Diacylglycerol(DAG)is a functional oil that can reduce body fat accumulation and postprandial triglycerides.In this study,lipase-catalyzed esterification of oleic acid with glycerol was investigated to elucidate the k...Diacylglycerol(DAG)is a functional oil that can reduce body fat accumulation and postprandial triglycerides.In this study,lipase-catalyzed esterification of oleic acid with glycerol was investigated to elucidate the kinetics and selectivity of each reaction step.1H NMR monitoring revealed equilibrated positional isomerization among acylglycerols:sn-1 monoolein comprised 97.3%of total monoacylglycerols,and sn-1,3 diolein comprised 73.3%of total diacylglycerols.Acyl migration(isomer equilibration)occurred faster than overall esterification.The observed rate constants for successive esterification steps(glycerol→monoacylglycerol,monoacylglycerol→diacylglycerol,diacylglycerol→triacylglycerol)were 0.01068,0.00615,and 0.00304 min^(-1),respectively,indicating progressively slower reaction rates for larger acylglycerol species.Furthermore,molecular distillation at 200–220℃ purified the DAG without altering its fatty acid profile.These findings establish a kinetic model of the three-step esterification and highlight the importance of acyl migration in enzymatic DAG synthesis.展开更多
Atropisomeric phosphines are crucial for asymmetric catalysis but remain synthetically challenging.Herein,an N-heterocyclic carbene(NHC)catalyzed esterification reaction of dialdehydes with arylboronic acids was devel...Atropisomeric phosphines are crucial for asymmetric catalysis but remain synthetically challenging.Herein,an N-heterocyclic carbene(NHC)catalyzed esterification reaction of dialdehydes with arylboronic acids was developed,successfully constructing the framework of axially chiral phosphorus compounds.Mechanistic studies have revealed that the reaction initially undergoes a desymmetrization process,followed by a kinetic resolution pathway,affording a series of axially chiral phosphorus compounds with high enantioselectivity(up to 92%ee).展开更多
Fhnctionalized ionic liquid samples （bmim-PW12） were synthesized by 1-butyl-3-methyl- imidazolium bromide （bmimBr） and 12-phosphotungstic heteropolyacid （PW12）. The samples were annealed at 100-450 ℃ and were c...Fhnctionalized ionic liquid samples （bmim-PW12） were synthesized by 1-butyl-3-methyl- imidazolium bromide （bmimBr） and 12-phosphotungstic heteropolyacid （PW12）. The samples were annealed at 100-450 ℃ and were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, thermal gravity-DTG, brunauer emmett teller, and NHa-temperature programmed desorption. The results showed that the bmim-PW12 samples were crystal and maintained intact Keggin structure. The organic parts of those samples were partly decomposed at a temperature more than 350 ℃. The sample annealed at 400 ℃ exhibited nano-porous structure, strong acidity, and excellent catalytic activity on the esterification of n-butanol with acetic acid. The higher ester yield was obtained when the mass ratio of catalyst over the reactants amount was 5% for bmim-PW12 catalyst annealed at 400 ℃.展开更多
Esterification of carboxylic acid with equimolar amounts alcohol can be efficiently catalyzed by biphasic 4-(benzylamino)formoyldiphenylammonium triflate (BDPAT, 3) in good yield. The catalyst can be easily recovered...Esterification of carboxylic acid with equimolar amounts alcohol can be efficiently catalyzed by biphasic 4-(benzylamino)formoyldiphenylammonium triflate (BDPAT, 3) in good yield. The catalyst can be easily recovered without loss of activity.展开更多
Sludge palm oil （SPO） is an attractive feedstock and a significant raw material for biodiesel production. The use of SPO can lower the cost ofbiodiesel production significantly. In this study biodiesel fuel was prod...Sludge palm oil （SPO） is an attractive feedstock and a significant raw material for biodiesel production. The use of SPO can lower the cost ofbiodiesel production significantly. In this study biodiesel fuel was produced from SPO by esterification process using P-toluenesulfonic acid （PTSA） as acid catalyst in different dosages in presence of methanol to convert free fatty acid （FFA） to fatty acid methyl ester （FAME）. Batch esterification process of SPO was carried out to study the influence of PTSA dosage （0.25-10% wt/wt）, molar ratio of methanol to SPO （6：1-20：1）, temperature （40-80 ℃）, reaction time （30-120 min）. The effects of those parameters on the yield of crude biodiesel and conversion of FFA to FAME were monitored. The optimum condition for batch esterification process was 0.75% wt/wt, 10：1 molar ratio, 60 ℃ temperature and 60 minutes reaction time.展开更多
From both fundamental and practical perspectives, the production of chemicals from biomass re-sources using high-efficiency non-precious metal catalysts is important. However, many processes require addition of stoic...From both fundamental and practical perspectives, the production of chemicals from biomass re-sources using high-efficiency non-precious metal catalysts is important. However, many processes require addition of stoichiometric or excess quantities of base, which leads to high energy consump-tion, leaching problems, and side reactions. In this study, we investigated the high-efficiency oxida-tive esterification of furfural to methylfuroate by molecular oxygen with a Co-N-C/MgO catalyst. The catalyst was prepared by direct pyrolysis of a cobalt（Ⅱ） phenanthroline complex on MgO at 800℃ under N2 atmosphere. From furfural, 93.0% conversion and 98.5% selectivity toward methylfuroate were achieved under 0.5 MPa O2 with reaction at 100 ℃ for 12 h without a basic additive. The con-version and selectivity were much higher than those obtained with cobalt catalysts produced by pyrolysis of a cobalt（Ⅱ） phenanthroline complex on activated carbon or typical basic supports, in-cluding NaX, NaY, and CaO. X-ray photoelectron spectroscopy, X-ray diffraction, transmission elec-tron microscopy, and experimental results revealed that the high efficiency of Co-N-C/MgO for pro-duction of methylfuroate was closely related to the cobalt-nitrogen-doped carbon species and its catalytic ability in hydrogen abstraction. In contrast, Co-N-C（HCl） that synthesized by removing MgO with HCl from Co-N-C/MgO, as the catalyst produced mainly an acetal as a condensation prod-uct, and chloride ions had a negative effect on the oxidative esterification. Although the catalytic performance of the cobalt-nitrogen-doped carbon species was greatly affected by HCl treatment, it could be recovered to a great extent by addition of MgO. Moreover, changes in the oxygen pressure hardly affected the oxidative esterification of furfural with Co-N-C/MgO. This study not only pro-vides an effective approach to prepare methylfuroate, but also for designing high-performance non-precious metal catalysts for the oxidative esterification of biomass-derived compounds.展开更多
随着人工智能(AI)技术的迅猛发展,AI for Science(AI4S)正逐渐成为科学研究的新范式,尤其在化学领域的实验方法上引发了一场革命。本研究创新性地引入了自驱动实验室(SDL)的概念,旨在解决未来化学研究中的挑战,并探索其在基础化学实验中...随着人工智能(AI)技术的迅猛发展,AI for Science(AI4S)正逐渐成为科学研究的新范式,尤其在化学领域的实验方法上引发了一场革命。本研究创新性地引入了自驱动实验室(SDL)的概念,旨在解决未来化学研究中的挑战,并探索其在基础化学实验中的AI数字化升级应用。研究团队采用了可循环利用的固体酸作为催化剂,以乙酸和苄醇的酯化反应为研究对象,开发了一种相对低成本、适用于教学的反应条件优化闭环系统。该系统由基于芯曙光自动合成仪的自动化反应器、自主设计的液相自动进样监控系统,以及基于Python的决策优化算法所组成。本研究展示了在现有条件下如何克服硬件兼容性和算法优化的挑战,为化学实验的未来创新发展奠定了坚实的基础。展开更多
基金Bureau of Science and Information of Guangzhou under grant 2024A04J3254the National Key Research and Development Program of China under grant 2024YFE0214900+2 种基金the National Natural Science Foundation of China under grant 32272341,he National Key Research and Development Program of China under grant 2023YFD2100401the Opening Project of Hubei Key Laboratory of Lipid Chemistry and Nutrition under grant 202401,are gratefully acknowledged.
文摘Diacylglycerol(DAG)is a functional oil that can reduce body fat accumulation and postprandial triglycerides.In this study,lipase-catalyzed esterification of oleic acid with glycerol was investigated to elucidate the kinetics and selectivity of each reaction step.1H NMR monitoring revealed equilibrated positional isomerization among acylglycerols:sn-1 monoolein comprised 97.3%of total monoacylglycerols,and sn-1,3 diolein comprised 73.3%of total diacylglycerols.Acyl migration(isomer equilibration)occurred faster than overall esterification.The observed rate constants for successive esterification steps(glycerol→monoacylglycerol,monoacylglycerol→diacylglycerol,diacylglycerol→triacylglycerol)were 0.01068,0.00615,and 0.00304 min^(-1),respectively,indicating progressively slower reaction rates for larger acylglycerol species.Furthermore,molecular distillation at 200–220℃ purified the DAG without altering its fatty acid profile.These findings establish a kinetic model of the three-step esterification and highlight the importance of acyl migration in enzymatic DAG synthesis.
基金Project supported by the Natural Science Foundation of Henan Province(Nos.232300421234,252300421726)the Leading Talents in Scientific and Technological Innovation in Shangqiu(No.SQRC202212004)the Program of Ecological Environmental Protection in the Area of Old Course of Yellow River of Shangqiu Normal University。
文摘Atropisomeric phosphines are crucial for asymmetric catalysis but remain synthetically challenging.Herein,an N-heterocyclic carbene(NHC)catalyzed esterification reaction of dialdehydes with arylboronic acids was developed,successfully constructing the framework of axially chiral phosphorus compounds.Mechanistic studies have revealed that the reaction initially undergoes a desymmetrization process,followed by a kinetic resolution pathway,affording a series of axially chiral phosphorus compounds with high enantioselectivity(up to 92%ee).
文摘Fhnctionalized ionic liquid samples （bmim-PW12） were synthesized by 1-butyl-3-methyl- imidazolium bromide （bmimBr） and 12-phosphotungstic heteropolyacid （PW12）. The samples were annealed at 100-450 ℃ and were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, thermal gravity-DTG, brunauer emmett teller, and NHa-temperature programmed desorption. The results showed that the bmim-PW12 samples were crystal and maintained intact Keggin structure. The organic parts of those samples were partly decomposed at a temperature more than 350 ℃. The sample annealed at 400 ℃ exhibited nano-porous structure, strong acidity, and excellent catalytic activity on the esterification of n-butanol with acetic acid. The higher ester yield was obtained when the mass ratio of catalyst over the reactants amount was 5% for bmim-PW12 catalyst annealed at 400 ℃.
文摘Esterification of carboxylic acid with equimolar amounts alcohol can be efficiently catalyzed by biphasic 4-(benzylamino)formoyldiphenylammonium triflate (BDPAT, 3) in good yield. The catalyst can be easily recovered without loss of activity.
文摘Sludge palm oil （SPO） is an attractive feedstock and a significant raw material for biodiesel production. The use of SPO can lower the cost ofbiodiesel production significantly. In this study biodiesel fuel was produced from SPO by esterification process using P-toluenesulfonic acid （PTSA） as acid catalyst in different dosages in presence of methanol to convert free fatty acid （FFA） to fatty acid methyl ester （FAME）. Batch esterification process of SPO was carried out to study the influence of PTSA dosage （0.25-10% wt/wt）, molar ratio of methanol to SPO （6：1-20：1）, temperature （40-80 ℃）, reaction time （30-120 min）. The effects of those parameters on the yield of crude biodiesel and conversion of FFA to FAME were monitored. The optimum condition for batch esterification process was 0.75% wt/wt, 10：1 molar ratio, 60 ℃ temperature and 60 minutes reaction time.
基金supported by the National Natural Science Foundation of China(21233008,21643013,21690084)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020300)the Youth Innovation Promotion Association CAS(2013121)~~
文摘From both fundamental and practical perspectives, the production of chemicals from biomass re-sources using high-efficiency non-precious metal catalysts is important. However, many processes require addition of stoichiometric or excess quantities of base, which leads to high energy consump-tion, leaching problems, and side reactions. In this study, we investigated the high-efficiency oxida-tive esterification of furfural to methylfuroate by molecular oxygen with a Co-N-C/MgO catalyst. The catalyst was prepared by direct pyrolysis of a cobalt（Ⅱ） phenanthroline complex on MgO at 800℃ under N2 atmosphere. From furfural, 93.0% conversion and 98.5% selectivity toward methylfuroate were achieved under 0.5 MPa O2 with reaction at 100 ℃ for 12 h without a basic additive. The con-version and selectivity were much higher than those obtained with cobalt catalysts produced by pyrolysis of a cobalt（Ⅱ） phenanthroline complex on activated carbon or typical basic supports, in-cluding NaX, NaY, and CaO. X-ray photoelectron spectroscopy, X-ray diffraction, transmission elec-tron microscopy, and experimental results revealed that the high efficiency of Co-N-C/MgO for pro-duction of methylfuroate was closely related to the cobalt-nitrogen-doped carbon species and its catalytic ability in hydrogen abstraction. In contrast, Co-N-C（HCl） that synthesized by removing MgO with HCl from Co-N-C/MgO, as the catalyst produced mainly an acetal as a condensation prod-uct, and chloride ions had a negative effect on the oxidative esterification. Although the catalytic performance of the cobalt-nitrogen-doped carbon species was greatly affected by HCl treatment, it could be recovered to a great extent by addition of MgO. Moreover, changes in the oxygen pressure hardly affected the oxidative esterification of furfural with Co-N-C/MgO. This study not only pro-vides an effective approach to prepare methylfuroate, but also for designing high-performance non-precious metal catalysts for the oxidative esterification of biomass-derived compounds.
文摘随着人工智能(AI)技术的迅猛发展,AI for Science(AI4S)正逐渐成为科学研究的新范式,尤其在化学领域的实验方法上引发了一场革命。本研究创新性地引入了自驱动实验室(SDL)的概念,旨在解决未来化学研究中的挑战,并探索其在基础化学实验中的AI数字化升级应用。研究团队采用了可循环利用的固体酸作为催化剂,以乙酸和苄醇的酯化反应为研究对象,开发了一种相对低成本、适用于教学的反应条件优化闭环系统。该系统由基于芯曙光自动合成仪的自动化反应器、自主设计的液相自动进样监控系统,以及基于Python的决策优化算法所组成。本研究展示了在现有条件下如何克服硬件兼容性和算法优化的挑战,为化学实验的未来创新发展奠定了坚实的基础。
