Halogenating aliphatic hydrocarbon(s) esp. ethylene - by first stage oxyhalogenation then vapour phase halogenation

摘要

Non-selective oxyhalogenation and/or oxyhydrohalogenation is effected in a fluidised bed reactor at 340-450 degrees C and 0-14 bars press. with 1-30 secs. contact time to give an intermediate partially halogenated prod. with a halogen/carbon atomic ratio over 1:1. The operating conditions are adjusted to control the halogen/carbon ratio. The prod. is subjected to a vapour phase halogenation with a halogen gas at 400-500 degrees C in the presence of a silica-alumina catalyst to form a final prod. having a carbon/hydrogen atomic ratio of at least 2:1. The halogen/carbon atomic ratio of the intermediate prod. is adjusted to control the amt. of by-prod. hydrogen halide in the vapour phase halogenation. The process is partic. used for prepg. trichloroethylene and perchloroethylene from ethylene. The process has the advantage in flexibility of reaction according to the prod. requirements; partic. with regard to the amt. of HCl produced in the second stage.