Selective aldolisation of acetone in diacetone alcohol with a solid basic catalyst

摘要

The double hydroxide acts as a basic heterogeneous catalyst, giving a good conversion of acetone and a good selectivity in diacetone alcohol, inhibiting the dehydration reaction to mesityl oxide or reaction with a third acetone molecule to give triacetone-dialcohol. The catalyst is of general formula ((Mg2+)1-x(Al3+)x(OH-)2)+x((OH)x(H2O)n)-x (I), where x is greater than or equal to 0.2 and less than or equal to 0.33, and n is less than 1. Catalyst preparation comprises calcination of a hydrotalcite, in which x has the values defined above, at 800 degrees C to give a mixed oxide of magnesium and aluminum, and rehydration of the mixed oxide by water in the absence of carbon monoxide (CO2).