1,4-Butynediol:Solubility,Reactions,Safety

1,4-Butynediol also called 2-Butyne-1,4-diol,is a white crystalline solid, was first preparedin 1906 by the action of acetylenedimagnesium bromide on formaldehyde.It aroused little interest until about 1940 when the direct synthesis from acetyleneand aqueous formaldehyde was revealed.Subsequently butynediol becamean exceedingly important commodity in the German chemical industry of theworld War II period.

Solubility

1,4-Butynediol is soluble in aqueous acids. Insoluble in benzene; slightly soluble in ethyl ether, choroform; very soluble in ethanol, acetone, methanol.

Stability

Air Sensitive, hygroscopic, moisture sensitive.

Reactions

One of the very typical reactions of acetylenes,the addition of alcohols，is described clearly in the case of I and methanol by Nazarov and Yurev who stated the product to be 1-hydroxy-4-methoxy-2-butanone (II, R = CHg).Henshall claimed that ethanol added across the triple bond to produce 2-ethoxy-2-butene-1,4-diol. In order to resolve this serious disagreement，the reaction of I with methyl, ethyl, n-propyl, and isobutyl alcohols was studied.All were found to yield produets of type II. This raises the question of the mechanismof the reaction. 

Yurev postulated the following steps,the first of whichresembles the Meyer-Schuster rearrangement. Butynediol can indeed berearranged to hydroxymethyl vinyl ketone (I-b) but it is significant that mer-curic, cupric,or silver salts of strong acids are required catalysts. 

Safety

1,4-Butynediol is corrosive and irritates the skin, eyes, and respiratory tract.