FORMATION OF 2-ETHYL ACROLEIN BY GAS-PHASE ALDOL CONDENSATION

The gas phase aldol condensation between n-butyraldehyde and formaldehyde to give 2-ethyl acrolein, CH//2 equals C(C//2H//5)-CHO, over a silica supported tungsten oxide catalyst, by feeding formaldehyde as hemiformal or trioxane, over a wide range of operating conditions has been studied. A maximum selectivity of about 95% to 2-ethyl acrolein based on n-butyraldehyde at 275-300 degree C, by using a feeding molar ratio of formaldehyde (supplied as hemiformal) to n-butyraldehyde of about 2 to 1, with 50% n-butyaldehyde conversion, was found. The reaction studied could provide a viable alternative to the usual liquid phase process for the synthesis of 2-ethyl acrolein.