GB978181A - Process for the dehydrogenation of hydrocarbons - Google Patents

Abstract

<PICT:0978181/C4-C5/1> <PICT:0978181/C4-C5/2> Hydrocarbons are dehydrogenated by reaction with iodine or bromine by passing the reactants through an elongated chamber having a length to diameter ratio of at least 10 together with a solid acceptor capable of binding hydrogen halide as inorganic halide. The acceptor used is preferably one which can be regenerated after use back into acceptor and halogen by reaction with oxygen as described in Specification 895,500, and may be supported on a carrier. In one embodiment the regeneration and reaction are effected simultaneously and continuously in two elongated tubes joined end to end or one outside the other coaxially or in a single tube. Reactants and solid may flow upwards or downwards. In Fig. 1 a fluidized bed of solid 4 is entrained by an oxygen-containing gas and flows upwardly through regeneration tube 1. Hydrocarbons are introduced by line 3 and react with regenerated halogen in the outer reactor tube and products recovered by line 7. In order to avoid loss of halogen a nitrogenous base, preferably ammonia, is added to the reaction effluent and then the effluent is cooled to 85-150 DEG C. The base is preferably added as an aqueous solution together with an organic solvent to prevent formation of tar. The halogen is recovered by decomposing the product by contact with the solid acceptor in the regenerator or a separate chamber. In Fig. 2, acceptor is regenerated in the lower half of tube 1 with oxygen from inlet 2 and hydrocarbon is added at 3. Nitrogenous base is added by line 8 in separator 5 together with recovered base from chamber 17. After further cyclone separator 7 the effluent is cooled and the condensate passed from separator 12 by line 16 to contact acceptor material in chamber 17 where the halogen is bound by the acceptor.