Pub Date : 2024-11-21DOI: 10.1016/j.jcat.2024.115850
Ekaterina A. Martynova, Vladislav V. Voloshkin, Marco Villa, Antonio Fiorentino, Marek Beliš, Kristof Van Hecke, Paola Ceroni, Steven P. Nolan
The use of [Au(SIPr)(Cbz)] as photosensitizer in [2+2]–cycloaddition reactions between benzothiophenes and activated (and non–activated) alkenes is presented. Commonly used organic and Ir–photosensitizers proved inefficient in the reaction with non–activated alkenes. The study emphasizes the dependence of the nature of the alkene, a parameter that has previously received little attention. Under mild reaction conditions, a wide array of alkenes and benzothiophenes were successfully coupled, showcasing remarkable tolerance of diverse functional groups. Additionally, we present intramolecular [2+2]–cycloaddition reactions, including benzothiophenes featuring various alkene linkers at the C2 and C3 positions.
{"title":"Access to cyclobutane–fused dihydrobenzothiophenes via gold–mediated photocatalyzed [2+2]–cycloaddition reactions","authors":"Ekaterina A. Martynova, Vladislav V. Voloshkin, Marco Villa, Antonio Fiorentino, Marek Beliš, Kristof Van Hecke, Paola Ceroni, Steven P. Nolan","doi":"10.1016/j.jcat.2024.115850","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115850","url":null,"abstract":"The use of [Au(SIPr)(Cbz)] as photosensitizer in [2+2]–cycloaddition reactions between benzothiophenes and activated (and non–activated) alkenes is presented. Commonly used organic and Ir–photosensitizers proved inefficient in the reaction with non–activated alkenes. The study emphasizes the dependence of the nature of the alkene, a parameter that has previously received little attention. Under mild reaction conditions, a wide array of alkenes and benzothiophenes were successfully coupled, showcasing remarkable tolerance of diverse functional groups. Additionally, we present intramolecular [2+2]–cycloaddition reactions, including benzothiophenes featuring various alkene linkers at the C2 and C3 positions.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"8 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142679091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As a green and sustainable alternative for producing ethyl pyruvate (EP), the selective aerobic oxidation of ethyl lactate (EL) is still facing issues such as low catalytic efficiency, harsh reaction conditions and catalyst instability. Herein, a novel crystalline vanadium-based coordination compound (VTC=VPTPYCl2(H2O), PTPY = 4′-phenyl-2,2′:6′,2′’-terpyridine) has been designed and synthesized. A highly efficient homogeneous catalytic system (VTC-400-O2-CH3CN, 400 represents the activation temperature) and a recyclable heterogeneous system (VTC-500-O2-CH3CN) for the liquid-phase conversion of EL to EP are developed using molecular oxygen as oxidant through activating VTC at different temperature. In VTC-400-O2-CH3CN system, EL can be completely converted within 4 h, and the yield of EP is 77.8 %, which outperforms the state-of-art reported catalytic system. Meanwhile, the heterogeneous VTC-500 catalyst can also promote the full conversion of EL within 4 h, and its activity remains basically unchanged after being used for 10 times. Structural characterization reveals that the soluble VTC breaks the weak coordination V-Cl bonds at a lower activation temperature of 400 ° C to expose more vanadium-based catalytic sites, but the framework of ligand remains intact. However, the organic derived carbon skeleton at higher temperature of 500 ° C can effectively confine the V-based active species and prevent the dissolution of the catalyst, which impels the transition of the homogeneous to heterogeneous catalytic system.
{"title":"Homogeneous and heterogeneous selective oxidation of ethyl lactate regulated by a novel vanadium complex","authors":"Yi Zhang, Shengyun Liao, Haitao Zhu, Qian Zhao, Jiaxin Zheng, Shuxian Ge, Jiaojiao Shi, Xinli Tong","doi":"10.1016/j.jcat.2024.115849","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115849","url":null,"abstract":"As a green and sustainable alternative for producing ethyl pyruvate (EP), the selective aerobic oxidation of ethyl lactate (EL) is still facing issues such as low catalytic efficiency, harsh reaction conditions and catalyst instability. Herein, a novel crystalline vanadium-based coordination compound (VTC=VPTPYCl<sub>2</sub>(H<sub>2</sub>O), PTPY = 4′-phenyl-2,2′:6′,2′’-terpyridine) has been designed and synthesized. A highly efficient homogeneous catalytic system (VTC-400-O<sub>2</sub>-CH<sub>3</sub>CN, 400 represents the activation temperature) and a recyclable heterogeneous system (VTC-500-O<sub>2</sub>-CH<sub>3</sub>CN) for the liquid-phase conversion of EL to EP are developed using molecular oxygen as oxidant through activating VTC at different temperature. In VTC-400-O<sub>2</sub>-CH<sub>3</sub>CN system, EL can be completely converted within 4 h, and the yield of EP is 77.8 %, which outperforms the state-of-art reported catalytic system. Meanwhile, the heterogeneous VTC-500 catalyst can also promote the full conversion of EL within 4 h, and its activity remains basically unchanged after being used for 10 times. Structural characterization reveals that the soluble VTC breaks the weak coordination V-Cl bonds at a lower activation temperature of 400 ° C to expose more vanadium-based catalytic sites, but the framework of ligand remains intact. However, the organic derived carbon skeleton at higher temperature of 500 ° C can effectively confine the V-based active species and prevent the dissolution of the catalyst, which impels the transition of the homogeneous to heterogeneous catalytic system.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"99 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.jcat.2024.115852
Parijat Borah, Preeti Nanda Sahu, Anik Sen, Miquel A. Pericàs
Primary amino-functionalized silicas (H2N-SiO2) are well known acid-base cooperative catalysts for many organic transformations, including carbon–carbon (C–C) bond forming condensation reactions, and much attention has been devoted to the elucidation of their action mode. However, to our surprise, the mechanism of Henry reactions and Knoevenagel condensations catalyzed by H2N-SiO2 is still paradoxical, and the identity of the actual base species, transition states, reactivity, and product selectivity, remain as debatable topics of discussion. Herein we propose a brand-new reaction mechanism for H2N-SiO2-catalyzed Henry reactions that overcomes all prior inconsistencies. With the aid of Hammett analysis and density functional theory (DFT) calculations, we have effectively identified several critical transition states and are able to explain reactivity and product selectivity. This study revealed that H2N-SiO2 catalyzed Henry reactions of aldehydes and nitro compounds follow the imine mechanism to afford olefin adducts as only possible products. In addition, we utilized our findings to comprehend the mechanism of Knoevenagel condensation, a comparable reaction, dispelling a more than two-decade old misconception regarding the nature of the active base involved.
{"title":"Unravelling the mechanistic ‘Black Box’ of heterogeneous condensation reactions catalyzed by aminosilicas","authors":"Parijat Borah, Preeti Nanda Sahu, Anik Sen, Miquel A. Pericàs","doi":"10.1016/j.jcat.2024.115852","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115852","url":null,"abstract":"Primary amino-functionalized silicas (H<sub>2</sub>N-SiO<sub>2</sub>) are well known acid-base cooperative catalysts for many organic transformations, including carbon–carbon (C–C) bond forming condensation reactions, and much attention has been devoted to the elucidation of their action mode. However, to our surprise, the mechanism of Henry reactions and Knoevenagel condensations catalyzed by H<sub>2</sub>N-SiO<sub>2</sub> is still paradoxical, and the identity of the actual base species, transition states, reactivity, and product selectivity, remain as debatable topics of discussion. Herein we propose a brand-new reaction mechanism for H<sub>2</sub>N-SiO<sub>2</sub>-catalyzed Henry reactions that overcomes all prior inconsistencies. With the aid of Hammett analysis and density functional theory (DFT) calculations, we have effectively identified several critical transition states and are able to explain reactivity and product selectivity. This study revealed that H<sub>2</sub>N-SiO<sub>2</sub> catalyzed Henry reactions of aldehydes and nitro compounds follow the imine mechanism to afford olefin adducts as only possible products. In addition, we utilized our findings to comprehend the mechanism of Knoevenagel condensation, a comparable reaction, dispelling a more than two-decade old misconception regarding the nature of the active base involved.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"17 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142642597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.jcat.2024.115847
Karoline L. Hebisch, Pawel A. Chmielniak, Violet A. Cutler, Rick B. Watson, Kinga Gołąbek, Carsten Sievers
This work examines how acid site concentration (FT-IR) and strength (NH3-TPD) as well as pore mouth accessibility modulate the activity of the microporous zeolite ferrierite (H-FER) during the skeletal isomerization of 1-butene to iso-butene. Restricting the accessibility of catalyst pores and strong acid sites is achieved by selective oxidation of residual organic structure directing agent (OSDA) through precise control of calcination conditions. Because this reaction is mediated by catalytically active carbonaceous deposits, residual OSDA affects their formation. This work demonstrates that small amounts of residual OSDA (∼ 0.2 wt%) are beneficial to the reaction under industrially relevant reaction conditions in three ways. Selective poisoning of strong BAS with OSDA nearly halves the amount of dimerization and cracking byproducts and improves catalyst lifetime. Simultaneously, carbonaceous fragments of the OSDA act as coke precursors and help shorten the startup time. Hence, catalyst lifetime may be significantly improved through both optimal pre-treatment conditions and by designing catalysts with an increased number of accessible pore mouths.
{"title":"Promoting role of residual organic structure directing agent in skeletal butene isomerization over ferrierite","authors":"Karoline L. Hebisch, Pawel A. Chmielniak, Violet A. Cutler, Rick B. Watson, Kinga Gołąbek, Carsten Sievers","doi":"10.1016/j.jcat.2024.115847","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115847","url":null,"abstract":"This work examines how acid site concentration (FT-IR) and strength (NH<sub>3</sub>-TPD) as well as pore mouth accessibility modulate the activity of the microporous zeolite ferrierite (H-FER) during the skeletal isomerization of 1-butene to <em>iso</em>-butene. Restricting the accessibility of catalyst pores and strong acid sites is achieved by selective oxidation of residual organic structure directing agent (OSDA) through precise control of calcination conditions. Because this reaction is mediated by catalytically active carbonaceous deposits, residual OSDA affects their formation. This work demonstrates that small amounts of residual OSDA (∼ 0.2 wt%) are beneficial to the reaction under industrially relevant reaction conditions in three ways. Selective poisoning of strong BAS with OSDA nearly halves the amount of dimerization and cracking byproducts and improves catalyst lifetime. Simultaneously, carbonaceous fragments of the OSDA act as coke precursors and help shorten the startup time. Hence, catalyst lifetime may be significantly improved through both optimal pre-treatment conditions and by designing catalysts with an increased number of accessible pore mouths.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"7 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.jcat.2024.115851
Xilun Zhang, Hongliang Liang, Fei Chang
Catalytic hydrogenation of alkynes to alkenes is pivotal in both petrochemical and fine chemical industries. Its implementation relies on the use of transition metals, especially those precious Pd-based catalysts. In this work, we utilize a melt infiltration method to prepare magnesium oxide-supported potassium hydride (KH/MgO), which is illustrated as a transition-metal-free catalyst for selective hydrogenation of alkynes. H2-D2 exchange experiment proves that dihydrogen activation and dissociation on KH/MgO is plausible at room temperature and ambient pressure. KH/MgO catalyzes hydrogenation of diphenylacetylene (DPA) already at 40 ℃, implying its high intrinsic activity at very mild conditions. Under an optimized condition of 80°C, 2 bar H2, and 40 h, 75 % conversion of DPA is achieved, affording 82 % selectivity to stilbenes. Mechanistic study suggests that surface hydride on KH/MgO plays an important role toward dihydrogen activation, and involved in the hydrogenation step to form stilbenes. This work shows the promise for using light metal hydrides consisting of earth-abundant elements as alternative hydrogenation catalysts.
{"title":"Magnesium oxide-supported potassium hydride as a transition-metal-free catalyst for the selective hydrogenation of alkynes","authors":"Xilun Zhang, Hongliang Liang, Fei Chang","doi":"10.1016/j.jcat.2024.115851","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115851","url":null,"abstract":"Catalytic hydrogenation of alkynes to alkenes is pivotal in both petrochemical and fine chemical industries. Its implementation relies on the use of transition metals, especially those precious Pd-based catalysts. In this work, we utilize a melt infiltration method to prepare magnesium oxide-supported potassium hydride (KH/MgO), which is illustrated as a transition-metal-free catalyst for selective hydrogenation of alkynes. H<sub>2</sub>-D<sub>2</sub> exchange experiment proves that dihydrogen activation and dissociation on KH/MgO is plausible at room temperature and ambient pressure. KH/MgO catalyzes hydrogenation of diphenylacetylene (DPA) already at 40 ℃, implying its high intrinsic activity at very mild conditions. Under an optimized condition of 80°C, 2 bar H<sub>2</sub>, and 40 h, 75 % conversion of DPA is achieved, affording 82 % selectivity to stilbenes. Mechanistic study suggests that surface hydride on KH/MgO plays an important role toward dihydrogen activation, and involved in the hydrogenation step to form stilbenes. This work shows the promise for using light metal hydrides consisting of earth-abundant elements as alternative hydrogenation catalysts.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"166 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142642599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the structure–activity relationships were investigated in converting biomass-derived furfural into cyclopentanone (CPO) or tetrahydrofuran alcohol (THFA) using a rinsing method to modulate the NiCoAl catalyst. Characterization of two catalysts, NiCoAl (without rinsing) and NiCoAl-R (with rinsing), reveals differences in morphology, composition, and acidity. Rinsing induced a transition from agglomerate to layered structure in NiCoAl-R, which exhibited higher acid strength and improved Lewis to Brønsted acid ratio. NiCoAl-R contained a high percentage of metal oxides, while NiCoAl had a high percentage of metallic species on its surface. These distinctions resulted in varied performance in FFA hydrogenolysis, with NiCoAl-R favoring CPO formation and NiCoAl facilitating THFA production. In situ DRIFTS experiments reveals differing furfural sorption states, and DFT calculations highlighted the higher activity of metal oxides in ring-opening reactions. This investigation elucidates the intricate relationship between catalyst properties and performance, offering insights for tailored catalyst design in biomass conversion.
{"title":"Tailoring selectivity in furfural hydrogenolysis over NiCoAl catalyst through a simple rinsing process","authors":"Zepeng Zhao, Wenguang Zhou, Guozhang Chang, Lungang Chen, Chenguang Wang, Yuhe Liao, Jinxing Long, Longlong Ma, Yong Liu","doi":"10.1016/j.jcat.2024.115845","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115845","url":null,"abstract":"In this study, the structure–activity relationships were investigated in converting biomass-derived furfural into cyclopentanone (CPO) or tetrahydrofuran alcohol (THFA) using a rinsing method to modulate the NiCoAl catalyst. Characterization of two catalysts, NiCoAl (without rinsing) and NiCoAl-R (with rinsing), reveals differences in morphology, composition, and acidity. Rinsing induced a transition from agglomerate to layered structure in NiCoAl-R, which exhibited higher acid strength and improved Lewis to Brønsted acid ratio. NiCoAl-R contained a high percentage of metal oxides, while NiCoAl had a high percentage of metallic species on its surface. These distinctions resulted in varied performance in FFA hydrogenolysis, with NiCoAl-R favoring CPO formation and NiCoAl facilitating THFA production. <em>In situ</em> DRIFTS experiments reveals differing furfural sorption states, and DFT calculations highlighted the higher activity of metal oxides in ring-opening reactions. This investigation elucidates the intricate relationship between catalyst properties and performance, offering insights for tailored catalyst design in biomass conversion.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"7 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The synthesis of N-substituted pyrrolidones starting from biomass-derived levulinic acid (LA) and nitroarenes is a highly attractive route for LA valorization, but still faces challenges. Herein, we report an electron deficient Niδ+ catalyst (Ni2P/NPCB-600) prepared by doping N and P into coffee biochar using a one-pot carbonization method. Ni2P/NPCB-600 shows outperform catalytic performance compared with the corresponding metallic Ni catalysts (Ni/CB-600 and Ni/NPCB-600) in the domino reductive amination and amidation of LA with nitroarenes. Characterization and controlled experiments demonstrate that the high catalytic activity and selectivity of Ni2P/NPCB-600 are mainly attributed to the formation of electron deficient Niδ+ (Ni2δ+-Pδ-), which could promote the decomposition of methyl formate, and the adsorption and activation of C=O bonds in LA during the domino reactions. Furthermore, Ni2P/NPCB-600 also shows good substrate scope, various N-substituted pyrrolidones can be directly synthesized from LA and different nitroarenes with good to excellent yields (87.5–99 %). This study provides a potential pathway for efficiently producing N-substituted pyrrolidones by adjusting the electron density of Ni.
从生物质衍生的左旋乙酸（LA）和硝基烯烃开始合成 N-取代的吡咯烷酮是一条极具吸引力的 LA 价值化途径，但仍然面临着挑战。在此，我们报告了一种缺电子的 Niδ+ 催化剂（Ni2P/NPCB-600），该催化剂是采用一锅碳化法在咖啡生物炭中掺入 N 和 P 制备而成的。与相应的金属镍催化剂（Ni/CB-600 和 Ni/NPCB-600）相比，Ni2P/NPCB-600 在 LA 与硝基烯烃的多米诺还原胺化和酰胺化反应中表现出更优异的催化性能。表征和对照实验表明，Ni2P/NPCB-600 的高催化活性和选择性主要归功于形成了缺电子的 Niδ+ （Ni2δ+-Pδ-），它可以促进甲酸甲酯的分解，并在多米诺反应过程中吸附和活化 LA 中的 C=O 键。此外，Ni2P/NPCB-600 还显示出良好的底物范围，可以直接从 LA 和不同的硝基烯烃合成各种 N-取代的吡咯烷酮，而且产率良好甚至极佳（87.5-99%）。这项研究为通过调整镍的电子密度高效生产 N-取代的吡咯烷酮提供了一条潜在的途径。
{"title":"N, P co-doped porous biochar supported electron deficient Niδ+ for domino reductive amination and amidation of levulinic acid with nitroarenes to N-substituted pyrrolidones using methyl formate","authors":"Honghui Gong, Longxing Wei, Qi Li, Fei Wang, Yihan Jin, Xiaojing Zhang, Kexin Guo, Yuan Ma, Xian-Lei Shi","doi":"10.1016/j.jcat.2024.115848","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115848","url":null,"abstract":"The synthesis of N-substituted pyrrolidones starting from biomass-derived levulinic acid (LA) and nitroarenes is a highly attractive route for LA valorization, but still faces challenges. Herein, we report an electron deficient Ni<sup>δ+</sup> catalyst (Ni<sub>2</sub>P/NPCB-600) prepared by doping N and P into coffee biochar using a one-pot carbonization method. Ni<sub>2</sub>P/NPCB-600 shows outperform catalytic performance compared with the corresponding metallic Ni catalysts (Ni/CB-600 and Ni/NPCB-600) in the domino reductive amination and amidation of LA with nitroarenes. Characterization and controlled experiments demonstrate that the high catalytic activity and selectivity of Ni<sub>2</sub>P/NPCB-600 are mainly attributed to the formation of electron deficient Ni<sup>δ+</sup> (Ni<sub>2</sub><sup>δ+</sup>-P<sup>δ-</sup>), which could promote the decomposition of methyl formate, and the adsorption and activation of C=O bonds in LA during the domino reactions. Furthermore, Ni<sub>2</sub>P/NPCB-600 also shows good substrate scope, various N-substituted pyrrolidones can be directly synthesized from LA and different nitroarenes with good to excellent yields (87.5–99 %). This study provides a potential pathway for efficiently producing N-substituted pyrrolidones by adjusting the electron density of Ni.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"248 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142642977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.jcat.2024.115846
Jinyu Li , Sunzai Ke , Jiayu Yi , Xiang Li , Lijuan Shen , Ruidan Zhang , Min-Quan Yang
Surface modification plays an important role in extending light absorption and enhancing the catalytic performance of semiconductor photocatalysts. However, most current studies focus on pre-modification of the semiconductors before reaction, while surface self-modification of catalyst during photocatalytic reaction process is often neglected. Here, we report the surface self-modification of TiO2 catalyst during photocatalytic oxidation of toluene under UV light irradiation, which changes the colour of TiO2 from white to yellow, and effectively extends its light absorption range into visible light region. The absorbed visible light is primarily released as thermal energy, significantly increasing the temperature of the catalytic system. Mechanistic studies reveal that the temperature elevation facilitates the separation of photogenerated charge carriers in TiO2 and promotes the generation of •O2−, consequently accelerating the surface redox reactions. The surface self-modified TiO2 exhibits an enhanced photothermal catalytic benzaldehyde generation of 4485 μmol g−1 h−1 under UV–visible light irradiation, which surpasses the UV-driven activity by a factor of 1.9. This study offers new perspectives on the surface modification of semiconductor photocatalysts during organic transformations. It is anticipated to trigger increased research attention to this effect, ultimately advancing solar-to-chemical energy conversion.
{"title":"Surface self-modification of TiO2 for enhanced photocatalytic toluene oxidation via photothermal effect","authors":"Jinyu Li , Sunzai Ke , Jiayu Yi , Xiang Li , Lijuan Shen , Ruidan Zhang , Min-Quan Yang","doi":"10.1016/j.jcat.2024.115846","DOIUrl":"10.1016/j.jcat.2024.115846","url":null,"abstract":"<div><div>Surface modification plays an important role in extending light absorption and enhancing the catalytic performance of semiconductor photocatalysts. However, most current studies focus on pre-modification of the semiconductors before reaction, while surface self-modification of catalyst during photocatalytic reaction process is often neglected. Here, we report the surface self-modification of TiO<sub>2</sub> catalyst during photocatalytic oxidation of toluene under UV light irradiation, which changes the colour of TiO<sub>2</sub> from white to yellow, and effectively extends its light absorption range into visible light region. The absorbed visible light is primarily released as thermal energy, significantly increasing the temperature of the catalytic system. Mechanistic studies reveal that the temperature elevation facilitates the separation of photogenerated charge carriers in TiO<sub>2</sub> and promotes the generation of •O<sub>2</sub><sup>−</sup>, consequently accelerating the surface redox reactions. The surface self-modified TiO<sub>2</sub> exhibits an enhanced photothermal catalytic benzaldehyde generation of 4485 μmol g<sup>−1</sup> h<sup>−1</sup> under UV–visible light irradiation, which surpasses the UV-driven activity by a factor of 1.9. This study offers new perspectives on the surface modification of semiconductor photocatalysts during organic transformations. It is anticipated to trigger increased research attention to this effect, ultimately advancing solar-to-chemical energy conversion.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115846"},"PeriodicalIF":6.5,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.jcat.2024.115839
Xin Qi , Yuanrui Wang , Xiao-Feng Wu
γ-Lactams are important core structure found in various natural and biologically active compounds. And the introducing of difluoromethylene group into a molecule can change its physical, chemical, and biological properties. As carbonylation chemistry represent a powerful and efficient method for the synthesis of carbonylated compounds, we report here an efficient procedure for the construction of difluoroalkylative γ-lactams via palladium-catalyzed carbonylative cyclization of alkenes. The desired γ-lactams were produced in moderate to good yields under relatively mild conditions.
{"title":"Palladium-catalyzed difluoroalkylative carbonylation of unactivated alkenes toward γ-Lactams","authors":"Xin Qi , Yuanrui Wang , Xiao-Feng Wu","doi":"10.1016/j.jcat.2024.115839","DOIUrl":"10.1016/j.jcat.2024.115839","url":null,"abstract":"<div><div>γ-Lactams are important core structure found in various natural and biologically active compounds. And the introducing of difluoromethylene group into a molecule can change its physical, chemical, and biological properties. As carbonylation chemistry represent a powerful and efficient method for the synthesis of carbonylated compounds, we report here an efficient procedure for the construction of difluoroalkylative γ-lactams via palladium-catalyzed carbonylative cyclization of alkenes. The desired γ-lactams were produced in moderate to good yields under relatively mild conditions.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115839"},"PeriodicalIF":6.5,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.jcat.2024.115844
Zhendong Yu, Zihao Qin, Hongyuan Liu, Shaoyu Yuan, Renjie Huang, Binglin Chen, Zheng Li, Lu Lin, Carol Sze Ki Lin, Xianhai Zeng
The selective hydrogenolysis of C-OH in renewable furanic compounds to corresponding high-value products has been attractive yet challenging, and the mechanism remains vague. Herein, a non-noble catalyst (Ni-TT-Nb2O5) was prepared to address this challenge. Batch and continuous reaction results show that Ni-TT-Nb2O5 can selectively hydrodeoxygenate 5-hdyroxymethylfurfural to 5-methylfurfural with a very high selectivity of 99 %. Moreover, Ni-TT-Nb2O5 can also selectively hydrodeoxygenate various furanic, benzenoid and aliphatic alcohols, achieving up to > 95 % selectivity. In-situ FTIR and DFT calculations showed that compared with other Ni-supported (supports = Al2O3, CeO2, SiO2, ZrO2) catalysts, HMF was adsorbed on Ni-TT-Nb2O5 surface via parallel mode exclusively, and the C-OH bond was easier to be activated. This work therefore explained the mechanism of selective hydrogenolysis of C-OH in HMF over Ni-TT-Nb2O5, and offered an advanced approach for the upgrading of C-OH-containing furanic compounds as well as benzenoid and aliphatic alcohols.
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