RSC Advances
·
2016
·Vol. 6
·期 16
·12782-12787
·
IF 3.289
Ye-Min Lu,Hu Li,Jian He,Yan-Xiu Liu,Zhi-Bing Wu,De-Yu Hu,Song Yang
Partially hydroxylated AlF3 (denoted as AlF3) was synthesized by using a sol–gel method, and unambiguously characterized by FT-IR, XRD, NH3-TPD, SEM, TEM, N2 adsorption–desorption, and FTIR (pyridine-adsorption) techniques. The resulting mesoporous material (AlF3) simultaneously bearing Lewis and Brønsted acid sites was efficient for producing 5-hydroxymethylfurfural (HMF) from glucose, and an optimized HMF yield of 57.3% at a glucose conversion of 95.5% was obtained within 10 h at 140 °C. The effects of reaction temperature, time, catalyst amount, solvent and substrate type, and the amount of Brønsted/Lewis acid sites on conversion of glucose to HMF were also investigated. The existence of both Lewis and Brønsted acid sites in AlF3 was found to play a key role in glucose-to-HMF conversion.
研究领域:
化学工程
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催化化学
✓ 已验证
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2024
·
IF 4.8
Wenfeng Hao,Peng Lu,Xiaosheng Wang,Yuxiang Liu
A simple and facile co-calcination strategy of Beta molecular sieves and cerous nitrate is proposed. Based on the results of XRD , UV–Vis, in-situ FTIR, and 29 Si MAS NMR techniques, open-site configurations of Ce(III)O 4 and Ce(IV)O 4 tetrahedrons are observed due to a large ionic radius of Ce 3+ and Ce 4+ ions. Open-site configurations result in a low ratio of BrØnsted and Lewis acid sites in HBeta-Ce-6. In the isomerization of α- pinene, a higher amount of Lewis acid sites increases the yield for camphene . BrØnsted acids are accessible for α- pinene to form limonene due to a high surface area and low coke deposition. Isomorphous incorporation of Ce 3+ occurs and a decreasing selectivity for limonene are observed using regenerated catalysts. These results indicate that co-calcination strategy protects Beta molecular sieves from thermal destruction, endows Beta molecular sieves with a higher relative crystallinity and porosity during calcination .
研究领域:
材料科学
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催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
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2024
·
IF 4
Mengjiao Yu,Xiong-Fei Zhang,Siting Yang,Yunhua Bai,Zhongguo Wang,Jianfeng Yao
Developing functional catalysts with both Lewis and Brønsted acid sites is an essential task for achieving the direct conversion of glucose to 5-hydroxymethylfurfural (5-HMF), a process that is crucial for the sustainable production of renewable fuels and chemicals. In this work, a mixed-linker strategy is proposed to prepare defective MIL-53(Al)-NH 2 by introducing trifluoroacetic acid into the MIL-53(Al)-NH 2 synthesis process. The creation of defects facilitates the exposure and accessibility of Al 3+ centers, as well as changes the coordination environment within the MIL-53(Al)-NH 2 skeleton. Both the number of Lewis and Brønsted acid sites are boosted, which is beneficial for glucose activation and 5-HMF generation. Through optimizing the reaction conditions, a glucose conversion of 98.3 % with a 5-HMF yield of 59.3 % was achieved by using defective 6d-MIL-53(Al)-NH 2 in a biphasic tetrahydrofuran/H 2 O NaCl system. Moreover, the 6d-MIL-53(Al)-NH 2 catalyst showed excellent recyclability and reusability, with its catalytic efficiency maintained almost unchanged for consecutive 10 cycles. The catalytic mechanism was elucidated and the acidity of the Lewis and Brønsted acid was modulated by defect engineering to achieve exceptional performance.
研究领域:
化学工程
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催化科学
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可再生资源
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Jiarong Qiu,Yi Liu,Jingwen Zhang,Ben Zhou,Qiyue Yang,Liangqing Zhang,Jianfeng Chen,Bingshu Wang,Lu Lin,Xianhai Zeng
A series of zirconium phosphate (ZrP) loaded H-beta-25 zeolite (i.e., ZrP@HB) multifunctional composite catalysts were synthesized by a simple co-precipitation method, and the one-pot upgrading for the transfer hydrogenation of furfural to γ-valerolactone (GVL) was systematically investigated through various characterizations and catalytic evaluation experiments. Comparative characterization analysis of the ZrP@HB-X(Y) catalysts showed that the ZrP@HB-4(4) catalyst has uniform distribution of elements, exhibiting a large specific surface area and hierarchical mesoporous/microporous structure. Fourier transform infrared spectroscopy of pyridine (Py-FTIR) and NH 3 temperature-programmed desorption characterizations indicated the presence of Lewis and Brønsted acid sites, as well as weak, moderate, and strong acid sites in the ZrP@HB-4(4) catalyst. It was confirmed by X-ray photoelectron spectroscopy and FTIR that the main reason for Lewis and Brønsted acid sites formation is the presence of P-O-Zr, P-O-H, and HB zeolite on the ZrP@HB-4(4) catalyst. The HB zeolite as well as Zr and P ratio, can be easily adjusted to efficiently regulate the acidity strength and Lewis and Brønsted acid sites of the ZrP@HB-X(Y) catalysts. The catalytic experiments demonstrated that the physicochemical properties of the ZrP@HB-4(4) catalyst mentioned above significantly enhance the GVL production. Notably, Lewis and Brønsted acid sites as well as transition metal sites of Zr in the ZrP@HB-4(4) catalyst were identified as the main factors that enhance the yield of the target product. By optimizing the reaction conditions, the yield of GVL could be as high as 88.16%. Reusability experiments demonstrate that the ZrP@HB-4(4) catalyst possesses excellent stability. Using levulinic acid as the substrate, the yield of GVL reached 93.92%, suggesting its potential versatility.
研究领域:
催化化学
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可再生化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2023
·
IF 16.5
Cheng Liu,Mengning Chen,Yingzhang Shi,Zhiwen Wang,Wei Guo,Sen Lin,Jinhong Bi,Ling Wu
Two ultrathin ZnTi-LDH nanosheets with different thickness (1.4 and 4.0 nm) were prepared to study the interplay between the active site and catalytic performance in photocatalytic synthesis of N -benzylideneanilline via a tandem reaction. ZnTi-LDH nanosheet possesses dual isolated active sites including the coordinatively unsaturated Ti atoms (Lewis acid sites) and the H atoms of OH groups (Brönsted acid sites), achieving the activation of benzyl alcohol and nitrobenzene via C–O···Ti species and N–O···H–O species, respectively. Photogenerated holes and electrons facilitate the oxidation of benzyl alcohol to benzaldehyde and the reduction of nitrobenzene to aniline, respectively. The thinner sample possesses more active sites, facilitating not only the activation of reactants but also the separation of photogenerated carriers. Therefore, a thinner ZnTi-LDH nanosheet shows the high conversion (100%) and the high selectivity (96%). Finally, a synergetic photocatalytic mechanism connected to the molecular activation is illustrated at the molecule level.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2021
·Vol. 12
·期 2
·596-605
·
IF 6.119
Daofeng Huang,Siyue Chen,Sicong Ma,Xin Chen,Yuanhang Ren,Meiyin Wang,Lin Ye,Li Zhang,Xueying Chen,Zhi-Pan Liu,Bin Yue,Heyong He
Sulfated zirconia (SZ) plays an important role in solid acid catalysts. To understand the origin of the super acidity over the surface of sulfated zirconia, pure monoclinic and tetragonal phase zirconia and their sulfated counterparts (M-SZ and T-SZ, respectively) were prepared, and the acid properties of these samples were characterized by 31P MAS NMR using TMP as the probe molecule. In comparison with zirconia, stronger Lewis acid (LA) and Brønsted acid (BA) sites were generated over the SZ samples after sulfation. The density ratios of the newly generated LA and strong BA sites were found to be ca. 2.0 : 1.0 on M-SZ and ca. 1.8 : 1.0 on T-SZ. Based on this quantitative relationship between the newly generated LA and strong BA sites, the possible acid structures on the SZ surface with different crystal phases are established. After structural optimization and theoretical calculation, the super acid sites originating from the bisulfate ions on the monoclinic (001) plane and the tetragonal (111) plane are determined.
研究领域:
催化化学
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材料科学
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理论计算化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Jinyu Huang,Zhuoqian Li,Jingyi Yang,Zhikun Peng,Qiaoyun Liu,Zhongyi Liu
Bifunctional Pd/Hβ catalysts with uniformly distributed palladium nanoparticles (Pd NPs) were successfully synthesized by a facile methanol-mediated weakly capping growth approach (WCGA). A series of Pd/Hβ catalysts with different metal loadings and Si/Al ratios were used for benzene hydroalkylation, and the identification of metal/acid matching balance over bifunctional Pd/Hβ toward benzene hydroalkylation performance was investigated. The obtained characterization and catalytic activity test results demonstrated that the weak acid site and Lewis acid site have greatly affected the benzene conversion, and the strong acid site as well as Brønsted acid site had more of an effect on the alkylation process. The best hydroalkylation performance was achieved by tuning the acid/metal molar ratio at 22.4 μmol of H+/μmol of exposed Pd with a high cyclohexylbenzene (CHB) selectivity of 51.7% at a benzene conversion of 63.4%, which is the best CHB yield currently obtained for all we know. In addition, the stability of Pd/Hβ catalysts was tested and compared with that prepared by the incipient wetness impregnation (IWI) method, which showed good stability, and no obvious particle aggregation was found. This work provides guidance for exploring the construction of bifunctional catalysts and the balance of metal/acid sites.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Jie Yang,Liyuan Huai,Jiang Gan,Hualei Hu,Shenghu Zhou,Jian Zhang
The 5,5′(oxy-bis(methylene))bis-2-furfural (OBMF) formation from the 5-hydroxymethylfurfural (HMF) self-etherification over zeolites is an important reaction for the synthesis of value-added chemicals from biomass resources. However, there is still a lack of knowledge about the reaction mechanism and the roles of different acid sites that impedes the exploitation of zeolite catalysts for efficient OBMF production. In the present study, the ZSM-5 (HPZ) catalysts of four hierarchically micromesopores were successfully synthesized in different Si/Al ratios by adjusting the amount of Al in the solvent evaporation with the assistance of a dry gel conversion method. The kinetics of OBMF formation from HMF self-etherification was investigated. The apparent activation energy and the conversion reaction order were calculated to be 104.6 kJ/mol and 0.65, respectively. The intrinsic activity comparison of four catalysts and density functional theory (DFT) calculations showed that HMF adsorption and etherification benefit from Brønsted-acid sites. Besides, the DFT results suggested that the etherification proceeds via a concerted step, instead of the sequential pathways, thus leading to the high selectivity of OBMF on hierarchically micromesoporous ZSM-5 (HPZ) catalysts.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Jinjin Zhang,Fumin Wang,Xubin Zhang,Yi Zhai,Kaiwei Wang,Changhao Bing,Xiaolu Fan,Xinyuan He,Qi Shen,Linfang Jiang,Jiawei Wang,Zheng Wang
Achieving excellent conversion and high stability is crucial in promoting practical applications of many emerging oxidative desulfurization (ODS) catalysts. Herein, POM@HUSYs were prepared through an in situ procedure, which enhanced the dispersion of polyoxometalate (POM) and reduced the leaching of active components. The catalyst was prepared in an acidic environment, which served a dual purpose. One purpose was to introduce Lewis acid sites in the zeolite, while the other was to synthesize the corresponding POM to provide Bro̷nsted acid sites. By adjusting the synthesis conditions, catalysts with the best synergistic impact between the Lewis and Bro̷nsted acid sites were discovered. The best sample HPW@HUSY24H-0.06M could achieve 99.2% DBT conversion in 120 min. Additionally, the obtained catalyst could efficiently adsorb the ODS products from the oil phase without extraction. The concept of a synergistic catalytic mechanism guides the future design and development of heterogeneous catalysts for ODS reactions.
研究领域:
催化化学
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材料科学
·
环境化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2019
·
IF 4.191
Xiaoyun Li,Rui Xu,Qingling Liu,Min Liang,Jiaxin Yang,Shuangchun Lu,Guangbi Li,Lefu Lu,Chuanling Si
A one-step process was proposed for valorization of corn stover into furfural and levulinic acid catalyzed by SAPO-18 zeolites. With the aim to produce furfural and levulinic acid, the Brønsted to Lewis acid site ratios of SAPO-18 were modified. The influence of reaction temperature, time and the ratios of Brønsted to Lewis acid site on the valorization of corn stover were investigated. At the fixed catalyst concentration of 20 g/L, a furfural yield of 95.1% was observed at 205 °C for 40 min using SAPO-18 with Brønsted to Lewis acid site ratio of 0.11, and a levulinic acid yield of 70.2% achieved at 190 °C for 80 min using SAPO-18 with Brønsted to Lewis acid site ratio of 0.17. The Brønsted to Lewis acid site ratios of SAPO-18 were adjusted by altering the framework Si/Al ratio of SAPO-18. The SAPO-18 with lower Brønsted to Lewis acid site ratios showed higher activity for furfural production from corn stover and that with higher ratios exhibit superior catalytic effect for levulinic acid formation. The kinetic models considering the effect of Brønsted to Lewis acid site ratios agreed with the experiment values well, which provided detailed insights on the conversion of hemicellulose and cellulose fraction of corn stover into furfural and levulinic acid.
研究领域:
化学工程
·
生物质能
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Armin Rezayan,Ke Wang,Renfeng Nie,Tianliang Lu,Jianshe Wang,Yongsheng Zhang,Chunbao Charles Xu
Catalytic transformation of carbohydrates to bio-chemicals such as 5-Hydroxymethylfurfural (HMF) has become a hot research topic, but development of cost-effective/efficient catalysts and processes remains a challenge for industrial application. In this study, efficient bifunctional Sn/KIT-1/C catalysts with controllable acid sites were synthesized and applied for glucose-to-HMF conversion. Strong Lewis acid sites were introduced into the framework of disordered mesoporous silica by liquid-phase grafting of tin chloride, and Bronsted acid sites were generated by inserting carbon into the mesopores, followed by controlled oxidation of the carbon. Characterizations revealed that optimizing the amount of carbon source, and carbonization and oxidation temperature provided a proper amount and strength of acidity that could significantly catalyze glucose dehydration reaction to HMF with suppressed byproducts formation. The best catalyst Sn/KIT-1/C(75–400-300) demonstrated superior catalytic performance at 175 °C for 2 h under THF/H 2 O biphasic system, obtaining 78.4 ± 2.1% and 82.9 ± 2.4% HMF yield and selectivity, respectively. The high activity may be attributed to catalyst high surface area/porosity, and the presence of well-balanced amounts and strength of Lewis/Bronsted acid sites. The catalyst could maintain its excellent catalytic activity for five consecutive runs, suggesting the high physical–chemical stability of the catalyst. The results obtained in this work demonstrated that bifunctional metal-supported silica–carbon composites can be a promising catalyst for simple/complex carbohydrates conversion to HMF/bio-based chemicals.
研究领域:
催化
·
化学工程
·
材料科学
·
生物化学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Lijie Fu,Juanjuan Gong,Hengyu Li,Jinhua Xiao,Bihong Lv,Xiaomin Wu,Zhiwei Huang,Zuoming Zhou,Guohua Jing
The regeneration of catalytic amine-based solvents using solid acid offers a promising approach to reduce energy consumption in CO 2 capture processes. Nickel-based solid acid catalysts, endowed with multiple Lewis acid sites, could enhance the efficiency of regeneration reactions. Nevertheless, the irregular pore structure of NiO and the deficiency in Brønsted acid sites posed significant challenges to the practical use of amine solvent regeneration in CO 2 vapor stripping processes. A highly effective solid acid catalyst, nickel-modified H-β (Ni/β), were synthesized to enhance CO 2 desorption from MEA solutions saturated with CO 2 . The catalyst with 1.25% Ni (1.25% Ni/β) exhibited the highest activity and stability, with a 43.19% increase in the amount of desorbed CO 2 and a 30.16% reduction in relative heat duty. The catalyst maintained excellent stability, enhancing the desorption performance of MEA after ten cyclic absorption–desorption experiments. According to theoretic calculations and experimental analyses, the incorporation of H-β zeolite significantly enhanced the specific surface area of the composite and introduced a substantial number of Brønsted acid sites. Concurrently, the introduction of metal nickel substituted the hydrogen proton on the hydroxyl groups of the H-β molecular sieve, increasing the Lewis acid sites and modulating the Brønsted-to-Lewis acid site ratio. The Brønsted acid sites functioned as proton donors, while the Lewis acid sites facilitated N-C bond cleavage, promoting carbamate decomposition and the deprotonation of protonated amines. This work presents a valuable solid acid catalyst for amine-based CO 2 capture and offers insights for developing innovative solid acids for various catalytic processes.
研究领域:
化学工程
·
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）