Cocondensation of urea with methylolphenols in acidic conditions

The reactions of urea with methylolphenols under acidic conditions were investigated using 2‐ and 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‐trimethylophenol. 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.