Lemon oils are broadly used as flavoring agents in beverages,foods,cosmetics and pharmaceuticals,yet the adulteration of natural,particularly cold pressed lemon oils is very common in the industry due to its unmet dem...Lemon oils are broadly used as flavoring agents in beverages,foods,cosmetics and pharmaceuticals,yet the adulteration of natural,particularly cold pressed lemon oils is very common in the industry due to its unmet demand and high cost.Nowadays,most quality control(QC)analysis of lemon oils is conducted by gas chromatography(GC)analysis,which is far from a reliable method.Oxygen heterocyclic compounds(OHCs)in non-volatile fraction are gaining increasing attention in authentication process because of the nearly finger-printing profiles of OHCs in cold pressed citrus essential oils.Our goal in this study was to identify OHCs using high performance liquid chromatography(HPLC)in lemon oils,establish OHC profiles,perform stepwise logistic regression analysis(SLRA)and build effective predicting model and further determine adulterated lemon oils by referencing the OHC profiles and established models.After HPLC analyses,profiling and SLRA modeling of 154 OHCs samples of industrial lemon oils,we found that the combination of isopimpinellin and total OHC concentration are essential and robust predictors to differentiate authentic samples from adulterated lemon oils with a success rate of 98%from the 5-fold cross validation.This study provided a reliable and efficient method in determining the authenticity of lemon oils.展开更多
Vapor wall losses can affect the yields of secondary organic aerosol.The effects of surfaceto-volume(S/V)ratio and relative humidity(RH)on the vapor-wall interactions were investigated in this study.The oxygenated vol...Vapor wall losses can affect the yields of secondary organic aerosol.The effects of surfaceto-volume(S/V)ratio and relative humidity(RH)on the vapor-wall interactions were investigated in this study.The oxygenated volatile organic compounds(OVOCs)were generated from toluene-H_(2)O_(2)irradiations.The average gas to wall loss rate constant(k_(gw))of OVOCs in a 400 L reactor(S/V=7.5 m^(-1))is 2.47(2.41 under humid conditions)times higher than that in a 5000 L reactor(S/V=3.6 m-1)under dry conditions.In contrast,the average desorption rate constant(k_(wg))of OVOCs in 400 L reactor is only 1.37(1.20 under humid conditions)times higher than that in 5000 L reactor under dry conditions.It shows that increasing the S/V ratio can promote the wall losses of OVOCs.By contrast,the RH effect on k_(gw)is not prominent.The average k_(gw)value under humid conditions is almost the same as under dry conditions in the 400 L(5000 L)reactor.However,increasing RH can decrease the desorption rates.The average k_(wg)value under dry conditions is 1.45(1.27)times higher than that under humid conditions in the 400 L(5000 L)reactor.The high RH can increase the partitioning equilibrium timescales and enhance the wall losses of OVOCs.展开更多
The continual growth in transportation fuels and more strict environmental legislations have led to immense interest in developing green biomass energy.In this work,a proposed catalytic transformation of oxygenated or...The continual growth in transportation fuels and more strict environmental legislations have led to immense interest in developing green biomass energy.In this work,a proposed catalytic transformation of oxygenated organic compounds(related to bio-oil)into pure hydrogen was desighed,involving the catalytic reforming of oxygenated organic compounds to hydrogen-rich mixture gas followed by the conversion of CO to CO_(2)via the water gas reaction and the removal of CO_(2).The optimization of the different reforming catalyst,the reaction conditions as well as various sources of oxygenated organic compounds were investigated in detail.The production of pure hydrogen,with the H2 content up to 99.96%and the conversion of 97.1%,was achieved by the integrated catalytic transformation.The reaction pathways were addressed based on the investigation of decomposition,catalytic reforming,and the water gas reaction.展开更多
It is reported in this paper a polarographic catalytic double wave of oxygen reduction caused by diphenylamine compounds(diphs).The electrochemical process of the wave includes the polarographic generation of the supe...It is reported in this paper a polarographic catalytic double wave of oxygen reduction caused by diphenylamine compounds(diphs).The electrochemical process of the wave includes the polarographic generation of the superoxide anion O_2^- and the dismutation of O_2^- catalyzed by diphs with redox pseudoreversibility.展开更多
A series of both unsupported and coal‐supported iron–oxygen compounds with gradual changes in microstructure were synthesized by a precipitation‐oxidation process at 20 to 70°C.The relationship between the mic...A series of both unsupported and coal‐supported iron–oxygen compounds with gradual changes in microstructure were synthesized by a precipitation‐oxidation process at 20 to 70°C.The relationship between the microstructures and catalytic activities of these precursors during direct coal liquefaction was studied.The results show that the microstructure could be controlled through adjusting the synthesis temperature during the precipitation‐oxidation procedure,and that compounds synthesized at lower temperatures exhibit higher catalytic activity.As a result of their higher proportions ofγ‐FeOOH orα‐FeOOH crystalline phases,the unsupported iron–oxygen compounds synthesized at 20–30°C,which also had high specific surface areas and moisture levels,generate oil yields 4.5%–4.6%higher than those obtained with precursors synthesized at 70°C.It was also determined that higher oil yields were obtained when the catalytically‐active phase formed by the precursors during liquefaction(pyrrhotite,Fe1-xS)had smaller crystallites.Feed coal added as a carrier was found to efficiently disperse the active precursors,which in turn significantly improved the catalytic activity during coal liquefaction.展开更多
The oxygen-containing compounds in Fischer Tropsch synthetic oil greatly affect the downstream deep processing of hydrocarbons,and effective removal is required.Com-pared to traditional removal technologies such as hy...The oxygen-containing compounds in Fischer Tropsch synthetic oil greatly affect the downstream deep processing of hydrocarbons,and effective removal is required.Com-pared to traditional removal technologies such as hydrogenation deoxygenation,solvent extraction,and extraction distillation,adsorption deoxygenation technology has the advantages of low cost,mild operating conditions,easy removal and recovery,and mini-mal impact on oil quality.Therefore,adsorption deoxygenation technology has devel-oped rapidly in various removal processes and has become a research hotspot in the cur-rent Fischer Tropsch oil deoxygenation.Adsorbents are the core of adsorption deoxygen-ation technology.Therefore,this article briefly introduces the adsorption mechanism and summarizes the research progress of adsorbents widely used in recent years,such as silica gel,alumina,molecular sieves,and metal organic frameworks,in adsorbing oxygen-containing compounds in Fischer Tropsch synthetic oils.And provide reference sugges-tions for further adsorption and deoxygenation directions in the future.展开更多
Surface ozone pollution is a critical global environmental challenge driven by the complex,nonlinear photochemical cycling of RO x radicals(OH+HO_(2)+RO_(2)).Oxygenated volatile organic compounds(OVOCs)are central to ...Surface ozone pollution is a critical global environmental challenge driven by the complex,nonlinear photochemical cycling of RO x radicals(OH+HO_(2)+RO_(2)).Oxygenated volatile organic compounds(OVOCs)are central to these cycles as both radical sources and sinks,yet their quantitative impact on regional radical budgets remains poorly understood due to historical limitations in ambient measurements.This knowledge gap hinders the accurate prediction of persistent ozone exceedances.Here we show that constraining atmospheric models with a broad suite of 23 OVOCs-specifically reactive dicarbonyls-is essential for the accurate simulation of radical chemistry in southern China's background air through comprehensive field observations and photochemical modeling.We find that models constrained with only the three most common OVOCs(formaldehyde,acetaldehyde,and acetone)overestimate hydroxyl radical concentrations by 50%-100%,whereas comprehensive constraints align simulations with observations.This discrepancy is caused by complex offsetting errors,including the severe overestimation of isoprene-derived intermediates and the significant underestimation of secondary biacetyl production.Our results reveal that photolysis of the measured OVOCs contributes 49-61%of total RO x production,with species such as methylglyoxal and biacetyl playing unexpectedly dominant roles in driving ozone formation.These findings highlight critical deficiencies in current chemical mechanisms and demonstrate that high-resolution monitoring of reactive OVOC intermediates is vital for developing effective emission control strategies to mitigate persistent regional ozone pollution.展开更多
文摘Lemon oils are broadly used as flavoring agents in beverages,foods,cosmetics and pharmaceuticals,yet the adulteration of natural,particularly cold pressed lemon oils is very common in the industry due to its unmet demand and high cost.Nowadays,most quality control(QC)analysis of lemon oils is conducted by gas chromatography(GC)analysis,which is far from a reliable method.Oxygen heterocyclic compounds(OHCs)in non-volatile fraction are gaining increasing attention in authentication process because of the nearly finger-printing profiles of OHCs in cold pressed citrus essential oils.Our goal in this study was to identify OHCs using high performance liquid chromatography(HPLC)in lemon oils,establish OHC profiles,perform stepwise logistic regression analysis(SLRA)and build effective predicting model and further determine adulterated lemon oils by referencing the OHC profiles and established models.After HPLC analyses,profiling and SLRA modeling of 154 OHCs samples of industrial lemon oils,we found that the combination of isopimpinellin and total OHC concentration are essential and robust predictors to differentiate authentic samples from adulterated lemon oils with a success rate of 98%from the 5-fold cross validation.This study provided a reliable and efficient method in determining the authenticity of lemon oils.
基金supported by the National Key R&D Program of China(No.2017YFC0210005)the National Natural Science Foundation of China(Nos.41875166,41875163 and 41375129)
文摘Vapor wall losses can affect the yields of secondary organic aerosol.The effects of surfaceto-volume(S/V)ratio and relative humidity(RH)on the vapor-wall interactions were investigated in this study.The oxygenated volatile organic compounds(OVOCs)were generated from toluene-H_(2)O_(2)irradiations.The average gas to wall loss rate constant(k_(gw))of OVOCs in a 400 L reactor(S/V=7.5 m^(-1))is 2.47(2.41 under humid conditions)times higher than that in a 5000 L reactor(S/V=3.6 m-1)under dry conditions.In contrast,the average desorption rate constant(k_(wg))of OVOCs in 400 L reactor is only 1.37(1.20 under humid conditions)times higher than that in 5000 L reactor under dry conditions.It shows that increasing the S/V ratio can promote the wall losses of OVOCs.By contrast,the RH effect on k_(gw)is not prominent.The average k_(gw)value under humid conditions is almost the same as under dry conditions in the 400 L(5000 L)reactor.However,increasing RH can decrease the desorption rates.The average k_(wg)value under dry conditions is 1.45(1.27)times higher than that under humid conditions in the 400 L(5000 L)reactor.The high RH can increase the partitioning equilibrium timescales and enhance the wall losses of OVOCs.
基金supported by the National Sci-Tech Support Plan(No.2014BAD02B03)the Program for Changjiang Scholars and Innovative Research Team in University and the Fundamental Research Funds for the Central Universities(No.wk2060190040)
文摘The continual growth in transportation fuels and more strict environmental legislations have led to immense interest in developing green biomass energy.In this work,a proposed catalytic transformation of oxygenated organic compounds(related to bio-oil)into pure hydrogen was desighed,involving the catalytic reforming of oxygenated organic compounds to hydrogen-rich mixture gas followed by the conversion of CO to CO_(2)via the water gas reaction and the removal of CO_(2).The optimization of the different reforming catalyst,the reaction conditions as well as various sources of oxygenated organic compounds were investigated in detail.The production of pure hydrogen,with the H2 content up to 99.96%and the conversion of 97.1%,was achieved by the integrated catalytic transformation.The reaction pathways were addressed based on the investigation of decomposition,catalytic reforming,and the water gas reaction.
文摘It is reported in this paper a polarographic catalytic double wave of oxygen reduction caused by diphenylamine compounds(diphs).The electrochemical process of the wave includes the polarographic generation of the superoxide anion O_2^- and the dismutation of O_2^- catalyzed by diphs with redox pseudoreversibility.
文摘A series of both unsupported and coal‐supported iron–oxygen compounds with gradual changes in microstructure were synthesized by a precipitation‐oxidation process at 20 to 70°C.The relationship between the microstructures and catalytic activities of these precursors during direct coal liquefaction was studied.The results show that the microstructure could be controlled through adjusting the synthesis temperature during the precipitation‐oxidation procedure,and that compounds synthesized at lower temperatures exhibit higher catalytic activity.As a result of their higher proportions ofγ‐FeOOH orα‐FeOOH crystalline phases,the unsupported iron–oxygen compounds synthesized at 20–30°C,which also had high specific surface areas and moisture levels,generate oil yields 4.5%–4.6%higher than those obtained with precursors synthesized at 70°C.It was also determined that higher oil yields were obtained when the catalytically‐active phase formed by the precursors during liquefaction(pyrrhotite,Fe1-xS)had smaller crystallites.Feed coal added as a carrier was found to efficiently disperse the active precursors,which in turn significantly improved the catalytic activity during coal liquefaction.
文摘The oxygen-containing compounds in Fischer Tropsch synthetic oil greatly affect the downstream deep processing of hydrocarbons,and effective removal is required.Com-pared to traditional removal technologies such as hydrogenation deoxygenation,solvent extraction,and extraction distillation,adsorption deoxygenation technology has the advantages of low cost,mild operating conditions,easy removal and recovery,and mini-mal impact on oil quality.Therefore,adsorption deoxygenation technology has devel-oped rapidly in various removal processes and has become a research hotspot in the cur-rent Fischer Tropsch oil deoxygenation.Adsorbents are the core of adsorption deoxygen-ation technology.Therefore,this article briefly introduces the adsorption mechanism and summarizes the research progress of adsorbents widely used in recent years,such as silica gel,alumina,molecular sieves,and metal organic frameworks,in adsorbing oxygen-containing compounds in Fischer Tropsch synthetic oils.And provide reference sugges-tions for further adsorption and deoxygenation directions in the future.
基金funded by the Hong Kong Research Grants Council via Theme-Based Research Scheme(T24-504/17-N)General Research Fund(HKBU 15219621)+2 种基金the National Natural Science Foundation of China(42325504)the National Key Research and Development Program of China(2023YFC3706205)the Shenzhen Science and Technology Program(JCYJ20220818100611024).
文摘Surface ozone pollution is a critical global environmental challenge driven by the complex,nonlinear photochemical cycling of RO x radicals(OH+HO_(2)+RO_(2)).Oxygenated volatile organic compounds(OVOCs)are central to these cycles as both radical sources and sinks,yet their quantitative impact on regional radical budgets remains poorly understood due to historical limitations in ambient measurements.This knowledge gap hinders the accurate prediction of persistent ozone exceedances.Here we show that constraining atmospheric models with a broad suite of 23 OVOCs-specifically reactive dicarbonyls-is essential for the accurate simulation of radical chemistry in southern China's background air through comprehensive field observations and photochemical modeling.We find that models constrained with only the three most common OVOCs(formaldehyde,acetaldehyde,and acetone)overestimate hydroxyl radical concentrations by 50%-100%,whereas comprehensive constraints align simulations with observations.This discrepancy is caused by complex offsetting errors,including the severe overestimation of isoprene-derived intermediates and the significant underestimation of secondary biacetyl production.Our results reveal that photolysis of the measured OVOCs contributes 49-61%of total RO x production,with species such as methylglyoxal and biacetyl playing unexpectedly dominant roles in driving ozone formation.These findings highlight critical deficiencies in current chemical mechanisms and demonstrate that high-resolution monitoring of reactive OVOC intermediates is vital for developing effective emission control strategies to mitigate persistent regional ozone pollution.
