凝胶色谱和二极管阵列检测器对煤乙腈抽提物的分析

Analysis of Coal Acetonitrile Extracts by Gel Permeation Chromatography Combined with Photodiode Array Detector

研究发现 ,煤乙腈抽提物的分子量分布范围为 110～ 2 2 0 0amu。乙腈抽提物样品中低聚合度的共轭体系含量为 5 0 %～ 80 % ,分子量分布范围为 110～ 2 2 0amu ;主要由含有两个双键的共轭体系构成 ,随煤阶的增加 ,不饱和的桥键侧链逐渐趋于芳构化 ;聚合度较大的共轭体系占 19%～ 4 7% ,分子量分布范围为 2 2 0～2 2 0 0amu ,主要由以共轭的多烯为主构成 ,随煤阶的增加 ,共轭程度加大 ,不饱和的含氧基团消失。

For the purpose of getting the molecular weight ( MW) distribution and structure features about aliphatic hydrocarbons in coal, acetonitrile was used as the elution solvent to extract four ranks of Chinese typical coal samples, lignite, long flame coal, gas coal and meager coal. The extraction rates of 5.71 wt%, 8.43 wt% 4.44 wt% and 2.28 wt% were respectively got. Gel permeation chromatography (GPC) was employed to separate these coal extracts with photodiode array (PDA) detector to analyze the ultraviolet (UV) spectra between 210 to 380 nm. Results showed that the range of MW for coal acetonitrile' extracts were from 110 amu to 2200 amu. Two parts were obviously divided into, one was mainly consisted of two double-bond conjugate system with MW from 110 to 220 amu in lower polymerization, the ratio was about 50% similar to 80%; another was existed in the polyene conjugate system with MW 220 amu to 2200 amu in higher polymerization, the ratio of this part was about 47% similar to 19%. With an increase of coal rank, the first part of coal extracts has the trend of being aromatic-structured and the UV spectra of the other part had a shift to the longer wavelengths, which indicted the higher conjugation.