Patent GB-356189-A (GB)
Title: Improvements in the manufacture and production of condensation products from aromatic hydrocarbons
IPC: C07C2/76
Filed: 1930-05-02
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 difficulty reducible and difficulty fusible metal oxides or compounds which decompose into said oxides under the reaction conditions.  Catalysts mentioned are the oxides of alkaline-earth or earth metals such as calcium, barium, strontium, magnesium, titanium, cerium, zirconium and thorium, or of tungsten, molybdenum, manganese, chromium, uranium, aluminium, vanadium and beryllium; also vanadates, chromates, tungstates, molybdates, aluminates and zincates, e.g. calcium or aluminium borate or phosphate, calcium, barium, cerium or zinc chromate, cerium tungstate or molybdate.  Cobalt oxide which is easily reducible may be present in small quantities as an activator. The catalysts may be mounted on carriers such as pumice and are preferably 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 are condensed; the remaining vapours serve as diluent, but other diluents, such as nitrogen, methane, water vapour or carbon dioxide, may be employed.  According to the examples, (1) diphenyl together with some diphenylbenzene is obtained by passing benzene vapour over a catalyst prepared by graphiting moulded magnesium oxide with ethylene; (2) naphthalene vapour diluted with steam is passed over a catalyst prepared by graphiting a mixture of equal parts of tungstic and aluminium oxides with the aid of benzine vapour; the condensed products are distilled with superheated steam to remove naphthalene, leaving a residue from which a .a <1>- and b .b <1>- dinaphthyl can be isolated; the uncondensed vapours and unconverted naphthalene are recirculated.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 and difficultly fusible metal oxides or compounds which decompose into said oxides under the reaction conditions.  Catalysts mentioned are the oxides of alkaline earth or earth metals such as calcium, barium, strontium, magnesium, titanium, cerium, zirconium and thorium, or of tungsten, molybdenum, manganese, chromium, uranium, aluminium, vanadium, and beryllium; also vanadates, chromates, tungstates, molybdates, aluminates and zincates, e.g. calcium or aluminium borate or phosphate, calcium, barium, cerium or zinc chromate, cerium tungstate or molybdate. Cobalt oxide which is easily reducible may be present in small quantities as an activator.  The catalysts may be mounted on carriers such as pumice and are preferably 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.  According to the examples, (1) diphenyl together with some diphenylbenzene is obtained by passing benzene vapour over a catalyst prepared by graphiting moulded magnesium oxide with ethylene; (2) naphthalene vapour diluted with steam is passed over a catalyst prepared by graphiting a mixture of equal parts of tungstic and aluminium oxides with the aid of benzine vapour; the condensed products are distilled with superheated steam to remove naphthalene, leaving a residue from which a . a 1- and b . b 1-dinaphthyl can be isolated; the uncondensed vapours and unconverted naphthalene are recirculated.