Vinylacetylene

Vinylacetylene or butenyne is the organic compound with the formula C₄H₄. This easily condensed, colorless gas (b.p. 5.5 °C) was discovered by workers at duPont. Its synthesis entails dehydrohalogenation of 1,3-dichloro-2-butene. The original industrial synthesis of chloroprene (2-chloro-1,3-butadiene) entailed the production of vinyl acetylene. In this process, acetylene is dimerized to give vinyl acetylene, which is then combine with hydrogen chloride to afford in succession vinyl acetylene, 3-chloro-1,2-butadiene, which, finally in the presence of cuprous chloride, rearranges to the targeted 2-chloro-1,3-butadiene.

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