和丰次烟煤逐级萃取物和萃余物官能团组成FT-IR分析  

Functional groups of sequential extracts and corresponding residues from Hefeng sub-bituminous coal based on FT-IR analysis

作　　者：王越[1] 马亚亚 莫文龙[1] 龚文涛 马凤云[1] 魏贤勇 樊星[1,3] 张书培 WANG Yue;MA Ya-ya;MO Wen-long;GONG Wen-tao;MA Feng-yun;WEI Xian-yong;FAN Xing;ZHANG Shu-pei(Key Laboratory of Coal Clean Conversion&Chemical Engineering Process(Xinjiang Uyghur Autonomous Region),College of Chemical Engineering,Xinjiang University,Urumqi 830046,China;Key Laboratory of Coal Processing and Efficient Utilization,Ministry of Education,China University of Mining&Technology,Xuzhou 221116,China;College of Chemical and Biological Engineering,Shandong University of Science and Technology,Qingdao 266590,China;Xinjiang Yihua Chemical Industry Co.,Ltd.,Changji 831700,China)

机构地区：[1]新疆大学化工学院煤炭清洁转化与化工过程新疆维吾尔自治区重点实验室,新疆乌鲁木齐830046 [2]中国矿业大学煤炭加工与高效利用教育部重点实验室,江苏徐州221116 [3]山东科技大学化学与生物工程学院,山东青岛266590 [4]宜化集团新疆宜化化工有限公司,新疆昌吉831700

出　　处：《燃料化学学报》2021年第7期890-901,共12页Journal of Fuel Chemistry and Technology

基　　金：新疆大学高层次人才项目“新疆典型重质碳资源的高值化利用”,新疆维吾尔自治区引进高层次人才天池计划和煤炭加工与高效洁净利用教育部重点实验室(中国矿业大学)开放基金资助。

摘　　要：以酸洗和丰次烟煤为研究对象,依次采用石油醚、二硫化碳、甲醇、丙酮和丙酮/二硫化碳对煤样进行超声五级萃取,每级萃取物和萃余物分别记为Ei和Ri(i=1、2、3、4、5)。通过对Ei及Ri进行FT-IR表征,借助分段分峰拟合手段分析了萃取产物的分子结构。结果表明,五级萃取物的羟基氢键结构均以自缔合羟基氢键为主;在脂肪类物质中,除第三级萃取物E_(3)以脂肪族−CH_(3)和不对称的−CH_(2)伸缩振动为主之外,其余几级萃取物均以对称和不对称的−CH_(2)伸缩振动为主;E_(1)主要以脂肪链末端−CH_(3)的对称弯曲振动和−CH_(3)、−CH_(2)的不对称变形振动为主,说明石油醚主要将煤样中易于解离的化学键断裂;五级萃取中CS2溶解了更大比例的含脂肪侧链的芳香结构。各级萃余物所含官能团种类相同,说明煤样主体结构并未因逐级萃取而发生改变。萃取对残渣中芳香结构和羟基氢键结构影响较大。其中,酸洗煤样以苯环二取代为主,而萃取后以苯环四取代为主。萃取前,酸洗煤样中羟基氢键结构以羟基醚氢键为主,而萃取后转变成以自缔合羟基氢键为主。另外,分级萃取对含氧官能团和脂肪类官能团影响较小。对比红外结构参数发现,E_(1)、E_(3)及R5有较高的芳环缩合度,E_(4)的脂肪直链较长、支链较少。Petroleum ether,carbon disulfide,methanol,acetone,and acetone/carbon disulfide were selected as solvents for ultrasonic-assisted extraction of acid-washed Hefeng sub-bituminous coal.The extract and residue were identified as Ei and Ri(i=1,2,3,4,5)for each stage.By FT-IR characterization of Ei and Ri,molecular structure of the extracted product was analyzed by means of segmented peak fitting.The results show that the hydroxy hydrogen bond in the fifth-order extract is dominated by self-associating hydroxy hydrogen bond;in aliphatic substances,only E_(3) was dominated by aliphatic−CH_(3)and asymmetric−CH_(2) stretching vibration,while the other extracts were dominated by symmetric and asymmetric−CH_(2) stretching vibration.E_(1) is dominated by symmetric bending vibration of aliphatic chain terminal−CH_(3)and asymmetric deformation vibration of−CH_(3)and−CH_(2),indicating that petroleum ether mainly break the easily dissociated chemical bonds in coal samples;CS2 dissolve a higher proportion of aromatic structure containing aliphatic side chains.The functional groups contained in the five residues are the same,indicating that the main structure of the coal sample is not changed due to the stepwise extraction.Extraction has an obvious influence on aromatic structure and hydroxy hydrogen bond in the residue.Aromatic structures change from di-substituted benzene dominant to tetra-substituted benzene dominant.Before extraction,the hydroxyl hydrogen bond in the acid-washed coal sample was dominated by hydroxyl ether hydrogen bonds,and after extraction,it was transformed into self-associated hydroxyl ones.In addition,sequential extraction has little effect on oxygen-containing functional groups and aliphatic functional groups.By comparing structural parameters,it is found that E_(1),E_(3),and R5 has a higher degree of aromatic condensation,and E_(4) has a longer straight-chain and less branched chain.

关 键 词：煤结构 红外光谱谱图 官能团 萃余煤 

分 类 号：O657.3[理学—分析化学]