1H NMR STUDY OF 2,5-DIMETHYLRESORCINOL-METHYLOLPHENOL CO-CONDENSATION
P. CHRISTJANSON
A. KÖÖSEL
A. SUURPERE
Tallinn Technical University
Tallinn, Estonia
| Co-condensation of 2,5-dimethylresorcinol with ortho- and
para-methylolphenols in the melt at 150 °C has been studied. 100 MHz 1H NMR spectroscopy was
used for evaluation the reaction kinetics and for the product identification. Low co-condensation
rate with para-methylolphenol as compared to ortho-methylolphenol is the specific phenomenon of
the reaction. The rate- -determining role of 2,5-dimethylresorcinol reveals mainly in the co-condensation with para-methylolphenol. The hydroxyl and methyl substituent effects are responsible for the resolution of co-condensate 1H methylene signals. The co-condensation reaction occurs as the mono- and disubstitution of 2,5-dimethylresorcinol with methylol compound. The reaction with ortho-methylolphenol and particularly in the presence of alkaline catalyst enhances the part of 4,6-disubstitution in comparison with 4-monosubstitution. |