摘要
泥煤的<sup>13</sup>C CP/MAS NMR 研究已见报道,前人的研究结果表明,由泥煤的<sup>13</sup>C CP/MAS NMR 可直接得到芳香度参数,其芳香度 f<sub>a</sub> 值反映了不同类别植物残体的组成,并可追踪泥煤各组分分解演化过程。Atalla 等人报道了纤维素的<sup>13</sup>C CP/MAS NMR 表征的结果。Kolodziejski 等人归属了纤维素,半纤维素和木质素的<sup>13</sup>C NMR 谱。土壤中的腐植酸的<sup>13</sup>C 固体高分辩 NMR 研究见Wilson 等人的报道。Hatcher 研究了由泥煤中提取的腐植酸<sup>13</sup>C CP/MAS NMR 的表征,发现泥煤中的腐植酸是高度芳构化的物质。
Four low rank coals(peat and lignite)and their derived humic acids have been investigated by the ^(13)C CP/MAS/TOSS NMR technique.It is a significant way to under- stand the course of formation and change of coal and humic acids.The NMR analysis indi- cates that the peat contains a significant amount of unaltered plant components including cel- lulose,hemicellulose,lignin,wax and resin.Variable contact time and dipolar dephasing ex- periments were performed on each sample.The data from above experiments,together with normal CP/MAS integration over selected chemical shift range,were used to derive 12 pa- rameters of carbon skeletal structure including the aromaticity.From the ratio of aromatic bridgehead carbons,f_a^B,,to the aromatic peripheral carbons,f_a^B,X_(BP),as measured by NMR,the aromatic cluster size may be estimated for each coal.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
1993年第3期327-331,共5页
Journal of Fuel Chemistry and Technology
基金
国家基金资助课题
关键词
煤
结构
固体
NMR
contact time
structure parameter
course of change
