对煤分子中活性基团氧化机理的分析

STUDY ON THE OXIDATION MECHANISM OF ACTIVE GROUPS OF COAL

根据煤分子结构的研究成果，推断桥键中的次甲基醚键、α位碳原子带羟基和带支链亚甲基的次烷基键、与两个芳环相连的次甲基键，以及侧链中的甲氧基、醛基、α位碳原子带羟基的烷基为常温常压下发生煤氧复合的活性结构．其氧化活性以醛基侧链、次甲基醚键、α位带羟基的次烷基键、α位带亚甲基的次烷基键、甲氧基、α位带羟基的烷基侧链、与两个芳环相连的次甲基键的顺序排列．由于氧分子存在两个未饱和分子轨道，煤分子活性基团在共轭效应和诱导效应作用下，呈现部分未成对的电子云进入氧分子轨道产生化学吸附，进而有部分发生各步氧化反应，放出热量．根据每步反应的键能变化，采用加权平均法可推算出煤氧复合每产生 １ｍｏｌ ＣＯ，ＣＯ２和 Ｈ２Ｏ的热效应值．由于煤中七种活性结构的氧化性不同及不同种类煤中各种活性结构的数量不同，煤氧化反应放出的热量不同，煤自燃性也就不同．

In this paper, according to the last achievements in coal structure research, the hypomethylether bond, hypoalkyl bond of α-carbon atom with hydroxy and α-carbon atom with hypomethyl side chain, hypomethyl bonds linking up two aromatic hydrocarbon in bridge bonds, and methoxy, aldehyde and alkyl of α-carbon atom with hydroxy in side bonds are in- ferred to be free radical easily to lead to oxidize coal under the ambient temperature and pressure. The order from strong to weak of oxidic activation of the seven active groups is aldehyde side chain, hypomethylether bonds, hypoalkyl bonds of α-carbon atom with hydroxy, hypoalkyl bonds of α-carbon atom with hypomethyl side chian, methoxy, alkyls side chains of α-carbon atom with hydroxy, hypomethyl bonds linking up two aromatic hydrocarbon. Because of the two unsaturated molecular tracks of O2, unpaired electron clouds of active groups of coal enter molec- ular tracks of O2, to lead to chemically adsorb on the conjugate effect and induced effect of active groups, and then chemical reaction followed heat happens. On the basis of change of bond ener- gy, weighted average method is adopted to count the reaction heat value of each mol CO, CO2 and H2O. The property of coal spontaneous combustion is different for the different number and oxid- ability of the active structure resulting in the different oxidation heat.