高阳炼焦煤碳、氧结构研究与光谱学表征

通过对山西高阳炼焦煤煤质分析及¹³C交叉极化/魔角旋转-核磁共振(¹³C CP/MASNMR)、傅里叶红外光谱(FTIR)、X射线光电子能谱(XPS)的联合解析,获取煤中芳香结构、脂肪结构、羟基基团、含氧官能团结构特征,以及芳碳率、芳氢率、芳核平均结构尺寸(Xb)等煤结构单元基本参数。研究结果表明,高阳炼焦煤中芳碳率为0.73~0.77,芳核平均结构尺寸Xb为0.43。苯环五取代、苯环四取代和苯环三取代是高阳煤中主要的芳香烃结构,占比分别为41.42%,30.65%和19.82%。亚甲基是高阳煤中最主要的脂肪烃结构,占比达到41.85%,甲基和次甲基含量分别为29.86%,28.29%,说明煤中含有较多的烷基侧链和环状脂肪烃。羰基和酚羟基是煤中最主要的含氧官能团,与芳环上π电子形成的羟基π氢键占煤中羟基结构的73.20%。在芳香烃碳原子个数为118的高阳炼焦煤分子模型中,脂肪烃碳原子个数为25~32,其中,甲基碳、亚甲基碳、次甲基碳、羰基和羧基的个数分别为7~8,9~11,6~8,5。氧原子个数为7,其中,羰基和酚羟基为6个,醚氧键和有机硫中的砜或者亚砜结构共用1个氧原子。构建高阳炼焦煤精准大分子模型需要更多的碳、氧原子个数,因此,必须对煤中硫、氮等杂原子结构做进一步的分析。

Study and spectroscopy characterization of carbon&oxygen structures of Gaoyang coking coal

Coal structure is an important research content of coal chemical industry.Carbon is the backbone of the coal structure.Oxygen is the most abundant heteroatom in coal.The studies on the structure of carbon and oxygen are of great significance to build macromolecular models,acknowledge the structural characteristics and reaction characteristics and then improve the comprehensive utilization level of coking coal.The basic parameters of coal structural units,such as aromatic structure,fatty structure,hydroxyl group,oxygen-containing functional group structure,aromatic carbon ratio,aromatic hydrogen ratio and average structure size of aromatic nucleus in the Shanxi Gaoyang coking coal are obtained by investigating proximate,ultimate,^13C Cross Polarization/Magic Angle Rotation-Nuclear Magnetic Resonance(^13C CP/MAS-NMR),Fourier Infrared Spectroscopy(FTIR)and X-ray Photoelectron Spectroscopy(XPS).The results show that the aromatic carbon ratio of the Gaoyang coking coal is 0.73-0.77 and is 0.43.Phenyl ring penta-substituted,benzene ring tetra-substituted and benzene ring tri-substituted are the main aromatic hydrocarbon structures in the Gaoyang coal,accounting for 41.42%,30.65%and 19.82%respectively.Methylene is the main aliphatic hydrocarbon structure in the Gaoyang coal,accounting for 41.85%,the methyl and methine content is 29.86%and 28.29%,respectively,which demonstrate that coal contains more alkyl side chains and cyclic aliphatic hydrocarbons.Carbonyl and phenolic hydroxyl groups are the most important oxygen-containing functional groups in coal.Hydrogenπbonding withπelectrons on the aromatic ring accounts for 73.20%of the hydroxyl structure in coal.There are 118 aromatic carbon atoms and 25-32 aliphatic carbon atoms in the Gaoyang coking coal molecular model.Among them,the number of methyl carbons,methylene carbons,methine carbos,carbonyl groups and carboxyl groups are 7-8,9-11,6-8,and 5 respectively.At the same time,there are seven oxygen atoms,which be made up of six carbonyl groups and the phenolic hydroxyl groups,the last oxygen atom is divided with thioether,sulfone and sulfoxide.Further investigation should be made on the heteroatom structures of sulfur and nitrogen in coal and comprise more carbon atoms and oxygen atoms to build a precise macromolecular model of the Gaoyang coking coal.