulty reducible but fusible metal oxides, or compounds which decompose into said oxides under the reaction conditions, mounted upon a carrier.  Catalysts mentioned are the oxides of alkali metals fixed on such carriers as pumice, silica, chamotte, or pieces of electrode carbon.  Difficultly fusible metal oxides may also be present and can be regarded as carriers; cobalt oxide, which is easily reducible, may be added in small quantities as an activator.  The catalysts may be subjected to a pretreatment with aliphatic or other easily decomposed hydrocarbons, such as ethylene or benzine hydrocarbons, at temperatures of about 700 DEG  C. in order to form a coating thereon of lustrous or crystalline carbon.  It is advantageous to employ a velocity of flow of the hydrocarbon vapours such that only 10-15 per cent is condensed; the remaining vapours serve as a diluent, but other diluents such as nitrogen, methane, water vapour, or carbon dioxide may be employed.  The product is condensed and the unconverted hydrocarbon preferably recirculated.  According to p  the examples, (1) diphenyl together with some diphenylbenzene is obtained by passing benzene vapour over a catalyst consisting of a mixture of potash, thoria, and cobalt oxide deposited on pumice; (2) carbon dioxide saturated with benzene vapour is circulated over a mixture of magnesium and lithium carbonates which has been pressed into granules; diphenyl and diphenylbenzene separate out on cooling the reaction product; (3) carbon dioxide saturated with toluene vapour is conducted over a catalyst prepared by soaking pumice with an aqueous solution of potash, thorium nitrate, and cobalt nitrate in equimolecular proportions and heating; a hydrocarbon mixture is obtained which contains small quantities of diphenylmethane and anthracene; (4) vapours of xylene are passed over pumice impregnated with potassium hydroxide, yielding a mixture of solid and liquid hydrocarbons.