CHEMICAL ENGINEERING & TECHNOLOGY
·
2018
·Vol. 41
·期 4
·867-874
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IF 1.588
Jing Yang,Shaotong Liu,Chunze Liu,Yuanyuan Wang,Liyi Dai
Despite the vast potential for the depolymerization of kraft lignin in supercritical systems, selective access to desired renewable products remains a very challenging target. Catalytic depolymerization of kraft lignin was carried out in an isopropanol-water mixture system over a Rh/La 2 O 3 /CeO 2 -ZrO 2 catalyst. The H 2 selectivity was adjusted by changing the proportions of isopropanol and water. The introduction of formic acid was more helpful to extend the selectivity range. A correlation was established between liquid product distribution and H 2 selectivity. It was used for predicting the composition of the liquid oil by H 2 selectivity or, optionally, for converting kraft lignin to the desired liquid products. This correlation was applicable to different solvents, temperatures, and catalysts.
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高影响因子
POLYMER
·
2018
·
IF 3.483
Bing Zhang,Chunxiang Lu,Yaodong Liu,Pucha Zhou
Alkali lignin, a by-product of commercialized paper making process, is an abundant and environmental-friendly material. In this paper, polyacrylontrile (PAN) -based hollow fiber was fabricated by one-step wet-spinning technique through blending with alkali lignin at different ratios. The phase diagram of the blends was determined by titration method. When alkali lignin is added into the PAN solution, the clouding points move away from polymer-DMSO axis, and miscibility gap increases. The phase separation of PAN was slowed down by mixing with alkali lignin which resulted in the formation of hollow structure and promoted the pore formation in the wall. This work clearly explains the roles that alkali lignin plays in the system consisting of polymer, solvent and nonsolvent, and provides a feasible method to produce PAN-based hollow fibers.
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高影响因子
COMPOSITES COMMUNICATIONS
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2018
·
IF 0
Ru Yan,Yangyang Liu,Baijun Liu,Yumei Zhang,Qi Zhao,Zhaoyan Sun,Wei Hu,Niaona Zhang
Organosolv lignin (OL) was used to synthesize organosolv-lignin-based epoxy acrylate (OLBEA) coatings. The reaction process was determined by epoxy and acid values. OLBEA coatings were prepared by dual (Ultraviolet (UV) and thermal) curing to achieve a deep and complete process. The structures of lignin-based epoxy (OLBE) and OLBEA were characterized by Fourier transform infrared spectroscopy (FTIR). The properties of the dual- and UV-cured coatings were then compared by measuring gel content and mechanical properties . Results revealed that the dual-cured films had higher cross-linking degree and better mechanical properties than the UV-cured films. The chemical resistance of the dual-cured coatings was also examined. The properties of OLBEA coatings obtained by dual curing were shown to be excellent and promising for wide-ranging applications.
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MACROMOLECULES
·
2019
·
IF 5.997
Weifeng Liu,Chang Fang,Shengyu Wang,Jinhao Huang,Xueqing Qiu
High-performance lignin-containing polyurethane elastomers (LPUes) were successfully synthesized via partially substituting petroleum-derived polyols with depolymerized enzymatic hydrolysis lignin (DEL). The influences of DEL on the structure, thermostability, mechanical performance, and thermal reprocessability of LPUes were systematically studied. The tensile strength and toughness of PUes were significantly enhanced after the introduction of DEL, with the maximum tensile strength reaching up to 60.7 MPa and the toughness up to 263.6 MJ/m3. The enhancement for the strength and toughness was attributed to the dual cross-linking network structure and the interfacial hydrogen bonds between lignin and the PU matrix, which were demonstrated to facilitate the orientation of chain segments and lead to strain-induced crystallization and self-reinforcement. LPUes also exhibited much better elasticity than the control sample without lignin and could maintain excellent mechanical performance after being hot reprocessed.
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高影响因子
RSC Advances
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2016
·Vol. 6
·期 22
·17880-17887
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IF 3.289
Guodian Zhu,Xinping Ouyang,Yun Yang,Tao Ruan,Xueqing Qiu
Lignin is an abundant renewable feedstock with a complicated and ill-defined structure. As β-O-4 aryl ether bonds are dominant among all the linkages in lignin, it is important to explore lignin depolymerization targeting the cleavage of the β-O-4 aryl ether bond for efficiently utilizing this biomass. Selective cleavage of chemical bonds in β-O-4 lignin model compounds was investigated by using Fe2(SO4)3, HZSM-5 and Pd/C as catalysts under microwave irradiation. When Fe2(SO4)3 or HZSM-5 was used as a catalyst, the Cα–Cβ bond of the C3 side chain in the model compound was broken to form aldehyde, secondary alcohol or ketone compounds. When Pd/C and formate were used as the catalyst, the β-O-4 aryl bond of the non-phenolic model compound was selectively cleaved and hydrogenation of CC on the side chain occurred at the same time. However, the hydrogenation reaction of CC on the side chain was faster than that of cleavage of the ether bond. Increasing Pd content favored the selective cleavage of the β-O-4 bond, and microwave irradiation accelerated the cleavage of the β-O-4 bond dramatically. At a high dosage of formate or high temperature, the condensation reaction among phenolic products was promoted due to the presence of an active phenolic hydroxyl group. The β-O-4 bond of the phenolic model compound was also selectively cleaved with Pd/C as the catalyst, and the reaction temperatures of cleaving about one half β-O-4 bonds of the non-phenolic and phenolic model compounds were 120 and 100 °C, respectively.
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高影响因子
BIORESOURCE TECHNOLOGY
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2015
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IF 4.494
Riyang Shu,Jinxing Long,Ying Xu,Longlong Ma,Qi Zhang,Tiejun Wang,Chenguang Wang,Zhengqiu Yuan,Qingyun Wu
Structure has a significant effect on the lignin degradation, so the investigation of structural effect on the lignin depolymerization is important and imperative. In this study, hydrogenolysis of three typical lignins with different structures, dealkaline lignin, sodium lignosulfonate and organosolv lignin, was intensively compared over the synergistic catalyst of CrCl 3 and Pd/C. The effects of reaction temperature, time, hydrogen pressure and catalyst dosage on the catalytic performance of lignin species were investigated. The structure evolution of lignins during the hydrogenolysis process was also compared. The results showed that organosolv lignin was more sensitive for hydrogenolysis than others due to its high unsaturation degree and low molecular weight. Further analysis indicated that the hydrogenolysis, hydrodeoxygenation and repolymerization reactions took place and competed intensely. Wherein, the depolymerization products with unsaturated carbonyl groups were prone to repolymerize. And the methylation was helpful to stabilize the depolymerization products and suppress the further repolymerization.
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PubMed
高影响因子
ENERGY & FUELS
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2015
·
IF 2.79
Jingying Pan,Jie Fu,Xiuyang Lu
A systematic study on microwave-assisted oxidative degradation of lignin model compounds, such as 2-phenoxy-1-phenylethanol, vanillyl alcohol, and 4-hydroxybenzyl alcohol, was performed by evaluating the catalytic activity of 14 types of metal salts. The acidity of each metal salt solution for the oxidative degradation of 2-phenoxy-1-phenylethanol, vanillyl alcohol, and 4-hydroxybenzyl alcohol under the microwave irradiation and conventional heating conditions was measured and compared. The results showed that CrCl3 and MnCl2 were the most effective for the degradation of the lignin model compounds. The acidity of metal salt is in favor of the catalytic activity for the degradation of 2-phenoxy-1-phenylethanol, vanillyl alcohol, and 4-hydroxybenzyl alcohol, and microwave irradiation is able to accelerate the degradation rate in a large scale. The possible mechanisms for the degradation of 2-phenoxy-1-phenylethanol, vanillyl alcohol, and 4-hydroxybenzyl alcohol are proposed on the basis of the product distributions.
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高影响因子
JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY
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2014
·
IF 1.176
Lihong Hu,Hui Pan,Yonghong Zhou,Chung-Yun Hse,Chengguo Liu,Baofang Zhang,Bin Xu
A new approach to increase the reactivity of lignin by thiol-mediated demethylation was investigated in this study. Demethylated lignin was characterized by the changes in its hydroxyl and methoxyl groups, molecular weight, and other properties using titration and spectroscopy methods including FT-IR, 1H NMR, UV, and GPC. The total, phenolic, and aliphatic hydroxyl contents in lignin increased while the methoxyl content decreased after demethylation reaction, which indicated the occurrence of demethylation reaction. The results from FT-IR and UV analysis also indicated that the kraft lignin in this study contains mainly guaiacyl moiety and demethylated lignin has a higher guaiacyl content than original lignin. The average molecular weight of lignin decreased after demethylation reaction due to the cleavage of ether linkages in lignin macromolecules. No severe degradation of lignin was observed during the demethylation reaction.
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IRANIAN POLYMER JOURNAL
·
2013
·Vol. 23
·期 1
·47-52
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IF 1.053
Gan Linhuo,Zhou Mingsong,Yang Dongjie,Qiu Xueqing
Carboxymethylated lignin (CML), a water-soluble lignin derivative with more carboxylic groups introduced by chemical modification, can be used as dispersant in industry. In this paper, using the methods of zeta potential measurement, X-ray photoelectron spectroscopy and UV spectroscopy, natural graphite (NG) and high-purity graphite (HPG) were selected to investigate the adsorption characteristics of CML at the hydrophobic solid/water interface. The adsorption isotherm of CML on HPG was more suitable for the Langmuir model than the Freundlich model, whereas the opposite result was obtained for the adsorption of CML on NG. Moreover, the amounts adsorbed of CML on HPG increased with higher ionic strength and lowering solution pH. However, the uptake of CML on NG increased dramatically with adding NaCl under acidic condition, while the ionic strength had no obvious influence on the adsorption under neutral condition. With increasing solution pH, the amounts of CML adsorbed on NG were dropped under acidic condition followed by increases under alkaline condition. It is suggested that the interactions between CML and the minor metallic impurities on NG surface probably contribute considerably to the differences between adsorption behaviors of CML on NG and HPG in varying solution conditions. Moreover, the results showed that the adsorption mechanism of CML at graphite/water interface could be described by Lennard-Jones potential.
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Wenwei Zhang,Tianjin Li,Xinping Ouyang,Xueqing Qiu
To cope with the challenge of insufficient interaction between lignin macromolecules and catalytic active sites in heterocatalysis systems which hindered the efficient hydrogenolysis of lignin, a lignin-derived N-doped macroporous carbon supported Ru catalyst (Ru/LNPC) was prepared via the pyrolysis of alkali lignin with potassium hydroxide as the activator and ammonium oxalate as the pore forming agent. The LNPC carrier featured a hierarchical porous structure with the diameter of macropores ranging from 50 nm to 10 μm, enhancing the adequately contact between the lignin macromolecules and Ru NPs. The doping nitrogen in the carbon carrier led to well dispersed Ru nanoparticles with average size of 1.08 nm, providing abundant active metallic centers. Therefore, Ru/LNPC exhibited excellent catalytic activity and stability to hydrogenolysis of lignin. Under the condition of 1.0 MPa H 2 at 280 ºC for 2 h, Ru/LNPC contributed to the yield of 45.6 % aromatic monomers from the depolymerization of lignin. After five recycling, Ru/LNPC still showed significant activity. This work provided a new strategy for designing catalysts for efficient hydrogenolysis of lignin and further facilitating its high-value utilization.
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高影响因子
MACROMOLECULAR RAPID COMMUNICATIONS
·
2024
·
IF 4.2
Xin Zhang,Shanpeng Qiao,Hong Zhang,Bo Wang,Xu Zeng,Bo Ren,Xiaodong Yang
The literature on polyvinyl alcohol (PVA) films is extensive, however, these methods often necessitate intricate synthesis processes or the addition of plasticizers to modify the strength and water solubility of the PVA material. A high-strength UV radiation-resistant composite film by chelating Fe 3+ with lignin and PVA, which exhibits excellent hydrolysis resistance is developed. This composite film is prepared simply by incorporating a small amount of dealkalized lignin (APPL) and ferric chloride (FeCl 3 ) into PVA through a straightforward composite process. During the scanning test, it is noted that the film exhibits a high density of uniformly dispersed particles, endowing it with efficient ultraviolet absorption capabilities. The infrared and anti-dissolution tests reveal that the coordination of Fe 3+ with lignin imparts an outstanding hydrolysis resistance to the film, obviating the need for any extender, curing agent, acid or base. The tensile fracture strength reaches an impressive 187.81Mpa in the tensile test. UV and indicator card tests unequivocally demonstrate that the film achieves a remarkable 100% anti-UV efficiency. This Fe 3+ chelated lignin/PVA composite film, with its facile preparation, environmental sustainability, high strength, and outstanding anti-ultraviolet efficiency, can be deployed across diverse applications requiring robust protection against ultraviolet radiation.
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PubMed
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2025
·
IF 6.2
Quan Yan,Bailiang Xue,Qinyu Zhao,Wenliang Wang,Xinping Li,Yongsheng Zhao,Jialong Wen,Xianzhi Meng,Wei Zhao
The incorporation of lignin into polybutylene succinate (PBS) is considered as a green approach to enhance the mechanical properties, durability, and biodegradability of PBS. However, it often leads to only a limited improvement in the toughness of PBS due to the poor compatibility of lignin with PBS. Herein, we present a novel approach to prepare lignin reinforced PBS composites with fully biobased, ultra-tough and high tensile strength characteristics through reactive extrusion and mold-pressing methodology, involving lignin epoxy vitrimer (LEV), sebacic acid (SA) and PBS. The influences of the LEV content on the structure, mechanical property, morphology, reprocessability, self-healing, creep resistance characteristics of the resultant PBS/LEV composites were systematically investigated. The incorporation of LEV in PBS could induce unique dynamic micro-crosslinked structure within PBS through dynamic transesterification reaction, which offered the resultant PBS/LEV composites with a extraordinary 18 times enhancement in elongation at break and a 13 times enhancement in toughness compared with that of pure PBS. Furthermore, the PBS/LEV composites exhibited excellent reprocessing, self-healing, creep resistance and UV resistance properties. The novel approach provides a potential avenue for enhancing the compatibility between lignin and PBS, which is beneficial for development new brand of lignin-containing fully biobased and biodegradable materials.
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危险品化学品经营许可证（带存储）