Cocondensation of Urea with Methylolphenols in Acidic Conditions

The reactions of urea with methylolphenols under acidic conditions were investigated using 2and 4-hydroxybenzyl alcohol and crude 2,4,6-trimethylophenol as model compounds. The reaction products were analyzed with 13C-NMR spectroscopy and GPC. From the reaction of urea with 4-hydroxybenzyl alcohol, the formations of 4-hydroxybenzylurea, N,N'-bis(4-hydroxybenzyl)urea, and tris (4-hydroXybenzyl) urea were confirmed and the formations of N,N-bis(4-hydroxybenzyl)urea and tetrakis(4-hydroxybenzyl)urea were suggested. From the reaction of urea and 2-hydroxybenzyl alcohol, 2-hydroxybenzylurea and N,N'-bis (2-hydroxybenzyl) urea were identified. Further, the alternative copolymer of urea and phenol could be synthesized by the reaction of urea with 2,4,6-trimethylolphenol. It was also found that the cocondensation between p-methylol group and urea prevails against the self-condensation of the methylolphenol even at the low pH below 3.0, and that p-methylol group has the stronger reactivity to urea than o-methylol group. @ 1992 John Wiley & Sons, Inc.