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
Catalysis Science & Technology
·
2024
·
IF 4.4
Renjie Deng,Huajie Liu,Haishuai Cui,Yao Tian,Hai Yang
In this work, we have developed a green method for the preparation of para-nitrotoluene through the catalytic nitration of toluene with nitrogen dioxide (NO2) under the promotion of dioxygen (O2). The experimental results reveal that the dealumination of Hβ zeolite has a significant effect on the catalysis of the developed NO2–O2–acetic anhydride (Ac2O) system, in which the conversion of toluene is 78.1% and the selectivity to para-nitrotoluene is 71.8%. Furthermore, the nature of different dealuminated catalysts was investigated by nitrogen adsorption–desorption analysis, X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), thermal gravimetric analysis (TGA), inductively coupled plasma (ICP), ammonia temperature-programmed desorption (NH3-TPD), pyridine adsorbed Fourier-transform infrared (Py-FT-IR), scanning electron microscopy (SEM) and 27Al magic-angle spinning nuclear magnetic resonance (27Al MAS NMR) techniques. The results of characterization indicate that the structure of the Hβ zeolite still remains and that of Al species in the extra-framework is preferentially removed after acid treatment. Based on the combined results of catalytic characterization and DFT calculation, a feasible reaction mechanism of improved para-selectivity in toluene nitration was suggested for the NO2–O2–Ac2O system.
研究领域:
催化化学
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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
·
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
RSC Advances
·
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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产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
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
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
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
ACS Omega
·
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
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
FUEL
·
2020
·
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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产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2024
·Vol. 154
·期 8
·4756-4767
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IF 2.3
Liu Kande,Wang Sitan,Zheng Lishan,Lou Shifeng,Meng Xuan,Cao Fahai,Liu Naiwang,Shi Li
The catalytic performance of Hβ zeolite treated with different concentration of NaOH on the alkylation of tert-butanol with phenol was studied. The effect of NaOH concentration on the crystallinity, morphology, textural property and acidity of Hβ zeolite was studied by X-ray diffraction (XRD), scanning electron microscope characterization (SEM), N 2 adsorption–desorption, Fourier transform infrared spectroscopy (FT-IR) and pyridine adsorption infrared spectra (Py-IR) techniques. A certain concentration of NaOH treatment can regulate the pore structure of Hβ zeolite and remove part of framework aluminum and framework silicon, thus achieving the purpose of regulating the pore structure and acidity of the catalyst. Though lower Bronsted to Lewis acid amount ratio when treated NaOH concentrations were 0.15 mol/L, leading to the increasing of selectivity to 4-TBP. The Hβ-0.2 M showed the high selectivity of 90.21% for synthesis of 4-tert-butyl-phenol (4-TBP), compared with the unmodified parent zeolite, the selectivity of 4-TBP improved 16.7%. Graphical Abstract
研究领域:
催化化学
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材料科学
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DOI
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2016
·Vol. 43
·期 3
·1557-1574
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IF 1.833
Xiong Yuannan,Chen Wenqi,Zeng Aiwu
The liquid phase acylation of 2-methylfuran with acetic anhydride over modified Hβ zeolite was first conducted in a continuous flow reactor. The deactivation of Hβ zeolites was attributed to strong adsorption of reactants or products and was verified by GC–MS and 13 C MAS NMR. Deactivated zeolites can be regenerated to their original state by calcination. The acidic properties was adjusted by surface modification on Hβ, the maximum yield of 89.5 mol% and selectivity of 100 % were obtained over tartaric acid modified by Hβ. The deposition of tetraethoxysilane to silica on Hβ contributed to enhancing the catalytic stability. Combined with the results of NH 3 -TPD and Py-FTIR, the amount of Broensted acids played a major role on catalytic activity. A close relationship between the catalytic stability and the ratio of the amount of strong to weak acids at 1:1 was highlighted here. The solvents' effect on the catalytic performances was examined, and 1,2-dichloroethane with moderate polarity exerted a positive effect on catalytic stability.
研究领域:
化学工程
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催化材料科学
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产品关联
DOI
高影响因子
FUEL
·
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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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）