Selectivity control is a difficult scientific and industrial challenge in methanol-to-olefins(MTO)conversion.It has been experimentally established that the topology of zeolite catalysts influenced the distribution of...Selectivity control is a difficult scientific and industrial challenge in methanol-to-olefins(MTO)conversion.It has been experimentally established that the topology of zeolite catalysts influenced the distribution of products.Besides the topology effect on reaction kinetics,the topology influences the diffusion of reactants and products in catalysts as well.In this work,by using COMPASS force-field molecular dynamics method,we investigated the intracrystalline diffusion of ethene and propene in four different zeolites,CHA,MFI,BEA and FAU,at different temperatures.The self-diffusion coefficients and diffusion activation barriers were calculated.A strong restriction on the diffusion of propene in CHA was observed because the self-diffusion coefficient ratio of ethene to propene is larger than 18 and the diffusion activation barrier of propene is more than 20 kJ/mol in CHA.This ratio decreases with the increase of temperature in the four investigated zeolites.The shape selectivity on products from diffusion perspective can provide some implications on the understanding of the selectivity difference between HSAPO-34 and HZSM-5 catalysts for the MTO conversion.展开更多
Biobutanol is attracting increasingly interest as a source of renewable energy and biofuels because of its many advantages over bioethanol that include higher energy density, fuel efficiency, and reduced engine damage...Biobutanol is attracting increasingly interest as a source of renewable energy and biofuels because of its many advantages over bioethanol that include higher energy density, fuel efficiency, and reduced engine damages. Currently, there is a growing interest in producing biobutanol from bioethanol, in view of the tremendous potential benefits of this transformation for the bulk production of biobutanol in a target specific manner. This perspective paper describes recent progress for the ethanol to butanol process. The different catalysts, including homogeneous and heterogeneous catalytic systems, for ethanol to butanol are outlined and compared, and the key issues and requirements for future developments are highlighted. A major challenge for further development and application of ethanol to butanol process is to find an optimal balance between different catalytic functions and to suppress the formation of side products that has plagued most catalytic bioethanol upgrading systems. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B. V. and Science Press. All rights reserved.展开更多
The tree of Litsea cubeba is widely spread in China, Indonesia and other part of Southeast Asia. The essential oil of Litsea cubeba (EOLC) is obtained by steam distillation from the pepper-like fruits tree Litsea cube...The tree of Litsea cubeba is widely spread in China, Indonesia and other part of Southeast Asia. The essential oil of Litsea cubeba (EOLC) is obtained by steam distillation from the pepper-like fruits tree Litsea cubeba. The EOLC consists of about 29 active compounds. Among them, citral is the main component;the content of citral is nearly 80% of the EOLC. Due to the special function group, citral is easy to react with many chemicals. Thus, EOLC is usually applied as starting material to carry out aldol condensation, reduction, and six-member ring forming reaction. The EOLC is extensively employed to synthesis of geranal nitriles, pseudonoe, ionone, methyl ionone, Vitamin E and Vitamin A. These products are broadly applied in the fields of fragrance, perfume, medicine and so on. This paper presents comprehensive utilization of EOLC as raw materials to synthesize many active chemicals.展开更多
Fusarium oxysporum,a global soil-borne pathogen,causes severe disease in various cultivated plants.The mechanism underlying infection and resistance remains largely elusive.Vernicia fordii,known as the tung tree,suffe...Fusarium oxysporum,a global soil-borne pathogen,causes severe disease in various cultivated plants.The mechanism underlying infection and resistance remains largely elusive.Vernicia fordii,known as the tung tree,suffers from disease caused by F.oxysporum f.sp.fordiis(Fof-1),while its sister species V.montana displays high resistance to Fof-1.To investigate the process of infection and resistance ability,we demonstrated that Fof-1 can penetrate the epidermis of root hairs and then centripetally invade the cortex and phloem in both species.Furthermore,Fof-1 spread upwards through the root xylem in susceptible V.fordii trees,whereas it failed to infect the root xylem in resistant V.montana trees.We found that D6 PROTEIN KINASE LIKE 2(VmD6PKL2)was speci fically expressed in the lateral root xylem and was induced after Fof-1 infection in resistant trees.Transgenic analysis in Arabidopsis and tomato revealed that VmD6PKL2 signi ficantly enhanced resistance in both species,whereas the d6pkl2 mutant displayed reduced resistance against Fof-1.Additionally,VmD6PKL2 was identi fied to interact directly with synaptotagmin(VmSYT3),which is speci fically expressed in the root xylem and mediates the negative regulation responding to Fof-1.Our data suggested that VmD6PKL2 could act as a resistance gene against Fof-1 through suppression of VmSYT3-mediated negative regulation in the lateral root xylem of the resistant species.These findings provide novel insight into Fusarium wilt resistance in plants.展开更多
Litsea cubeba(Lour.)Pers.(Lauraceae),also known as May Chang tree or Chinese pepper,is frequently utilized for its essential oil,which is widely used in flavors,perfumes,and antimicrobials.Despite its myriad of uses,t...Litsea cubeba(Lour.)Pers.(Lauraceae),also known as May Chang tree or Chinese pepper,is frequently utilized for its essential oil,which is widely used in flavors,perfumes,and antimicrobials.Despite its myriad of uses,the stability and diversity of the various chemical components of L.cubeba oil have not been sufficiently investigated.Here,we utilized 31 families planted in a test forest.The stability of the essential oil content in each family was assessed over a four-year period.The chemical profiles of the essential oils from the 31 families were established.A total of 103 components were identified,with approximately 30 components found per family.Additionally,the antifungal and antibacterial activities were investigated,with significant variations found among families.The most abundant component was citral,which has previously been shown to possess antifungal activities.In addition,inhibition rates,EC50,and MIC values were measured,and the F7,G3,G4,and F9 families were found to manifest significantly stronger antifungal activity,with inhibition rates above 91%at a concentration of 250μL/L.The F7,G3,G4,and L24 families possessed strong antibacterial activity on gram-negative bacteria at a concentration of 50μL/mL.In summary,we assessed the chemical profiles of L.cubeba essential oil for different families and found that there were significant differences in essential oil components and antibacterial activities among families.Our results suggest that L.cubeba families can be further selected to improve their industrial applications and increase the quality of essential oils extracted from them.展开更多
Zeolites catalyzed methanol-to-olefins （MTO） conversion provides an alternative process to produce light olefins such as ethene and propene from nonpetroleum resources. Despite of successful industrialization of the...Zeolites catalyzed methanol-to-olefins （MTO） conversion provides an alternative process to produce light olefins such as ethene and propene from nonpetroleum resources. Despite of successful industrialization of the MTO process, its detailed reaction mechanism is not yet well understood. Here we summarize our work on the hydrocarbon pool reaction mechanism based on theoretical calculations. We proposed that the olefins themselves are likely to be the dominating hydrocarbon pool species, and the distribution of cracking precursors and diffusion constraints affect the selectivity. The similarities between aromatic-based and olefin-based cycles are highlighted.展开更多
Toluene methylation with methanol offers an alternative method to produce p-xylene by gathering methyl group directly from C1 chemical sources. It supplies a ＂molecular engineering＂ process to realize directional co...Toluene methylation with methanol offers an alternative method to produce p-xylene by gathering methyl group directly from C1 chemical sources. It supplies a ＂molecular engineering＂ process to realize directional conversion of toluene/methanol molecules by selective catalysis in complicated methylation system. In this review, we introduce the synthesis method ofp-xylene, the development history of methylation catalysts and reaction mechanism, and the effect of reaction condition in para-selective technical process. If constructing p-xylene as the single target product, the major challenge to develop para-selective toluene methylation is to improve the p-xylene selectivity without, or as little as possible, losing the fraction of methanol for methylation. To reach higher yield ofp-xylene and more methanol usage in methylation, zeolite catalyst design should consider improving mass transfer and afterwards coveting external acid sites by surface modification to get short ＂micro-tunnels＂ with shape selectivity. A solid understanding of mass transfer will benefit realizing the aim of converting more methanol feedstock into para-methyl group.展开更多
基金supported by the National Key R&D Program of China(2017YFB0702800)National Natural Science Foundation of China(21802168,21503280,21603277)China Petrochemical Corporation(Sinopec Group)~~
基金supported by National Key Basic Research Program of China (2013CB934101, 2009CB623500)the National Natural Science Foundation of China (21433002, 21573046)the National Key Research and Development Program of China (2016YFB0701100)~~
基金supported by the National Basic Research Program of China (2009CB623504)the National Science Foundation of China (21103231)Shanghai Science Foundation (11ZR1449700)
文摘Selectivity control is a difficult scientific and industrial challenge in methanol-to-olefins(MTO)conversion.It has been experimentally established that the topology of zeolite catalysts influenced the distribution of products.Besides the topology effect on reaction kinetics,the topology influences the diffusion of reactants and products in catalysts as well.In this work,by using COMPASS force-field molecular dynamics method,we investigated the intracrystalline diffusion of ethene and propene in four different zeolites,CHA,MFI,BEA and FAU,at different temperatures.The self-diffusion coefficients and diffusion activation barriers were calculated.A strong restriction on the diffusion of propene in CHA was observed because the self-diffusion coefficient ratio of ethene to propene is larger than 18 and the diffusion activation barrier of propene is more than 20 kJ/mol in CHA.This ratio decreases with the increase of temperature in the four investigated zeolites.The shape selectivity on products from diffusion perspective can provide some implications on the understanding of the selectivity difference between HSAPO-34 and HZSM-5 catalysts for the MTO conversion.
基金supported by the National Natural Science Foundation of China(21273044,21473035,and 91545108)SINOPEC(X514005)the Open project of State Key Laboratory of Chemical Engineering(SKL-Ch E-15C02)
文摘Biobutanol is attracting increasingly interest as a source of renewable energy and biofuels because of its many advantages over bioethanol that include higher energy density, fuel efficiency, and reduced engine damages. Currently, there is a growing interest in producing biobutanol from bioethanol, in view of the tremendous potential benefits of this transformation for the bulk production of biobutanol in a target specific manner. This perspective paper describes recent progress for the ethanol to butanol process. The different catalysts, including homogeneous and heterogeneous catalytic systems, for ethanol to butanol are outlined and compared, and the key issues and requirements for future developments are highlighted. A major challenge for further development and application of ethanol to butanol process is to find an optimal balance between different catalytic functions and to suppress the formation of side products that has plagued most catalytic bioethanol upgrading systems. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B. V. and Science Press. All rights reserved.
文摘The tree of Litsea cubeba is widely spread in China, Indonesia and other part of Southeast Asia. The essential oil of Litsea cubeba (EOLC) is obtained by steam distillation from the pepper-like fruits tree Litsea cubeba. The EOLC consists of about 29 active compounds. Among them, citral is the main component;the content of citral is nearly 80% of the EOLC. Due to the special function group, citral is easy to react with many chemicals. Thus, EOLC is usually applied as starting material to carry out aldol condensation, reduction, and six-member ring forming reaction. The EOLC is extensively employed to synthesis of geranal nitriles, pseudonoe, ionone, methyl ionone, Vitamin E and Vitamin A. These products are broadly applied in the fields of fragrance, perfume, medicine and so on. This paper presents comprehensive utilization of EOLC as raw materials to synthesize many active chemicals.
基金The work was financially supported by the National Natural Science Foundation of China(31971685)the Fundamental Research Funds for the Central Nonprofit Research Institution of Chinese Academy of Forestry(CAFYBB2019ZB002).
文摘Fusarium oxysporum,a global soil-borne pathogen,causes severe disease in various cultivated plants.The mechanism underlying infection and resistance remains largely elusive.Vernicia fordii,known as the tung tree,suffers from disease caused by F.oxysporum f.sp.fordiis(Fof-1),while its sister species V.montana displays high resistance to Fof-1.To investigate the process of infection and resistance ability,we demonstrated that Fof-1 can penetrate the epidermis of root hairs and then centripetally invade the cortex and phloem in both species.Furthermore,Fof-1 spread upwards through the root xylem in susceptible V.fordii trees,whereas it failed to infect the root xylem in resistant V.montana trees.We found that D6 PROTEIN KINASE LIKE 2(VmD6PKL2)was speci fically expressed in the lateral root xylem and was induced after Fof-1 infection in resistant trees.Transgenic analysis in Arabidopsis and tomato revealed that VmD6PKL2 signi ficantly enhanced resistance in both species,whereas the d6pkl2 mutant displayed reduced resistance against Fof-1.Additionally,VmD6PKL2 was identi fied to interact directly with synaptotagmin(VmSYT3),which is speci fically expressed in the root xylem and mediates the negative regulation responding to Fof-1.Our data suggested that VmD6PKL2 could act as a resistance gene against Fof-1 through suppression of VmSYT3-mediated negative regulation in the lateral root xylem of the resistant species.These findings provide novel insight into Fusarium wilt resistance in plants.
基金supported by the the National Science and Technology Basic Resources Survey Program of China(2019FY100803_05)Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding(2021C02070-3).
文摘Litsea cubeba(Lour.)Pers.(Lauraceae),also known as May Chang tree or Chinese pepper,is frequently utilized for its essential oil,which is widely used in flavors,perfumes,and antimicrobials.Despite its myriad of uses,the stability and diversity of the various chemical components of L.cubeba oil have not been sufficiently investigated.Here,we utilized 31 families planted in a test forest.The stability of the essential oil content in each family was assessed over a four-year period.The chemical profiles of the essential oils from the 31 families were established.A total of 103 components were identified,with approximately 30 components found per family.Additionally,the antifungal and antibacterial activities were investigated,with significant variations found among families.The most abundant component was citral,which has previously been shown to possess antifungal activities.In addition,inhibition rates,EC50,and MIC values were measured,and the F7,G3,G4,and F9 families were found to manifest significantly stronger antifungal activity,with inhibition rates above 91%at a concentration of 250μL/L.The F7,G3,G4,and L24 families possessed strong antibacterial activity on gram-negative bacteria at a concentration of 50μL/mL.In summary,we assessed the chemical profiles of L.cubeba essential oil for different families and found that there were significant differences in essential oil components and antibacterial activities among families.Our results suggest that L.cubeba families can be further selected to improve their industrial applications and increase the quality of essential oils extracted from them.
文摘Zeolites catalyzed methanol-to-olefins （MTO） conversion provides an alternative process to produce light olefins such as ethene and propene from nonpetroleum resources. Despite of successful industrialization of the MTO process, its detailed reaction mechanism is not yet well understood. Here we summarize our work on the hydrocarbon pool reaction mechanism based on theoretical calculations. We proposed that the olefins themselves are likely to be the dominating hydrocarbon pool species, and the distribution of cracking precursors and diffusion constraints affect the selectivity. The similarities between aromatic-based and olefin-based cycles are highlighted.
基金Acknowledgements We would like to greatly acknowledge the financial support from the National Natural Science Foundation of China （NSFC, Grant No. 21403303） and Major Research Plan of NSFC （No. 91434102）.
文摘Toluene methylation with methanol offers an alternative method to produce p-xylene by gathering methyl group directly from C1 chemical sources. It supplies a ＂molecular engineering＂ process to realize directional conversion of toluene/methanol molecules by selective catalysis in complicated methylation system. In this review, we introduce the synthesis method ofp-xylene, the development history of methylation catalysts and reaction mechanism, and the effect of reaction condition in para-selective technical process. If constructing p-xylene as the single target product, the major challenge to develop para-selective toluene methylation is to improve the p-xylene selectivity without, or as little as possible, losing the fraction of methanol for methylation. To reach higher yield ofp-xylene and more methanol usage in methylation, zeolite catalyst design should consider improving mass transfer and afterwards coveting external acid sites by surface modification to get short ＂micro-tunnels＂ with shape selectivity. A solid understanding of mass transfer will benefit realizing the aim of converting more methanol feedstock into para-methyl group.
