Despite of its great importance, the detailed molecular mechanism for carbohydrate pyrolysis remains poorly understood. We perform a density functional study with a newly developed XYG3 functional on the processes for...Despite of its great importance, the detailed molecular mechanism for carbohydrate pyrolysis remains poorly understood. We perform a density functional study with a newly developed XYG3 functional on the processes for D-glucose pyrolysis to acrolein. The most feasible reaction pathway starts from an isomerization from D-glucose to D-fructose, which then undergoes a cyclic Grob fragmentation, followed by a concerted electrocyclic dehydration to yield acrolein. This mechanism can account for the known experimental results.展开更多
A mesoporous sulfated zirconia-silica catalyst bearing only Br？nsted acid sites converted glycerol to acrolein in 81%yield with 82% selectivity.Space time yield as high as 9.0 mmol h^（-1） g_（cat）^（-1） was achie...A mesoporous sulfated zirconia-silica catalyst bearing only Br？nsted acid sites converted glycerol to acrolein in 81%yield with 82% selectivity.Space time yield as high as 9.0 mmol h^（-1） g_（cat）^（-1） was achieved even at a low reaction temperature of 523 K.The catalytic activity and selectivity were higher than those of typical sulfated zirconia.It is proposed that the milder acidity due to dilution of zirconium species by silica and large pore size for faster diffusion contributed towards the better catalytic performance.展开更多
Precursor decomposition was used for the preparation of VTeO/SBA-15 catalyst for the selective oxidation of propane to acrolein. The catalyst shows a better performance compared with those prepared by conventional imp...Precursor decomposition was used for the preparation of VTeO/SBA-15 catalyst for the selective oxidation of propane to acrolein. The catalyst shows a better performance compared with those prepared by conventional impregnant method. A yield of 9.3% of acrolein was achieved with 2% V loadings at 500 ℃. XRD, N2-adsorption, H2-TPR, Py-IR and XPS measurements were used to unclose the relationship between the structure and performance of the catalyst.展开更多
Glycerol dehydration to acrolein over a series of supported silicotungstic acid catalysts(SiWx‐Al/Zry)was investigated.Characterization results showed that the final catalyst had high thermal stability,a large pore d...Glycerol dehydration to acrolein over a series of supported silicotungstic acid catalysts(SiWx‐Al/Zry)was investigated.Characterization results showed that the final catalyst had high thermal stability,a large pore diameter,strong Lewis acidic sites,and a large specific surface area.X‐ray photoelectron survey spectra clearly showed peaks attributable to W(W4f=35.8eV),Al2O3(Al2p=74.9eV),and ZrO2(Zr3d=182.8eV).The highest acrolein selectivity achieved was87.3%at97%glycerol conversion over the SiW20‐Al/Zr10catalyst.The prepared catalysts were highly active and selective for acrolein formation even after40h because of the presence of high concentrations of Lewis acidic sites,which significantly reduced the amount of coke on the catalyst surface.Response surface methodology optimization showed that87.7%acrolein selectivity at97.0%glycerol conversion could be obtained under the following optimal reaction conditions:0.5wt%catalyst,reaction temperature300°C,and feed glycerol concentration10wt%.Evaluation of a mass‐transfer‐limited regime showed the absence of internal and external diffusions over pellets of diameter dP<20μm.These results show that glycerol dehydration over a strong Lewis acid catalyst is a promising method for acrolein production.展开更多
In the hours to weeks following traumatic spinal cord injuries （SCI）, biochemical processes are initiated that further damage the tissue within and surrounding the initial injury site： a process termed secondary in...In the hours to weeks following traumatic spinal cord injuries （SCI）, biochemical processes are initiated that further damage the tissue within and surrounding the initial injury site： a process termed secondary injury. Acrolein, a highly reactive unsaturated aldehyde, has been shown to play a major role in the secondary injury by contributing significantly to both motor and sensory defi- cits. In particular, efforts have been made to eluddate the mechanisms of acrolein-mediated dam- age at the cellular level and the resulting paralysis and neuropathic pain. In this review, we will highlight the recent developments in the understanding of the mechanisms of acrolein in motor and sensory dysfunction in animal models of SCI. We will also discuss the therapeutic benefits of using acrolein scavengers to attenuate acrolein-mediated neuronal damage following SCI.展开更多
Direct epoxidation of propylene with H_(2)/O_(2),being the dream reaction for propylene oxide(PO)production,has raised wide scientific and industrial interests.Fundamentally understanding the formation mechanism of ac...Direct epoxidation of propylene with H_(2)/O_(2),being the dream reaction for propylene oxide(PO)production,has raised wide scientific and industrial interests.Fundamentally understanding the formation mechanism of acrolein,as the main by-product of this epoxidation process,is very important to achieve the high yield of PO.In this study,we perform the spin-polarized density functional theory(DFT)calculations to investigate the reaction pathway from propylene to acrolein over two representative Au surfaces,that is,Au(111)and Au(100),which incorporates propylene adsorption,methyl hydrogen activation and acrolein formation.The results show that the oxygenated species(mainly O^(*),OH^(*)and OOH^(*))are able to stabilize the adsorption of propylene to decrease the energy barrier for its activation.It is demonstrated that the OOH^(*)on Au(111)surface emerges as the most easily formed oxygenated species via the H-assisted O_(2) dissociation,which is also the most active for the cleavage of methyl CAH bond in propylene.Furthermore,three pathways of acrolein formation activated by O^(*)/OH^(*)/OOH^(*)are analyzed,in which O^(*)is found as the key species to form acrolein.Finally,Bader charge analysis was conducted to explore the reasons behind the promotion effect of the oxygenated species.The insights reported here could be valuable in the design and optimization of gold catalysts for the direct epoxidation of propylene.展开更多
Lipid peroxidation-derived aldehydes,such as acrolein,the most reactive aldehyde,have emerged as key culprits in sustaining post-spinal cord injury(SCI)secondary pathologies leading to functional loss.Strong evidence ...Lipid peroxidation-derived aldehydes,such as acrolein,the most reactive aldehyde,have emerged as key culprits in sustaining post-spinal cord injury(SCI)secondary pathologies leading to functional loss.Strong evidence suggests that mitochondrial aldehyde dehydrogenase-2(ALDH2),a key oxidoreductase and powerful endogenous anti-aldehyde machinery,is likely important for protecting neurons from aldehydesmediated degeneration.Using a rat model of spinal cord contusion injury and recently discovered ALDH2 activator(Alda-1),we planned to validate the aldehyde-clearing and neuroprotective role of ALDH2.Over an acute 2 day period post injury,we found that ALDH2 expression was significantly lowered post-SCI,but not so in rats given Alda-1.This lower enzymatic expression may be linked to heightened acrolein-ALDH2 adduction,which was revealed in co-immunoprecipitation experiments.We have also found that administration of Alda-1 to SCI rats significantly lowered acrolein in the spinal cord,and reduced cyst pathology.In addition,Alda-1 treatment also resulted in significant improvement of motor function and attenuated post-SCI mechanical hypersensitivity up to 28 days post-SCI.Finally,ALDH2 was found to play a critical role in in vitro protection of PC12 cells from acrolein exposure.It is expected that the outcome of this study will broaden and enhance anti-aldehyde strategies in combating post-SCI neurodegeneration and potentially bring treatment to millions of SCI victims.All animal work was approved by Purdue Animal Care and Use Committee(approval No.1111000095)on January 1,2021.展开更多
Oxide-supported copper-containing materials have attracted considerable research attention as promising candidates for acrolein formation.Nevertheless,the elucidation of the structure-performance relationships for the...Oxide-supported copper-containing materials have attracted considerable research attention as promising candidates for acrolein formation.Nevertheless,the elucidation of the structure-performance relationships for these systems remains a scientific challenge.In this work,copper oxide clusters deposited on a high-surface-area silica support were synthesized via a deposition-precipitation approach and exhibited remarkable catalytic reactivity(up to 25.5%conversion and 66.8%selectivity)in the propylene-selective oxidation of acrolein at 300℃.Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy combined with X-ray absorption fine structure measurements of the catalyst before and after the reaction confirmed the transformation of the small-sized copper oxide(CuO)clusters into cuprous oxide(Cu2O)clusters.With the aid of in situ X-ray diffraction and in situ dual beam Fourier transform infrared spectroscopy(DB-FTIR),the allyl intermediate(CH2=CHCH2*)was clearly observed,along with the as-formed Cu2O species.The intermediate can react with oxygen atoms from neighboring Cu2O species to form acrolein during the catalytic process,and the small-sized Cu2O clusters play a crucial role in the generation of acrolein via the selective oxidation of propylene.展开更多
Several Mo-V-Te-O mixed metal oxides catalysts with different dopant were prepared and used for catalytic oxidation propane to acrolein. It was revealed that the addition of P could greatly improve the performance of ...Several Mo-V-Te-O mixed metal oxides catalysts with different dopant were prepared and used for catalytic oxidation propane to acrolein. It was revealed that the addition of P could greatly improve the performance of the Mo-V-Te-O catalyst. The catalysts were examined by XRD and H2-TPR. The XRD characteristic of the Mo-V-Te-P-O showed that the addition of P could aggrandize the (V0.07Mo0.93)5O14 phase. H2-TPR illuminated that the MoV0.3Te0.23P0.15On catalyst took on the best redox ability.展开更多
The increase of biodiesel production results in the accumulation of glycerol, which requires an increasing demand towards the study of chemical application of glycerol. Glycerol has to be transformed to other valuable...The increase of biodiesel production results in the accumulation of glycerol, which requires an increasing demand towards the study of chemical application of glycerol. Glycerol has to be transformed to other valuable chemicals, which can be used as starting materials for organic synthesis. With the final goal to find a reasonable solution for this problem we have studied the dehydration of glycerol in liquid phase using a supported HPA catalyst and developed an environmentally benign production of acrolein. Our method does not have any extreme conditions and produces a total conversion with high (93%) selectivity.展开更多
The gas-phase dehydration of glycerol was conducted over HPW/MCM-41 catalysts,which were prepared by impregnation of different amount of H3PW（12）O（40）（HPW）on the MCM-41 support.The samples were characterized by ...The gas-phase dehydration of glycerol was conducted over HPW/MCM-41 catalysts,which were prepared by impregnation of different amount of H3PW（12）O（40）（HPW）on the MCM-41 support.The samples were characterized by XRD,N2 physisorption,FTIR,NH3-TPD,and pyridine-FTIR measurements.N2 physisorption results suggested that the uniform framework of MCM-41 could still be well maintained after modified with HPW.Pyridine-FTIR experiments indicate that HPW modified MCM-41 can generate rich Br？nsted acid sites.Moreover,Brnsted acid sites facilitated to improve acrolein selectivity.Under the optimized reaction conditions：40wt%HPW loading,20%glycerol concentration,and 320℃reaction temperature,the glycerol conversion and acrolein selectivity reach 85%and 80%,respectively.展开更多
Photodecarbonylation reaction of acrolein at 193nm was investigated by ab initio molecular orbital method.Our result supports photodecarbonylation mechanisms proposed by Fujimoto,and predicts that the reaction should ...Photodecarbonylation reaction of acrolein at 193nm was investigated by ab initio molecular orbital method.Our result supports photodecarbonylation mechanisms proposed by Fujimoto,and predicts that the reaction should occur in ~3ππ potential energy surface prior to the ~1ππ potential energy surface.展开更多
基金Acknowledgments This work was supported by the National Natural Science Foundation of China （No.I0774126） and the Ministry of Science and Technology （No.2007CB815206 and No.2011CB808505）.
文摘Despite of its great importance, the detailed molecular mechanism for carbohydrate pyrolysis remains poorly understood. We perform a density functional study with a newly developed XYG3 functional on the processes for D-glucose pyrolysis to acrolein. The most feasible reaction pathway starts from an isomerization from D-glucose to D-fructose, which then undergoes a cyclic Grob fragmentation, followed by a concerted electrocyclic dehydration to yield acrolein. This mechanism can account for the known experimental results.
基金supported by Grant-in-Aid for Research Activity Start-up(KAKENHI,21860004)for Young Scientists(KAKENHI,26709060) from Japan Society for the Promotion of Science(JSPS)
文摘A mesoporous sulfated zirconia-silica catalyst bearing only Br？nsted acid sites converted glycerol to acrolein in 81%yield with 82% selectivity.Space time yield as high as 9.0 mmol h^（-1） g_（cat）^（-1） was achieved even at a low reaction temperature of 523 K.The catalytic activity and selectivity were higher than those of typical sulfated zirconia.It is proposed that the milder acidity due to dilution of zirconium species by silica and large pore size for faster diffusion contributed towards the better catalytic performance.
基金Supported by the Ministry of Science and Technology of China(No. 2005CB221408)the National Natural Science Founda-tion of China(Nos. 20423002, 20571061)Key Scientific Project of Fujian Province, China(No. 2005HZ01-3)
文摘Precursor decomposition was used for the preparation of VTeO/SBA-15 catalyst for the selective oxidation of propane to acrolein. The catalyst shows a better performance compared with those prepared by conventional impregnant method. A yield of 9.3% of acrolein was achieved with 2% V loadings at 500 ℃. XRD, N2-adsorption, H2-TPR, Py-IR and XPS measurements were used to unclose the relationship between the structure and performance of the catalyst.
基金the Ministry of Science, Technology and Innovation (MOSTI), Malaysia for supporting the project under project no. 03–01–06–SF0963
文摘Glycerol dehydration to acrolein over a series of supported silicotungstic acid catalysts(SiWx‐Al/Zry)was investigated.Characterization results showed that the final catalyst had high thermal stability,a large pore diameter,strong Lewis acidic sites,and a large specific surface area.X‐ray photoelectron survey spectra clearly showed peaks attributable to W(W4f=35.8eV),Al2O3(Al2p=74.9eV),and ZrO2(Zr3d=182.8eV).The highest acrolein selectivity achieved was87.3%at97%glycerol conversion over the SiW20‐Al/Zr10catalyst.The prepared catalysts were highly active and selective for acrolein formation even after40h because of the presence of high concentrations of Lewis acidic sites,which significantly reduced the amount of coke on the catalyst surface.Response surface methodology optimization showed that87.7%acrolein selectivity at97.0%glycerol conversion could be obtained under the following optimal reaction conditions:0.5wt%catalyst,reaction temperature300°C,and feed glycerol concentration10wt%.Evaluation of a mass‐transfer‐limited regime showed the absence of internal and external diffusions over pellets of diameter dP<20μm.These results show that glycerol dehydration over a strong Lewis acid catalyst is a promising method for acrolein production.
文摘In the hours to weeks following traumatic spinal cord injuries （SCI）, biochemical processes are initiated that further damage the tissue within and surrounding the initial injury site： a process termed secondary injury. Acrolein, a highly reactive unsaturated aldehyde, has been shown to play a major role in the secondary injury by contributing significantly to both motor and sensory defi- cits. In particular, efforts have been made to eluddate the mechanisms of acrolein-mediated dam- age at the cellular level and the resulting paralysis and neuropathic pain. In this review, we will highlight the recent developments in the understanding of the mechanisms of acrolein in motor and sensory dysfunction in animal models of SCI. We will also discuss the therapeutic benefits of using acrolein scavengers to attenuate acrolein-mediated neuronal damage following SCI.
基金financially supported by the Research Fund for National Key Research and Development Program of China (2021YFA1501403)the National Natural Science Foundation of China (22208094,22038003,21922803,22178100)+1 种基金the Innovation Program of Shanghai Municipal Education Commission,the Program of Shanghai Academic/Technology Research Leader (21XD1421000)the Shanghai Science and Technology Innovation Action Plan (22JC1403800)。
文摘Direct epoxidation of propylene with H_(2)/O_(2),being the dream reaction for propylene oxide(PO)production,has raised wide scientific and industrial interests.Fundamentally understanding the formation mechanism of acrolein,as the main by-product of this epoxidation process,is very important to achieve the high yield of PO.In this study,we perform the spin-polarized density functional theory(DFT)calculations to investigate the reaction pathway from propylene to acrolein over two representative Au surfaces,that is,Au(111)and Au(100),which incorporates propylene adsorption,methyl hydrogen activation and acrolein formation.The results show that the oxygenated species(mainly O^(*),OH^(*)and OOH^(*))are able to stabilize the adsorption of propylene to decrease the energy barrier for its activation.It is demonstrated that the OOH^(*)on Au(111)surface emerges as the most easily formed oxygenated species via the H-assisted O_(2) dissociation,which is also the most active for the cleavage of methyl CAH bond in propylene.Furthermore,three pathways of acrolein formation activated by O^(*)/OH^(*)/OOH^(*)are analyzed,in which O^(*)is found as the key species to form acrolein.Finally,Bader charge analysis was conducted to explore the reasons behind the promotion effect of the oxygenated species.The insights reported here could be valuable in the design and optimization of gold catalysts for the direct epoxidation of propylene.
基金supported by a grant from National Institute of Neurological Disorders and Stroke R21(No.1R21NS115094-01)。
文摘Lipid peroxidation-derived aldehydes,such as acrolein,the most reactive aldehyde,have emerged as key culprits in sustaining post-spinal cord injury(SCI)secondary pathologies leading to functional loss.Strong evidence suggests that mitochondrial aldehyde dehydrogenase-2(ALDH2),a key oxidoreductase and powerful endogenous anti-aldehyde machinery,is likely important for protecting neurons from aldehydesmediated degeneration.Using a rat model of spinal cord contusion injury and recently discovered ALDH2 activator(Alda-1),we planned to validate the aldehyde-clearing and neuroprotective role of ALDH2.Over an acute 2 day period post injury,we found that ALDH2 expression was significantly lowered post-SCI,but not so in rats given Alda-1.This lower enzymatic expression may be linked to heightened acrolein-ALDH2 adduction,which was revealed in co-immunoprecipitation experiments.We have also found that administration of Alda-1 to SCI rats significantly lowered acrolein in the spinal cord,and reduced cyst pathology.In addition,Alda-1 treatment also resulted in significant improvement of motor function and attenuated post-SCI mechanical hypersensitivity up to 28 days post-SCI.Finally,ALDH2 was found to play a critical role in in vitro protection of PC12 cells from acrolein exposure.It is expected that the outcome of this study will broaden and enhance anti-aldehyde strategies in combating post-SCI neurodegeneration and potentially bring treatment to millions of SCI victims.All animal work was approved by Purdue Animal Care and Use Committee(approval No.1111000095)on January 1,2021.
文摘Oxide-supported copper-containing materials have attracted considerable research attention as promising candidates for acrolein formation.Nevertheless,the elucidation of the structure-performance relationships for these systems remains a scientific challenge.In this work,copper oxide clusters deposited on a high-surface-area silica support were synthesized via a deposition-precipitation approach and exhibited remarkable catalytic reactivity(up to 25.5%conversion and 66.8%selectivity)in the propylene-selective oxidation of acrolein at 300℃.Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy combined with X-ray absorption fine structure measurements of the catalyst before and after the reaction confirmed the transformation of the small-sized copper oxide(CuO)clusters into cuprous oxide(Cu2O)clusters.With the aid of in situ X-ray diffraction and in situ dual beam Fourier transform infrared spectroscopy(DB-FTIR),the allyl intermediate(CH2=CHCH2*)was clearly observed,along with the as-formed Cu2O species.The intermediate can react with oxygen atoms from neighboring Cu2O species to form acrolein during the catalytic process,and the small-sized Cu2O clusters play a crucial role in the generation of acrolein via the selective oxidation of propylene.
文摘Several Mo-V-Te-O mixed metal oxides catalysts with different dopant were prepared and used for catalytic oxidation propane to acrolein. It was revealed that the addition of P could greatly improve the performance of the Mo-V-Te-O catalyst. The catalysts were examined by XRD and H2-TPR. The XRD characteristic of the Mo-V-Te-P-O showed that the addition of P could aggrandize the (V0.07Mo0.93)5O14 phase. H2-TPR illuminated that the MoV0.3Te0.23P0.15On catalyst took on the best redox ability.
文摘The increase of biodiesel production results in the accumulation of glycerol, which requires an increasing demand towards the study of chemical application of glycerol. Glycerol has to be transformed to other valuable chemicals, which can be used as starting materials for organic synthesis. With the final goal to find a reasonable solution for this problem we have studied the dehydration of glycerol in liquid phase using a supported HPA catalyst and developed an environmentally benign production of acrolein. Our method does not have any extreme conditions and produces a total conversion with high (93%) selectivity.
基金Funded by the National Natural Science Foundation of China(No.21303154)
文摘The gas-phase dehydration of glycerol was conducted over HPW/MCM-41 catalysts,which were prepared by impregnation of different amount of H3PW（12）O（40）（HPW）on the MCM-41 support.The samples were characterized by XRD,N2 physisorption,FTIR,NH3-TPD,and pyridine-FTIR measurements.N2 physisorption results suggested that the uniform framework of MCM-41 could still be well maintained after modified with HPW.Pyridine-FTIR experiments indicate that HPW modified MCM-41 can generate rich Br？nsted acid sites.Moreover,Brnsted acid sites facilitated to improve acrolein selectivity.Under the optimized reaction conditions：40wt%HPW loading,20%glycerol concentration,and 320℃reaction temperature,the glycerol conversion and acrolein selectivity reach 85%and 80%,respectively.
基金Project supported by NSFC a.Department of Modern chemistry,University of Science and Technology of China.
文摘Photodecarbonylation reaction of acrolein at 193nm was investigated by ab initio molecular orbital method.Our result supports photodecarbonylation mechanisms proposed by Fujimoto,and predicts that the reaction should occur in ~3ππ potential energy surface prior to the ~1ππ potential energy surface.
