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122 results on '"Guo, Daliang"'

39. Catalytic Depolymerization of Alkali Lignin in Sub- and Super-critical Ethanol

Author

Shuhua Tong, Yanjun Tang, Xia Xinxing, Junhua Zhang, Guo Daliang, and Bei Liu

Subjects
Environmental Engineering, Chemistry, Depolymerization, Inorganic chemistry, Infrared spectroscopy, Bioengineering, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Supercritical fluid, 0104 chemical sciences, Autoclave, Catalysis, chemistry.chemical_compound, Lignin, Char, Fourier transform infrared spectroscopy, 0210 nano-technology, Waste Management and Disposal
Abstract

The effects of reaction parameters on catalytic depolymerization of alkali lignin in sub- and super-critical ethanol were investigated using a high pressure autoclave, and the liquid oil and solid char products were characterized. The experimental data indicated that Rh catalysis, controlling reaction conditions at ethanol critical temperature (240 oC) and pressure (7.0 MPa), high ethanol/water ratios (100/0), and the medium reaction time (4 h) enhanced the depolymerization of alkali lignin to liquid oil and decreased the char formation. A gas chromatography/mass spectroscopy (GC/MS) analysis showed that the main compositions of liquid oils were phenols, esters, ketones, and acid compounds, and the supercritical state favored the formation of bio-phenols, but the subcritical state improved the generation of bio-esters. Scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FTIR) spectra analysis showed that the addition of the Raney/Ni and Rh/C catalysis could inhibit the re-fusion of alkali lignin micron-sized spheres in the supercritical ethanol, which led to an increase in the occurrence of the depolymerization reactions.

Published
2017

45. Subcritical Ethanol Catalyzed with Deep Eutectic Solvent Extract Phenolic Lignin for Preparation of an Ultraviolet-Blocking Composite Film

Author

Guo, Daliang, Guo, Yunpu, Sha, Lizheng, Lyu, Gaojin, Li, Jing, Zhang, Xin, and Liu, Bei

Abstract

To investigate the high phenolic lignin extraction process, deep eutectic solvents based on oxalic acid and glycerol as a hydrogen bond donor were first prepared and analyzed. Two different types of deep eutectic solvent lignin and ethanol lignin were extracted using a high-pressure autoclave at different temperatures and times, and then the obtained lignin was used to prepare an ultraviolet (UV)-blocking composite film with nanofibrillated cellulose. The extract yield, phenolic hydroxyl group content, molecular weight distribution, and UV-blocking property of extracted lignin were characterized, and the UV-blocking and water-resisting properties of the lignin composite films were also analyzed. Gel permeation chromatography and phenolic hydroxyl content analysis results showed that the hydrogen bond donor type of oxalic acid cooperates with the extraction temperature of 160 °C as an important factor for obtaining the high phenolic hydroxyl content and uniform molecular weight lignin. UV spectrophotometer and thermogravimetry results indicated that the high phenolic hydroxyl lignin has excellent UV-blocking property, while the thermal stability of lignin may be slightly reduced. Meanwhile, in comparison to glycerol deep eutectic solvent lignin, an oxalic hydrogen-bond-donor-type lignin composite film exhibited higher UV absorption and water-resisting properties with lower lignin addition.

Published
2020
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