Kinetics of phenolic resol resin formation by HPLC.: III:: Zinc acetate

Zinc acetate was used as catalyst in the synthesis of a phenolic resol resin. The evolution of the addition and condensation reactions was quantitatively followed by high performance liquid chromatography. The addition of formaldehyde to phenol was almost exclusively ortho directed. Very low advancement in polymerization was observed, and diaryl compounds were only slightly formed. C-13 NMR studies did not show pam, para methylene bridges as a result of the poor addition of hydroxymethyl groups onto the pam phenolic sites. The change in concentration of free phenol as a parameter of the evolution of the resin during storage was followed by gas chromatography. Disappearance of free phenol did not stop at any of the analysed storing temperatures (room temperature, 4 degrees C, and -20 degrees C). (C) 1999 Elsevier Science Ltd. All rights reserved.