| 摘要 |
<p>548,901. Isoparaffin hydrocarbons. ANGLOIRANIAN OIL CO., Ltd., HOWES, D. A., and FAWCETT, E. W. M. April 2, 1940, No. 5943. [Class 2 (iii)] Normal paraffin hydrocarbons having at least four carbon atoms in the molecule are isomerized by contacting with a catalyst comprising an oxide or sulphide of a metal of the sixth group of the periodic system, with or without the addition of an oxide or sulphide of a metal of the eighth group. The process is preferably effected at a temperature of 200- 600‹C. and under a pressure of 1-300 atmospheres. An inert gas, such as methane, nitrogen or carbon dioxide, may be present, but hydrogen should be absent. Catalysts mentioned are tungsten disulphide, a mixture of nickel and tungsten sulphides, a mixture of molybdenum disulphide and tungsten trioxide, a tungsten sulphide on silica gel, molybdenum sulphide on kieselguhr, tungsten trioxide on kieselguhr, and molybdenum trioxide mounted on alumina gel. The tungsten sulphide catalyst may be prepared by soaking silica gel with a dilute solution of ammonium tungstate, heating to form tungsten trioxide and treating with hydrogen sulphide ; whilst the molybdenum sulphide catalyst is produced by adding kieselguhr to a dilute ammonia solution of ammonium molybdate saturated with hydrogen sulphide, making acid with hydrochloric acid, filtering, washing and drying. When using sulphide catalysts, it is advantageous to introduce with the hydrocarbon stock a small quantity of a sulphur compound, e.g. hydrogen sulphide or methyl mercaptan, thereby prolonging the life of the catalyst. Regeneration of any of the catalysts may be effected by treatment with an oxygen-containing gas at elevated temperature, the sulphide catalysts being then reformed by passing sulphur vapour or hydrogen sulphide over. Examples describe the conversion of n-butane to isobutane by batch and continuous methods using some of the foregoing catalysts and the treatment of n-pentane is mentioned. Specification 527,767 is referred to.</p> |
