Improvements in or relating to the manufacture of acetylenic alcohols

摘要

Acetylenic alcohols are produced by reacting acetylene under substantially anhydrous conditions and in the substantial absence of alkali metal hydroxides, with a ketone in the presence of an alkali metal alcoholate of a primary or secondary, saturated alcohol, containing only one oxygen atom in the molecule and which is not soluble in water in all proportions at room temperature. The reaction temperature is preferably between -15 DEG C. and +10 DEG C. Such alcohols are, e.g. sec-butyl-, n-butyl- and isoamyl alcohol and cyclohexanol, commercial amyl alcohol consisting mainly of 2-methyl-and 3-methyl-butan-1-ol being very suitable. It is preferable to remove excess alcohol from the alcoholate, e.g. by heating in the presence of an inert organic liquid such as cumene, n-butyl formal, diisopropyl benzene and the dialkyl ethers of ethylene and polyalkylene glycols which has a boiling point at atmospheric pressure at least 50 DEG C. higher than the alcohol of the alcoholate. The process can be carried out cyclically, acetylene being passed into the substantially anhydrous solution of alcoholate in the high boiling inert liquid. The alkali metal alcoholates may be prepared in a continuous manner by feeding the aqueous hydroxide and alcohol to the top of a fractionating column, removing water azeotropically and continuously removing the alcoholate solution in excess alcohol from the bottom of the tower. The excess alcohol may be removed by feeding the solution with the inert solvent to the top of a fractionating column and distilling. In examples: (a) acetylene is passed into a solution of potassium amylate free of excess amyl alcohol, in the ethyl butyl ethers of diethylene glycol at 0 DEG C., acetone is then added whilst continuing the passage of acetylene until absorption ceases. Water is added to hydrolyse the potassium alcoholate of the acetylenic alcohol, the latter being extracted with amyl alcohol. The potassium hydroxide solution is recovered and used together with the residue of amyl alcohol and the inert liquid remaining after distilling off the acetylenic alcohol, to prepare a fresh batch of potassium amylate; (2) potassium amylate in diethylaniline is saturated with acetylene and acetone vapour mixed with acetylene introduced; the product as in (1) is 3-methyl-but-1-yn-3-ol. Methylethyl-, methyl propyl-, diethyl-, methyl-amyl-and di-isopropyl-ketone and cyclohexanone may also be employed. Specification 304,585, [Class 2 (iii)], U.S.A. Specification 2,161,191 and German Specification 291,185 are referred to.