JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2019
·Vol. 95
·期 3
·798-805
·
IF 2.659
Dan Luo,Shengnan Liu,Wang Yin,Shuqian Xia
BACKGROUND Fast pyrolysis of lignocellulosics has provided an abundant sugar source for production of value-added chemicals, and levoglucosan is the most representative sugar in pyrolysis liquid (bio oil). This paper explored the potential for producing methyl lactate from levoglucosan by employing the mixed catalysts of zeolite tin beta (Sn-Beta) and zeolite hydrogen beta (H-Beta). RESULTS Under the optimal conditions (at 200 °C and mixed catalysts with H-Beta:Sn-Beta ratio of 1:5), the yield of methyl lactate obtained from levoglucosan conversion was as high as 35%. And the yield was comparable to that of methyl lactate obtained from glucose conversion under the similar conditions (at 200 °C and pure Sn-Beta). In order to investigate the reason, a contrasting experiment with glucose as substrate also was carried out with the mixed catalysts. The results indicated that during the levoglucosan conversion process, ‘the methanolysis of levoglucosan’ was likely to compete with ‘the dehydration of glucose’ for the Brønsted acid sites of H-Beta. In addition, the catalytic functions of H-Beta and Sn-Beta, and the reaction pathway were deeply investigated through tracking and comparing the conversion of levoglucosan over mixed H-Beta/Sn-Beta and over pure Sn-Beta catalysts, respectively. CONCLUSION The appropriately lower ratio of H-Beta:Sn-Beta and relatively higher temperature were favorable for the reaction. H-Beta containing Brønsted acid could remarkably accelerate the conversion of levoglucosan and methyl-glucosides to glucose. Sn-Beta containing Lewis acid mainly promoted the retro-aldol condensation of glucose and formation of methyl lactate. © 2019 Society of Chemical Industry
研究领域:
化学工程
·
生物质能
·
催化化学
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Changzhou Chen,Peng Liu,Haihong Xia,Jianchun Jiang,Xiaohui Yang,Minghao Zhou
Lignin is an abundant source of aromatics with low effective hydrogen-to-carbon ratio (H/Ceff), and the depolymerization of lignin provides significant potential for producing liquid products with an improved H/Ceff value. In this work, the catalytic conversion of lignin monomers, dimer, trimers, and realistic lignin over spherical MOF-derived NiMo@C catalysts was well established, to get liquid fuels with a higher H/Ceff. The optimal ratio of the Ni4Mo1@C catalyst exhibited good hydrodeoxygenation activity and stability for the hydrotreatment of lignin model compounds and lignin. The addition of Mo facilitated the decrease of the particle size of a spherical structure, strengthened the electron-transfer capability between metals Mo and Ni, and enhanced the acid strength. All of these factors contributed to higher hydrodeoxygenation activity in the hydrotreatment process. Up to 100% conversion and 90% yields of ethylcyclohexane and cyclohexanol with H/Ceff values of 2.0 and 1.667, respectively, were obtained. The Ni4Mo1@C catalyst achieved a decrease of the oxygen element and an increase of H/Ceff and HHV values. The physicochemical characterizations were performed by various means including X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), H2-temperature-programmed reduction (H2-TPR), NH3-temperature-programmed desorption (NH3-TPD), pyridine-infrared spectroscopy (Py-IR), inductively coupled plasma emission spectrometer (ICP), and Raman and X-ray photoelectron spectroscopy (XPS) analyses, which definitely elucidated the formation of a synergistic effect between metals Mo and Ni. Additionally, a control experiment also illustrated the synergistic effect that facilitated the occurrence of the hydrotreatment process under lower temperatures after the addition of metal Mo. Based on the optimal reaction condition (240 °C, 4 h, 2.0 MPa H2), both lignin and its monomers/dimers/trimers could be effectively hydrotreated to afford liquid products with improved H/Ceff value compared to raw lignin.
研究领域:
能源化学
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催化化学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 149
·期 8
·2078-2088
·
IF 2.372
He Xiaoxia,Chen Yu,Liu Ya,Fang Lina,Chen Zeng,Ji Hongbing
Abstract A series of metal-modified hierarchical M/H-ZSM-5 catalysts were prepared for catalytic conversion of cellulose in an aqueous medium. Characterization of the catalysts showed that the impregnation of metal into H-ZSM-5 did not change the basic framework and pore structure of H-ZSM-5, but it decreased the total acidity. Analysis of the products indicated that the catalysts significantly affected products distribution. When Co/H-ZSM-5 and Fe/H-ZSM-5 were used as the catalysts, the yields of lactic acid and cyclic ketones obviously increased. At last, a recommendable catalytic transformation pathway of cellulose over M/H-ZSM-5 was proposed on the basis of the obtained experimental results and the published literatures. Graphical Abstract In this paper, a series of metal-modified hierarchical M/H-ZSM-5 (M = Ce, Co, Ga, and Fe) catalysts were prepared and employed in catalytic conversion of cellulose in aqueous media to examined the products distribution of cellulose catalytic conversion. Based on our results and previous works, the plausible general reaction pathways of cellulose over M/H-ZSM-5 were proposed.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 12
·2861
·
IF 4.2
Yonghui Sun,Qiyu He,Xucheng Lv,Naizhen Zhang,Wei Yan,Jianghui Sun,Lili Zhuang
Regioselective benzanilide bromination that generates either regioisomer from the same starting material is desirable. Herein, we develop switchable site-selective C(sp2)-H bromination by promoter regulation. This protocol leads to regiodivergent brominated benzanilide starting from the single substrate via selection of promoters. The protocol demonstrates excellent regioselectivity and good tolerance of functional groups with high yields. The utility effectiveness of this method has been well exemplified in the late-stage modification of biologically important molecules.
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
PubMed
高影响因子
RESOURCES CONSERVATION AND RECYCLING
·
2021
·
IF 10.204
Liming Yang,Genping Yi,Bo Wang,Penghui Shao,Yufa Feng,Yanbiao Liu,Kai Yu,Fuqiang Liu,Lingling Liu,Xubiao Luo,Shenglian Luo
Simultaneous recovery and value-added conversion of hazardous heavy metal ions from complex wastewater sources is of great significance yet challenging. Herein, we demonstrate that highly toxic antimonite Sb(III) could be effectively recovered from antimony (Sb) mine flotation wastewater and converted into high-value-added metallic Sb using a novel facile atomic H* enhanced electrochemical reduction avenue coupled with thermal reduction by H 2 gas. The high production of atomic H* generated from the electrochemical cathode with an optimum reduction potential of –1.2 V vs . Ag/AgCl, which is lower than the Sb(III) reduction potential of –1.0 V, might be attributable to the superior Sb recovery capabilities. Furthermore, the metallic Sb concentration at –1.2 V was 14.43 times greater than at –1.0 V due to the strong reductivity of atomic H*. In addition, Sb(III) removal efficiency was found to be as high as 98.52%, with a metallic Sb recovery rate of up to 1.67 mg min –1 . The efficiency of Sb(III) recovery was demonstrated throughout a wide pH range, with metallic Sb being the main product, independent of the presence of multiple coexisting ions. Economic analysis also indicated that treating Sb mine flotation wastewater per ton may yield a net profit of $40.09. This research contributes to the advancement of an atomic H* enhanced electrochemical technology for high-valued heavy metal recovery from complex heavy metal-polluted wastewater.
研究领域:
环境科学
·
冶金工程
·
电化学工程
✓ 已验证
DOI
高影响因子
Evidence-based Complementary and Alternative Medicine
·
2013
·
IF 1.722
Huiqing Lv,Xiaoping Zhang,XueZhi Chen,Zhijun Xie,Changfeng Hu,Chengping Wen,Kezhi Jiang
Background. Ficus pandurata H. (Moraceae) is widely used in traditional Chinese medicine as a healthy food condiment or a medicine for treatment of various diseases including inflammation. Objective. The purpose of the present study is to investigate the phytochemical compositions and antioxidant and anti-inflammatory activities of crude water (FPW) and ethanolic extracts (FPE) from Ficus pandurata H. Methods. Phytochemical compositions were identified by a high-performance liquid chromatography-electrospray ionization-mass spectrometry method (HPLC-ESI-MS). The antioxidant activities were evaluated by diphenylpicrylhydrazyl (DPPH) and hydroxyl radical assays, and the anti-inflammatory activities were evaluated by paw edema and levels of inflammatory mediator TNF-α and PGE2 in monosodium urate (MSU) crystal-induced rats. Results. Six compounds were identified by HPLC-MS method, and abundance of phenolics was found in FPE. The FPE showed concentration-dependent-significant scavenging of DPPH and hydroxyl radicals with IC50 values 118.4 and 192.9 μg/mL, respectively. The FPE treatment significantly inhibited the paw edema and the production of TNF-α and PGE2 in MSU crystal-induced rats. Conclusion. The FPE exerted stronger antioxidant and anti-inflammatory activities which may be attributed to its high phenolic content.
研究领域:
药理学
·
植物化学
·
传统医学
✓ 已验证
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Tianyu Bai,Jinquan Tao,Yijing Jia,Wenbin Huang,Rongpeng Yao,Xinan Xue,Yasong Zhou,Qiang Wei
In the research of directly synthesizing H-form ZSM-5, ammonium hydroxide is commonly used as an alkali source instead of NaOH to avoid multiple ion exchange steps. However, the volatile nature and the lack of structure-directing effect of ammonium hydroxide limit its application in practical. In this study, n -butylamine (NBA) was used as the main alkali source to directly prepare HZSM-5 zeolites with SiO 2 /Al 2 O 3 ratios ranging from 40 to 300 under traditional hydrothermal conditions. The influence of the amount of NBA, ethanol, seed, and pre-crystallization on the synthesis products was investigated under the condition of SiO 2 /Al 2 O 3 = 80. Theoretical simulation suggested that n -butylamine cations (NBA + ) play the most potent directing role in the formation of the MFI structure but could lead to difficulties in removal during calcination. The addition of ethanol as the zeolite growth modifier (ZGM) could decrease the usage of NBA and reduce the difficulties in calcination, and the addition of seed provided the conditions for initiating crystallization in the system that could not spontaneously nucleate. HZSM-5 with different SiO 2 /Al 2 O 3 ratios were prepared under the optimal crystallization conditions, and the as-synthesized samples exhibited superior textural and acid properties compared to commercial zeolite. Finally, the 1 L scale-up synthesis and MTP reaction were conducted to demonstrate the practicality of this economically and environmentally-friendly synthesis strategy.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Biobased Materials and Bioenergy
·
2017
·Vol. 11
·期 6
·562-567
·
IF 0.975
Wang Lan-Ying,Zhuang Jun-Ping,Yu Kai-Rong,Wu Shu-Bin
Sn-Beta zeolite is a promising catalysts for isomerization of glucose to fructose, which is a key step in the conversion of biomass to various platform chemicals. Herein, Sn-Beta-H zeolite was efficiently prepared via hydrothermal synthesis by using Al-Beta. Finally, the product was
heated to 423 K for 48 h then calcined at 550 °C for 6 h to obtain Sn-Beta-H sample. The results of XRD patterns confirmed that the prepared catalyst had both microporous and mesoporous; N2 sorption isotherms showed that the main pore size centered at around 3.5 nm; TD-DTG revealed
that the Sn-Beta-H zeolite had good thermal stability with the peaks on the DTG curves was 283 °C; FTIR and UV-Vis spectra also successfully indicated that tin substitution into the zeolite framework. The effects of various reaction conditions including reaction temperature, reaction time
and the amount of catalyst on glucose conversion and fructose yield and selectivity were investigated. Under optimized operating conditions, 10% glucose solution in 40 ml water, catalyst (4 g), at 120 °C for 2 h, resulting in fructose yield of 30.8% and selectivity of 61.3%. Moreover,
Sn-Beta-H zeolite could be easily recovered and efficiently reused without significant loss in its catalytic activity.
研究领域:
催化化学
·
生物质转化
·
材料科学
✓ 已验证
DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2014
·Vol. 28
·期 9
·673-677
·
IF 2.017
Limin Ren,Wenyi Chu,Dinghui Guan,Yanjun Hou,Man Wang,Xiaobin Yuan,Zhizhong Sun
A simple and efficient route for the preparation of terphenyl derivatives via palladium-catalyzed sequential directed C―H arylation/Suzuki–Miyaura cross-coupling in ‘one-pot’ has been developed. 4,4′-(Cyclohexane-1,1-diyl)diphenol is an essential ligand. This reaction can tolerate a series of functional groups and provides the terphenyl derivatives in moderate to good yield. Copyright © 2014 John Wiley & Sons, Ltd.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2019
·
IF 3.834
Yunchao Feng,Miao Zuo,Ting Wang,Wenlong Jia,Xiaoyu Zhao,Xianhai Zeng,Yong Sun,Xing Tang,Tingzhou Lei,Lu Lin
Production of 5-hydroxymethylfurfural (HMF) from glucose with high yield remains a big challenge. Thereinto, assembling catalysts with outstanding performance is the bottleneck at the current stage. In this study, effective catalysts were synthesized by loading SO 4 2− /ZrO 2 (SZ) on a series of H + zeolites to investigate the catalytic dehydration of glucose into HMF. Among all the catalysts applied, 2-SZ-HM-550 (HZSM-5 with Si/Al molar ratios of 80∼150, calcined at 550 °C) gave the yields of HMF 41.32%, 61.14%, 54.67% and 40.71% in 4 applied reaction systems, respectively. Moreover, HMF with desirable yield was obtained while other carbohydrates were dehydrated catalyzed by 2-SZ-HM-550, such as fructose, sucrose, inulin and starch.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Wei Ji,Guofeng Liu,Zijian Li,Chuanliang Feng
For CH···O hydrogen bonds in assembled structures and the applications, one of the critical issues is how molecular spatial structures affect their interaction modes as well as how to translate the different modes into the macroscopic properties of materials. Herein, coumarin-derived isomeric hydrogelators with different spatial structures are synthesized, where only nitrogen atoms locate at the ortho, meso, or para position in the pyridine ring. The gelators can self-assemble into single crystals and nanofibrous networks through CH···O interactions, which are greatly influenced by nitrogen spatial positions in the pyridine ring, leading to the different self-assembly mechanisms, packing modes, and properties of the nanofibrous networks. Typically, different cell proliferation rates are obtained on the different CH···O bonds driving nanofibrous structures, implying that tiny variation of the stereo-position of nitrogen atoms can be sensitively detected by cells. The study paves a novel way to investigate the influence of isomeric molecular assembly on macroscopic properties and functions of materials.
研究领域:
材料科学
·
生物学
·
医学
✓ 已验证
DOI
PubMed
高影响因子
CATALYSIS LETTERS
·
2018
·Vol. 148
·期 11
·3445-3453
·
IF 2.911
Li Xia,Dong Hao,Wang Bo,Lv Jun,Xu Guangqing,Wang Dongmei,Wu Yucheng
Firstly, h-CdS/c-CdS homojunction was prepared by solvothermal method with controlling the Cd-to-S molar ratio. Then, the MoS 2 /h-CdS/c-CdS nanocomposites were constructed by ultrasonic method with different MoS 2 amount. The experimental results showed that when the molar ratio of Cd and S was 1:1 and the amount of MoS 2 was 1.5 wt%, the MoS 2 /h-CdS/c-CdS nanocomposites exhibited excellent photocatalytic performance for hydrogen evolution under visible light. The total amount of hydrogen evolution was 3753.12 µmol for 5 h, and its average hydrogen evolution rate was 40.79 mmol h −1 g −1 with an apparent quantum efficiency of 38.16% irradiated at 420 nm, which was about 7.3 times when compared with the h-CdS/c-CdS homojunction (Cd:S = 1:8). The enhanced photocatalytic performance of MoS 2 /h-CdS/c-CdS could be attributed to the improved specific surface area and formation of well bonded interface structure, which not only enhanced the response to visible light but also decreased the recombination rates of photogenerated charge carriers. Graphical Abstract
研究领域:
材料科学
·
光催化
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）