ACS Sustainable Chemistry & Engineering
·
2024
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IF 7.1
Kun Li,Chengjie Duan,Weitao Mao,Dongliang Wang,Yumeng Liang,Wenbo Ye,Guangke He,Xiang Liu
A direct and efficient synthesis of N-methyl-1,2,3,4-tetrahydroquinolines (MTHQs) is achieved through the one-pot reductive N-methylation of quinolines. The SnOx-decorated Pt/Al2O3 (Pt-SnOx/Al2O3) catalyst proves to be highly effective in the transformation from quinolines to MTHQs, using methanol as the exclusive source for hydrogen (H) and methyl (CH3), without the addition of additional bases or additives. Mechanistic and kinetic studies reveal a tandem reaction pathway: (1) the dehydrogenation of methanol, (2) reduction of quinolines to 1,2,3,4-tetrahydroquinolines (THQs), and (3) N-methylation of THQs to MTHQs, with the dehydrogenation of methanol identified as the rate-determining step. Characterization and catalytic performance results demonstrate that SnOx modifies the morphology and electronic properties of Pt-based metal active sites, which dramatically facilitates the cleavage of O–H and less reactive C–H bonds in methanol, and maintains a delicate balance between methanol dehydrogenation and reductive N-methylation of quinolines, thus obtaining a high reactivity for the total transformation.
研究领域:
催化化学
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有机合成
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DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2025
·
IF 4.3
Zerui Su,Jian Zhang,Yang Li,Zheyu Qiao,Ziyuan Qiao,Lihang Wei,Xiaoyuan Qin,Xiaoxue Mu,Feng-Shou Xiao
Cu-based catalysts are crucial for the dehydrogenation of ethanol (EtOH) to acetaldehyde (AcH); however, their performance decreases at higher temperatures due to the low Tammann temperature of Cu species. In this study, we synthesized silica-supported Cu catalysts using microwave-assisted wet-kneading. Characterization revealed a typical core–shell structure (Cu@SiO 2 -WK), which demonstrated high activity, excellent selectivity, and superior stability for ethanol dehydrogenation. The Cu@SiO 2 -WK achieved 96.2 % EtOH conversion with 99.9 % selectivity to AcH at 260 °C. After 160 h of reaction, it maintained an EtOH conversion of 90.5 % and AcH selectivity of ∼99.9 %. Following simple calcination, the catalyst’s activity was fully regenerated to 96.1 %. Model catalysts and in situ FT-IR spectra indicate that the core–shell structure significantly enhances the catalyst’s performance in the dehydrogenation of EtOH to AcH.
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
MOLECULES
·
2023
·Vol. 28
·期 15
·5683
·
IF 4.6
Yan Xiao,Nannan Zhan,Jie Li,Yuan Tan,Yunjie Ding
The catalytic upgrading of ethanol into butanol through the Guerbet coupling reaction has received increasing attention recently due to the sufficient supply of bioethanol and the versatile applications of butanol. In this work, four different supported Cu catalysts, i.e., Cu/Al2O3, Cu/NiO, Cu/Ni3AlOx, and Cu/Ni1AlOx(Ni2+/Al3+molar ratios of 3 and 1), were applied to investigate the catalytic performances for ethanol conversion. From the results, Ni-containing catalysts exhibit better reactivity; Al-containing catalysts exhibit better stability; but in terms of ethanol conversion, butanol selectivity, and catalyst stability, a corporative effect between Ni–Al catalytic systems can be clearly observed. Combined characterizations such as XRD, TEM, XPS, H2-TPR, and CO2/NH3-TPD were applied to analyze the properties of different catalysts. Based on the results, Cu species provide the active sites for ethanol dehydrogenation/hydrogenation, and the support derived from Ni–Al–LDH supplies appropriate acid–base sites for the aldol condensation, contributing to the high butanol selectivity. In addition, catalysts with strong reducibility (i.e., Cu/NiO) may be easily deconstructed during catalysis, leading to fast deactivation of the catalysts in the Guerbet coupling process.Keywords:copper catalyst;hydrotalcite;stability;ethanol;butanol
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
PubMed
高影响因子
Materials Today Chemistry
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2024
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IF 6.7
Jun-Fei Gu,Cheng Chen,Somboon Chaemchuen,Wei Sang,Xing-Chuan Li,Ye Yuan,Zongkui Kou,Francis Verpoort
The dehydrogenation of primary alcohols to carboxylic acids is a crucial process in chemical industries such as fibers and plastics. Carboxylic acids, the resulting products, are not only important chemical raw materials but also fundamental pharmaceutical intermediates. Zn-based catalysts have gained attention as a promising option for this transformation owing to their economic cost and abundant reserves. However, stability issues, including structure collapse and morphological changes, have plagued the reported Zn-based catalysts during this transformation. In response to these challenges, this study focused on the design and development of Zn-based catalysts via controlled incorporation of Zn into nitrogen-doped porous carbon to modulate the numbers of defects and Lewis acid-base site pairs. Through extensive screening of various parameters, the best-performing catalyst, namely Zn@NC-800, exhibited high activity and remarkable stability, surpassing all the reported Zn-based catalysts. Moreover, this catalyst demonstrated great recyclability since it could maintain approximately 90 % yields after 9 cycles. Notably, the product formation rate of this catalyst could reach 3833 μmol·g cat . −1 ·h −1 , exceeding that of most reported non-noble metal heterogeneous catalysts. Consequently, this study offers a promising approach for efficiently and stably catalyzing alcohol dehydrogenation reactions using non-noble metals.
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
Molecular Catalysis
·
2019
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IF 2.938
Guochao Xu,Wei Dai,Yue Wang,Lu Zhang,Zewen Sun,Jieyu Zhou,Ye Ni
Structure-guided rational design revealed the molecular switch manipulating the Prelog and anti-Prelog priorities of an NADPH-dependent alcohol dehydrogenase toward prochiral ketones with bulky and similar substituents. Synergistic effects of unconserved residues at 214 and 237 in small and large substrate binding pockets were proven to be vital in governing the stereoselectivity. The ee values of E214Y/S237A and E214C/S237 G toward (4-chlorophenyl)-(pyridin-2-yl)-methanone were 99.3% ( R ) and 78.8% ( S ) respectively. Substrate specificity analysis revealed that similar patterns were also found with (4’-chlorophenyl)-phenylmethanone, (4’-bromophenyl)-phenylmethanone and (4’-nitrophenyl)-phenylmethanone. This study provides valuable evidence for understanding the molecular mechanism on enantioselective recognition of prochiral ketones by alcohol dehydrogenase.
研究领域:
生物化学
·
酶学
✓ 已验证
DOI
高影响因子
MOLECULAR BIOTECHNOLOGY
·
2021
·Vol. 63
·期 6
·491-501
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IF 2.695
Tang Wanggang,Lian Chaoqun,Si Yu,Chang Jianrong
2,3-Butanediol dehydrogenase (BDH), also known as acetoin/diacetyl reductase, is a pivotal enzyme for the formation of 2,3-butanediol (2,3-BD), a chiral compound with potential roles in the virulence of certain pathogens. Here, a NAD(H)-dependent (2 R ,3 R )-BDH from Neisseria gonorrhoeae FA1090 (NgBDH), the causative agent of gonorrhoea, was functionally characterized. Sequence analysis indicated that it belongs to zinc-containing medium-chain dehydrogenase/reductase family. The recombinant NgBDH migrated as a single band with a size of around 45 kDa on SDS-PAGE and could be confirmed by Western blotting and mass spectrometry. For the oxidation of either (2 R ,3 R )-2,3-BD or meso -2,3-BD, the enzyme exhibited a broad pH optimum between pH 9.5 to 11.5. For the reduction of (3 R /3 S )-acetoin, the pH optimum was around 6.5. The enzyme could catalyze the stereospecific oxidation of (2 R ,3 R )-2,3-BD ( K m = 0.16 mM, k cat / K m = 673 s −1 · mM −1 ) and meso -BD ( K m = 0.72 mM, k cat / K m = 165 s −1 · mM −1 ). Moreover, it could also reduce (3 R /3 S )-acetoin with a K m of 0.14 mM and a k cat / K m of 885 s −1 · mM −1 . The results presented here contribute to understand the 2,3-BD metabolism in N. gonorrhoeae and pave the way for studying the influence of 2,3-BD metabolism on the virulence of this pathogen in the future.
研究领域:
微生物学
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生物化学
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DOI
PubMed
高影响因子
Catalysts
·
2022
·Vol. 12
·期 9
·1049
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IF 4.501
Yan Hao,Dajie Zhao,Wen Liu,Min Zhang,Yixiao Lou,Zhenzhen Wang,Qinghu Tang,Jinghe Yang
Selective dehydrogenation of ethanol to acetaldehyde has been considered as an important pathway to produce acetaldehyde due to the atom economy and easy separation of acetaldehyde and hydrogen. Copper catalysts have attracted much attention due to the high activity of Cu species in O-H and C-H bonds oxidative cleavage, and low process cost; however, the size of the Cu nanoparticle is difficult to control since it is easily suffers from metal sintering at high temperatures. In this work, the Cu/KIT-6 catalyst exhibited an ultra-high metal dispersion of 62.3% prepared by an electrostatic adsorption method, due to the advantages of the confinement effect of mesoporous nanostructures and the protective effect of ammonia water on Cu nanoparticles. The existence of an oxidation atmosphere had a significant effect on the valence state of copper species and enhancing moderate acid sites. The catalyst treated by reduction and then oxidation possessed a moderate/weak acid site ratio of ~0.42 and a suitable proportion of Cu+/Cu0ratio of ~0.53, which conceivably rendered its superior ethanol conversion of 96.8% and full acetaldehyde selectivity at 250 °C. The catalyst also maintained a high selectivity of >99% to acetaldehyde upon time-on-stream of 288 h.Keywords:copper;ethanol dehydrogenation;mesoporous silica
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
CHEMICAL ENGINEERING JOURNAL
·
2024
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IF 13.3
Yue Wu,Cailing Chen,Zhuo Xiong,Meng Xu,Yue Zhao,Yihu Dai,Yu Han,Yu Zhou,Xiaoling Liu,Jun Wang
Direct hydrogen transfer amination of alcohols with amines is an environmentally friendly and atom-economical route for the synthesis of N-alkylamines. Noble metal species are highly catalytic active sites, but the exorbitant price makes the urgency to boost the atom efficiency with stable recyclability. Herein, we demonstrated that encapsulation of Ru nanoparticles (NPs) within BEA zeolite through direct hydrothermal approach greatly promoted the catalytic efficiency in the N-alkylation of aromatic alcohols and amines under additive- and solvent-free conditions, resulting in the high yield (∼93 %), maximum turnover number (TON) of 12,822 and turnover frequency (TOF) of 9012 h −1 , with stable recyclability and extendable substrate scope. The kinetic studies and in-situ characterizations revealed that the synergy of confined Ru NPs and adjacent acid sites of BEA zeolite significantly promoted the C–H bond activation in the rate-determining step of alcohol dehydrogenation into aldehydes. Besides, the acid sites also accelerated the condensation of aldehyde intermediates and anilines to promote the kinetic equilibrium, while the moderate strength of the Ru–H bond resulting from the confined Ru NPs is advantageous to balance the dehydrogenation and hydrogenation steps to reach the fascinating H-transfer process.
研究领域:
催化化学
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材料科学
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有机合成
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产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Weikun Chen,Xiao Fu,Xiaoying Liu,Linmin Ye,Youzhu Yuan
N -alkylated piperazines can be synthesized by the thermal catalytic alkylation of piperazine with alkyl halides or alcohols in the presence of supported metal catalysts. However, these processes either discharge large amounts of waste or require harsh conditions. Here, we report the results of N -alkylation of piperazine with lower alcohols (methanol, ethanol, and propanol) without external hydrogen addition at room temperature in the presence of a TiO 2 -supported Pd catalyst (Pd/TiO 2 -P) prepared by photodeposition method. Compared with the catalysts prepared by the conventional chemical reduction or hydrogen reduction, the Pd/TiO 2 -P catalyst showed the highest conversion of piperazine and the best selectivity to N -alkypiperazines. The mechanistic studies indicated that this phenomenon occurs via tandem photocatalytic reactions involving alcohol dehydrgenation to aldehyde, aldehyde condensation with piperazine to enamine, and enamine hydrogenation to N -alkylated piperazines. Considering the experimental results of methanol isotope kinetics, the α-C–H cleavage of methanol to form hydroxymethyl radical (·CH 2 OH) was proven to be the rate-determining step in the N -alkylation reaction of piperazine with low carbon alcohols. The characterization and control experiments revealed that the size of Pd nanoparticles and the valence of Pd species were vital to the reaction. The Pd/TiO 2 -P catalyst with an average of 2.5 ± 0.5 nm Pd particles and approximately 68% Pd 0 species on surfaces presented the highest activity for the photocatalytic tandem reactions of methanol dehydrogenation and enamine hydrogenation.
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
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Yanhong Quan,Yuting Jin,Na Wang,Jinxian Zhao,Jun Ren
CuZn/SiO 2 lamellar catalysts are obtained through the introduction of zinc oxide with different amount to Cu/SiO 2 prepared by the ammonia-evaporation method and investigated for the dehydrogenation of methanol to methyl formate. The 20CuZn/SiO 2 catalyst showed the best catalytic activity with a methanol conversion of 44.5% and a selectivity to methyl formate of ~92.7% at 300 °C and 0.2 MPa. The reason for this excellent activity could be ascribed to the strong interaction between Cu and ZnO, which promoted the decomposition of the copper phyllosilicate precursor to release copper oxide and thereby achieved more active Cu 0 species upon reduction on the catalyst surface. In addition, the agglomeration of Cu species was mainly responsible for the slight decline in the methanol conversion in ZnO modified Cu based catalysts for the methanol dehydrogenation reaction.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
·
IF 24.319
Haolan Liu,Zhili Chang,Jie Fu,Zhaoyin Hou
Cu-based catalysts play pivotal role in many industrial processes, however, its application under high temperature is restricted due to the low Tammann temperature of Cu. Improving the stability and activity of Cu-based catalysts at high temperature is a challenge. In this work, a stable Cu/ZnO@SiO 2 catalyst was prepared, in which silicon was introduced into CuZn-BTC precursor via a steam-assisted hydrolysis method before calcination and reduction. Characterizations found that Cu/ZnO@SiO 2 catalyst prepared via above strategy possesses increased surface area, more exposed active sites and excellent stability for ethanol dehydrogenation than Cu/ZnO (prepared from CuZn-BTC without SiO 2 ). It was confirmed that the space-time yield of acetaldehyde reached 9.0 g-acetaldehyde/g-cat/h, and Cu/ZnO@SiO 2 could maintain its activity within 200 h at 350 °C due to the ZnO decorated Cu particles (Cu/ZnO) were encapsulated in the octahedral shaped SiO 2 hollow.
研究领域:
化学工程
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催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Fungi
·
2023
·Vol. 9
·期 5
·512
·
IF 4.7
Xuan Wang,Xianhao Xu,Jiaheng Liu,Yanfeng Liu,Jianghua Li,Guocheng Du,Xueqin Lv,Long Liu
Retinol, the main active form of vitamin A, plays a role in maintaining vision, immune function, growth, and development. It also inhibits tumor growth and alleviates anemia. Here, we developed aSaccharomyces cerevisiaestrain capable of high retinol production. Firstly, the de novo synthesis pathway of retinol was constructed inS. cerevisiaeto realize the production of retinol. Second, through modular optimization of the metabolic network of retinol, the retinol titer was increased from 3.6 to 153.6 mg/L. Then, we used transporter engineering to regulate and promote the accumulation of the intracellular precursor retinal to improve retinol production. Subsequently, we screened and semi-rationally designed the key enzyme retinol dehydrogenase to further increase the retinol titer to 387.4 mg/L. Lastly, we performed two-phase extraction fermentation using olive oil to obtain a final shaking flask retinol titer of 1.2 g/L, the highest titer reported at the shake flask level. This study laid the foundation for the industrial production of retinol.Keywords:vitamin A;retinol;Saccharomyces cerevisiae;retinol dehydrogenase;olive oil
研究领域:
代谢工程
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生物技术
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微生物生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）