焦油渣萃取物的组成特征和萃余物的热裂解行为OA

The compositional characteristics of the extracts and the distribution of pyrolysis products of the extracted residues after the extraction of coal tar residue(CTR)by different solvents(CS2,acetone,and equal volume acetone/CS2 mixed solvents,be respectively denoted as RCTR1,RCTR2,RCTR3),were investigated using advanced characterization instruments such as gas chromatography-mass spectrometry(GC/MS),Fourier transform infrared spectrometry(FTIR),and pyrolysis gas chromatography/mass spectrometry(Py-GC/MS).By further combining thermogravi-metric analysis(TG-DTG)with the Coats-Redfern kinetic model,the potential reaction pathways during the pyrolysis process of CTR residue were explored.The results show that compared to CTR,the content of benzene ring functional groups in the three extracted decreases(FTIR)and exhibites better thermal stability(TG-DTG).The detectable compounds in the extract are mainly aromatic hydrocarbons(GC/MS),with relative contents of 37.06%,32.86%,and 33.61%,respectively.This indicates that the above three solvents can selectively disrupt the π—π stacking interactions,strong hydrogen bonding,and hydrogen bonding/π—π recombination between aromatic rings,thereby weakening the interaction between smaller polycyclic aromatic hydrocarbons(1‒5 rings)and larger molecules(such as polycyclic aromatic hydrocarbons,≥6 rings)in CTR,making smaller aromatic compounds easier to extract.In addition,the pyrolysis products of the three residues at 460℃are mainly alkanes(Py-GC/MS),among which the pyrolysis products of RCTR1 and RCTR3 are mainly normal alkanes of C21‒C30,while the alkanes in the pyrolysis products of RCTR2 are mainly C11‒C20.Finally,the kinetic model shows a gradual transition from D1 type to F2 type with increasing tempera-ture,indicating the synergistic mechanism of physical diffusion and chemical bond breaking during the pyrolysis process of the extracted residues.