| 摘要 |
Olefins are obtained from more saturated hydrocarbons by reacting with bromine to form a bromine derivative, dehydrobrominating in contact with an oxide of calcium, magnesium or zinc and recovering the olefin and reactivating the oxide and recovering bromine by treatment with oxygen. The starting hydrocarbon may be a cyclic or acylic paraffin or mono-olefin, the product being the corresponding mono- or di-olefin. Reaction with bromine is effected at a hydrocarbon to bromine mol ratio up to 20:1, with recycle of monobromides if dibromides are required, using a packed or unpacked reactor at 0-400 DEG C. with a space velocity of 500-2500 volumes of reactant mixture per volume of reaction space per hour preferably at autogenous pressure. Liquid or gaseous phase may be used and a catalyst such as copper oxide or platinum on alumina or light activation may be used and a catalyst such as copper oxide or plainum on alumina or light activation may be used. Hydrogen bromide is separated, unreacted hydrocarbons recovered and recycled and bromine compounds passed to dehydrobromination. This is effected over a solid sorbent comprising an oxide of calcium, magnesium or zinc and preferably 0.1-15% of copper, cerium, iron, nickel or cobalt. Reaction is effected at 50-550 DEG C. Preferably two reactors are used which are alternatively on reaction or regeneration. Regeneration is effected, e.g. with air, at 50-50 DEG C. The regeneration gases containing bromine are combined with products of a bromine recovery plant in which hydrogen bromide from the bromination is oxidized to bromine and water and bromine recovered and recycled. In examples (a) cyclohexane is converted to cycloehexane, (b) n-butane via dibromobutanes to butadiene, (c) isopentene to isoprene, (d) isobutane to isobutene, (e) methylcyclohexane to methylcyclohexene.
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