| 摘要 |
Olefines are prepared by passing chlorinated paraffins having 4 to 20 carbon atoms in the vapour phase over a silica gel catalyst at a flow rate of 5 to 30 liquid volumes of chlorinated paraffin per volume of catalyst per hour. The process reduces skeletal isomerization of the product. The catalysts preferably have pore diameters of at least 40 </>r and the dehydrochlorination takes place at 200 DEG to 500 DEG C. The preferred starting materials are obtained by chlorinating normal paraffins with up to 40 mole per cent of chlorine. The feed gas stream may contain diluents, e.g. nitrogen and lower paraffins. In a preferred embodiment, dehydrochlorination may take place in two stages, the first stage using a silica gel pretreated with alkali (cf. Specification 970,338) and a flow rate of below 5 liquid volumes of chlorinated paraffin per volume of catalyst per hour. The olefines produced are used to prepare detergent alkylates by condensing with benzene in the presence of anhydrous HF catalyst. |
