FUEL PROCESSING TECHNOLOGY
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2022
·
IF 8.129
Huiyan Zhang,Chenjun Yang,Yujie Tao,Min Chen,Rui Xiao
The unstable oxygenates of raw bio-oil limit its high-value utilization, which renders the refinement process necessary. Catalytic cracking is one of the promising refining methods and HZSM-5 was found to be an effective catalyst. To investigate the reaction mechanism of catalytic cracking of the oxygenated components in bio-oil, guaiacol and acetic acid, are employed for the catalytic conversion over HZSM-5 and metal modified zeolite Zn/HZSM-5 in a self-designed micro-reactor. Herein, the mechanism of pyrolysis and catalytic cracking was calculated by density functional theory (DFT). For guaiacol, the selectivity of salicylaldehyde decreased from 57.41% to 41.84% and 40.31% over HZSM-5 and Zn/HZSM-5, respectively. In the catalytic cracking over Zn/HZSM-5, the yield of aromatic hydrocarbon increased. More specifically, benzene appeared in the liquid product. For acetic acid, the removal of the oxy-functional group was further promoted by Zn/HZSM-5, the as-formed ketene intermediate continues to react with zeolite catalysts, generating acetyl cation, and finally formed CO and ethylene. Zn/HZSM-5 has a better effect on promoting the reaction of ketene and methoxide since the energy barrier of the rate-determining step in this reaction decreased from 163.27 kJ/mol to 151.19 kJ/mol. Demethoxylation and dehydration were considered to be favored by Lewis acid sites.
研究领域:
化学工程
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能源科学
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DOI
高影响因子
GREEN CHEMISTRY
·
2023
·Vol. 25
·期 3
·1179-1190
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IF 9.8
Yaohong Zhou,Wanming Xiong,Yujing Jin,Peng Wang,Weiqi Wei,Jiliang Ma,Xiaohua Zhang
Conversion of lignin feedstocks into aromatic chemicals is a highly desirable target for biorefineries, and their depolymerization often requires high temperatures and harsh conditions. In this work, a process optimization involving several factors, including catalyst dosage, reaction temperature, reaction time, oxygen pressure and solvent effect, towards vanillin production from the oxidation of lignin-based vanillyl alcohol in a base-free solvent over a LaFeO3 perovskite was proposed. The results pronounced that the LaFeO3 perovskite exhibited excellent catalytic performance for affording a 100.0% conversion rate of vanillyl alcohol and 33.0% vanillin yield with the addition of 0.1 g LaFeO3 dosage at 180 °C for 2 h under 1.0 MPa O2 supply in ethyl acetate solvent. Furthermore, the presence of oxygen vacancies (Fe3+–□–Fe2+) in the LaFeO3 perovskite contributed to combining with molecular oxygen to generate the active species [Fe3+O2−], which played a key role in the oxidation of vanillyl alcohol and dominated the formation pathway of vanillin. On the other hand, reusability tests manifested that the performance of LaFeO3 decreased gradually with the increase of consecutive runs and was strongly negatively related to the amount of carbon deposits, as carbon deposits would prevent vanillyl alcohol from being accessible to active sites. Nevertheless, the performance of the spent LaFeO3 catalyst could be easily regenerated by a simple calcination approach. Overall, this work provides the possibility of a scalable strategy for constructing LaFeO3-based perovskites as efficient and reusable catalysts for vanillin production from biorefinery lignin.
研究领域:
化学工程
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生物炼制
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催化材料
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DOI
高影响因子
CATALYSIS TODAY
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2019
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IF 4.888
Le Yang,Rui Ma,Hui Zeng,Zebao Rui,Yongdan Li
This work provides a facile strategy to prepare core-shell structured catalysts with MOF-templated metal active species embedded carbon matrix core and a functional metal oxide shell in a controllable way. The procedure features with the facile introduction of functional shell metal oxide and delivery of MOF morphology. Co(II/Ⅲ)@ZnO hexagonal prisms are fabricated with this procedure and ZIF-67 as the template. When being used in the selective oxidation of vanillyl alcohol to produce vanillin, ZnO shell plays an important role by faciliating redox of Co 3+ /Co 2+ for promoting vanillyl alcohol oxidation to vanillin and protecting the Co species against leaching into the reaction system. Co(II/Ⅲ)@ZnO exhibits a conversion of 20% with a selectivity of 80% after a 2 h reaction and shows stability after 3 catalytic cycles.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
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IF 7.7
Ruijin Li,Danlian Huang,Yashi Chen,Guangfu Wang,Zhen Wei,Wei Zhou,Ruihao Xiao
Selective oxidation of vanillyl alcohol (VAL) to vanillin (VN) is a key step towards sustainable valorization of lignin biomass. The combination of Cu metal and TEMPO has been shown to be an effective catalytic system for the oxidation of alcohols to aldehydes. However, most previous studies have stayed in homogeneous catalytic systems, where the catalysts are difficult to recycle. In this study, Carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) were utilized as the substrate, and the carboxyl functional groups could provide partial ligands for MOFs (Cu 3 (BTC) 2 ), thus allowing MOFs to be encapsulated by MWCNTs. And the hydroxyl group of 4-OH-TEMPO could be dehydrated and condensed with the carboxyl group to graft with carbon nanotubes to form a multiphase catalytic system. The addition of carbon nanotubes improved the stability and thermal conductivity of the catalyst, which was beneficial to the catalytic conversion of VAL. Under the conventional oven heating, the conversion of VAL and the selectivity of VN could reach 98.33% and 91.37% at 120 ℃ for 2 h, respectively. And under microwave radiation , the complete conversion of VAL to VN could be achieved at 120 ℃ for 1 h. After five cycles, the efficiency of the catalyst could still reach more than 85%, which proved to be a stable and reusable integrated catalyst for the oxidation of VAL to VN.
研究领域:
化学工程
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材料科学
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催化化学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
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2016
·Vol. 52
·期 1
·164-172
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IF 2.302
Yuan Ziliang,Chen Shaohua,Liu Bing
Nitrogen-doped reduced graphene oxide-supported Mn 3 O 4 nanoparticles (N-RGO/Mn 3 O 4 ) were prepared by solvothermal method and characterized by several physical techniques such as TEM images, XRD, XPS, and N 2 adsorption–desorption techniques. The as-made N-RGO/Mn 3 O 4 catalyst was used for the oxidation of vanillyl alcohol to vanillin. Several important reaction parameters were investigated such as reaction solvent, oxygen concentration, reaction temperature, and catalyst loading. N,N -Dimethylformamide was found to be the best solvent, affording both high conversion and vanillin selectivity. 92.5 % conversion of vanillyl alcohol and 91.4 % selectivity of vanillin were achieved after 12 h at 120 °C under oxygen balloon by the use of 40 mg of the N-GO/Mn 3 O 4 catalyst. Kinetic studies revealed that the active energy for the oxidation of vanillyl alcohol to vanillin over N-GO/Mn 3 O 4 catalyst was 39.67 kJ.mol −1 . More importantly, the catalyst was stable and could be reused for 6 times without the significant loss of its catalytic activity.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
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IF 7.7
Daobin Tang,Xuebin Lin,Qi Zhang,Zhenni Wang,Yuhang Liu,Yanqiao Jin,Xinru Wu,Cejun Hu,Pei Yuan
Lignin is continuously investigated by various techniques for valorization due to its high content of oxygen-containing functional groups. Catalytic systems employing hydrolysis‑hydrogenolysis, leveraging the synergistic effect of redox metal sites and acid sites, exhibit efficient degradation of lignin. The predominance of either hydrolysis or hydrogenolysis reactions hinges upon the relative activity of acid and metal sites, as well as the intensity of the reductive atmosphere. In this study, the Pd-MoO x /TiO 2 catalyst was found to primarily catalyze hydrolysis in the lignin depolymerization process, attributed to the abundance of moderate acidic sites on Pd and the redox-assisted catalysis of MoO x under inert conditions. After subjecting the reaction to 240 °C for 30 h, a yield of 48.22 wt% of total phenolic monomers , with 5.90 wt% consisting of diphenols, was achieved. Investigation into the conversion of 4-propylguaiacol (4-PG), a major depolymerized monomer of corncob lignin, revealed the production of ketone intermediates, a phenomenon closely linked to the unique properties of MoO x . Dehydrogenation of the propyl is a key step in initiating the reaction, and 4-PG could be almost completely transformed, accompanied by an over 97 % of 4-propylcatechol selectivity. This distinctive system lays a new theoretical groundwork for the eco-friendly valorization of lignin.
研究领域:
化学工程
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催化科学
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2017
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IF 3.359
Ayang Zhou,Chang Shi,Xiao He,Yan Fu,Abdul Waqas Anjum,Jinli Zhang,Wei Li
Ammonium lignosulfonate (AL), a cheap lignin derivative with abundant phenolic building block structures, was first used as the monomer to synthesize a thin film composite nanofiltration (NF) membrane via interfacial polymerization with trimesoyl chloride (TMC) on the cross-linked poly(ether imide) substrate. The AL-TMC NF membranes show superior organic solvent resistance, the optimal NF-2AL membrane has a permeance of 0.97 L m −2 h −1 MPa −1 and a 98% rejection for Brilliant Blue R-250 (BB, 825 g mol −1 ) in DMSO. To enhance the permeance further, we adopted vanillic alcohol (VA), which possesses a molecular structure similar to the subunit of AL, to synthesize a VA-TMC NF membrane. Combining with characterizations of ATR-FTIR, 13 C NMR, XPS, SEM and AFM, etc., it is illustrated that the VA-TMC NF membrane is composed of polyarylester and exhibits high DMSO permeance about 21 L m −2 h −1 MPa −1 , the comparable BB rejection of 89% and a rejection of 81% for clindamycin phosphate. These results suggest a promising route to select potential monomers to synthesize desirable nanofiltration membrane with superior antisolvent property and separation performance.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2016
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IF 3.652
Qiang Lu,Zhi-bo Zhang,Xiao-ning Ye,Wen-tao Li,Bin Hu,Chang-qing Dong,Yong-ping Yang
A new technique was proposed to selectively produce 4-ethyl guaiacol (4-EG), a valuable phenolic compound, via low-temperature catalytic fast pyrolysis of softwood biomass using the Pd/SBA-15 catalyst. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to compare 4-EG production from three biomass materials with different lignin types (pine wood, poplar wood and bagasse) and two catalytic patterns (in-situ and ex-situ). Further experiments were performed to reveal 4-EG formation affected by the pyrolysis temperature, catalyst-to-biomass ratio and Pd content of the Pd/SBA-15 catalyst. The results indicated that 4-EG could be selectively produced from pine wood by the in-situ catalytic pattern. 4-EG was a very minor pyrolytic product in the non-catalytic process, while it could be selectively produced in the catalytic process, via the decomposition and hydrogenation of lignin. Our results suggested that several holocellulose-derived pyrolytic products could serve as the hydrogen-donors (H-donors) for the formation of 4-EG, without any extra H-donors. The highest 4-EG yield of 18.44 mg/g from pine wood was obtained at the temperature of 350 °C and catalyst-to-biomass ratio of 2, and the corresponding peak area% (calculated by GC/MS) was 38.34%.
研究领域:
能源与燃料化学
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生物质转化技术
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DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
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2025
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IF 6.2
Guoqiang Han,Wanqi Wang,Jialong Lv,Baibing Zhao,Zijian Zhang,Yan Zeng,Yongzhuang Liu,Haipeng Yu,Xiaoxue Song
Fractionation of softwood lignocellulose poses challenges due to its relatively high lignin content and complex interlinkages. In this study, an acidified deep eutectic solvent (choline chloride/ethylene glycol with 1 wt% AlCl₃) was employed to effectively fractionate Chinese fir chips into cellulose-rich and lignin fractions, achieving good to excellent yields. The cellulose-rich fraction was directly valorized into lignin-containing cellulose nanofibers (LCNFs) with a high yield. The prepared LCNFs were utilized as functional nanofillers in waterborne polyurethane wood coatings (WWC), resulting in an increase in tensile strength from 15.2 ± 0.35 MPa to 18.5 ± 0.43 MPa with the optimal addition of 0.5 wt% LCNFs. Furthermore, the addition of LCNFs significantly improved the coating properties, including hardness and wear resistance. The remaining lignin in the LCNFs imparted excellent optical properties to the WWC film, imparting a warm amber hue and improved texture convexity after coating. Analysis of the lignin fractions revealed a high total content of β-O-4 linkages. Following a catalytic hydrogen transfer depolymerization process, 9.8 wt% of propylguaiacol was obtained with near-quantitative selectivity. This study highlights the effectiveness of acidified deep eutectic solvents in the refinery of softwood lignocellulose, providing a novel pathway for the production of value-added bio-based nanomaterials and chemicals.
研究领域:
生物质精炼
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材料科学
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林业工程
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DOI
高影响因子
ENERGY & FUELS
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2024
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IF 5.2
Jia-yuan Tian,Jun Hu,Feng Lin,Yu-long Ma,Yong-gang Sun,Ying-bo Zhu,Jin-peng Wei,Yi-ting Lei,Jing-jing Wu
The catalytic selective hydrodeoxygenation of guaiacol to value-added cyclohexane is one of the sustainable biomass utilization pathways for which the Ru/HZSM-5 support catalyst has been considered as promising. However, the effect of the catalyst morphology on the catalytic properties must be further investigated. Four Ru catalysts with different support morphologies, two-dimensional nanosheets (Ru/HZSM-5-P), brick-shaped (Ru/HZSM-5-G), cross-shaped (Ru/HZSM-5-J), and irregular particles (Ru/HZSM-5-D), were prepared by the impregnation method to investigate the effects of catalyst morphology and acidity on the conversion efficiency of lignin-derived guaiacol to cyclohexane. The catalytic activity data showed that Ru/HZSM-5-P exhibited the best catalytic performance among the four catalysts with a conversion rate of 99.9% for guaiacol and a yield of 99.9% for cyclohexane. The characterization results showed significant differences among the four catalysts in terms of accessibility (thickness and pore volume), acidity, metal particle size, and reduction temperature. The Ru/HZSM-5-P catalyst with a two-dimensional nanosheet structure showed the best accessibility, smaller metal particle size, reasonable metal–support interaction, and appropriate B/L. The relatively strong acid centers facilitate the activation of C–C and C–O bonds. Besides, the reduced Ru species on the Ru/ZSM-5 catalyst exhibited high H2 adsorption activity, which was beneficial for the adsorption of guaiacol. This indicates that the difference in catalyst morphology could greatly affect its catalytic activity, thereby altering the conversion rate of reactants and selectivity of the products.
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Zijiang Zhao,Songtao Huang,Guanglu Dong,Yi Chen,Mingxuan Wang,Molin Xia,Xin Song,Xiaonian Li,Zhongzhe Wei,Jianguo Wang
The hydrogenation of vanillin stands as a pivotal platform reaction within biomass conversion processes, presenting a significant challenge in achieving controlled synthesis of different products. Here, we proffer different methodology for elaborately designing the electronic structure of Pt via regulating the strong metal-support interactions (SMSI) between Pt and Mo 2 TiC 2 , thereby facilitating the targeted synthesis of vanillyl alcohol (VA) and 2-methoxy-4-methylphenol (MMP) from vanillin. Appropriate H 2 reduction can enhance the SMSI between Pt and Mo 2 TiC 2 , promoting the electron transfer from Mo 2 TiC 2 to Pt, resulting in 200-Pt/Mo 2 TiC 2 with 68.1 of Pt 2+ . However, the SR-Pt/Mo 2 TiC 2 obtained through the galvanic replacement strategy possesses 64.7 % of Pt 4+ , which is attributed to the weaker spontaneous SMSI between Pt and Mo 2 TiC 2 . XPS adsorption experiments highlight the pivotal role of Pt 2+ in facilitating the desorption of VA, resulting in the 200-Pt/Mo 2 TiC 2 catalyst demonstrating exceptional selectivity towards VA (96 %). Meanwhile, SR-Pt/Mo 2 TiC 2 showcases a predilection for the direct hydrogenation and deoxygenation of vanillin into MMP. This research not only marks the application of the MXene system to biomass conversion but also illuminates the relationship between the electronic structure of Pt and its selectivity towards VA and MMP.
研究领域:
化学工程
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催化
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生物质转化
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材料科学
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 21
·10347-10356
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IF 3.925
Zegang Qiu,Xiaoxia He,Shaobo Ma,Zhiqin Li,Yu Xiong,Yueling Cao
The selective hydrogenation of oxygen containing functional groups is of great importance for the high value utilization of biomass resources such as lignin. However, it remains a great challenge to design and synthesize non-noble metal catalysts with high efficiency for the hydrogenation of lignin derivatives under mild reaction conditions. Here, a promising non-noble Ni@CN (CN: nitrogen doped carbon) catalyst was fabricated by direct pyrolysis of Ni metal–organic frameworks (Ni–ZIF). Characterization results reveal that the Ni nanoparticles (NPs) are embedded in nitrogen doped carbon, and the size of Ni NPs increases with the rising pyrolysis temperature. The severe aggregation of the particles of the Ni@CN composite occurs when the pyrolysis temperature is higher than 525 °C. The as-prepared Ni@CN catalysts were tested for selective hydrogenation of the aldehyde group of vanillin (lignin monomer molecule) for the purpose of producing vanillyl alcohol. The Ni@CN-425 catalyst obtained at a pyrolysis temperature of 425 °C exhibits the highest catalytic performance for the selective hydrogenation of vanillin to vanillyl alcohol. A vanillin conversion of 99.5% and vanillyl alcohol selectivity of 98.3% are achieved under a low temperature of 80 °C. In addition, Ni@CN-425 presents excellent stability in the hydrogenation reaction of vanillin. This work provides some useful insights into the design of novel non-noble metal catalysts with high efficiency for selective hydrogenation of oxygen containing functional groups in lignin derivatives.
研究领域:
催化化学
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材料科学
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生物质转化
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DOI
高影响因子
危险品化学品经营许可证（带存储）