Research on the Synthesis of Phenol-Urea Alternative Copolymer

以2-羟基苄醇、4-羟基苄醇和2，4，6-间苯二酚为模型化合物，研究了酸性条件下羟甲基苯酚与尿素共缩合反应的化学动力学。共缩合反应的反应性进行了比较之间的o-和p-羟甲基。同时测定了单羟甲基苯酚自缩合反应和单羟甲基苯酚与尿素共缩合反应的动力学，结果表明：（1）2-或4-羟基苯甲醇与过量尿素的共缩合反应均为准一级反应;（2）生成4-羟基苄基脲的准一级速率常数比生成2-羟基苄基脲的准一级速率常数大一个数量级;（3）2，4，6-间苯二酚与尿素共缩合反应的邻、对羟甲基竞聚率为0.066-0.075;（4）测定了单羟甲基苯酚与尿素同时反应的自缩合与共缩合竞聚率;（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-羟基苯甲醇与尿素自缩合反应速率常数的2倍。本研究在甲醛树脂化学领域首次阐明了这两类同时发生的反应的动力学，为开发新型脲醛树脂和酚醛树脂提供了理论依据。

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.