| 摘要 |
A new catalyst comprises (a) a support, (b) gallium, (c) an additional element from gps. IA or IIA. Also claimed is its prepn. and use in the dehydrogenation of a charge - mainly comprising satd. hydrocarbon contg. 3-8C atoms per mole of catalyst. The catalyst comprises alumina-Ga and Li, K or Na: the proportions are 0.01-10% of Ga and 0.01-5% of additional metal relative to support. Prepn. comprises the following steps (a) introduction of a Ga cpd. on to the support, (b) calcination in air of the prod. obtd., and (c) addn. to the prod. from (b) of the additional metal. The following parameters are used: temp. 450-650 deg.C, pressure 5x10 power4 - 2x10 power6 Pa, spatial velocity 0.1-20 litre of charge per litre catalyst per hr. Molar ratio of H2:hydrocarbon = 0.1:1 to 20:1. The hydrocarbons are propane, n-butane, isobutane, n-pentane and iso-pentane. ADVANTAGE - Use of the catalyst obviates disadvantages encountered with previous traditional catalysts based on chromium oxide-alumina, i.e. limited life (necessitating frequent re-generation) and progressive attrition of the catalyst (balls or extrudates) which involves frequent rejection of toxic dusts contg. Cr into the atmos. The gp. IA or IIA element used in addn. to Ga greatly improves selectivity and limits the quantity of aromatics formed. |
