ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2017
·Vol. 409
·期 10
·2531-2537
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IF 3.431
Cheng Hao,Wu Shubin,Huang Jinbao,Zhang Xiaohua
Although o -quinonemethide (6-methylene-2,4-cyclohexadien-1-one) has been proposed as a key intermediate in char formation during the pyrolysis of guaiacol (2-methoxyphenol), direct evidence of this (e.g., spectroscopic data) has not yet been provided. Using in situ FTIR spectroscopy, the pyrolysis of guaiacol was investigated from 30 °C to 630 °C at 40 °C/min. The IR profiles showed direct evidence of o -quinonemethide production at about 350 °C, which vanished rapidly at around 420 °C in the vapor phase, indicating char formation. In addition, at 400 °C, salicyl aldehyde was observed, which decomposed slowly at about 500 °C. In combination with the known products of guaiacol pyrolysis, these results allowed the major reaction pathways of guaiacol pyrolysis to be discerned. Density functional theory calculations were performed, and the results were found to be in good agreement with the experimentally obtained IR profiles. These findings provide guidance on how to suppress secondary reactions of guaiacol during lignin pyrolysis.
On-line analysis of pyrolysis process of guaiacol using in situ FTIR
研究领域:
化学
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材料科学
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能源科学
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产品关联
DOI
PubMed
高影响因子
ACS Catalysis
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2022
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IF 13.7
Ping He,Qisong Yi,Huawei Geng,Yuanchao Shao,Meng Liu,Zhijie Wu,Wenhao Luo,Yuanshuai Liu,Valentin Valtchev
Liquid-phase hydrodeoxygenation (HDO), catalyzed by metal or metal-acid sites, provides an effective catalytic strategy to remove oxygen-containing functionalities of lignin-derived phenolic compounds on the route to fuels and chemicals. Developing the catalyst with high activity and stability is crucial for such a chemical process but still remains a significant challenge. In this contribution, highly dispersed subnanometric Ru metal clusters (<1.5 nm) encapsulated in the cavities of MWW zeolites, including HMCM-22 and its siliceous analog ITQ-1, have been developed for the HDO of guaiacol, an important lignin-derived phenolic monomer, in an apolar liquid phase under mild conditions (160 °C, 3 MPa H2). We validate the effective encapsulation of Ru metal clusters in ITQ-1 and HMCM-22 zeolite cavities via complementary characterization methods. The detailed reaction pathways of the HDO of guaiacol are depicted by using guaiacol, phenol, and anisole as reactants. The subnanometric Ru metal clusters confined in MWW zeolite thin layers (20–30 nm in thickness) show remarkable enhancement in HDO activity compared to the large metal particles. The close proximity between Ru metal clusters and Brønsted acid sites (BAS) confined in zeolite constraints delivers a synergistic effect, leading to an additional enhancement in catalytic activity as well as product selectivity. The super stability of the ultrafine Ru metal clusters against sintering and leaching after successive catalytic runs is achieved. The well-defined mono- or bifunctional Ru-containing MWW zeolite catalysts enable the fundamental understanding of HDO of lignin-derived phenolic compounds in the apolar liquid phase and also provide a prototype for the design of superior catalysts for other energy-related transformations.
研究领域:
催化
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化学工程
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材料科学
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能源
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产品关联
DOI
高影响因子
ENERGY & FUELS
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2024
·
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
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2025
·
IF 3.7
Mengting Chen,Minjie Zhu,Tingyu Zhou,Qifeng Zhong,Meihua Zhang,Yingxin Liu,Zuojun Wei
SAPO-5 zeolite supported RuMn was a highly efficient catalyst for the aqueous-phase selective hydrodeoxygenation of guaiacol to cyclohexanol. The optimal catalyst achieved a high cyclohexanol yield of 93.7% at full guaiacol conversion under mild conditions, with a high TOF of 920 h -1 . Moreover, the catalyst displayed remarkable performance for the hydrogenation of phenol to cyclohexanol, where a 100% yield of cyclohexanol was obtained at a phenol-to-Ru molar ratio of about 17900. In particular, the catalyst exhibited excellent recyclability and could be recycled for 20 times without obvious activity loss. The as-prepared RuMn/SAPO-5 catalyst exhibited higher performance than most of the reported Ru-based catalysts.
研究领域:
催化化学
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能源化学
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2025
·
IF 3.9
Jin-Hua Liu,Yong Chen,Hongwei Zhang,Yong Guo,Ji-Fan Zhao,Ting-Ting Qi,Shu-Liang Lu,Bao-Chang Sun,Ji-Hui Li,Ying-Jiao Li,Shu-Ying Xu
Exploiting efficient catalysts to promote the sustainable production of chemicals from biomass remains an important challenge. Here, a series of ultrathin NixCoyAlz (∼1–3 nm) layered double hydroxides (LDHs) were successfully prepared to fabricate highly active catalysts for catalytic transfer hydrogenation (CTH) of guaiacol. Among the prepared catalysts, the Ni0.1Co3.9Al1 catalyst exhibits the best catalytic performance with ∼100% guaiacol conversion and 94% cyclohexanol selectivity under 180 °C and 0 MPa N2. Moreover, the reaction rate of 63.60 × 10–5 mol·gcat–1·min–1 is superior to the reported catalysts under comparable reaction condition. In addition, the Ni0.1Co3.9Al1 catalyst reduced at 600 °C exhibits excellent performance, achieving 99.9% guaiacol conversion and 92.5% selectivity for cyclohexanol under 160 °C and 0 MPa of N2. This reaction temperature is significantly lower than those reported for comparable systems. This excellent activity is mainly due to the small metal particle size and highly dispersed metal particles induced by the ultrathin LDHs, and the synergy between Ni and Co sites in the Ni–Co alloy. Due to the high oxygen affinity of the Co catalyst, it favors the cleavage of the Caryl–OCH3 bond, while the Ni catalyst enhances the aromatic ring hydrogenation. The addition of Ni to the Co catalyst enables the formation of the Ni–Co alloy, which promotes the cleavage of the Caryl–OCH3 bond and intermediate phenol hydrogenation, thus leading to an excellent performance of guaiacol CTH. Moreover, the Ni0.1Co3.9Al1 catalyst displays good stability with negligible activity loss over six runs. This work provides an efficient route for synthesizing highly active catalysts and fundamental insights into the CTH of guaiacol.
研究领域:
催化化学
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材料科学
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可持续化学
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生物质转化
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多相催化
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产品关联
DOI
高影响因子
ACS Catalysis
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2019
·
IF 12.221
Xiaoqiang Zhang,Peifang Yan,Bin Zhao,Kairui Liu,Mayfair C. Kung,Harold H. Kung,Shanyong Chen,Z. Conrad Zhang
The catalytic properties of physical mixtures of Ni particles (100–200 nm) with nanoparticles of anatase TiO2 (TiO2-A), ZrO2, Al2O3, rutile TiO2 (TiO2-R), and CeO2 were investigated for the hydrodeoxygenation (HDO) of guaiacol. High selectivities to phenolics were obtained only for Ni mixed with anatase TiO2 (Ni and TiO2-A), while saturated hydrocarbons were the main products for the mixtures with other supports. By thermal treatment in hydrogen gas only at 300 °C or higher and subsequently separating the large Ni particles from the TiO2-A particles with a magnet, it was further discovered that there was migration of TiO2 from TiO2-A onto the large Ni particles, resulting in an amorphous TiO2 overlayer on the Ni particles as evidenced by high-resolution TEM, and vice versa, migration of Ni onto TiO2-A. The TiO2 overlayer rendered the Ni particles completely inactive as a hydrogenation/hydrodeoxygenation catalyst. Conversely, the small amounts of Ni (<1.5 wt %) migrated onto TiO2-A formed highly dispersed Ni, undetectable by high-resolution TEM (<2 nm), that were remarkably highly active for HDO of guaiacol, producing selectively phenolics. Such highly selective HDO catalysts could also be formed by incipient wetness impregnation of Ni in loadings above 2 wt % onto the TiO2-A, but it was essential to pretreat the sample in H2 at 300 °C or higher. Pretreatment in H2 at 200 °C generated catalysts that produced saturated ring products. The activity of the impregnated catalysts, as measured by guaiacol conversion, increased linearly with Ni loading below 0.5 wt %. The activity continued to increase with Ni loading but more slowly up to 2 wt %, beyond which there was little further change. The results suggested that two types of Ni species existed on the TiO2-A surface. One type consisted of a cluster of Ni atoms that were dominant on larger Ni particles that were active in aromatic ring hydrogenation and hydrodeoxygenation. They were readily covered by reducible TiO2-A at 300 °C or higher due to the traditional strong metal support interaction (SMSI) effect and became inactive. Another type was clusters of a very small number of Ni atoms, perhaps one atom, that were present as highly dispersed Ni clusters interacting strongly with the defect sites of TiO2-A. The strong interaction of this type of Ni with the TiO2 defect deterred TiOx migration allowing surface exposed Ni atoms to catalyze the HDO of guaiacol with very high selectivities that were not characteristic of typical Ni particles.
研究领域:
催化化学
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能源化学
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材料科学
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产品关联
DOI
高影响因子
MOLECULES
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2023
·Vol. 28
·期 22
·7591
·
IF 4.6
Jian Huang,Yu Zhu,Huiyang Bian,Liang Song,Yifan Liu,Yuancai Lv,Xiaoxia Ye,Chunxiang Lin,Xiaojuan Li
A boron and iron co-doped biochar (B-Fe/biochar) from Masson pine bark was fabricated and used to activate peroxydisulfate (PDS) for the degradation of guaiacol (GL). The roles of the dopants and the contribution of the radical and non-radical oxidations were investigated. The results showed that the doping of boron and iron significantly improved the catalytic activity of the biochar catalyst with a GL removal efficiency of 98.30% within 30 min. The degradation of the GL mainly occurred through the generation of hydroxyl radicals (·OHs) and electron transfer on the biochar surface, and a non-radical degradation pathway dominated by direct electron transfer was proposed. Recycling the B-Fe/biochar showed low metal leaching from the catalyst and satisfactory long-term stability and reusability, providing potential insights into the use of metal and non-metal co-doped biochar catalysts for PDS activation.Keywords:Masson pine bark;biochar;peroxydisulfate activation;B/Fe co-doping
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DOI
PubMed
高影响因子
Molecular Catalysis
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2023
·
IF 4.6
Yanlin Xu,Zhuoyi Liu,Bin Liu,Bin Dong,Yuan Pan,Yanpeng Li,Yichuan Li,Hailing Guo,Yongming Chai,Chenguang Liu
Transformation of lignin-derived feedstocks into valuable hydrocarbons is of significant importance but still challenging. This work investigates the hydrodeoxygenation (HDO) of lignin compound guaiacol on Pt-based catalysts with improved surface hydrophobicity and metal dispersion for the first time. The efficiency of guaiacol hydrodeoxygenation into hydrocarbons over Nb 2 O 5 -modified Pt-based catalyst reaches 51 %, nearly doubling that over unmodified Pt/γ-Al 2 O 3 catalyst (25 %). On the one hand, Nb 2 O 5 causes the decrease of hydroxyl groups on catalyst, leading to the enhanced hydrophobicity of catalysts, which increases the reaction rate of guaiacol into hydrocarbons on unit of Pt metal sites. On the other hand, Nb 2 O 5 strengthens the metal-support interaction, which minimizes the size of Pt nanoparticles, providing more exposed metal sites, thus leading to a higher hydrocarbons yield on catalyst. However, excess introduction of Nb 2 O 5 leads to partial coverage of Pt metal sites, resulting in decreased yield of hydrocarbons. Furthermore, the routes of guaiacol HDO reaction over modified Pt-based catalysts are investigated. This work further illustrates the influence of catalyst surface properties on the HDO process of lignin compound, and thereby provides a promising approach for adjustment of catalyst surface properties in order to promote water-liberated reactions.
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
Catalysis Science & Technology
·
2020
·Vol. 11
·期 1
·297-311
·
IF 5.721
Xiaoqiang Zhang,Peifang Yan,Bin Zhao,Z. Conrad Zhang
The electronic and structural differences of anatase TiO2 (TiO2-A) and rutile TiO2 (TiO2-R) supported Ni catalysts are studied to understand the distinctively different catalytic pathways in guaiacol hydrodeoxygenation over Ni/TiO2-A and Ni/TiO2-R catalysts. Temperature programmed reduction profiles of NiO/TiO2-A and NiO/TiO2-R reveal two types of metal–support interactions. NiO on TiO2-R requires much higher temperature to reduce than NiO on TiO2-A by hydrogen reduction. Surface TiO2-A is partially reduced together with NiO at low temperature driven by strong interaction between reduced Ni and the reducible TiO2-A surface. In situ X-ray photoelectron spectroscopy (XPS), high resolution TEM (HRTEM), and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy of adsorbed CO reveal two types of reduced Ni species on Ni/TiO2-A: Ni0 particles and atomically dispersed electron-rich Niδ− atoms. While Ni0 particles are formed only at high Ni loadings, they are fully encapsulated by an overlayer of partially reduced TiOx, making the surface of Ni particles totally inaccessible to CO and to reactants. The electron-rich Niδ− atoms are favorably formed at all Ni loadings on the TiO2-A surface and show only linearly adsorbed CO in the DRIFT spectra. Electron transfer from Ti and O on the TiO2-A surface to atomically dispersed Ni is indicated by the observation of dominant electron-rich Niδ− species in conjunction with Ti(4+δ)+ and O(2−δ)− on Ni/TiO2-A following H2 reduction. In contrast, the chemical states of metallic Ni0 and Ti4+ remain unchanged on Ni/TiO2-R after H2 reduction. The atomically dispersed Niδ− species, formed only on the Ni/TiO2-A surface, is proposed as the active site responsible for the selective hydrodeoxygenation of guaiacol to phenolics. In contrast, the metallic Ni0 particles formed on the Ni/TiO2-R surface catalyze the typical catalytic hydrogenation, preferentially saturating the aromatic ring.
研究领域:
化学
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材料科学
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催化反应
✓ 已验证
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
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2023
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IF 5.9
Shasha Tang,Haidan Lin,Kai Dong,Jun Zhang,Chengji Zhao
The waste and desertion of petroleum-based epoxy resins have attracted increasing concerns on the damage and pollution to the environment because they are difficult to reprocess and reuse after curing. Once broken or injured, the recovery or degradation of composites is a tough challenge owing to their permanently cross-linked networks. In this paper, a novel guaiacol-based epoxy resin (BGF-EP) was prepared from renewable resources instead of conventional petroleum-based bisphenol A, curing with 4-aminophenyl disulfide (AFD). The epoxy vitrimer BGF-EP-AFD had appreciable thermal stability ( T g :143 °C, T d5% :295 °C), sufficient mechanical properties (tensile strength:55.54 MPa, elongation at break:12.23%) and stress relax from 300 min at 130 °C to 27.5 s at 200 °C. And the vitrimer could be reprocessed into a complete film. More excitingly, an efficient strategy was proposed to dissolve the cured resin and recycle its carbon fiber reinforced composites in a closed loop in an appropriate mixing solution (50%DMF/50%β-ME) at room temperature. The recovered carbon fibers are not altered and remain intact for the next utilization as confirmed by SEM. This work contributes the development of guaiacol-based renewable functional materials and provides a feasible and economical way to recycle and reprocess the carbon fiber reinforced epoxy composites.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
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2024
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IF 5.6
Hong Yuan,Bo Chen,Jia-Meng He,Yi-Qing Xie,Xiao-Ran Wang,Yu Wang,Wen-Xin Zhu,Hong-Bing Zang,Zhi-Jun Diao
The high quality liquid products obtained from upgrading of bio-oil through hydrogenation can serve as viable alternatives to fossil fuels, thereby alleviating the strain on energy supply. In this study, a series of titanium-aluminum composite oxides (Ti x Al y O) was prepared by a sol-gel method and used as supports to fabricate ruthenium (Ru)-based catalysts for the hydrogenolysis upgrading of bio-oil. Various techniques, including in situ pyridine adsorption-Fourier-transform infrared spectroscopy (in situ Py-FTIR), in situ CO diffuse-reflectance Fourier-transform infrared spectroscopy (in situ CO DRIFTS), and CO 2 temperature-programmed desorption (CO 2 -TPD), were employed to characterize the physicochemical and electronic structures of the catalysts. Using guaiacol as a model compound for bio-oil, the compositions and structures of the Ti x Al y O supports, as well as the effect of calcination treatment of the supports in an N 2 atmosphere, on the hydrogenolysis reactivity, were investigated in detail. The results indicated that the hydrogenolysis rate of C aromatic −O bonds showed a significant linear correlation with the oxygen vacancy/Lewis acid content. Furthermore, the presence of oxygen vacancies facilitated the formation of small Ru nanoparticles. Importantly, calcination of the support in an N 2 atmosphere facilitated the formation of metal/oxide interface sites in the Ru/Ti 5 Al 5 O-N catalyst, further augmenting its Lewis acidity and reducing the activation energy for the hydrogenolysis of the C aromatic −O bonds. The hydrogenolysis rate of the C aromatic −O bond in guaiacol over the oxygen vacancy-rich catalyst Ru/Ti 5 Al 5 O-N was increased by a factor of 2–4 compared to those over Ru-based catalysts with a single oxide support. This study exemplified a novel strategy of oxygen vacancy-promoted hydrogenolysis upgrading of bio-oil.
研究领域:
催化
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材料科学
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可再生能源
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产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
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2021
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IF 6.186
Lin Hu,Xian-Yong Wei,Zhi-Ming Zong
Recently hydrocarbons with high yield from the selective hydrodeoxygenation (HDO) of lignin-derived bio-oil under low temperature still encounters the great challenges. However, metal nanoparticles size and acid site can greatly influence the HDO activity of metal catalyst . Herein, the efficient bifunctional Ru/Hβ catalyst was prepared by modified deposition-precipitation (DP) method for the HDO reaction of guaiacol and catalytic isoproanolysis lignin-derived bio-oil. Notably, compared to the impregnated Ru 3% /Hβ-25 catalyst, Ru 3% /Hβ-25 (DP) catalyst exhibited the higher catalytic activity on the HDO of guaiacol, smaller Ru nanoparticles size, and more acid sites. It was observed that guaiacol can be completely converted to cyclohexane under 180 °C, 3 MPa H 2 , and 2 h in n -hexane. This Ru 3% /Hβ-25 (DP) catalyst proved to be the good recyclability in the HDO reaction of guaiacol, the conversion decreased slightly to 82.3% and the yield of cyclohexane decreased to 71.2 mol% after four recycle times. Furthermore, this high active catalyst was also applied to the upgradation of bio-oil derived from the catalysis isoproanolysis of lignin in the organic phase. As a result, after the upgradation, bio-oil contained high relative content (RC) of hydrocarbons, including 42.99% cycloalkanes and 50.74% arenes, and oxygenated compounds of raw bio-oil were almost removed. Overall, during upgradation of raw lignin-derived bio-oil over Ru 3% /Hβ-25 (DP) catalyst process, not only HDO reaction, but also cleavage of C-O bonds can be achieved in one-pot.
研究领域:
催化化学
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能源化学
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生物质转化
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）