Acetol is a major light oxygenate and readily produced from staged or fast pyrolysis of lignocellulose biomass. Herein we report that acetol can be selectively converted to methyl pyruvate, an important fine chemical,...Acetol is a major light oxygenate and readily produced from staged or fast pyrolysis of lignocellulose biomass. Herein we report that acetol can be selectively converted to methyl pyruvate, an important fine chemical, through oxidative esterification over Au-based catalysts. Detailed experimental studies showed that Au on amphoteric supports with appropriate strength and balanced ratio of acid and base sites can facilitate the desired oxidative-esterification pathway without accelerating undesired aldol-condensation or Cannizzaro reactions. In particular, hydroxyapatite (with a Ca/P ratio of 1.62) supported Au achieved 87% selectivity to methyl pyruvate at an acetol conversion of 62%.展开更多
Pharmaceutical excipients for topical use may contain impurities, which are often neglected from a toxicity qualification viewpoint. The possible impurities in the most frequently used topical excipients were evaluate...Pharmaceutical excipients for topical use may contain impurities, which are often neglected from a toxicity qualification viewpoint. The possible impurities in the most frequently used topical excipients were evaluated in-silico for their toxicity hazard. Acetol, an impurity likely present in different topical pharmaceutical excipients such as propylene glycol and glycerol, was withheld for the evaluation of its health risk after dermal exposure. 〈br〉 An ex-vivo in-vitro permeation study using human skin in a Franz Diffusion Cell set-up and GC as quantification methodology showed a significant skin penetration with an overall Kp value of 1.82 ？ 10 ？ 3 cm/h. Using these data, limit specifications after application of a dermal pharmaceutical product were estimated. Based on the TTC approach of Cramer class I substances, i.e. 1800 mg/（day？person）, the toxicity-qualified specification limits of acetol in topical excipients were calculated to be 90 mg/mL and 180 mg/mL for propylene glycol and glycerol, respectively.展开更多
Designing a catalytic system that could convert cellulose to switchable C3 alcohols or esters with controllable selectivity is highly desired to meet the rapidly changing market demand.Herein,we develop RuSn catalysts...Designing a catalytic system that could convert cellulose to switchable C3 alcohols or esters with controllable selectivity is highly desired to meet the rapidly changing market demand.Herein,we develop RuSn catalysts with the altering Sn loadings that can achieve acetol formation from cellulose hydrogenation at240℃in presence of H_(2)or yield methyl lactate production from cellulose conversion in methanol and water mixture at 200℃in presence of N_(2).The increased Sn contents from 3%to 6%lead to form different surface sites from Ru_(3)Sn_(7),Ru,and SnO_(x)to Ru_(3)Sn_(7)and SnO_(x).The integrated Ru_(3)Sn_(7),Ru,and SnO_(x)species on 1.5%Ru-3%Sn/SiO_(2)catalyze isomerization,retro-aldol condensation,and hydrogenation individual steps with coordinated reaction rates,resulting in the acetol formation with a high yield of 53.7 C%.Furthermore,the optimum combination of Ru_(3)Sn_(7)and SnO_(x)on 1.5%Ru-6%Sn/SiO_(2)contributes to the isomerization,retro-aldol condensation,dehydration,and 1,2-hydride shift,giving rise to the preferential production of methyl lactate at a 25.1 C%yield.These results illustrate the feasibility of controlling the selective conversion of cellulose to C3 acetol or methyl lactate by devising a tunable catalytic system,which guides the rational design of catalysts for the selective conversion of cellulose.展开更多
An efficient metal-free strategy for the synthesis of pharmaceutically relevant benzo[α]carbazoles from the derivatives of readily available 2-phenylindole and bio-renewable acetol in an aqueous biphasic system was d...An efficient metal-free strategy for the synthesis of pharmaceutically relevant benzo[α]carbazoles from the derivatives of readily available 2-phenylindole and bio-renewable acetol in an aqueous biphasic system was developed. This protocol employed a sulfone-containing Bronsted acidic ionic liquid as the catalyst, which could be used for five times without a noticeable decrease in its activity and selectivity. Various substituted 2-phenylindoles and α-hydroxyketones participated in the reaction smoothly, with water as the sole byproduct. Mechanistically, the reaction involved the conventional carbon-nucleophile-induced Heyns-type rearrangement and downstream intramolecular olefination.展开更多
Cerium-promoted silica supported copper chromite catalyst was synthesized from acid hydrolysis of sodium silicate by sol-gel method.The catalyst was characterized by Brunauer-Emmett-Teller(BET)method,field-emission sc...Cerium-promoted silica supported copper chromite catalyst was synthesized from acid hydrolysis of sodium silicate by sol-gel method.The catalyst was characterized by Brunauer-Emmett-Teller(BET)method,field-emission scanning electron microscopy(FESEM),X-ray diffraction(XRD),H_(2)-temperature programmed reduction(H_(2)-TPR),NH3-temperature programmed desorption(NH3-TPD)and pyridine adsorbed Fourier transform infrared spectroscopy(Py-FTIR).Among cerium doped catalysts,5 wt%of Ce promoted copper chromite supported by 40 wt%of silica(SiCuCr40-Ce5)shows the largest BET surface area.XRD analysis of the reduced form of the catalyst shows both CeO_(2)/Ce_(2)O_(3) redox system and CuO/Cu_(2)O/Cu redox system.Py-FTIR shows the maximum number of Lewis acid sites for SiCuCr40-Ce5 than others.The highest acetol selectivity with analytical reagent(AR)grade glycerol conversion is observed for SiCuCr40-Ce5 at 200℃for 3 h in a batch reactor at atmospheric pressure.Cerium promotion lowers the reaction te mperature with enhanced glycerol conve rsion and increased acetol selectivity.Though the above catalyst shows higher conversion for laboratory reagent(LR)grade glycerol but it reduces acetol selectivity.The addition of glucose into the LR grade glycerol further reduces glycerol conversion and decreases the acetol selectivity to zero.This may be due to the presence of iron as impurity in LR grade glycerol.XRD analysis of spent catalyst shows the absence of redox catalytic system and the pore volume reduces identified by BET analysis.Raman analysis of the spent catalyst shows graphite-like carbon deposition in the spent catalvst.展开更多
基金supported by the National Natural Science Foundation of China(91545114,91545203,and 21576227)the 985 Program of the Chemistry and Chemical Engineering disciplines of Xiamen University~~
文摘Acetol is a major light oxygenate and readily produced from staged or fast pyrolysis of lignocellulose biomass. Herein we report that acetol can be selectively converted to methyl pyruvate, an important fine chemical, through oxidative esterification over Au-based catalysts. Detailed experimental studies showed that Au on amphoteric supports with appropriate strength and balanced ratio of acid and base sites can facilitate the desired oxidative-esterification pathway without accelerating undesired aldol-condensation or Cannizzaro reactions. In particular, hydroxyapatite (with a Ca/P ratio of 1.62) supported Au achieved 87% selectivity to methyl pyruvate at an acetol conversion of 62%.
基金funded by the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWTVlaanderen) to Jente Boonen (091257)the Special Research Fund (BOF) of Ghent University to Lien Taevernier (01D23812)
文摘Pharmaceutical excipients for topical use may contain impurities, which are often neglected from a toxicity qualification viewpoint. The possible impurities in the most frequently used topical excipients were evaluated in-silico for their toxicity hazard. Acetol, an impurity likely present in different topical pharmaceutical excipients such as propylene glycol and glycerol, was withheld for the evaluation of its health risk after dermal exposure. 〈br〉 An ex-vivo in-vitro permeation study using human skin in a Franz Diffusion Cell set-up and GC as quantification methodology showed a significant skin penetration with an overall Kp value of 1.82 ？ 10 ？ 3 cm/h. Using these data, limit specifications after application of a dermal pharmaceutical product were estimated. Based on the TTC approach of Cramer class I substances, i.e. 1800 mg/（day？person）, the toxicity-qualified specification limits of acetol in topical excipients were calculated to be 90 mg/mL and 180 mg/mL for propylene glycol and glycerol, respectively.
基金supported by“the Research Funds of Happiness Flower ECNU”(2019ST2101)。
文摘Designing a catalytic system that could convert cellulose to switchable C3 alcohols or esters with controllable selectivity is highly desired to meet the rapidly changing market demand.Herein,we develop RuSn catalysts with the altering Sn loadings that can achieve acetol formation from cellulose hydrogenation at240℃in presence of H_(2)or yield methyl lactate production from cellulose conversion in methanol and water mixture at 200℃in presence of N_(2).The increased Sn contents from 3%to 6%lead to form different surface sites from Ru_(3)Sn_(7),Ru,and SnO_(x)to Ru_(3)Sn_(7)and SnO_(x).The integrated Ru_(3)Sn_(7),Ru,and SnO_(x)species on 1.5%Ru-3%Sn/SiO_(2)catalyze isomerization,retro-aldol condensation,and hydrogenation individual steps with coordinated reaction rates,resulting in the acetol formation with a high yield of 53.7 C%.Furthermore,the optimum combination of Ru_(3)Sn_(7)and SnO_(x)on 1.5%Ru-6%Sn/SiO_(2)contributes to the isomerization,retro-aldol condensation,dehydration,and 1,2-hydride shift,giving rise to the preferential production of methyl lactate at a 25.1 C%yield.These results illustrate the feasibility of controlling the selective conversion of cellulose to C3 acetol or methyl lactate by devising a tunable catalytic system,which guides the rational design of catalysts for the selective conversion of cellulose.
基金supported by the National Natural Science Foundation of China(21761132014,21872060)the Fundamental Research Funds for the Central Universities of China(2016YXZD033)+1 种基金the Fundamental Research Funds for the Central Universities(2019kfyXJJS072)Opening fund of Hubei Key Laboratory of Material Chemistry and Service Failure(2017MCF01K)~~
文摘An efficient metal-free strategy for the synthesis of pharmaceutically relevant benzo[α]carbazoles from the derivatives of readily available 2-phenylindole and bio-renewable acetol in an aqueous biphasic system was developed. This protocol employed a sulfone-containing Bronsted acidic ionic liquid as the catalyst, which could be used for five times without a noticeable decrease in its activity and selectivity. Various substituted 2-phenylindoles and α-hydroxyketones participated in the reaction smoothly, with water as the sole byproduct. Mechanistically, the reaction involved the conventional carbon-nucleophile-induced Heyns-type rearrangement and downstream intramolecular olefination.
文摘Cerium-promoted silica supported copper chromite catalyst was synthesized from acid hydrolysis of sodium silicate by sol-gel method.The catalyst was characterized by Brunauer-Emmett-Teller(BET)method,field-emission scanning electron microscopy(FESEM),X-ray diffraction(XRD),H_(2)-temperature programmed reduction(H_(2)-TPR),NH3-temperature programmed desorption(NH3-TPD)and pyridine adsorbed Fourier transform infrared spectroscopy(Py-FTIR).Among cerium doped catalysts,5 wt%of Ce promoted copper chromite supported by 40 wt%of silica(SiCuCr40-Ce5)shows the largest BET surface area.XRD analysis of the reduced form of the catalyst shows both CeO_(2)/Ce_(2)O_(3) redox system and CuO/Cu_(2)O/Cu redox system.Py-FTIR shows the maximum number of Lewis acid sites for SiCuCr40-Ce5 than others.The highest acetol selectivity with analytical reagent(AR)grade glycerol conversion is observed for SiCuCr40-Ce5 at 200℃for 3 h in a batch reactor at atmospheric pressure.Cerium promotion lowers the reaction te mperature with enhanced glycerol conve rsion and increased acetol selectivity.Though the above catalyst shows higher conversion for laboratory reagent(LR)grade glycerol but it reduces acetol selectivity.The addition of glucose into the LR grade glycerol further reduces glycerol conversion and decreases the acetol selectivity to zero.This may be due to the presence of iron as impurity in LR grade glycerol.XRD analysis of spent catalyst shows the absence of redox catalytic system and the pore volume reduces identified by BET analysis.Raman analysis of the spent catalyst shows graphite-like carbon deposition in the spent catalvst.
