Kinetics and mechanism of phenol-formaldehyde and TBMP-formaldehyde base catalysed reactions

Reaction of formaldehyde with both phenol and 2-tertiary butyl 4-methyl phenol (TBMP) catalysed by tetraethyl ammonium hydroxide, triethylamine, diethylamine and ethylamine follows an overall second order rate kinetics. Overall rate constant k in phenol-HCHO reaction is resolved into stepwise rate constant k(1) for the formation of monomethylol phenol, k(2) for dimethylol phenol and k(3) for trimethylol phenol and their respective concentrations have also been calculated. The reaction is slower with TEMP and also in the presence of catalyst ethylamine. Change in the medium also influences the rate and it is higher in 1,4-dioxan-water and lower in methanol-water solvents indicating that the reactions are more non-ionic in character. Activation energy (E-a) and entropy of activation (DeltaS(#)) have been calculated and the mechanism of the reactions is proposed based on these results.