In this paper, it was found that isopropylidene (1-hydroxy-3-oxo-butylidene) malonate 4 was a heat unstable compound and the one step convenient methods for preparation of 4-hydroxy-6-methyl-2-pyrone 1 and 3-carboxy-4...In this paper, it was found that isopropylidene (1-hydroxy-3-oxo-butylidene) malonate 4 was a heat unstable compound and the one step convenient methods for preparation of 4-hydroxy-6-methyl-2-pyrone 1 and 3-carboxy-4-hydroxy-6-methyl-2-pyrone 2 in good yields were reported. Isopropylidene malonate 3、diketen and triethylamine reacted in chloroform to give 2, and in the mixture of dichloromethane and chlorobenzene to offer 1.展开更多
The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters.The catalysts generally preferred are sulfuric acid or p-toluene...The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters.The catalysts generally preferred are sulfuric acid or p-toluenesulfonic acid.But the products esters were racemic when（S）-3-（2′-oxocyclohexyl） propionic acid reacts with alcohols in the presence of sulfuric acid or with p-toluenesulfonic acid as catalyst.We replace sulfuric acid with Fe2(SO4)3·xH2O as the catalyst.The optical compound（S）-methyl-3-（2′-oxocyclohexyl）propionate,（（S）-ethyl-3-）（2′-oxocyclohexyl）propionate and（S）-n-butyl-3-（2′-oxocyclohexyl）propionate were obtained.In this paper we also reported that cyclohexanone reacted with methyl acrylate in the presence of potassium thiazolidine-2-thione-4-carboxylate（R）TTCA·K as the chiral catalyst to afford optically active（S）-3-（2′-oxocy-clohexyl） propionate.The mechanism of reaction of cyclohexanone with methyl acrylate in the presence of（R）TTCA·K as the catalyst would be a complex process.展开更多
Driven by safety issues,environmental concerns,and high costs,rechargeable aqueous zinc-ion batteries(ZIBs)have received increasing attention in recent years owing to their unique advantages.However,the sluggish kinet...Driven by safety issues,environmental concerns,and high costs,rechargeable aqueous zinc-ion batteries(ZIBs)have received increasing attention in recent years owing to their unique advantages.However,the sluggish kinetics of divalent charge Zn^(2+)in the cathode materials caused by the strong electrostatic interaction and their unsatisfactory cycle life hinder the development of ZIBs.Herein,organic cations and Zn^(2+)ions co-pre-inserted vanadium oxide([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O are reported as the cathode for ultra-stable aqueous ZIBs,in which the weaker electrostatic interactions between Zn^(2+)and organic ion-pinned vanadium oxide can induce the high reversibility of Zn^(2+)insertion and extraction,thereby improving the cycle life.It is demonstrated that([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O cathodes deliver a discharge capacity of 181 mA h g^(-1)at8 A g^(-1)and ultra-long life span(99.5%capacity retention after 2000 cycles).A reversible Zn^(2+)/H^(+)ions(de)intercalation storage process and pseudocapacitive charge storage are characterized.The weaker interactions between organic ion and Zn^(2+)open a novel avenue for the design of highly reversible cathode materials with long-term cycling stability.展开更多
文摘In this paper, it was found that isopropylidene (1-hydroxy-3-oxo-butylidene) malonate 4 was a heat unstable compound and the one step convenient methods for preparation of 4-hydroxy-6-methyl-2-pyrone 1 and 3-carboxy-4-hydroxy-6-methyl-2-pyrone 2 in good yields were reported. Isopropylidene malonate 3、diketen and triethylamine reacted in chloroform to give 2, and in the mixture of dichloromethane and chlorobenzene to offer 1.
文摘The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters.The catalysts generally preferred are sulfuric acid or p-toluenesulfonic acid.But the products esters were racemic when（S）-3-（2′-oxocyclohexyl） propionic acid reacts with alcohols in the presence of sulfuric acid or with p-toluenesulfonic acid as catalyst.We replace sulfuric acid with Fe2(SO4)3·xH2O as the catalyst.The optical compound（S）-methyl-3-（2′-oxocyclohexyl）propionate,（（S）-ethyl-3-）（2′-oxocyclohexyl）propionate and（S）-n-butyl-3-（2′-oxocyclohexyl）propionate were obtained.In this paper we also reported that cyclohexanone reacted with methyl acrylate in the presence of potassium thiazolidine-2-thione-4-carboxylate（R）TTCA·K as the chiral catalyst to afford optically active（S）-3-（2′-oxocy-clohexyl） propionate.The mechanism of reaction of cyclohexanone with methyl acrylate in the presence of（R）TTCA·K as the catalyst would be a complex process.
基金supported by the funding from the National Natural Science Foundation of China(grant nos.51902187,52072224,and 51732007)the Natural Science Foundation of Shandong Province(ZR2018BEM010)+3 种基金the Science Fund for Distinguished Young Scholars of Shandong Province(ZR2019JQ16)the Fundamental Research Funds of Shandong UniversityYoung Elite Scientist Sponsorship Program by CAST(YESS)the support from Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong
文摘Driven by safety issues,environmental concerns,and high costs,rechargeable aqueous zinc-ion batteries(ZIBs)have received increasing attention in recent years owing to their unique advantages.However,the sluggish kinetics of divalent charge Zn^(2+)in the cathode materials caused by the strong electrostatic interaction and their unsatisfactory cycle life hinder the development of ZIBs.Herein,organic cations and Zn^(2+)ions co-pre-inserted vanadium oxide([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O are reported as the cathode for ultra-stable aqueous ZIBs,in which the weaker electrostatic interactions between Zn^(2+)and organic ion-pinned vanadium oxide can induce the high reversibility of Zn^(2+)insertion and extraction,thereby improving the cycle life.It is demonstrated that([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O cathodes deliver a discharge capacity of 181 mA h g^(-1)at8 A g^(-1)and ultra-long life span(99.5%capacity retention after 2000 cycles).A reversible Zn^(2+)/H^(+)ions(de)intercalation storage process and pseudocapacitive charge storage are characterized.The weaker interactions between organic ion and Zn^(2+)open a novel avenue for the design of highly reversible cathode materials with long-term cycling stability.
