Reaction kinetics of glycerol acetal formation via transacetalization with 1,1-diethoxyethane

The kinetics of glycerol transacetalization with 1,1-diethoxyethane in ethanol over Amberlyst-15 cationic exchange resin catalyst at 25–40 °C have been investigated. The reaction must be run with DEE as the limiting reactant to avoid over-acetalization of glycerol, and below 50 °C to avoid formation of byproducts from DEE such as ethyl vinyl ether. A second order kinetic model describes the transacetalization reaction satisfactorily with a rate constant of 1.1 × 10−4 m6/kmol/kg cat/s at 40 °C and an activation energy of 58.6 kJ/mol. The equilibrium constant for the reaction is 900 kmol/m3 at 40 °C, and the heat of reaction is estimated at −20.6 kJ/mol. The reverse reaction has little influence on rate at reactant conversions less than 50%. The model and reaction conditions identified provide a framework to develop and better understand processes for glycerol acetalization.

► Describe potential for glycerol acetals as chemical and fuel intermediates. ► Identify conditions for glycerol acetal formation in high selectivity. ► Characterize undesirable side products that reduce selectivity. ► Report kinetics of glycerol acetal formation over Amberlyst catalyst.