Ab Initio Chemical Kinetics of Methyl Formate Decomposition: The Simplest Model Biodiesel

Abstract

The energetics and kinetics of methyl formate decomposition have been investigated by high-level ab initio calculations with rate constant predictions. The paucity of reliable experimental data for methyl formate has been circumvented by studying a very similar system, namely, the decarboxylation of acetic acid, in order to help validate the theoretical calculations. Our study shows that methyl formate decomposes to methanol and carbon monoxide, almost exclusively, with a high pressure limit rate constant of k(1)(infinity) = 2.128 x 10(12)T(0.735) exp(-34,535/T) s(-1), and the decomposition of acetic acid to methane and carbon dioxide proceeds with a rate constant, k(4)(infinity), of 1.668 x 10(10)T(1.079) exp -35,541/T s(-1). Experimental values for the formation enthalpy of methyl formate are discussed, and it is shown that these can be reconciled with our computed value for DeltaH(f) (298.15 K) of -360.1 +/- 2.2 kJ mol(-1). In turn, bond dissociation energies for all single bonds in the molecule are presented.