The efficient and selective electrocatalytic hydrogenation(ECH)of furfural is considered a green strategy for achieving biomass-derived high-value chemicals.Regulating an aqueous electrolytic environment,a green hydro...The efficient and selective electrocatalytic hydrogenation(ECH)of furfural is considered a green strategy for achieving biomass-derived high-value chemicals.Regulating an aqueous electrolytic environment,a green hydrogen energy source of water,is significant for improving the selectivity of products and reducing energy consumption.In this study,we systematically investigated the mechanism of pH dependence of product selectivity in the ECH of furfural on Cu electrodes.Under acidic conditions,the oxygen atom dissociated directly from hydrogenated furfural-derived alkoxyl intermediates,followed by stepwise hydrogenation until H_(2)O formation via a thermodynamically favorable proton-coupled electron transfer process,thereby inducing a high proportion of the hydrogenolysis product(2-methylfuran).However,under partial alkaline conditions,furfural could be directly hydrogenated to furfuryl alcohol(selectivity~98%)due to the high-energy barrier of the deoxidation process via a surface hydride(Had)transfer.Our results highlight the vital role of the electrolytic environment in furfural selective conversion and broaden our fundamental understanding of hydrodeoxygenation reactions in ECH.展开更多
Secondary metabolites produced by plants can be used in popular medicine, as well they can interact with plants and other organisms, in which case they are called allelochemicals and influence the neighboring ecosyste...Secondary metabolites produced by plants can be used in popular medicine, as well they can interact with plants and other organisms, in which case they are called allelochemicals and influence the neighboring ecosystem. This work aimed to evaluate the allelopathic effects of Schinus molle L. species widely used in reforestation and urban afforestation. Therefore, leaves of S. Molle were collected from different populations located at Alfenas and Nepomuceno in Minas Gerais, Brazil. Cypselae of lettuce （Lactuca sativa L.） were germinated in biochemical oxygen demand （BOD） chamber at 25 ℃ with a photoperiod of 12 h under different extracts concentrations. The experiment was performed in factorial design （2 × 4） with two kinds of extracts （aqueous and ethanol） and four concentrations （2.5, 5, 10 and 20 mg/mL） in randomized blocks. The variables analyzed were germination （%）, germination speed index （GS1）, % of normal seedlings, root length, fresh biomass and dry biomass. Changes in the cell cycle in meristematic cells of the used model were also evaluated. Concentration-dependent effect on all parameters was observed, with the exception of dry biomass exposed to ethanol extract. The root elongation parameter was different between the extracts even in lower concentrations, thus indicating that this is the most sensitive parameter of this species. Toxic effect from S. rnolle extracts was observed in all parameters regardless the kind of pruning management or method of extraction （water or ethanol）.展开更多
文摘The efficient and selective electrocatalytic hydrogenation(ECH)of furfural is considered a green strategy for achieving biomass-derived high-value chemicals.Regulating an aqueous electrolytic environment,a green hydrogen energy source of water,is significant for improving the selectivity of products and reducing energy consumption.In this study,we systematically investigated the mechanism of pH dependence of product selectivity in the ECH of furfural on Cu electrodes.Under acidic conditions,the oxygen atom dissociated directly from hydrogenated furfural-derived alkoxyl intermediates,followed by stepwise hydrogenation until H_(2)O formation via a thermodynamically favorable proton-coupled electron transfer process,thereby inducing a high proportion of the hydrogenolysis product(2-methylfuran).However,under partial alkaline conditions,furfural could be directly hydrogenated to furfuryl alcohol(selectivity~98%)due to the high-energy barrier of the deoxidation process via a surface hydride(Had)transfer.Our results highlight the vital role of the electrolytic environment in furfural selective conversion and broaden our fundamental understanding of hydrodeoxygenation reactions in ECH.
文摘Secondary metabolites produced by plants can be used in popular medicine, as well they can interact with plants and other organisms, in which case they are called allelochemicals and influence the neighboring ecosystem. This work aimed to evaluate the allelopathic effects of Schinus molle L. species widely used in reforestation and urban afforestation. Therefore, leaves of S. Molle were collected from different populations located at Alfenas and Nepomuceno in Minas Gerais, Brazil. Cypselae of lettuce （Lactuca sativa L.） were germinated in biochemical oxygen demand （BOD） chamber at 25 ℃ with a photoperiod of 12 h under different extracts concentrations. The experiment was performed in factorial design （2 × 4） with two kinds of extracts （aqueous and ethanol） and four concentrations （2.5, 5, 10 and 20 mg/mL） in randomized blocks. The variables analyzed were germination （%）, germination speed index （GS1）, % of normal seedlings, root length, fresh biomass and dry biomass. Changes in the cell cycle in meristematic cells of the used model were also evaluated. Concentration-dependent effect on all parameters was observed, with the exception of dry biomass exposed to ethanol extract. The root elongation parameter was different between the extracts even in lower concentrations, thus indicating that this is the most sensitive parameter of this species. Toxic effect from S. rnolle extracts was observed in all parameters regardless the kind of pruning management or method of extraction （water or ethanol）.
