Preparation of acetylenic alcohols

摘要

Acetylenic alcohols are prepared by reacting an acetylenic hydrocarbon of formula CH­CR, in which R represents hydrogen or a hydrocarbon radical, with a catalytic quantity of an alkali metal hydroxide and an aldehyde or ketone at a temperature of at least -10 DEG C. and at superatmospheric pressure in the presence of liquid ammonia, and subsequently hydrolysing the reaction mixture. The reaction is preferably carried out at a temperature from -10 DEG C. to 60 DEG C. and a pressure of 25-800 p.s.i.g. The aldehyde or ketone preferably has the formula R1COR2 in which R1 and R2 are the same or different and each is hydrogen, an alkyl radical of 1-20 carbon atoms, a cycloalkyl radical of 3-10 carbon atoms, an aryl radical of 6-12 carbon atoms, a hydroxyalkyl radical of 1-20 carbon atoms, a hydroxycycloalkyl radical of 3-10 carbon atoms, an alkoxyalkyl radical of 2-20 carbon atoms, or an alkoxyalkyl radical of 4-20 carbon atoms, or in which R1 and R2 are joined to form together with the shared carbon atom a cycloalkyl radical of 6-12 carbon atoms. The alkali metal hydroxide used is preferably of at least 90% purity, is finely divided, i.e. of 80-100 mesh or higher, and contains less than 5% of water. The hydrolysis is preferably carried out with water in the presence of an organic solvent, e.g. an ether of formula R3OR4 in which R3 and R4 are alkyl radicals having 1-6 carbon atoms. Examples are given of the preparation of 5-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-ethyl-1-pentyn-3-ol 1-ethynyl-cyclohexanol-1, 3-ethyl-1-heptyn-3-ol, 3-phenyl-1-butyn-3-ol, 1-hexyn-3-ol, 1-pentyn-3-ol, isodecynol and 1-butyn-3-ol.