Zeolites for the production of fine chemicals: Synthesis of the fructone fragrancy

Fructone (ethyl 3,3-ethylendioxybutyrate), a flavouring material, has been obtained by acetalization of ethyl acetoacetate with ethylene glycol using different microporous and mesoporous aluminosilicates as catalysts. Tridirectional zeolites (Y and Beta) are very effective and selective for carrying out this reaction. It has been found that a higher concentration of acid sites does not guarantee a better catalytic performance and the hydrophobic-hydrophilic properties of the material play a determinant role in this reaction due to the different polarity of the reactants. The coupling between the concentration of active sites and the adequate adsorption properties is achieved for Beta zeolites with a Si/Al ratio between 25 and 50. Optimisation of reaction conditions and the appropriate catalyst allow us to obtain fructone with conversions and selectivities close to 100%. (C) 2000 Academic Press.