ENERGY & FUELS
·
2024
·
IF 5.2
Xin Huang,Guangchuan Tang,Lei Tang,Chuan Ma,Yunlin Shao,Jingyu Ran
Bio-based platform chemicals are of great significance to future green fine and commodity chemicals. This study reports the performances and mechanisms of solvothermal dehydration of levoglucosan (LGA), the main precursor from noncatalytic pyrolysis of cellulose with a yield up to 80 wt %, to levoglucosenone (LGO) using cesium heteropolyacid salts at the catalyst in DMSO solvent. Catalyst characterizations revealed that cesium was well doped in the cubic of heteropolyacids, and the cesium doping ratio substantially influenced the catalytic performances toward LGO. LGO yield first increased and then decreased with the increase of cesium doping ratios, which is consistent with the change trends of pore structures and Brønsted/Lewis acid site ratios of the cesium heteropolyacid salts. LGO was obtained with the maximum yield at 41.2% over Cs2H2SiW12O40 compared to 39.2% over Cs2.5H0.5PW12O40. The catalyst can be regenerated by calcination without losing its catalytic performances. In addition, density functional theory calculation was used to reveal the mechanism for LGO formation, and the rate-determining step was the first step of the dehydration reaction with the energy barrier of 166 kJ/mol.
研究领域:
化学工程
·
可再生资源与环境科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 3.7
Dechang Cheng,Zhihong Ma,Ziyang Liu,Xiaohui Liu,Tao Liu,Weizhen Sun,Ling Zhao
Isosorbide is a novel bio-based material, derived as a secondary dehydration product of sorbitol. This work focuses on the kinetics of sulfuric acid-catalyzed dehydration of sorbitol under conditions of non-constant volume. Herein, the effects of stirring rate, catalyst dosage, reaction temperature, and reaction time on the dehydration reaction of sorbitol were investigated. The yield of isosorbide up to 77.13% was obtained after 1.5 hours of reaction time under conditions of 2 kPa, 1.0% (mass) catalyst dosage, and 413.15 K. Based on the sorbitol dehydration reaction mechanism and a simplified reaction network, a kinetic model was developed in this work. A good agreement was accomplished between kinetic modeling and experiments between 393.15 and 423.15 K. The fitting results indicate that side reactions with higher activation energy are more affected by reaction temperatures, and the main side reaction that influences the selectivity of isosorbide is the oligomerization reaction among the primary dehydration products of sorbitol. The model fitting of the catalyst amounts effect shows that the effective concentration of sulfuric acid would be reduced with the increase of dosage due to the molecular agglomeration effect. Hopefully, the kinetic experiments and modeling results obtained in this work will be helpful to the design and optimization of the industrial sorbitol dehydration process.
研究领域:
化学工程
·
生物化工
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产品关联
DOI
高影响因子
Journal of Biobased Materials and Bioenergy
·
2014
·Vol. 8
·期 4
·437-443
·
IF 0.586
Wang Wenju,Ren Junli,Li Huiling,Peng Feng,Sun Runcang,Liu Shijie
A feasible and environmental-friendly approach was developed for the dehydration of xylose into furfural using AlCl3-dominant catalysts in a homogeneous DMSO/H2O system. Results showed that the paired chlorides (AlCl3/KCl) in the molar fraction (χAlCl3
)
of 0.6 displayed the better catalytic performance than the single AlCl3 and the other paired chlorides. The influences of catalyst amount, reaction temperatures as well as xylose concentration on the dehydration of xylose into furfural were studied. The effects of co-solvents (DMF,
DMI, DMAC and NMP) on the production of furfural were also investigated. DMSO exhibited the better enhancement effect and the desirable DMSO/water volume ratio was 5:5, indicating DMSO could efficiently suppress the side reaction and enhance the selectivity. The maximum furfural yield of 43.6%
with xylose conversion of 97.9% and the selectivity of 44.6% was achieved at 170°C for 2 h with a total catalyst/xylose molar ratio of 0.5 at the solid to liquid ratio of 1:10.
研究领域:
化学工程
·
生物质转化
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Meng Chen,Wei Lu,Hejun Zhu,Leifeng Gong,Ziang Zhao,Yunjie Ding
Linear α-olefins (C8–C12 α-olefin, LAOs) are acknowledged as high-value-added chemicals in both lubricant production and the polyolefin industry. An alternative route to the synthesis of high-purity LAOs is the dehydration of linear long-chain n-alcohols, whereas elevating the activity and selectivity of catalysts remains a challenge. Herein, we presented that on using sodium-modified γ-Al2O3 as the catalyst, a high selectivity (up to 96.87%) to 1-decene was achieved, and an optimized experimental condition (329 °C and 0.25 h–1) was found using the response surface method. Characterization results including X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), pyrolysis (Py)-IR, NH3-temperature-programmed desorption (TPD), and CO2-TPD showed that a suitable ratio (∼0.4 wt %) of sodium impregnation could inhibit the strong acid sites of the catalyst, and sodium impregnation led to the formation of additional base sites, which accounted for the synergistic effect with other acid sites to promote further conversion of ethers to olefins. This work is of significance for the synthesis of LAOs from long-chain n-alcohols.
研究领域:
催化化学
·
材料科学
·
石油化工
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
·
IF 2.235
Yuyuan Deng,Qin Zhang,Huachuan Zhang,Chengxi Zhang,Wenhu Wang,Yi Gu
To study oxazine ring formation in benzoxazine synthesis from phenol, primary amine and formaldehyde, reactions between 2-phenylaminomethylphenol (Mannich base) and formaldehyde in homogeneous dioxane/water solution are researched. Reaction orders, rate constants at different temperatures, and activation energy are calculated, the process of reaction is proposed, and the influence of acid and base is discussed. The reaction can occur at low temperature and generate the product 3,4-dihydro-2H-3-phenyl-1,3-benzoxazine. No intermediate 2-(N-hydroxymethyl-N-phenylamino)methylphenols are observed. The concentration of a Mannich base has little effect on the reaction rate, while the reaction is first-order to formaldehyde. Based on chemical properties of formaldehyde in aqueous solution, the reaction process includes the following three steps: degradation of poly(oxymethylene) glycols to methylene glycol, dehydration of methylene glycol to formaldehyde molecule, and the reaction between a Mannich base and formaldehyde molecule to benzoxazine. Dehydration of methylene glycols to formaldehyde molecules is the rate-controlling step.
研究领域:
有机化学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2014
·
IF 3.309
Huiling Li,Aojie Deng,Junli Ren,Changyu Liu,Wenju Wang,Feng Peng,Runcang Sun
One of the most promising strategies for furfural production is to extract continually the target product from the aqueous solution utilizing organic solvents. With the aim to develop an ecologically viable catalytic pathway for furfural production without the addition of mineral acids, we presented a modified biphasic system using a solid acid (SO 4 2− /TiO 2 -ZrO 2 /La 3+ ) as catalyst for producing furfural from xylose. Different kinds of aprotic organic solvents (DMSO, DMF and DMI) in water phase and 2-butanol in organic phase (MIBK) were investigated as reaction media. Furfural yield and xylose conversion efficiency were dependent on the amounts of aprotic organic solvents and 2-butanol, the solid/liquid ratio, and the volume ratio of the organic phase and the aqueous phase as well as the reaction temperature and time. As a result, DMI showed the best performance on improving furfural yield during the furfural production. 3563.3 μmol of furfural/g of xylose with 97.9% xylose conversion efficiency was obtained after 12 h at 180 °C when the volume ratios of water to DMI and MIBK to 2-butanol were 8:2 and 7:3, respectively.
研究领域:
生物化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Xiao-Han Pan,Jelena Petrović,Jian-Hua Zu,Đorđe Cvjetinović
This research investigates the performance of new radiografted materials as adsorbents for ionic and colloidal 110 m Ag, a prominent pollutant in pressurized water reactor (PWR) wastewater. A comparative analysis was conducted to evaluate their effectiveness against commercially available resins. Due to the increasing demand for new nuclear power plants and the growing global dependence on nuclear energy, it is crucial to minimize radioactive waste production. The study was conducted on simulated inactive and radioactive waste samples with trace amounts of 110 m Ag that are hard or impossible to detect by standard analytic techniques. The synthesized materials were labeled PGE (amine functional groups) and PGM (sulfhydryl and amine functional groups). Functionalization with amine and sulfhydryl groups was chosen since it is well known that these groups strongly interact with Ag in both ionic and colloidal form. The tested materials demonstrate exceptional performance as adsorbents by completely removing (100 %) both ionic (PGM) and colloidal (PGE) forms of 110 m Ag. Additionally, depending on the adsorbed species excellent elution of 110 m Ag was achieved (>94 % for ions and >50 % for colloids) implying possible material reusability. Manufacturing cost of such adsorbents is orders of magnitude lower per kg (10 – 50 $/kg), compared to prices of commercial resins (100 – 10000 $/kg). These results indicate that such inexpensive materials could potentially be used in an efficient and selective way to treat PWR wastewater for 110 m Ag contamination while reducing the operating cost and minimizing resulting solid waste.
研究领域:
环境科学
·
核能工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SYNTHETIC COMMUNICATIONS
·
2024
·
IF 1.8
Xiaoyun Ma,Xiaoyan Wan,Jun Zhao
A method for the preparation of nitriles from primary amides using trichloroacetonitrile and a catalytic amount of cupric acetate is described. Using this method, amides including aromatic amides, aromatic heterocyclic amides and aliphatic amides were converted into the corresponding nitriles in moderate to good yields. Trichloroacetonitrile reacted with amide in the presence of cupric acetate to form trichloroacetamide, which has been isolated and confirmed.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2015
·
IF 4.494
Zhiping Xu,Wenzhi Li,Zhijie Du,Hao Wu,Hasan Jameel,Hou-min Chang,Longlong Ma
A novel solid acid catalyst was prepared by the copolymerization of p-toluenesulfonic acid and paraformaldehyde and then characterized by FT-IR, TG/DTG, HRTEM and N 2 -BET. Furfural was successfully produced by the dehydration of xylose and xylan using the novel catalyst in γ-valerolactone. This investigation focused on effects of various reaction conditions including solvent, acid catalyst, reaction temperature, residence time, water concentration, xylose loading and catalyst dosage on the dehydration of xylose to furfural. It was found that the solid catalyst displayed extremely high activity for furfural production. 80.4% furfural yield with 98.8% xylose conversion was achieved at 170 °C for 10 min. The catalyst could be recycled at least five times without significant loss of activity. Furthermore, 83.5% furfural yield and 19.5% HMF yield were obtained from raw corn stalk under more severe conditions (190 °C for 100 min).
研究领域:
化学工程
·
生物质能
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Biomass Conversion and Biorefinery
·
2021
·Vol. 13
·期 9
·7895-7907
·
IF 4.987
Xia Qi,Peng Hong,Zhang Yu,Fu Guiming,Liu Yuhuan,Xiao Zhihong,Huang Lingling,Bi Haoran
Exploring environmental-friendly routine for efficient furfural production from lignocellulosic biomass is meaningful. Here, bamboo hemicellulose (BH) and xylose were used to produce furfural under microwave irradiation in a biphasic medium, in which 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim]HSO 4 ) served as the reaction phase and catalyst, whereas 1,4-dioxane served as the extraction phase. The effects of retention time, temperature, [Bmim]HSO 4 dosage, and water addition on the furfural yield were evaluated. Results showed the highest total furfural yields of xylose and BH could reach 55.65 mol% and 68.37 mol%, respectively, which were further enhanced to 63.87 mol% and 85.69 mol%, respectively, by adding a small amount of water. The kinetic analysis showed the dehydration rate constant of the formed xylose from BH to furfural was almost twice that of directly using xylose as substrate. Compared with the hydrolysis of BH to xylose, the dehydration of xylose to furfural required higher activation energy. The activation energy of consuming furfural to form by-products was higher than 73 kJ/mol. The recycled [Bmim]HSO 4 performed great reusability, and a small amount of ethanol residue could enhance the total furfural yields of xylose and BH, up to 73.48 mol% and 88.28 mol%, respectively.
研究领域:
生物化学
·
可再生资源工程
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2015
·
IF 4.844
Weijuan Yang,Tianyou Zhang,Junhu Zhou,Wei Shi,Jianzhong Liu,Kefa Cen
Aluminum (Al) is a promising hydrogen carrier. Continuous reaction of pure Al and water (H 2 O) cannot proceed smoothly because Al particles are covered with a protective oxide layer . Thus, 20% Mg, Li, Zn, Bi, and Sn content were added as additives to Al–H 2 O reaction at high temperature. Thermogravimetric experiments were conducted to determine the reactivity of pure Al and five other samples with additives in a vapor atmosphere. Experiments indicated that Mg and Li drove the Al–H 2 O reaction, but Zn, Bi, and Sn had little effect. Thus, Mg and Li were selected as activators in the hydrogen generation of the Al–H 2 O reaction conducted on a specially designed experimental facility. Hydrogen was monitored in the reaction of Al-based composites with H 2 O vapor in real time. Among them, Al–20%Li achieved the fastest hydrogen generation rate (309.74 ml s −1 g −1 ) and the largest hydrogen amount (1038.9 ml g −1 ). XRD (X-ray diffraction), SEM (scanning electron microscopy), and TEM (transmission electron microscopy) were used for product analyses to identify the influence of adding Mg and Li. This method of Al energy utilization may be used in underwater propulsion systems .
研究领域:
能源科学
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Haiyang Wang,Shuo Wang,Xuanyan Liu,Youqi Zhu,Tinglu Song,Haiyue Yu,Hongdi Fu,Kangcheng Xu,Huaqiang Zhu,Yonghao Zhao,Siyuan Tang,Meishuai Zou
Aluminum-lithium alloy powders receive extensive concern as metal fuel in propellants for high heat value and coefficient of combustion. However, the presence of highly active metal lithium leads to the instability of alloy powder, limiting its application in propellants. Herein, the fluorination-energetic modification is developed to solve the activity problem of aluminum–lithium alloy (Al-5Li, Li 5 wt%) powders and increase their energy level. The first fluorinated layer is constructed by fluorosilane and epoxy silane coating to achieve the modifiable and functional aluminum–lithium alloy (Al-5Li@FS). Afterwards, the energetic layer is coated on Al-5Li@FS surface by glycidyl azide polymer (GAP) to obtain the fluorination-energetic composite powders (Al-5Li@FSG). The microstructural and chemical composition characterizations of Al-5Li@FSG are performed by SEM, FTIR, XPS, TEM, and TOF-SIMS. TG-DSC results show that the coated alloy powders can exhibit excellent thermal properties with remarkably enhanced exothermic enthalpy and thermal weight gain. The Al-5Li@FSG shows significantly improved combustion performances with reduced ignition delay time and repressed agglomeration phenomenon. Furthermore, hydrophobicity, water-reactivity, and compatibility with propellant components are also well modified of the Al-5Li@FSG. This work provides a guideline for preparing aluminum–lithium alloy powders with remarkable stability, excellent combustion performance, compatibility, and high energy level.
研究领域:
材料科学
·
能源工程
✓ 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）