ABSTRACT
The oldest method for the preparation of acrolein, the acid-catalyzed thermolysis of glycerol (dehydration) at about 190 C, is still used today to obtain acrolein on a laboratory scale [3]:
ð1Þ
By support of KHSO4 the yield can be enhanced up to 50% [14]. Further possibilities are the reaction of gaseous propene with a suspension of HgSO4 in aqueous sulfuric acid [15]:
ð2Þ
or the pyrolytic cleavage of 2,3-dihydropyrane [16,17]:
ð3Þ
The first efficient and profitable manufacturing process for acrolein was established by Degussa AG, Germany, in 1942 [8,18-20]. It depends on the gas-phase condensation (addition and dehydration) of formaldehyde with acetaldehyde at 300 to 320 C. In the presence of alkaline silica gel catalysts yields as high as 82% were achieved.
