RSC Advances
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2018
·Vol. 8
·期 43
·24534-24540
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IF 2.936
Jin Tan,Haiyong Wang,Longlong Ma,Chenguang Wang,Qiying Liu,Qi Zhang,Minghong He
Several simple and effective solvents combined with Hβ zeolite were tested to selectively convert glucose into furfural and hydroxymethylfurfural in this work. The physicochemical properties of typically different polar aprotic solvents were compared. Tetrahydrofuran was found to be a suitable solvent in the selective conversion of glucose. The effect of reaction parameters, such as temperature, reaction time, water content, glucose dosage and protonic acid addition, on the product distribution were investigated in detail. Furfural and hydroxymethylfurfural could be selectively produced in this system, and the highest yields of furfural and hydroxymethylfurfural were up to 35.2% and 49.7% respectively. Furfural could be stable in a tetrahydrofuran medium when adding 5 wt% water in the absence of extra protonic acid. However, furfural production was extremely suppressed after addition of an acidic inorganic salt, which increased the yield of hydroxymethylfurfural. This investigation indicates a simple and feasible method to selectively produce furfural and hydroxymethylfurfural from renewable cellulosic carbohydrates.
研究领域:
化学工程
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可再生资源转化
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DOI
PubMed
高影响因子
Catalysts
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2018
·Vol. 8
·期 2
·82
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IF 3.465
Yadong Bi,Xiaojuan Lei,Guihua Xu,Hui Chen,Jianli Hu
The hierarchical HZSM-5 and Hβ zeolites were prepared by alkaline post-treatment methods adopting Na2CO3, TMAOH/NaOH mixture, and NaOH as desilication sources, respectively. More mesopores are produced over two kinds of zeolites, while the micropores portion is well preserved. The mesopores formed in hierarchical Hβ zeolites were directly related to the basicity of the alkaline solution, indicating that Hβ zeolite is more sensitive to the alkaline post-treatment. The hierarchical HZSM-5 and Hβ zeolites are more active than the parent one for catalytic fast pyrolysis (CFP) of Kraft lignin. Hierarchical zeolites retained the function of acid catalysis, while additionally creating larger mesopores to ensure the entry of bulkier reactant molecules. The increase of the condensable volatiles yield can be attributed to the improvement of the mass transfer performance, which correlates well with the change of mesoporous surface area. In particular, the condensable volatiles yield for the optimized hierarchical Hβ reached approximately two times that of the parent Hβ zeolites. In contrast to the parent HZSM-5, the optimized hierarchical HZSM-5 zeolite significantly reduced the selectivity of oxygenates from 27.2% to 3.3%.Keywords:catalytic fast pyrolysis;Kraft lignin;hierarchical zeolites;HZSM-5;Hβ
研究领域:
化学工程
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材料科学
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DOI
高影响因子
Energy Advances
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2024
·Vol. 3
·期 7
·1571-1580
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IF 3.2
Zhaocai Jiao,Mingzu Liu,Ningbo Yang,Fengli Yu,Congxia Xie,Shitao Yu,Bing Yuan
α-Pinene and isobutene/isobutane can undergo hybrid alkylation under acid catalysis, resulting in C14 and C20 product fractions with favorable bio-based high-energy-density fuel properties after hydrogenation. In this study, the catalytic performance of zeolite molecular sieves, such as Hβ, HY, HZSM-5, HZSM-35, HSAPO-11, was investigated for the alkylation of α-pinene and Isobut-5 (a mixture of isobutene/isobutane with a mass ratio of 1 : 5) given the acidic sites and specific pore structures with shape-selective abilities of zeolite catalysts. Various characterization techniques, including temperature-programmed desorption of ammonia (NH3-TPD), Fourier transform infrared spectroscopy with pyridine adsorption (Py-IR), N2 adsorption/desorption, X-ray fluorescence spectrum (XRF), and particle size analysis, were conducted to analyze the acidic properties, pore characteristics, silica–aluminum ratio, and grain size of the zeolites, and their influence on the alkylation of α-pinene and Isobut-5. Moreover, the recycling performance of the favorite Hβ-25n catalyst and an effective regeneration method were investigated using temperature-programmed oxidation (TPO) analysis. This study provides essential research data for the preparation of α-pinene-based high-energy-density fuels.
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2022
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IF 9.224
Dawei Dong,Yafei Xiao,Minghua Zhang,Peixin Gong,Yingqing Ye,Shuhua Peng,Ke Wang,Minmin Fan
Polysaccharide is a kind of biological macromolecule with a complex structure, which plays an irreplaceable role in the organism. Due to the complex purification process of natural polysaccharide, chemical synthesis is an important means to obtain it. In this work, a green and efficient solid-phase polymerization method was used to synthesize glucan polysaccharide from unprotected glucose in one step under mild solid-phase conditions, using Hβ zeolites as acidic catalyst. The final polysaccharide product was characterized by high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) with a conversion of 35.0% and a maximum degree of polymerization of 26. More importantly, it was speculated that the glycosylation of unprotected glucose catalyzed by Hβ zeolites conforms to the Fischer glycosylation mechanism. In addition, the results of methylation analysis and one-dimensional, two-dimensional nuclear magnetic resonance (1D, 2D NMR) showed that the resulting polysaccharides were mainly linear, containing 10 different glycosidic linkages, and (1,6-Glcp), (1-Glcp), and (1,4-Glcp) were the most abundant linkage types among them.
研究领域:
有机化学
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生物化学
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DOI
高影响因子
CATALYSIS SURVEYS FROM ASIA
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2024
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IF 2.1
Zhou Hantao,Feng Shangzhen,Yang Jie,Jiang Huanjin,Zhang Xing,Chen Jixiang
Zeolites (Hβ, HZSM-5 and HM), TiO 2 and ZrO 2 supported NiCo alloy catalysts were tested for the hydrodeoxygenation of phenol in aqueous phase. It has been found that the catalyst acidity remarkably influences the catalyst activity and the product distribution. Zeolites supported catalysts give much higher yield of the deoxygenated products (mainly benzene and cyclohexane) than NiCo/TiO 2 and NiCo/ZrO 2 , where cyclohexanol and cyclohexanone are dominating. Associated with NH 3 -TPD, we suggest that the catalyst acidity promotes the hydrodeoxygenation. Hβ zeolite supported NiCo alloy is more active than others, attributed to its higher metal dispersion and more acid sites. Therein, the Hβ zeolite calcined at 750 o C has moderate acidity, and its supported NiCo alloy catalyst (NiCo/HB-750) shows the best performance. Under a suitable reaction condition, the phenol conversion and the total yield of deoxygenated products reaches 96.8% and 94.5% on NiCo/HB-750, respectively.
研究领域:
催化化学
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能源化学
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2025
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IF 7.3
Yu Zhang,Huai Liu,Rui Zhang,Wenlong Jia,Junhua Zhang,Lincai Peng
Simultaneous utilization of lignocellulose-related glucose and xylose to produce methyl levulinate (ML), a versatile industrial commodity, is important to fully expend biomass components. We herein report a promising catalytic protocol involving the Hβ zeolite in dimethoxymethane (DMM) and methanol (MeOH) cosolvent that enables the coconversion of glucose and xylose to ML under one-pot conditions. ML yield as high as 56% with a turnover frequency (TOF) of over 3.2 h–1 can be accomplished at 150 °C. Isomerization–dehydration of glucose/xylose represents the primary reaction path, whereas the production of glycosides through etherification constitutes the secondary reaction path. The suggested catalytic mechanism is the preferential adsorption of C–O–C and C–OH groups at different acid sites, which leads to the emergence of two distinct pathways for the conversion of glucose/xylose into ML. Hβ-25, featuring a high concentration of Lewis and Brønsted acid sites, facilitates two distinct pathways for the conversion of glucose/xylose into ML. DMM functions as a hydroxymethylation reagent in the conversion of xylose to ML and promotes the isomerization of glycosides via ether exchange reactions. This contribution devises an efficient strategy for producing ML from glucose and xylose while elucidating the reaction mechanism of a tailored monolithic catalytic system.
研究领域:
生物化学
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催化化学
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高影响因子
FUEL
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2025
·
IF 7.5
Kande Liu,Sitan Wang,Lishan Zheng,Yuan Fang,Ranran Tao,Naiwang Liu,Fahai Cao,Xuan Meng,Li Shi
As a crucial fine chemical intermediate, the compound 4-TBP holds significant importance in both antioxidant synthesis and the production of various fine chemical products, including resins, flame retardants, surfactants, and ultraviolet absorbers. However, traditional catalysts employed in the production of 4-TBP are plagued by several drawbacks, such as equipment corrosion, environmental contamination, and inadequate thermal stability. In order to overcome these challenges, a series of Hβ-x% MgO catalysts with varying MgO loadings were successfully synthesized using the immersion method. These catalysts were comprehensively characterized through multiple analytical techniques, including XRD, FT-IR, SEM, N 2 adsorption–desorption analysis, ICP-OES, Py-IR, 27 Al and 29 Si MAS NMR and CO 2 -TPD. These materials were subjected to catalytic evaluation through the phenol alkylation process using tert -butyl alcohol as the alkylating agent. Notably, the Hβ-2.5% MgO catalyst demonstrated superior performance, a remarkable selectivity of 88.2% toward 4-TBP production was attained, which represents a 14.7% improvement over the unmodified Hβ zeolite. The study scope was expanded to incorporate methanol as an alkylation agent, consistent reaction rules were observed, which contributes significantly to the understanding of alcohol-mediated phenol alkylation studies.
研究领域:
化学工程
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催化科学
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DOI
高影响因子
FUEL
·
2020
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IF 5.578
Xiao Zhou,Xian-Yong Wei,Yu-Miao Ma,Zhi-Min Zong
An active bifunctional nickel-based catalyst was prepared by decomposing Ni(CO) 4 to dispersive metallic Ni on Hβ zeolite and successfully applied in the catalytic hydroconversion (CHC) of an alkali lignin (AL). Detailed elemental composition, functional groups, and molecular compositions of the soluble portions (SPs) from non-catalytic hydroconversion (SP NCHC ) and CHC (SP CHC ) were characterized with an elemental analyzer, a Fourier transform infrared spectrometer, and a gas chromatograph/mass spectrometer (GC/MS). As a result, alkoxalkanes, phenol, cresol, veratrols, alkyl-substituted 1,4-dimethoxyphenols, 2,5-dimethylfuran, 3-hydroxyneopentanal, 4-methylpent-3-en-2-one, 4-methoxy-4-methylpentan-2-one, 1-(2,4-dihydroxy-3-tolyl)propan-1-one, and 2,5-dimethylhex-4-enoic acid only appear in SP CHC , and yields of multiple alkyl-substituted phenols, p -alkylanisoles, diols, non-substituted and alkyl-substituted methoxyphenols, and substituted phenylethanones in SP CHC are significantly higher than those in SP NCHC . The mechanism for catalytically hydrocracking >CH-O- bridged bonds over Ni/Hβ is proposed using benzyloxybenzene (BOB) and phenethoxybenzene as AL-related model compounds. Ni/Hβ proved to be stable after 3 cycles with relatively small loss in catalytic activity for catalyzing the hydrocracking of >CH-O- bonds in BOB.
研究领域:
化学工程
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材料科学
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能源科学
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DOI
高影响因子
ACS Omega
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2020
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IF 2.87
Nina Zhang,Ruili Li,Ge Zhang,Le Dong,Dongyuan Zhang,Guojiang Wang,Tongtong Li
Different metal ions were used to modify Hβ zeolite adsorbents by an impregnation method to remove organic chlorides from the model naphtha. The dechlorination performance of different ion-modified adsorbents was evaluated using a microcoulometer. The effects of calcination time and temperature, metal loading, adsorption time and temperature, and dosage of adsorbent were investigated by batch adsorption experiments. The modified adsorbents were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), NH3-temperature-programmed desorption (TPD), scanning electron microscopy (SEM), infrared spectroscopy of pyridine adsorption (Py-IR), and X-ray photoelectron spectroscopy (XPS). After modification, the modified Zn/Hβ zeolite exhibited the best dechlorination performance among the other metal-loaded zeolites. The removal percentage of organic chloride of the Zn/Hβ adsorbent prepared at optimum preparation and adsorption conditions can reach 72.54%, compared with 34.07% of Hβ zeolite. The Zn/Hβ adsorbent also maintained good dechlorination performance after regeneration by calcination for five times. The characterization results revealed that the concentration of the B acid sites in the zeolite decreased with the introduction of the metals, whereas that of the L acid sites increased. Zn/Hβ zeolite had the lowest B/L ratio but the best dechlorination performance, which meant that the type and amount of acidic sites present in zeolites played a significant role in dechlorination performance and L acid was beneficial for chloride compound removal.
研究领域:
化学工程
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环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
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2022
·Vol. 101
·期 3
·1591-1601
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IF 2.5
Renjie Deng,Yao Tian,Huajie Liu,Weiwei Yan
This work presents a novel heterogeneous catalytic system for the preparation of para -nitrotoluene ( p -NT) with nitrogen dioxide (NO 2 ) as a nitrating agent in the presence of oxygen (O 2 ). By applying dealuminated Hβ zeolite treated with oxalic acid (Hβ-Ox) as a catalyst, p -NT can be obtained with high conversion (90.5%) and selectivity (72.6%). In addition, it can be recycled at least five times without a significant decrease in catalytic activity. This result demonstrates that the catalyst has high efficiency, good stability, and regenerability. Meanwhile, the characteristics of pristine Hβ and different dealuminated Hβ zeolites modified with organic and inorganic acids were systematic contrastive studied using X-ray diffraction (XRD), nitrogen (N 2 ) adsorption-desorption, Fourier-transform infrared (FT-IR), scanning electron microscope (SEM), temperature-programed desorption of ammonia (NH 3 -TPD), pyridine adsorption infrared (Py-FT-IR), and solid state 27 Al nuclear magnetic resonance ( 27 Al MAS-NMR). Finally, the higher conversion and para -selectivity over Hβ-Ox also give a reasonable explanation in this paper.
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2024
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IF 5.9
Jian Yang,Daoming Chen,Meifang Cao,Xueqing Qiu,Xinping Ouyang
The catalytic dehydration of bio-derived lactic acid into acrylic acid is one of the research hotspots in the field of green chemical industry, but the selectivity of acrylic acid and the stability of catalyst still face great challenges. In this work, a modified Hβ zeolite catalyst was prepared by sequential nitric acid treatment and Rb ion-exchange for the gas phase dehydration of lactic acid to prepare acrylic acid. The nitric acid treatment increased the content of Lewis acid sites together with the decrease of the content of Bronsted acid sites, which enhanced the dehydration and hindered the decarboxylation/decarbonylation of lactic acid. Consequently, the selectivity of acrylic acid was improved. The Rb ion-exchange not only significantly decreased the density of acidic sites but also regulated the density of basic sites of the catalyst. The optimal 0.1NA-6.8Rb/Hβ catalyst treated by 0.1 mol/L of nitric acid and 6.8 wt% of Rb ion-exchange contributed to a 99.28 % conversion of lactic acid and 76.72 % yield of acrylic acid. The catalyst showed a better stability and was easy to regenerate, maintaining 87.35 % conversion of lactic acid and 62.49 % yield of acrylic acid, respectively, after two cycles of consecutive 48 h reaction.
研究领域:
绿色化学
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催化化学
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DOI
高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
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2023
·Vol. 101
·期 12
·6807-6816
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IF 2.1
Renjie Deng,Wenjin Ni,Yao Tian
Bimetallic cerium-manganese modified Hβ zeolite sample (Ce/Mn-Hβ) was prepared by ultrasonic assisted impregnation method and applied in nitration of toluene. The characterization results show that the active components (Ce and Mn) are successfully introduced into the framework of Hβ zeolite. The catalyst shows excellent catalytic activity and reusability for the nitration of toluene, giving high para selectivity. Under optimized conditions, it gives 68.7% selectivity to para -nitrotoluene at 88.6% conversion over Ce/Mn-Hβ in the presence of acetic anhydride (Ac 2 O). The theoretical calculations indicate that the Ce/Mn bimetallic active sites in modified Hβ zeolite can easily activate the nitrification reagent (AcONO 2 ), and the enhancement of para selectivity is owing to the steric hindrance of catalyst. Furthermore, the reaction mechanism was proposed by the combination of experimental results and theoretical calculations.
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）