GB698019A - Di-hydric alcohols - Google Patents

Abstract

Alkine diols are continuously produced by a liquid phase reaction between acetylene and an aldehyde or ketone, in which a copper acetylide catalyst is maintained in suspension in the liquid reaction medium in the form of a slurry by the continuous passage of acetylene upwards through the medium, a quiescent zone is maintained in the reaction mixture from which zone liquid is continuously withdrawn, and fresh aldehyde or ketone is supplied to maintain the volume of reaction liquid constant. The quiescent zone in the reaction medium can be effected by providing a baffled zone near the top of the reactor and this ensures that substantially no catalyst is withdrawn in the crude product being removed. The catalyst preferably comprises copper acetylide supported on silica gel. Preferably a catalyst of a particle size between 50 and 100 mesh is used. The reaction is preferably carried out at a temperature between 180 DEG and 220 DEG F. The alkine diol produced may be hydrogenated to give the alkane diol at temperatures of 210-300 DEG F. and a pressure of 800 to 1800 lb. per square inch in the presence of Raney nickel at a pH value between 7 and 8. In the example, a copper acetylide catalyst deposited on silica gel is suspended in an aqueous formaldehyde solution; acetylene and aqueous formaldehyde solution are continuously introduced into the reaction, the acetylene being introduced at such a rate as to keep the catalyst in suspension; the overflow of aqueous formaldehyde solution containing 1.4-butine diol is continuously removed from the zone at the top of the reactor where baffles are provided to maintain the reaction liquid in a quiescent state. The crude aqueous solution of 1.4-butine diol is steam stripped and distilled to give a solution of 1.4-butine diol which is subsequently hydrogenated to give a solution of 1.4-butane diol, which is purified by distilling and extracting with 2 ethyl hexanol.ALSO:A catalyst for the reaction between acetylene and an aldehyde p or ketone to produce alkine diols consists of a copper acetylide, preferably supported on silica gel. In an example silica gel is mixed with a solution of copper nitrate and bismuth nitrate in dilute nitric acid; the mixture is dried, calcined, reduced with formaldehyde and then treated with acetylene to give a an acetylide-acetylene complex which is the active catalyst.