Reactivity determination of carbon atoms on benzene rings of phenols

On the basis of the synthesis of novolac, resol resins and phenolic resins with carboxyl groups, several interesting results are found from the analyses on their properties and microstructures. It is indicated that the reactivity of some carbon atom on the benzene ring of a phenolic compound can be determined by its calculation of quantum chemistry or its C-NMR spectrum in its addition reaction and condensation polymerization with aldehydes, or in its addition reaction and polymerization with conjugated polyene compounds. In general, the lower the net charge values of some carbon atoms on the benzene ring of a phenolic compound, the lower the chemical shift values of the carbon atoms in its C-NMR spectrum, the greater the reactivity of the carbon atoms. The reactivity of a phenolic compound with a carboxyl group in its decarboxylation reaction can be determined in the same way. These conclusions are very important for the molecular design and the control of synthesis conditions of novolac, resol resins with carboxyl group. It is also of great importance for the design of resists and thermo- sensitive compositions used for thermo-sensitive CTP plates.