Alcoholysis of Linfen bituminous coal: effect of temperature and solvent

ABSTRACT

To investigate the effects of temperature and solvent type on the alcoholysis behavior of coals, the alcoholysis or thermal dissolution (TD) experiments of Linfeng bituminous coal (LF) were carried out in three low carbon alcohols (methanol, ethanol, and n-propanol), benzene, and toluene. During alcoholysis in methanol, the oil yields increase from 4.0% to 7.8%, and the gas yields increase from 0.8% to 42.2% with the temperature increasing from 220°C to 300°C. During the alcoholysis or TD in different solvents, the oil yields are in the order of n-propanol (15.7%) > toluene (12.5%) > ethanol (10.8%) > benzene (10.0%) > methanol (7.8%). The gas yields of alcoholysis are obviously higher than those of TD in benzene and toluene. Arenes are the dominated compounds in the oils from both alkanolysis and TD in benzene and toluene, while the amount of oxygen-containing organic compounds (OCOCs) in the oils of alkanolysis is obviously more than that in the oils of TD in benzene and toluene. FTIR analyses show that the spectra of oils from the alkanolysis possess stronger intensity of peaks attributed to phenolic-OH, and weaker peaks attributed to aliphatic C-H than those from the TD in benzene and toluene. Moreover, ¹³C NMR spectral analyses show that the amount of terminal-CH₃ and C_ar-OR groups in the residues from the alcoholysis is significantly more than that from the TD in benzene and toluene.

KEYWORDS:

• Alcoholysis
• aryl ether bonds
• bituminous coals
• oxygen-containing organic compounds
• thermal dissolution

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [Grant No.21878325], the Fundamental Research Funds for the Central Universities (China University of Mining and Technology, Grant No. 2019XKQYMS49), Open Foundation from State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Shanxi Province and Ministry Education [Grant No. MKX201502] and Priority Academic Program Development of Jiangsu Higher Education Institutions.

Notes on contributors

Yunpeng Zhao

Yun-Peng Zhao is a professor of Chemical Engineering at China University of Mining and Technology. He holds a BS in Chemical Technology from Zhengzhou University and MS and PhD in Chemical Technology from Dalian University of Technology. His research interests are in the areas of thermal conversion of coal and biomass. He is the author and co-author of more than 40 publications in international journals.

Xinggang Si

Xing-Gang Si is a Master student major in Chemical Technology at China University of Mining and Technology. He holds a BS in Chemical Engineering and Technology from Heze University. His research interests are related to the pyrolysis of low rank coals.

Jiaojiao Du

Jiao-Jiao Du is a Master student major in Chemical Technology at China University of Mining and Technology. She holds a BS in Chemical Engineering and Technology from North University of China. Her research interests are related to the thermal dissolution of bituminous coals.

Zhe Lin

Zhe Lin is an associated professor of Chemical Engineering at China University of Mining and Technology. He holds a BS, MS and PhD in Chemical Technology from China University of Mining and Technology. His research interests are in the areas of thermal conversion of coal and biomass. He is the author and co-author of more than 10 publications in international journals.

XianYong Wei

Xian-Yong Wei is a Professor of Applied Chemistry at China University of Mining and Technology. He holds a BS in Physical Chemistry from Nanjing University, and MS and PhD in Chemical Energy Engineering from The University of Tokyo. His research interests are in the areas of chemistry and chemical technology of heavy carbon resources, including coals and their derivatives (coal tar, coal char, coal liquefaction oil and residue), heavy oils, natural bitumen and crop stalks. He is the author and co-author of more than 200 publications in international journals.