GB1449032A - Procuction of olefinic hydrocarbons - Google Patents

Abstract

1449032 Mixtures of olefinic hydrocarbons IMPERIAL CHEMICAL INDUSTRIES Ltd 30 Jan 1974 [7 Feb 1973] 6035/73 Addition to 1297081 Heading C5E A mixture of olefinic hydrocarbons, suitable for co-polymerization with ethylene and propylene, is made by (a) distilling a pyrolyses gasoline to produce a distillate boiling in the range 10-80‹ C., (b) redistilling the distillate to produce an isoprene concentrate and a piperylene concentrate, (c) optionally adding cyclopentadiene and/or piperylene to the piperylene concentrate, and (d) heating the piperylene concentrate containing piperylene and cyclopentidiene at 250-350‹ C. to produce the mixture. In an example a debutanized gasoline, boiling in the range 0-200‹ C. and produced in the steam cracking of naphtha; is distilled to produce a 10-80‹ C. fraction which is distilled to produce an isoprene concentrate boiling in the range 20-37‹ C. as overhead and a piperylene concentrate as residue; the piperylene concentrate comprising 34 wt. per cent cyclopentadiene and dicyclopentadiene, 20 wt. per cent trans- and 13 wt. per cent cis-piperylene is heated at 260‹ C. in an autoclave to codimerize the piperylene and cyclopentadiene and the product distilled to yield a mixture comprising 90 wt. per cent 2-propen-1-yl-norbornene-5, 5 wt. per cent dicyclopentadiene and 5 wt. per cent piperylene dimers. Cyclopentadiene and dicyclopentadiene can be removed from the distillate of stage (a) or from the piperylene concentrate of stage (b) by heating at 100-120‹ C. and removing a dicyclopentadiene residue by distillation.