The catalytic decomposition of allyl alcohol has been studied by Ipatiev, who passed the vapour through a brass tube filled with brass filings maintained at 600° C. He found hydrogen and acrolein, some propylene and carbon monoxide, with a little divinyl in the reaction products, showing that under these conditions of elevated temperature very little hydrogenation of the double bond of the unsaturated alcohol takes place. Sabatier and Senderensf used reduced copper as catalyst at temperatures varying from 180-300° C. They found that a yield of over 50 per cent, of propionaldehyde could be obtained and only a little acrolein and hydrogen. The lower temperature seems to favour the production of the saturated aldehyde. The observations of Moureu and Boismenu have shown that acrolein is very appreciably hydrogenated by copper at temperatures between 110 and 250° C. At 300° C. the destruction of the acrolein is very rapid. It is evident, therefore, that there are two reactions to be followed in the initial stages of the dehydrogenation of allyl alcohol by copper CH
2
═ CH . CH
2
OH— ↗CH
3
. CH
2
. CHO ↘ CH
2
= CH. CHO + H
2
A detailed study was made of these two reactions to attempt to throw light on the state of the adsorbed molecules, and to consider in detail the mechanism of the two reactions and the connection between them.
The initial stages of the dehydrogenation and isomeric change of allyl alcohol
