吡啶醇封端的异佛尔酮二异氰酸酯热分解反应动力学及机理研究

Research on the Thermal Decomposition Reaction Kinetics and Mechanism of Pyridinol-Blocked Isophorone Diisocyanate.

作者信息

Guo Sen, He Jingwei, Luo Weixun, Liu Fang

机构信息

School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China.

出版信息

Materials (Basel). 2016 Feb 11;9(2):110. doi: 10.3390/ma9020110.

DOI:10.3390/ma9020110

PMID:28787907

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5456470/

Abstract

A series of pyridinol-blocked isophorone isocyanates, based on pyridinol including 2-hydroxypyridine, 3-hydroxypyridine, and 4-hydroxypyridine, was synthesized and characterized by ¹H-NMR, C-NMR, and FTIR spectra. The deblocking temperature of blocked isocyanates was established by thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), and the CO₂ evaluation method. The deblocking studies revealed that the deblocking temperature was increased with pyridinol nucleophilicity in this order: 3-hydroxypyridine > 4-hydroxypyridine > 2-hydroxypyridine. The thermal decomposition reaction of 4-hydroxypyridine blocked isophorone diisocyanate was studied by thermo-gravimetric analysis. The Friedman-Reich-Levi (FRL) equation, Flynn-Wall-Ozawa (FWO) equation, and Crane equation were utilized to analyze the thermal decomposition reaction kinetics. The activation energy calculated by FRL method and FWO method was 134.6 kJ·mol and 126.2 kJ·mol, respectively. The most probable mechanism function calculated by the FWO method was the Jander equation. The reaction order was not an integer because of the complicated reactions of isocyanate.

摘要

合成了一系列基于吡啶醇（包括2-羟基吡啶、3-羟基吡啶和4-羟基吡啶）的吡啶醇封端的异佛尔酮异氰酸酯，并通过¹H-NMR、C-NMR和FTIR光谱对其进行了表征。通过热重分析（TGA）、差示扫描量热法（DSC）和CO₂评估方法确定了封端异氰酸酯的解封温度。解封研究表明，解封温度按照吡啶醇亲核性的顺序升高：3-羟基吡啶>4-羟基吡啶>2-羟基吡啶。通过热重分析研究了4-羟基吡啶封端的异佛尔酮二异氰酸酯的热分解反应。利用Friedman-Reich-Levi（FRL）方程、Flynn-Wall-Ozawa（FWO）方程和Crane方程分析热分解反应动力学。通过FRL方法和FWO方法计算得到的活化能分别为134.6 kJ·mol和126.2 kJ·mol。通过FWO方法计算得到的最概然机理函数为扬德方程。由于异氰酸酯的反应复杂，反应级数不是整数。