ε-己内酰胺双封端异氰酸酯的合成及鉴定

研究了ε-己内酰胺双封端4，4'-二苯甲烷二异氰酸酯(MDI)的合成反应。讨论了加料方式、加料时间、催化剂用量、反应温度、原料物质的量比及反应时间对反应过程的影响。用正交试验设计方法,优选了反应条件：n(ε-己内酰胺)/n(MDI)=2.2、反应温度为80℃、反应时间为5h、催化剂用量为MDI质量的1.0%。双封端产物收率达到87.42%。用熔点和薄层层析(TLC)分析,定性验证了产物的质量。用质谱(ESI)核磁和气质联机分析证实了产物的结构。用高效液（HPLC）定量对比了处理前后产品的纯度。用热分析(TG-DSC)测定产品分解温度为184.1℃。

Synthesis and identification of the product of isocyanate diblocked by ε-caprolactam

The diblocking reaction between ε-caprolactam and diphenylmethane-4,4′-diisocyanate (MDI) has been studied. The effects of varying the sequence of addition of reactants, dosage of catalyst, temperature, reactant ratio and reaction time were investigated. The choice of reaction conditions was based on an orthogonal experiment design. The optimum conditions for the blocking reaction were found to be as follows: a molar ratio of ε-caprolactam to MDI of 22 at 80℃ for 5 hours, with mass of catalyst being 0.01 times of the mass of MDI. The yield of the diblocked product under these conditions was 87.42%. The purity and structure of the purified product were analyzed and identified by melting point, TLC, MS(ESI), NMR, GC-MS and HPLC. The thermal decomposition temperature of the purified was 184.1℃, as measured by TG-DSC.