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 degrees C have been investigated. The reaction must be run with DEE as the limiting reactant to avoid over-acetalization of glycerol, and below 50 degrees 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 x 10(-4) m(6)/kmol/kg cat/s at 40 degrees C and an activation energy of 58.6 kJ/mol. The equilibrium constant for the reaction is 900 kmol/m(3) at 40 degrees 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. (C) 2013 Elsevier B.V. All rights reserved.