| 摘要 |
The cracking of olefines, having a hydrocarbon group of at least two carbon atoms attached to at least one of the carbon atoms carrying the double bond, is effected in the presence of at least 0.5 mol per cent of the olefine of a mixture of (a) bromine or a source thereof and (b) at least one of the refractory olefines 2,3-dimethylbutene-2, 2-methylbutene-2, isobutylene, butene-2 and propylene, the mol ratio of (a) to (b) being 10:1 to 1:25. Suitable conditions are 300 DEG -1000 DEG C., 0.001-3 seconds and 10 mm. Hg. to 500 p.s.i.g., using 0.4-50 mol per cent of bromine and 0.1-50 mol per cent of refractory olefine and if desired 0.5-15 mols of a diluent per mol of olefine to be cracked, suitable diluents being steam, carbon dioxide, hydrogen, helium, neon, argon, methane, ethane and propane. Specified bromine precursors are hydrogen bromide, ethyl bromide, 1-bromobutane, 1-bromopropane, a -bromotoluene, bromobenzene, 1-bromochloromethane, 1,2-dibromoethane and ammonium bromide. The refractory olefine may also, if desired, be added in the form of an olefine which itself is cracked to the refractory olefine. Olefines are listed which may be used to produce; butadiene, isoprene, 2-ethylbutadiene, 2,3-dimethylbutadiene, 3-methylpentadiene-1,3, 2-methylpentadiene-1,3, 4-methylpentadiene-1,3 and piperylene.
|
