FUEL PROCESSING TECHNOLOGY
·
2014
·
IF 3.019
Wen Chen,Zhongyang Luo,Chunjiang Yu,Yi Yang,Guoxiang Li,Jixiang Zhang
In this paper, guaiacol was used as a model compound of bio-oil and its catalytic conversion was carried out in ethanol. The effect of supports (SBA-15, ZrO 2 /SBA-15 and SO 4 2 − /ZrO 2 /SBA-15) was studied on Pt–Ni based catalysts whereas the effect of active metals was investigated over C-supported Ru, Pt and Pd catalysts. Among the tested catalysts, Ru/C showed the best performance of total guaiacol conversion with high selectivity towards the desired products, cyclohexanol and 2-methoxycyclohexanol (MCH). The reaction pathways of guaiacol in ethanol were clarified based on the product analysis. With the catalysis of Ru/C, the effects of reaction temperature, initial hydrogen pressure, and other typical compounds from bio-oil were investigated. Temperatures had negligible effect on both the conversion of guaiacol and the yields of desired products in the range of 140–260 °C. Guaiacol conversion decreased significantly at initial hydrogen pressures lower than 4.0 MPa. The presence of furfural , acetone , and acetic acid decreased the conversion of guaiacol dramatically while the addition of water had a smaller impact. Further work revealed that the mass and energy efficiency of converting guaiacol into MCH are 100% and 97%, respectively.
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CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Daxin Jiang,Min Lin,Yuhao Yan,Lulu Zhan,Rui Li,Yulong Wu
Cyclohexanol is an important chemical intermediate. In recent years, guaiacol has received widespread attention as a lignin model compound for hydrodeoxygenation (HDO) to prepare cyclohexanol. However, it remains a major challenge to prepare a highly active and stable catalyst. In this work, a series of carbon-encapsulated Co-based catalysts with different Co/C ratios were synthesized using an extremely simple approach for the HDO of guaiacol to cyclohexanol. Among them, the Co 1 @C 1 catalyst (with a ratio of 1:1 between glucose and cobalt nitrate) showed the best catalytic activity, achieving almost complete directional conversion of guaiacol to cyclohexanol within 60 min at 200 °C, with a yield of up to 98.5 % for cyclohexanol. In addition, the catalyst also exhibited extremely high stability, and no significant deactivation was observed after 5 cycles under optimal conditions. The research outcomes point out that highly dispersed CoO NPs are the main active centers. The graphite layer ensures the stability of the Co x @C y catalyst, and effectively avoids the leaching of metals in high-temperature reactions. This work provides important reference for the development of high activity, high stability, and low-cost catalysts for the hydrogenation of phenolic derivatives in the future.
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BIOMASS & BIOENERGY
·
2024
·
IF 5.8
Yacong Deng,Yanlin Xu,Zhuoyi Liu,Wenhong Wang,Bin Liu,Hailing Guo,Yanpeng Li,Bin Dong,Yichuan Li,Yuan Pan,Yongming Chai,Chenguang Liu
The efficient utilization of lignin from the papermaking black liquor has attracted interest due to its carbon-neutral value and industrial application. This work illustrates a simple support-phosphate-pretreatment strategy to develop superdispersed Ni species in activated carbon (AC) to enhance the hydrodeoxygenation (HDO) reactions of the lignin model compound guaiacol into biohydrocarbons under alkaline conditions. For the first time, sodium polyphosphate was applied as a pretreatment agent for coconut carbon in the synthesis of carbon-supported Ni catalysts. Superdispersed Ni nanoparticles were achieved on Ni/NaP n OAC with a particle size of 2.5 nm, which was much smaller than that on unmodified Ni/C (13.1 nm). The characterization results and reactions revealed that the P−O that formed served as anchoring sites for the Ni species and strengthened the interaction between the Ni species and support (SMSI), which resulted in significantly improved dispersion of the Ni metal sites and, thus, a nearly 6-fold greater yield of hydrocarbons was obtained on Ni/NaP n OAC (58.1 %) than on Ni/C (10.1 %). In addition, compared with Ni 2 P/NaP n OAC and NiS/NaP n OAC, Ni/NaP n OAC exhibited higher HDO activity, especially higher direct deoxygenation (DDO) activity and higher benzene yield, reducing hydrogen consumption during the HDO reaction.
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BIOMASS & BIOENERGY
·
2024
·
IF 5.8
Chenglong Wen,Shuning Li,Peng Zhang,Mohong Lu,Jie Zhu,Mingshi Li,Chunshan Song
A series of Mo 2 N particles supported on nitrogen-doped carbon (Mo 2 N@NC) catalysts for guaiacol hydrodeoxygenation were synthesized in situ through a one-step method employing dopamine as C and N resources and ammonium molybdate as Mo resource, respectively. During synthesis, molybdate ions are adsorbed on dopamine because of a complexation between them; then dopamine/molybdate ions/TMB/F127 nanoemulsions are formed. After polymerization, growth, drying, and carbonization , Mo 2 N particles supported on nitrogen-doped carbon catalysts are obtained. Because of the interaction between Mo and N, Mo 2 N particles are anchored onto the support, preventing the aggregation of Mo 2 N during carbonization. As a result, ultrafine Mo 2 N particles with a size of 1.0–1.3 nm are highly dispersed on Mo 2 N@NC catalysts. The guaiacol hydrodeoxygenation for these Mo 2 N@NC catalysts was performed at 280–380 °C, a H 2 flow rate of 80 mL/min and different pressures and weight hourly space velocities. Among them, Mo 2 N@NC with a Mo 2 N loading of 40 % presents the highest guaiacol conversion (99.9 %) and aromatic hydrocarbon selectivity (80.2 %), which is also better than Mo 2 N/C with a Mo 2 N loading of 40 % prepared by the wet impregnation method.
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APPLIED CATALYSIS A-GENERAL
·
2025
·
IF 4.8
Xin Han,Shanguang Xu,Fan Zhang,Ruiying Chai,Shanguo Du,Xiuling Jiao,Dairong Chen,Jie Zhang
Bimetallic catalysts composed of a primary hydrogenation metal with an oxyphilic metal often exhibit superior catalytic performance compared to their single-metal counterparts. This study elucidates the bimetallic synergy of cobalt-modified MgO-supported Pt catalysts for promoting the selective hydrodeoxygenation of guaiacol to cyclohexanol. The incorporation of Co significantly enhanced both the activity and cyclohexanol selectivity of the Pt/MgO catalyst, with performance following a volcanic trend relative to Co content. The optimal catalyst, Pt-15Co/MgO, exhibited remarkable performance, achieving 98 % guaiacol conversion and 96 % cyclohexanol selectivity at 180 °C and 1 MPa H 2 pressure. The addition of Co effectively suppressed the growth of Pt particles and improved Pt dispersion. Moreover, Co modification could induce the electron transfer from Co to Pt and promote the reduction of Pt species, leading to the formation of more active Pt 0 sites beneficial for hydrogen activation. The presence of oxyphilic Co also could promote the adsorption of the guaiacol molecules and enhance hydrogen spillover. Pt and Co exhibited a distinct synergistic effect in the hydrodeoxygenation process: Co sites primarily promoted C–O bond cleavage, while Pt sites facilitated hydrogen activation. This complementary cooperation altered the reaction pathway, lowered the activation energy, and thereby improved the catalytic performance. These findings offer a rational strategy for designing highly efficient bimetallic catalysts and provide theoretical guidance for the catalytic conversion of lignin-derived oxygenates.
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RSC Advances
·
2025
·Vol. 15
·期 13
·9899-9909
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IF 4.6
Hanghang Zhang,Gang Xu
Copper-based catalysts are widely employed in the catalytic conversion of aromatic compounds to phenolic derivatives. However, single-atom copper catalysts often exhibit limited reactivity and stability. In this study, we addressed these limitations by loading Cu onto NaY zeolite via ion exchange to synthesize a CuY catalyst, followed by Yb modification. By optimizing the Yb content, we significantly enhanced the anisole conversion rate and guaiacol yield. Catalyst characterization revealed that Yb species modulate the electronic structure of copper, favoring the formation of abundant Cu+ species. This electronic modification promotes the catalytic generation of hydroxyl radicals (˙OH) from hydrogen peroxide, thereby accelerating the reaction kinetics. Furthermore, Yb incorporation into CuY induced the formation of oxygen vacancies, which improved hydroxyl radical adsorption and facilitated the generation of metal-oxo species. These synergistic effects collectively increased the reaction's overall conversion efficiency. Under optimized reaction conditions, the Yb/CuY catalyst achieved an anisole conversion of 56.2% and an ortho-selectivity of 74.6%, clearly outperforming previous reports.
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高影响因子
Journal of the Mechanical Behavior of Biomedical Materials
·
2025
·
IF 3.5
Yinan Sun,Lihua Hong,Lin Sun,Chengji Zhao
In dentistry, the use of bisphenol A glycidyl methacrylate (Bis-GMA) is being questioned since bisphenol A is regarded as an endocrine disruptor. As alternative candidates to Bis-GMA, bio-based dental resins face the crucial challenge of low mechanical strength and high water sorption. In this study, a novel guaiacol-based dimethacrylate containing fluorenyl cardo-structure was developed to effectively improve the hydrophobicity, enhance the mechanical properties, and reduce the polymerization shrinkage of bio-based dental restorative resins. Therefore, 9, 9-bis(3-methoxy-4-glycerolate methacrylate)fluorene (BMHF-GMA) was synthesized from a new guaiacol-based bisphenol, 9, 9-bis(3-methoxy-4-phenol)fluorene (BMHF), which is a lower estrogenic activity bisphenol monomer than commercial bisphenols from the results of cell proliferation test. The experimental dental resin (5 MHMA5T) was prepared containing BMHF-GMA and triethylene glycol dimethacrylate in a 1:1 ratio. The control group (5B5T) replaced BMHF-GMA completely with Bis-GMA. Evaluation of both dental resins revealed that 5 MHMA5T possessed comparable double bond conversion (>50 % in 20 s), better volumetric polymerization shrinkage (7.19 ± 0.09 %), shrinkage stress (0.92 ± 0.01 MPa in 1200 s), water sorption (39.9 ± 0.52 μg mm −3 ), water solubility (0.99 ± 0.04 μg mm −3 ) and lower cytotoxicity compared with 5B5T. 5 MHMA5T had superior mechanical properties (flexural strength: 122.30 ± 5.00 MPa; flexural modulus: 3.49 ± 0.02 GPa; Vickers hardness number: 25.21 ± 0.56 HV). Especially, after water immersion, it still maintained adequate mechanical properties (flexural strength: 97.34 ± 5.00 MPa; flexural modulus: 2.92 ± 0.02 GPa; Vickers hardness number: 19.33 ± 0.61 HV). Therefore, the new dimethacrylate BMHF-GMA shows great potential in complex and wet oral environments and offers a promising alternative to Bis-GMA in dental restorative resins.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2021
·
IF 5.541
Yang An,Jinxiao Dou,Lu Tian,Xiaohui Zhao,Jianglong Yu
To better understand the role of microwave and the mechanisms of thermal cracking and catalytic reforming of lignocellulosic bio-oils, this study compares the difference in the reaction characteristics between microwave-assisted and conventional heating of representative bio-oil model compounds. Syringol and guaiacol were selected as bio-oil model compounds. The effects of the heating method on the conversion of the model compound and the yield and composition of products were systematically investigated in the temperature range of 600–700 °C. The results showed that high reaction temperature and microwave-assisted heating favoured the conversion of model compounds, and the conversions of syringol were generally higher than those of guaiacol under the same conditions (temperature, heating method). The heating method was found to greatly influence the yield and composition of products. The bio-oil obtained from conventional thermal cracking of model compounds contained phenolics, aromatic hydrocarbons, aryl alkyl ethers, and oxygen-containing heterocyclic compounds. In contrast, microwave-induced polarisation of poorly stable methoxy groups promotes the formation of phenolics, the concentration of the phenolic in the guaiacol and syringol bio-oil reached 62.5–66.17 area% and 85.18–87.65 area%, respectively, in the temperature range of 600–700 °C. Catalytic reforming of model compounds showed that activated carbon catalyst drastically promoted the phenol formation, particularly under microwave-assisted heating, the phenol concentration reached 93.9–97.97 area% in bio-oil during catalytic reforming of guaiacol. The formation of electron-hole pairs on the active metal sites induced by microwave radiation possibly enhanced the demethoxylation to selectively generate phenol due to the strong electron-donating ability of the methoxyl group. Microwave-assisted catalytic reforming of the model compounds was also beneficial for H 2 formation because of the direct dehydrogenation of methyl radicals and the gas-phase reactions. The H 2 concentrations of 81.07–82.41 vol.% and 75.2–79.16 vol.% were obtained during microwave-assisted catalytic reforming of guaiacol and syringol, respectively.
研究领域:
能源科学
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化学工程
·
生物质能
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Catalysts
·
2016
·Vol. 6
·期 9
·134
·
IF 2.964
Songbai Qiu,Ying Xu,Yujing Weng,Longlong Ma,Tiejun Wang
A series of MCM-41 supported Ni catalysts with high metal dispersion was successfully synthesized by simple co-impregnation using proper ethylene glycol (EG). The acquired Ni-based catalysts performed the outstanding hydrogenolysis activity of guaiacol. The effects of the synthesis parameters including drying temperature, calcination temperature, and metal loading on the physical properties of NiO nanoparticles were investigated through the use of X-ray diffraction (XRD). The drying temperature was found to significantly influence the particle sizes of NiO supported on MCM-41, but the calcination temperature and metal loading had less influence. Interestingly, the small particle size (≤3.3 nm) and the high dispersion of NiO particles were also obtained for co-impregnation on the mixed support (MCM-41:HZSM-5 = 1:1), similar to that on the single MCM-41 support, leading to excellent hydrogenation activity at low temperature. The guaiacol conversion could reach 97.9% at 150 °C, and the catalytic activity was comparative with that of noble metal catalysts. The hydrodeoxygenation (HDO) performance was also promoted by the introduction of acidic HZSM-5 zeolite and an 84.1% yield of cyclohexane at 240 °C was achieved. These findings demonstrate potential applications for the future in promoting and improving industrial catalyst performance.
研究领域:
催化化学
·
能源化学
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材料化学
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工业催化
·
生物质转化
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高影响因子
COMPOSITES PART B-ENGINEERING
·
2020
·
IF 7.635
Jingkai Liu,Jinyue Dai,Shuaipeng Wang,Yunyan Peng,Lijun Cao,Xiaoqing Liu
With the purpose to obtain an eco-friendly flame retardant for epoxy resin, a facile method for the synthesis of a bio-based epoxy monomer containing DOPO units (DGEBDB) from lignin-derived vanillin and guaiacol, was presented in this work. During the synthesis process, guaiacol acted as both reactant and solvent. And it could be recycled in situ and re-used as the fresh one. In order to evaluate the flame retardancy of DGEBDB, it was mixed with diglycidyl ether of bisphenol A (DGEBA) and cured with 4,4-diaminodiphenylmethane (DDM). Results showed that, DGEBDB demonstrated a good compatibility with DGEBA, and the mechanical properties of cured resins were obviously improved with the addition of DGEBDB. As expected, the limiting oxygen index (LOI) of cured resin reached 30.2% with the content of phosphorus only 0.67 wt%, in which the weight ratio between DGEBDB and DGEBA was 1:9 (B1D9/DDM). When the weight ratio of DGEBDB to DGEBA was further increased to 2:8 for the B2D8/DDM system, the UL-94 V-0 grade was achieved. Meanwhile, the mechanism of DGEBDB in improving the flame retardancy of cured resin was discussed and revealed. This easily available and eco-friendly DGEBDB was proved to be a highly efficient reactive flame retardant for epoxy resin.
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RSC Advances
·
2019
·Vol. 9
·期 5
·2764-2771
·
IF 3.049
Fuhang Mai,Kai Cui,Zhe Wen,Kai Wu,Fei Yan,Mengmeng Chen,Hong Chen,Yongdan Li
The conversion of guaiacol is examined at 300 °C in supercritical ethanol over a H2WO4 catalyst. Guaiacol is consumed completely, meanwhile, 16.7% aromatic ethers and 80.0% alkylphenols are obtained. Interestingly, tert-butylphenols are produced mainly with a high selectivity of 71.8%, and the overall selectivity of 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-4-ethylphenol is as high as 63.7%. The experimental results indicate that catechol and 2-ethoxyphenol are the intermediates. Meanwhile, the WO3 sites play an important role in the conversion of guaiacol and the Brønsted acid sites on H2WO4 enhance the conversion and favour a high selectivity of the tert-butylphenols. The recycling tests show that the carbon deposition on the catalyst surface, the dehydration and partial reduction of the catalyst itself are responsible for the decay of the H2WO4 catalyst. Finally, the possible reaction pathways proposed involve the transetherification process and the alkylation process during guaiacol conversion.
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高影响因子
JOURNAL OF CATALYSIS
·
2018
·
IF 6.759
Kairui Liu,Peifang Yan,Hong Jiang,Zhi Xia,Zhanwei Xu,Shi Bai,Z. Conrad Zhang
Selective hydrocleavage of aromatic C O bond while preserving the aromatic ring is a desired catalytic process in hydrodeoxygenation (HDO) of biomass derived aromatic oxygenates to high value biochemicals. Guaiacol with typical methoxy and phenolic hydroxyl groups is a representative aromatic di-oxygenates of lignin fragments. Sub-nanometer sized silver, a poor hydrogenation metal catalyst, was found to initiate H 2 dissociation and H spillover onto anatase TiO 2 (TiO 2 -A) surface. The spillover hydrogen enhanced the partial reduction of TiO 2 -A surface at a substantially lowered temperature as compared to the reduction of TiO 2 -A by molecular H 2 . The reduction of TiO 2 -A surface by spillover hydrogen was enhanced at Ag loading as low as 0.01 wt% on TiO 2 -A. The ratio of spillover H to Ag was as high as 675 at Ag loading of 0.01 wt% and the ratio decreased with increasing Ag loading. We found that the yield of phenolic products was linearly correlated with the amount of spillover hydrogen that created oxygen vacancy (Ov) through partial reduction of TiO 2 -A surface. Methanol was formed as the main side-product, indicating that the direct hydrocleavage of aromatic C-OCH 3 in guaiacol is favored over that of aromatic C-OH on the created site.
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