二羟甲基脲与三聚氰胺共缩聚反应研究

Study on copolycondensation between dimethylol urea and melamine

采用高分辨超导13C-NMR（核磁共振碳谱）法和ESI—MS（电喷雾电离质谱）法对碱性条件下模型化合物uF2（N，N-二羟甲基脲）与M（三聚氰胺）的共缩聚反应进行了分析。研究结果表明：在UF2的反应体系中，UF2发生了一定程度的缩聚反应，产物中亚甲基醚键占主导地位；经典理论认为碱性条件下很难生成亚甲基桥键，但13C—NMR谱图中观测到化学位移为47．77×10^-6、54．36×10“和54．54×10^-6处是亚甲基桥键的特征峰。在UF2／M的反应体系中，UF2大量水解并导致M羟甲基化和UF2／M的共缩聚反应；仅根据13C—NMR谱图难以确认M／UF2反应体系中发生了共缩聚反应，但结合ESI—MS谱图可以确认质荷比为221～341的对应结构是共缩聚反应产物。

The copolycondensation between model compound UF2 （N, N＇-dimethylol urea） and M （melamine） under the alkaline condition was analysed by high resolution superconducting 13C-NMR （13C-nuclear magnetic resonance） and ESI-MS （electrospray ionization mass spectrometry） methods. The research results showed that a certain degree of copolycondensation of UF2 happened in the UF2 reaction system, and the proportion of methylene ether bonds in the products was dominant. The classical theory is that it is difficult to generate the methylene bridge bonds in the alkaline condition, but the chemical shifts observed at 47.77x10^-6、54.36x10^-6and 54.54x10^-6 in 13C-NMR spectra were assigned to the characteristic peak of methylene bridge bonds. The hydroxymethylation of M and copolycondensation between UF2 and M were generated because UF： was largely hydrolyzed in M/UF： reaction system. Only on the basis of 13C-NMR spectra it was difficult to confirm the existence of copolycondensation in M/UF2 reaction system, but on the basis of ESI-MS spectra the corresponding structure could be identified as copolycondensation products when the mass-to-charge ratio was 221-341.