Research on the Synthesis of Phenol-Urea Alternative Copolymer

以2-羟基苯醇、4-羟基苯醇和2，4，6-三羟甲基苯酚为模型化合物，研究了2-羟基苯酚与尿素在酸性条件下缩合反应的化学动力学。比较了邻羟甲基和对羟甲基的缩合反应活性。结果表明：(1)2-或4-羟基苯甲醇与过量尿素的共缩合反应为准一级反应；(2)生成4-羟基苯基脲的准一级速率常数比2-羟基苯基脲大一个数量级；(3)2，4，6-三羟甲基苯酚与尿素的共缩合反应活性比为0.066~0.075；(4)测定了单羟基酚与尿素同时反应的自缩合反应与共缩合反应的竞聚率：(5)2-羟基苯甲醇自缩合反应的速率常数比2-羟基苯甲醇与尿素共缩合反应的速率常数大一个数量级；(6)4-羟基苯甲醇与尿素共缩合反应的速率常数约为4-羟基苯甲醇自缩合反应速率常数的两倍。本研究首次在甲醛树脂化学领域阐明了这两种反应的动力学，为新型尿素和酚醛树脂的开发奠定了基础。

The chemical kinetics on Cocondensation between methylolphenols and urea under acidic condition were investigated using 2- and 4-hydroxybenzyl alcohols as well as 2, 4, 6-trimethylolphenol as model compounds. The reactivities of the cocondensations were compared between o- and p-methylol groups. Moreover the kinetics on the concurrent reactions involving self-condensation between monomethylolphenols and cocondensation between monomethylolphenol and urea were determined simultaneously.The results showed : (1) cocondensations of 2- or 4-hydroxybenzyl alcohol with an excessive amount of urea were determined as the pseudo-first order reaction ; (2) the pseudo-first order rate constant for a formation of 4-hydroxybenzylurea was larger by one order than that of 2-hydroxybenzylurea ; (3) reactivity ratio of o-methylol group to p-methylol group was 0.066-0.075 for the cocondensation of 2, 4, 6-trimethylolphenol and urea ; (4) the reactivity ratio of self-condensation to cocondensa-tion was determined for the concurrent reaction of mono-methylol-phenols with urea ; (5) the rate constant of the self-condensation of 2-hydroxybenzyl alcohols was larger by one order than that of the cocondensation 2-hydroxybenzyl alcohol and urea ; (6) the rate constant of the cocondensation between 4-hydroxybenzyl alcohol with urea was approximately twofold as that of the self-condensation between 4-hydoxybenzyl alcohols.This study shows for the first time in the field of formaldehyde resin chemistry that the kinetics on the two kinds of concurrent reaction can be elucidated, and will lead to the development of new urea and phenolic resins.