| 摘要 |
A process step in the preparation of butyl rubber, using a Friedel-Crafts catalyst in solution at a low temperature, comprises introducing into a flashing zone the slurry of polymer in cold reaction liquid, including volatile unreacted reactants and volatile catalyst solvent, to flash off the volatile materials, passing the flashed volatile materials through a compressing and drying zone to a condensing zone to obtain a mixture of vapour and liquid, transporting the resulting mixture to a separating zone to separate vapour from liquid, passing the separated vapour into a diluent recovery and fractionation system, passing part of the separated liquid to the diluent recovery and fractionation system, and maintaining the remaining part of the liquid as a reservoir in the separating zone, and periodically passing a portion of the reservoir liquid as a flushing medium to the reaction zone. As an additional step, a portion of the reservoir liquid may be used as a feed charge for the reaction zone. The butyl rubber is made by the copolymerization of an iso-olefin, e.g. isobutylene or 2-methyl butene-1, with up to 30% by weight of a diolefin such as isoprene, butadiene, dimethyl butadiene, cyclopentadiene or piperylene. The preferred diluent is methyl chloride and the preferred catalyst is an aluminium halide.
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