Transesterification of methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate with tetrakis(hydroxymethyl)methane. The properties of the reaction products

The transesterification of methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate with tetrakis(hydroxymethyl)methane depends on the equilibrium constants of the reversible reactions; for the final step, the equilibrium constant is K a parts per thousand(a) 1. The molecular geometries and the enthalpies and entropies of the equilibrium reactions were calculated by the semiempirical PM6 quantum chemical method. The thermodynamic equilibrium constants of the reversible reactions were calculated by the Boltzmann equation from the Gibbs energies G (f) (au <). For tris-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyloxymethyl](hydroxymethyl)methane, the dipole moment is mu = 0.97 D and the energy of the O-H homolysis is D (OH) = 347.3 kJ mol(-1). For tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyloxymethyl]methane, mu is 5.6 D and D (OH) is 321 kJ mol(-1). The geometry of the structure affects the H-O homolysis energy and the chain termination coefficient under the conditions of inhibited cumene oxidation.