Pub Date : 2024-09-25DOI: 10.1016/j.mcat.2024.114563
Xu Sun , Gan Zhang , Bo Ye , Wen-Chao Yang , Lei Wang , Xiaoyu Xie , Yicheng Zhang , Jie Liu
A three-component coupling of alkenes, sodium sulfinates and acyl imidazoles to access γ-keto sulfones with good functional group tolerance via cooperative N‒heterocyclic carbene (NHC)/photocatalysis is developed. Radical mechanism was proposed for the cascade reaction, revealing that a rare radical/radical cation cross-coupling reaction plays an important role.
{"title":"Synthesis of γ-keto sulfones through sulfonylation/acylation of alkenes merging NHC- and photo-catalysis","authors":"Xu Sun , Gan Zhang , Bo Ye , Wen-Chao Yang , Lei Wang , Xiaoyu Xie , Yicheng Zhang , Jie Liu","doi":"10.1016/j.mcat.2024.114563","DOIUrl":"10.1016/j.mcat.2024.114563","url":null,"abstract":"<div><div>A three-component coupling of alkenes, sodium sulfinates and acyl imidazoles to access γ-keto sulfones with good functional group tolerance via cooperative N‒heterocyclic carbene (NHC)/photocatalysis is developed. Radical mechanism was proposed for the cascade reaction, revealing that a rare radical/radical cation cross-coupling reaction plays an important role.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114563"},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-25DOI: 10.1016/j.mcat.2024.114573
Hai-Min Zhang , Pan Ning , Han-Yu Liu , Feng Qian , Yao-Wu Wang , Pu Wang
Carbonyl reductase exhibits significant potential in the asymmetric production of chiral alcohols. (αR)-4-Chloro-2-(3-methyl-1H-pyrazol-1-yl)-α-(trifluoromethyl)benzenemethanol ((R)-CMPPFO) is a critical precursor for the synthesis of Telotristat ethyl, an oral drug for the treatment of diarrhea in carcinoid syndrome. Herein, a novel carbonyl reductase KrSDR5 from Kosakonia radicincitans was obtained using gene hunting strategy, capable of asymmetrically reducing the precursor ketone 1-[4‑chloro-2-(3-methyl-1H-pyrazol-1-yl)phenyl]-2,2,2-trifluoroethanone (CMPPFA) to (R)-CMPPFO with strict R-stereoselectivity (>99.9 % ee). Further, semi-rational design was adopted to acquire a positive mutant KrSDR5T91V/V141M/I159V, with assistance from a comparative analysis of enzyme-substrate binding mode in molecular dynamics (MD) simulations. This variant displayed a 12.4-fold increase in kcat/Km towards CMPPFA compared to the wild-type (WT) KrSDR5. Insights were gained on the high enantioselectivity and the enhancement of enzyme catalytic activity of the mutant through MD simulations. Using the whole-cells of KrSDR5T91V/V141M/I159V as biocatalyst, the asymmetric synthesis of (R)-CMPPFO was achieved within 20 h at 500 mM CMPPFA concentration, resulting in a 95.0 % yield with >99.9 % ee, and a highest space-time yield (STY) of 165.7 g·L-1·d-1 compared with previous reports. This study provides a robust biocatalyst for highly efficient production of the key precursor (R)-CMPPFO for Telotristat ethyl, highlighting its potential in the biosynthesis of pharmaceutical intermediates.
{"title":"Gene hunting and semi-rational design of carbonyl reductase from Kosakonia radicincitans for highly efficient synthesis of the key chiral intermediate of Telotristat ethyl","authors":"Hai-Min Zhang , Pan Ning , Han-Yu Liu , Feng Qian , Yao-Wu Wang , Pu Wang","doi":"10.1016/j.mcat.2024.114573","DOIUrl":"10.1016/j.mcat.2024.114573","url":null,"abstract":"<div><div>Carbonyl reductase exhibits significant potential in the asymmetric production of chiral alcohols. (α<em>R</em>)-4-Chloro-2-(3-methyl-1<em>H</em>-pyrazol-1-yl)-α-(trifluoromethyl)benzenemethanol ((<em>R</em>)-CMPPFO) is a critical precursor for the synthesis of Telotristat ethyl, an oral drug for the treatment of diarrhea in carcinoid syndrome. Herein, a novel carbonyl reductase <em>Kr</em>SDR5 from <em>Kosakonia radicincitans</em> was obtained using gene hunting strategy, capable of asymmetrically reducing the precursor ketone 1-[4‑chloro-2-(3-methyl-1<em>H</em>-pyrazol-1-yl)phenyl]-2,2,2-trifluoroethanone (CMPPFA) to (<em>R</em>)-CMPPFO with strict <em>R</em>-stereoselectivity (>99.9 % ee). Further, semi-rational design was adopted to acquire a positive mutant <em>Kr</em>SDR5<sub>T91V/V141M/I159V</sub>, with assistance from a comparative analysis of enzyme-substrate binding mode in molecular dynamics (MD) simulations. This variant displayed a 12.4-fold increase in <em>k</em><sub>cat</sub>/<em>K</em><sub>m</sub> towards CMPPFA compared to the wild-type (WT) <em>Kr</em>SDR5. Insights were gained on the high enantioselectivity and the enhancement of enzyme catalytic activity of the mutant through MD simulations. Using the whole-cells of <em>Kr</em>SDR5<sub>T91V/V141M/I159V</sub> as biocatalyst, the asymmetric synthesis of (<em>R</em>)-CMPPFO was achieved within 20 h at 500 mM CMPPFA concentration, resulting in a 95.0 % yield with >99.9 % ee, and a highest space-time yield (STY) of 165.7 g·L<sup>-1</sup>·d<sup>-1</sup> compared with previous reports. This study provides a robust biocatalyst for highly efficient production of the key precursor (<em>R</em>)-CMPPFO for Telotristat ethyl, highlighting its potential in the biosynthesis of pharmaceutical intermediates.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114573"},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-25DOI: 10.1016/j.mcat.2024.114551
Renan B.G. Caetano , Pedro H.O. Santiago , Javier A. Ellena , Daniel A.S. Oliveira , Ataualpa A.C. Braga , Benedito S. Lima-Neto
Cationic complexes of type [RuCl(Cym)(PR3)(NH2R)]PF6 were synthesized from reactions of the precursors [RuCl2(Cym)(PPh3)] (1) and [RuCl2(Cym)(P(tol3)] (2) with NH2Bn (1a; 2a) and NH2Bu (1b; 2b), where p-Cym = η6-p-cymene, pH = phenyl, tol = p-tolyl, Bu = butyl, and Bn = benzyl. These four phosphine/amine-complexes were thoroughly characterized using single X-ray crystallography, various spectroscopic techniques (FTIR; UV–Vis; 1H and 13C NMR), and DFT calculations. The impact of different ligand combinations within the coordination spheres on opening metathesis polymerization (ROMP) of norbornene (NBE) was studied as a function of temperature (20–50 °C) and irradiation using a 456 nm lamp. Both gravimetric and NMR analyses in the absence of light showed low NBE conversion, which increased under light irradiation. NMR spectra revealed that irradiation at wavelengths corresponding to the metal-centered absorption band causes the amines to decoordinate, while the p-cymene and phosphine ligands remain coordinated. NMR spectra from non-irradiated solutions, in the absence of monomer, indicated dimerization of ethyl diazoacetate, which was used as a carbene source. This observation suggests that the amine ligand is replaced during metal-carbene formation. Electrochemical measurements of the oxidation potentials for the phosphine/amine complexes indicate low dπ electronic density at the ruthenium centers, with evidence of substantial PR3←Ru(II) backbonding. These findings were further confirmed by Natural Bond Orbital (NBO) analysis. The substitution of a chloride ion in the precursors was found to weaken the arene←Ru(II) π bond. The combination of electron density from both the phosphine and the amine ligands helps maintains the p-cymene-Ru bond, rendering the complex inert in the absence of light.
{"title":"Intriguing combinations of p-cymene, chloride ion, phosphines, and amines in ruthenium metal centers: Which ligand decoordinates for ROMP?","authors":"Renan B.G. Caetano , Pedro H.O. Santiago , Javier A. Ellena , Daniel A.S. Oliveira , Ataualpa A.C. Braga , Benedito S. Lima-Neto","doi":"10.1016/j.mcat.2024.114551","DOIUrl":"10.1016/j.mcat.2024.114551","url":null,"abstract":"<div><div>Cationic complexes of type [RuCl(Cym)(PR<sub>3</sub>)(NH<sub>2</sub>R)]PF<sub>6</sub> were synthesized from reactions of the precursors [RuCl<sub>2</sub>(Cym)(PPh<sub>3</sub>)] (<strong>1</strong>) and [RuCl<sub>2</sub>(Cym)(P(tol<sub>3</sub>)] (<strong>2</strong>) with NH<sub>2</sub>Bn (<strong>1a; 2a</strong>) and NH<sub>2</sub>Bu (<strong>1b; 2b</strong>), where p-Cym = η<sup>6</sup>-<em>p</em>-cymene, pH = phenyl, tol = <em>p</em>-tolyl, Bu = butyl, and Bn = benzyl. These four phosphine/amine-complexes were thoroughly characterized using single X-ray crystallography, various spectroscopic techniques (FTIR; UV–Vis; <sup>1</sup>H and <sup>13</sup>C NMR), and DFT calculations. The impact of different ligand combinations within the coordination spheres on opening metathesis polymerization (ROMP) of norbornene (NBE) was studied as a function of temperature (20–50 °C) and irradiation using a 456 nm lamp. Both gravimetric and NMR analyses in the absence of light showed low NBE conversion, which increased under light irradiation. NMR spectra revealed that irradiation at wavelengths corresponding to the metal-centered absorption band causes the amines to decoordinate, while the <em>p</em>-cymene and phosphine ligands remain coordinated. NMR spectra from non-irradiated solutions, in the absence of monomer, indicated dimerization of ethyl diazoacetate, which was used as a carbene source. This observation suggests that the amine ligand is replaced during metal-carbene formation. Electrochemical measurements of the oxidation potentials for the phosphine/amine complexes indicate low d<sub>π</sub> electronic density at the ruthenium centers, with evidence of substantial PR<sub>3</sub>←Ru(II) backbonding. These findings were further confirmed by Natural Bond Orbital (NBO) analysis. The substitution of a chloride ion in the precursors was found to weaken the arene←Ru(II) π bond. The combination of electron density from both the phosphine and the amine ligands helps maintain<del>s</del> the <em>p</em>-cymene-Ru bond, rendering the complex inert in the absence of light.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114551"},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-25DOI: 10.1016/j.mcat.2024.114574
Xiaoman Li , Chengyue Lai , Yaping Zhang , Sheng Wang , Shipeng Ding
The simultaneous removal of CO and NOx in the sintering flue gas over a single catalyst is desirable but challenging. Herein, 2 %V2O5–5 %CuO/TiO2 bifunctional catalysts that efficiently catalyzed CO and NOx at low temperatures were reported, with CO and NOx conversions of 100 % at 200–300 °C. The synergistic effect between copper and vanadium oxides enhanced the redox and CO adsorption capacities of 2 %V2O5–5 %CuO/TiO2, rendering it abundant acid sites and surface chemisorbed oxygen. The in situ DRIFTS experiments demonstrated that CO oxidation over the dual-active-sites 2 %V2O5–5 %CuO/TiO2 catalyst follows the Mars-van Krevelen mechanism, while the E-R mechanism was the primary NH3-SCR pathway. Due to the presence of dual-active-sites (i.e., separated of the V active sites for the NH3-SCR reaction and the Cu active sites for CO oxidation), the competition adsorption of CO and NH3 on the Cu sites was weakened, resulting in higher CO oxidation performance than the single-active-site catalysts. This work provided insights into the control of flue gas containing CO and NOx over a single catalyst.
在单一催化剂上同时去除烧结烟气中的一氧化碳和氮氧化物是一种理想但具有挑战性的方法。本文报告了 2 %V2O5-5 %CuO/TiO2 双功能催化剂，该催化剂可在低温下高效催化一氧化碳和氮氧化物，在 200-300 °C 温度下，一氧化碳和氮氧化物的转化率达到 100%。铜和钒氧化物之间的协同效应增强了 2 %V2O5-5 %CuO/TiO2 的氧化还原能力和 CO 吸附能力，使其具有丰富的酸性位点和表面化学吸附氧。原位 DRIFTS 实验表明，双活性位点 2 %V2O5-5 %CuO/TiO2 催化剂上的 CO 氧化遵循 Mars-van Krevelen 机制，而 E-R 机制则是主要的 NH3-SCR 途径。由于存在双活性位点（即用于 NH3-SCR 反应的 V 活性位点和用于 CO 氧化的 Cu 活性位点分离），CO 和 NH3 在 Cu 位点上的竞争吸附作用减弱，因此 CO 氧化性能高于单活性位点催化剂。这项工作为在单一催化剂上控制含有 CO 和 NOx 的烟气提供了启示。
{"title":"Bifunctional catalysts V-Cu/TiO2 for selective catalytic reduction of NOx and CO oxidation under oxygen-rich conditions","authors":"Xiaoman Li , Chengyue Lai , Yaping Zhang , Sheng Wang , Shipeng Ding","doi":"10.1016/j.mcat.2024.114574","DOIUrl":"10.1016/j.mcat.2024.114574","url":null,"abstract":"<div><div>The simultaneous removal of CO and NO<sub>x</sub> in the sintering flue gas over a single catalyst is desirable but challenging. Herein, 2 %V<sub>2</sub>O<sub>5</sub>–5 %CuO/TiO<sub>2</sub> bifunctional catalysts that efficiently catalyzed CO and NO<sub>x</sub> at low temperatures were reported, with CO and NO<sub>x</sub> conversions of 100 % at 200–300 °C. The synergistic effect between copper and vanadium oxides enhanced the redox and CO adsorption capacities of 2 %V<sub>2</sub>O<sub>5</sub>–5 %CuO/TiO<sub>2</sub>, rendering it abundant acid sites and surface chemisorbed oxygen. The in situ DRIFTS experiments demonstrated that CO oxidation over the dual-active-sites 2 %V<sub>2</sub>O<sub>5</sub>–5 %CuO/TiO<sub>2</sub> catalyst follows the Mars-van Krevelen mechanism, while the E-R mechanism was the primary NH<sub>3</sub>-SCR pathway. Due to the presence of dual-active-sites (i.e., separated of the V active sites for the NH<sub>3</sub>-SCR reaction and the Cu active sites for CO oxidation), the competition adsorption of CO and NH<sub>3</sub> on the Cu sites was weakened, resulting in higher CO oxidation performance than the single-active-site catalysts. This work provided insights into the control of flue gas containing CO and NO<sub>x</sub> over a single catalyst.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114574"},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.mcat.2024.114568
Tadeja Vajdič , Bernd Nidetzky
Long-chain fatty acid esters of sucrose are nonionic surfactants with important applications in food, cosmetics and pharmacy. Their synthesis by chemical and biocatalytic methods involves the difficult task of coordinating efficiency and selectivity of the reaction used. Here, we show transesterification of sucrose (200 mM; ∼70 g/L) from vinyl palmitate (≥ 1 mole equivalent) in dry 2-methyl-2-butanol (2M2B) containing variable amount of 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) ionic liquid (5–60 % by volume), in the absence or presence of immobilized lipase (Candida antarctica; Thermomyces lanuginosus). Due to its combined effect on sucrose solubility and catalytic rate acceleration, the [Bmim][OAc] (≥ 20 % by volume) was sufficient to promote the transesterification efficiently, with no additional benefit provided by the enzyme, not even on the product selectivity and the initial rate. Using ≥ 2 mole equivalents of vinyl palmitate, sucrose was converted nearly fully (93 %) at low hydrolysis of the palmitoyl donor (∼7 %) in 72 h at 60°C, giving sucrose ester product comprised of ∼75 % monoester. Other general strategies of reaction intensification for carbohydrate (trans)esterification, such as substrate microdispersion in organic solvent (here: 2M2B with 20 vol.% DMSO) or usage of low-solvent conditions, proved by far less efficient with sucrose, failing in conversion and monoester selectivity. Overall, this study shows reaction intensification (product ≥ 110 g/L; productivity ≥ 1.5 g/L h) for [Bmim][OAc]-driven synthesis of palmitoyl sucrose (mono)esters of desired hydrophilic-lipophilic balance.
{"title":"Reaction intensification and selectivity control for palmitoyl transesterification of sucrose","authors":"Tadeja Vajdič , Bernd Nidetzky","doi":"10.1016/j.mcat.2024.114568","DOIUrl":"10.1016/j.mcat.2024.114568","url":null,"abstract":"<div><div>Long-chain fatty acid esters of sucrose are nonionic surfactants with important applications in food, cosmetics and pharmacy. Their synthesis by chemical and biocatalytic methods involves the difficult task of coordinating efficiency and selectivity of the reaction used. Here, we show transesterification of sucrose (200 mM; ∼70 g/L) from vinyl palmitate (≥ 1 mole equivalent) in dry 2-methyl-2-butanol (2M2B) containing variable amount of 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) ionic liquid (5–60 % by volume), in the absence or presence of immobilized lipase (<em>Candida antarctica; Thermomyces lanuginosus</em>). Due to its combined effect on sucrose solubility and catalytic rate acceleration, the [Bmim][OAc] (≥ 20 % by volume) was sufficient to promote the transesterification efficiently, with no additional benefit provided by the enzyme, not even on the product selectivity and the initial rate. Using ≥ 2 mole equivalents of vinyl palmitate, sucrose was converted nearly fully (93 %) at low hydrolysis of the palmitoyl donor (∼7 %) in 72 h at 60°C, giving sucrose ester product comprised of ∼75 % monoester. Other general strategies of reaction intensification for carbohydrate (trans)esterification, such as substrate microdispersion in organic solvent (here: 2M2B with 20 vol.% DMSO) or usage of low-solvent conditions, proved by far less efficient with sucrose, failing in conversion and monoester selectivity. Overall, this study shows reaction intensification (product ≥ 110 g/L; productivity ≥ 1.5 g/L h) for [Bmim][OAc]-driven synthesis of palmitoyl sucrose (mono)esters of desired hydrophilic-lipophilic balance.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114568"},"PeriodicalIF":3.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468823124007508/pdfft?md5=5c0faf90749fa4890b97a98d2c52170e&pid=1-s2.0-S2468823124007508-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High entropy alloys (HEAs) are composed of five or more atomic components, forming a homogeneous solid solution with a highly disordered crystal structure. This unique structure can increase the number and diversity of surface active sites, which is conducive to improving the rate and selectivity of catalytic reactions. Additionally, it exhibits good catalytic activity, stability, and antioxidant properties. This paper detailedly discusses the preparation method, structural characteristics, and application in catalysis of HEAs catalysts for oxygen evolution reaction (OER). Different methods can control the composition and microstructure of the alloy, thereby affecting the catalytic performance. Through density functional theory (DFT) studies on HEAs, it is demonstrated that Gibbs free energy is reduced, further confirming the effect of HEAs on OER performance. The various techniques for preparing HEAs and their derivatives, as well as the incorporation of different elements, are summarized. These different methods and introductions can synthesize diverse catalyst structures with evaluated electrocatalytic performances. HEAs catalysts can utilize waste metals or recycled materials along with green synthesis methods, making them promising in terms of sustainability and environmental protection to promote sustainable development and application of catalytic technology.
{"title":"A review of properties and applications of utilization of high entropy alloys in oxygen evolution reactions","authors":"Tao Tian , Xiaolin Zhang , Yanze Xue , Huabo Huang , Qianqian Jiang , Jianguo Tang","doi":"10.1016/j.mcat.2024.114571","DOIUrl":"10.1016/j.mcat.2024.114571","url":null,"abstract":"<div><div>High entropy alloys (HEAs) are composed of five or more atomic components, forming a homogeneous solid solution with a highly disordered crystal structure. This unique structure can increase the number and diversity of surface active sites, which is conducive to improving the rate and selectivity of catalytic reactions. Additionally, it exhibits good catalytic activity, stability, and antioxidant properties. This paper detailedly discusses the preparation method, structural characteristics, and application in catalysis of HEAs catalysts for oxygen evolution reaction (OER). Different methods can control the composition and microstructure of the alloy, thereby affecting the catalytic performance. Through density functional theory (DFT) studies on HEAs, it is demonstrated that Gibbs free energy is reduced, further confirming the effect of HEAs on OER performance. The various techniques for preparing HEAs and their derivatives, as well as the incorporation of different elements, are summarized. These different methods and introductions can synthesize diverse catalyst structures with evaluated electrocatalytic performances. HEAs catalysts can utilize waste metals or recycled materials along with green synthesis methods, making them promising in terms of sustainability and environmental protection to promote sustainable development and application of catalytic technology.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114571"},"PeriodicalIF":3.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.mcat.2024.114547
Yueling Cao , Haoyang Li , Fubin Ma , Hao Wen , Jinhui Wang , Hepeng Zhang
Catalyst stability is believed to be one of the greatest challenges faced for the supported metal catalysts in the catalytic conversion of biomass and its derivatives because many biomass transformations are conducted in the aqueous phase. In this work, we report a simple yet efficient coating-impregnation-pyrolysis (CIP) strategy to fabricate Al2O3 supported Ru catalyst (Ru-Al2O3@CN) with Ru NPs (nanoparticles) semi-embedded into N-doped carbon (CN) layer for the efficient hydrogenation of levulinic acid (LA) to γ-valerolactone in the aqueous phase. Benefit from the special structure of Ru-Al2O3@CN catalyst, it possesses both high catalytic activity and stability, giving a TOF of 28,099 h-1 for LA hydrogenation at 120 °C and 2 MPa H2, which is superior to the most of reported Ru-based catalysts. More importantly, compared with conventional impregnated Ru/Al2O3 catalyst, the Ru-Al2O3@CN catalyst exhibits a remarkably improved hydrothermal stability. Based on series of catalyst characterizations and control experiments, it was found that the presence of CN can weak the interaction between Ru and Al2O3, as well as protect the Al2O3 and Ru NPs from hydrolysis and aggregation, respectively. We anticipate that such a novel strategy may provide some valuable insights into the synthesis of oxides-supported metal catalyst with high hydrothermal stability.
{"title":"Enhanced hydrothermal stability by a semi-embedded structure: An efficient Ru catalyst for levulinic acid conversion in the aqueous phase","authors":"Yueling Cao , Haoyang Li , Fubin Ma , Hao Wen , Jinhui Wang , Hepeng Zhang","doi":"10.1016/j.mcat.2024.114547","DOIUrl":"10.1016/j.mcat.2024.114547","url":null,"abstract":"<div><div>Catalyst stability is believed to be one of the greatest challenges faced for the supported metal catalysts in the catalytic conversion of biomass and its derivatives because many biomass transformations are conducted in the aqueous phase. In this work, we report a simple yet efficient coating-impregnation-pyrolysis (CIP) strategy to fabricate Al<sub>2</sub>O<sub>3</sub> supported Ru catalyst (Ru-Al<sub>2</sub>O<sub>3</sub>@CN) with Ru NPs (nanoparticles) semi-embedded into N-doped carbon (CN) layer for the efficient hydrogenation of levulinic acid (LA) to γ-valerolactone in the aqueous phase. Benefit from the special structure of Ru-Al<sub>2</sub>O<sub>3</sub>@CN catalyst, it possesses both high catalytic activity and stability, giving a TOF of 28,099 h<sup>-1</sup> for LA hydrogenation at 120 °C and 2 MPa H<sub>2</sub>, which is superior to the most of reported Ru-based catalysts. More importantly, compared with conventional impregnated Ru/Al<sub>2</sub>O<sub>3</sub> catalyst, the Ru-Al<sub>2</sub>O<sub>3</sub>@CN catalyst exhibits a remarkably improved hydrothermal stability. Based on series of catalyst characterizations and control experiments, it was found that the presence of CN can weak the interaction between Ru and Al<sub>2</sub>O<sub>3</sub>, as well as protect the Al<sub>2</sub>O<sub>3</sub> and Ru NPs from hydrolysis and aggregation, respectively. We anticipate that such a novel strategy may provide some valuable insights into the synthesis of oxides-supported metal catalyst with high hydrothermal stability.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114547"},"PeriodicalIF":3.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.mcat.2024.114570
Jiaqi Zhou , Qingrong Wang , Hong Liu , Ming Bao , Jiasheng Wang
Gas-phase selective oxidation of toluene with air is a promising method for producing high-purity benzaldehyde, but the yields of existing catalysts are limited, so the development of more efficient catalysts is of great importance to the chemical industry. Herein VMoNb/CeO2 was prepared and characterized by SEM, XRD, Raman, XPS, H2-TPR, and NH3-TPD. The introduction of Mo generated V–O–Mo “asymmetric lattice oxygen” and thus brought high activity. Nb moderated the acidity and oxygen vacancy so as to improve the selectivity. The VMoNb/CeO2 catalyst showed very high catalytic activity at 500 °C, with 35% toluene conversion and 82% benzaldehyde selectivity at an air flow rate of 30 mL/min for V:Mo:Nb =2:5:0.8. This work could serve as a reference for designing mixed metal oxide catalysts for selective oxidation of aromatic hydrocarbons.
{"title":"VMoNb/CeO2 as an efficient catalyst for the gas-phase selective oxidation of toluene to benzaldehyde","authors":"Jiaqi Zhou , Qingrong Wang , Hong Liu , Ming Bao , Jiasheng Wang","doi":"10.1016/j.mcat.2024.114570","DOIUrl":"10.1016/j.mcat.2024.114570","url":null,"abstract":"<div><div>Gas-phase selective oxidation of toluene with air is a promising method for producing high-purity benzaldehyde, but the yields of existing catalysts are limited, so the development of more efficient catalysts is of great importance to the chemical industry. Herein VMoNb/CeO<sub>2</sub> was prepared and characterized by SEM, XRD, Raman, XPS, H<sub>2</sub>-TPR, and NH<sub>3</sub>-TPD. The introduction of Mo generated V–O–Mo “asymmetric lattice oxygen” and thus brought high activity. Nb moderated the acidity and oxygen vacancy so as to improve the selectivity. The VMoNb/CeO<sub>2</sub> catalyst showed very high catalytic activity at 500 °C, with 35% toluene conversion and 82% benzaldehyde selectivity at an air flow rate of 30 mL/min for V:Mo:Nb =2:5:0.8. This work could serve as a reference for designing mixed metal oxide catalysts for selective oxidation of aromatic hydrocarbons.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114570"},"PeriodicalIF":3.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.mcat.2024.114560
Junwei Hou , Yingxiao Chen , Mihemanjang Yimiti , Yangfan Xue , Han Zhang , Qingyao Wang
H2 energy causes the increasing attention as the green, environmental friendly energy style, and photocatalytic H2 production is the effective strategy by the inexhaustible solar energy conversion. Herein, CdS-Bi2S3 nanoparticles were decorated on TiO2 nanotube arrays (TiO2 NTs) via one-pot solvothermal synthesis method. The cosensitization effectively extended the optical response region, reduced electron/hole recombination and strengthened the photocatalytic H2 evolution performance. The high photocatalytic H2 evolution rate (79.92 μmol·cm−2·h−1) was obtained by TiO2 NTs/Bi2S3CdS, and the photocatalyst also exhibited dramatically high stability. The photocatalytic water splitting for H2 evolution mechanism and charge carrier transportation were proposed.
{"title":"One-pot solvothermal synthesis of Bi2S3-CdS sensitized TiO2 NT films for improved photocatalytic performance","authors":"Junwei Hou , Yingxiao Chen , Mihemanjang Yimiti , Yangfan Xue , Han Zhang , Qingyao Wang","doi":"10.1016/j.mcat.2024.114560","DOIUrl":"10.1016/j.mcat.2024.114560","url":null,"abstract":"<div><div>H<sub>2</sub> energy causes the increasing attention as the green, environmental friendly energy style, and photocatalytic H<sub>2</sub> production is the effective strategy by the inexhaustible solar energy conversion. Herein, CdS-Bi<sub>2</sub>S<sub>3</sub> nanoparticles were decorated on TiO<sub>2</sub> nanotube arrays (TiO<sub>2</sub> NTs) via one-pot solvothermal synthesis method. The cosensitization effectively extended the optical response region, reduced electron/hole recombination and strengthened the photocatalytic H<sub>2</sub> evolution performance. The high photocatalytic H<sub>2</sub> evolution rate (79.92 μmol·cm<sup>−2</sup>·<em>h</em><sup>−1</sup>) was obtained by TiO<sub>2</sub> NTs/Bi<sub>2</sub>S<sub>3</sub><sub><img></sub>CdS, and the photocatalyst also exhibited dramatically high stability. The photocatalytic water splitting for H<sub>2</sub> evolution mechanism and charge carrier transportation were proposed.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114560"},"PeriodicalIF":3.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-23DOI: 10.1016/j.mcat.2024.114554
Abdolreza Rezaeifard , Maasoumeh Jafarpour , Maryam Rostaminasab , Selina Olthof , Klaus Meerholz , Axel Klein
Simple stirring of an acidic aqueous solution (pH=3) containing sodium molybdate and thiamine hydrochloride (VB1) at room temperature resulted in an octamolybdate-containing VB1 (MoB1) material as an efficient and cost-effective epoxidation catalyst using tert‑butyl hydroperoxide (TBHP) under solvent-free condition. The stereospecific stilbene oxidation (>99 %) observed in the presence of MoB1 can be originated from the steric hindrance of some groups on the thiamine molecule and π–π stacking interactions of its pyrimidine and/or thiazole rings with phenyl rings of stilbenes. Further olefins such as cyclooctene, indene, 1-octene, and styrenes are efficiently oxidized using MoB1/TBHP catalytic system. The catalyst is composed of two thiaminium dications (C12H18N4OS)2+ and one Mo8O264– tetraanion based on different characterization techniques and chemical compositional analyses. Field Emission Scanning Electron Microscope (FE-SEM) images shows a sheet-like nanostructure for MoB1 comprising layers with thicknesses ranging from 50 to 500 nm. It exhibits a heterogeneous nature in catalysis evidenced by hot filtration test and ICP-OES analysis. X-ray photoelectron spectroscopy (XPS) indicates minor contributions of Mo in the oxidation states +V and +IV in addition to MoVI attributed to partial electron transfer from VB1 to Mo8O264–. The scavenging experiments support the presence of radical species during catalysis, while, they do not damage the structural integrity of the MoB1 catalyst based on the recycling experiments and FT-IR spectra.
{"title":"Thiamine-modified octamolybdate catalyzes solvent-free stereoselective olefin epoxidation with TBHP","authors":"Abdolreza Rezaeifard , Maasoumeh Jafarpour , Maryam Rostaminasab , Selina Olthof , Klaus Meerholz , Axel Klein","doi":"10.1016/j.mcat.2024.114554","DOIUrl":"10.1016/j.mcat.2024.114554","url":null,"abstract":"<div><div>Simple stirring of an acidic aqueous solution (pH=3) containing sodium molybdate and thiamine hydrochloride (VB1) at room temperature resulted in an octamolybdate-containing VB1 (<strong>MoB1</strong>) material as an efficient and cost-effective epoxidation catalyst using <em>tert</em>‑butyl hydroperoxide (TBHP) under solvent-free condition. The stereospecific stilbene oxidation (>99 %) observed in the presence of <strong>MoB1</strong> can be originated from the steric hindrance of some groups on the thiamine molecule and π–π stacking interactions of its pyrimidine and/or thiazole rings with phenyl rings of stilbenes. Further olefins such as cyclooctene, indene, 1-octene, and styrenes are efficiently oxidized using <strong>MoB1/</strong>TBHP catalytic system. The catalyst is composed of two thiaminium dications (C<sub>12</sub>H<sub>18</sub>N<sub>4</sub>OS)<sup>2+</sup> and one Mo<sub>8</sub>O<sub>26</sub><sup>4</sup><sup>–</sup> tetraanion based on different characterization techniques and chemical compositional analyses. Field Emission Scanning Electron Microscope (FE-SEM) images shows a sheet-like nanostructure for <strong>MoB1</strong> comprising layers with thicknesses ranging from 50 to 500 nm. It exhibits a heterogeneous nature in catalysis evidenced by hot filtration test and ICP-OES analysis. X-ray photoelectron spectroscopy (XPS) indicates minor contributions of Mo in the oxidation states +<em>V</em> and +IV in addition to Mo<sup>VI</sup> attributed to partial electron transfer from VB1 to Mo<sub>8</sub>O<sub>26</sub><sup>4</sup><sup>–</sup>. The scavenging experiments support the presence of radical species during catalysis, while, they do not damage the structural integrity of the <strong>MoB1</strong> catalyst based on the recycling experiments and FT-IR spectra.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"569 ","pages":"Article 114554"},"PeriodicalIF":3.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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