Nucleophilic addition to acetylenes in superbasic catalytic systems: X. Catalytic effect of alkali metal hydroxides in the vinylation of 1-heptanol

The catalytic activity of alkali metal hydroxides in base-catalyzed additio n of 1-heptanol to acetylene depends on the alkali metal nature and degree of hydration of its hydroxide. In a closed system, the catalytic activity o f alkali metal hydroxides decreases in the series 2KOH .H2O > RbOH .H2O > C sOH .H2O > NaOH > KOH .H2O The corresponding series for a flow system is as follows: RbOH .H2O > CsOH .H2O > 2KOH .H2O < NaON > KOH .H2O. The differen ce is explained by participation of the catalyst in side reactions with bot h 1-heptanol and acetylene. Addition of dimethyl sulfoxide to the catalytic system accelerates the vinylation process.