The structure-performance relationship of Cu/Al_(2)O_(3) catalysts in the hydrogenation of diethyl oxalate(DEO)for the synthesis of alcohol ether esters has been investigated by various characterization techniques inc...The structure-performance relationship of Cu/Al_(2)O_(3) catalysts in the hydrogenation of diethyl oxalate(DEO)for the synthesis of alcohol ether esters has been investigated by various characterization techniques including XRD,XPS,N2O titration,and 27Al MAS-NMR.The results showed that when the crystal configurations of Al_(2)O_(3) were the same,increasing the specific surface area could effectively refine the size of copper nanoparticles(Cu NPs),and ultimately improve the conversion of DEO.Meanwhile,the smaller size ofγ-Al_(2)O_(3)(HSAl and SBAl)loaded Cu NPs promotes the reaction towards the deep hydrogenation to produce ethanol(EtOH)and ethylene glycol(EG).Besides,the larger size of Cu NPs on the surface of amorphous Al_(2)O_(3)(HTAl and SolAl)resulted in a lower conversion rate,where ethyl glycolate(Egly)is the main product.Despite there are differences in Al^(3+)ionic coordination in Al_(2)O_(3) with different crystal structures,the experimental data showed that the differences in Al^(3+)ionic coordination did not significantly affect the catalytic performance in the hydrogenation reaction.The formation of alcohol-ether ester chemicals is critically dependent on the interactions between Cu sites and acidic sites.Among them,EG and EtOH were dehydrated to form 2-ethoxyethanol via the SN2 mechanism,while Egly and EtOH were reacted to form ethyl ethoxyacetate(EEA)via the SN2 mechanism.This study provides a theoretical basis for the optimization of the coal-based glycol processes to achieve a diversified product portfolio.展开更多
Surfactant sodium alcohol ether carboxylate(AEC-9Na)was added to the magnesium sulfate solution in order to enhance the leaching efficiency of ionic rare earth ore,and the mechanism of action for AEC-9Na was elucidate...Surfactant sodium alcohol ether carboxylate(AEC-9Na)was added to the magnesium sulfate solution in order to enhance the leaching efficiency of ionic rare earth ore,and the mechanism of action for AEC-9Na was elucidated.Under optimal conditions,the addition of AEC-9Na with a mass fraction of 0.03% can enhance the leaching rate by 5.2% and reduce the leaching cycle.Kinetic analysis demonstrates that the leaching process follows the model of internal diffusion control.The analysis of the mass transfer process reveals that the addition of AEC-9Na results in a decrease in the height equivalent to a theoretical plate(HETP)and an improvement in mass transfer efficiency.The addition of AEC-9Na can reduce the thickness of the water layer adsorbed on particles during leaching,which in turn reduces hydration and facilitates penetration of the leaching solution into ore body pores.This improves mass transfer concentration differences during leaching,and facilitates desorption of rare earth ions.Periodic density functional theory(DFT)calculations show that the adsorption of AEC-9Na onto the surface of kaolinite(001)enhances the hydrophilicity of the mineral surface and improves its permeability efficiency.Simultaneously,AEC-9Na forms complexes with hydrated rare earth ions on the kaolinite(001)surface,thereby reducing their adsorption strength on clay minerals.This promotes the exchange and desorption process of magnesium ions to hydrated rare earth ions,ultimately enhancing the mass transfer process for leaching rare earth elements.展开更多
Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high...Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high condensate content,high temperature,and high salinity)often affect foaming agent performance.In this study,surfactants were screened using an airflow method that closely resembles field treatment method.Notably,alcohol ether sulfates(AE_(n)S)with various polyoxyethylene(EO)units demonstrated exceptional performance in terms of liquid unloading efficiency and foam stability.At 80℃,the unloading efficiency of AE_(n)S with two EO units(AE_(2)S)in a high NaCl mass concentration(up to 200 g/L)and high condensate volume fraction(up to 20%)reached 84%.The dynamic surface tension and interfacial tension measured at the same temperature were used to analyze the influence of the diffusion rate and interfacial characteristics on the AE_(n)S foam,while the viscosity and liquid film thickness measurements reflected the mechanical strength and liquid-carrying capacity.In addition,transmission electron microscopy(TEM)revealed that AE_(2)S formed“dendritic”micellar aggregates at a high NaCl mass concentration,which significantly enhanced the viscosity and stability of the foam.The interactions among AE_(n)S,NaCl,and H2O were analyzed using molecular dynamics,and it was confirmed from a molecular mechanics perspective that a stable structure can form among the three,contributing to the foam stability.These findings demonstrate the significant potential of the AE_(2)S foam for gas well deliquification.展开更多
Based on QSPR of alcohol and ether organic compounds in water,geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G＊ level for 73 alcohol and ether organic compounds.Linear ...Based on QSPR of alcohol and ether organic compounds in water,geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G＊ level for 73 alcohol and ether organic compounds.Linear relationships between infinite dilution activity coef-ficient（lnγ∞） of alcohols and ethers in water and theoretical descriptors of the molecular structure were established by multiple regression method.The result shows that the parameters derived from molecular electrostatic potential together with molecular surface area can be preferably used to express the quantitative structure-lnγ∞ relationship of alcohols and ethers in water.This reveals that this model has good predictive capabilities（RCV=0.969）.The molecular electrostatic potential has also been proved to have the general applicability in QSPR model of alcohol and ether organic compounds about γ∞ in water.The QSPR model established may provide a new powerful method for predicting γ∞ of organic compounds in aqueous systems.展开更多
A new electrophilic polymer, 2,4-dinitrophenyl ether of polyvinyl alcohol (PVA-DNP), having a degree of substitution of 0.5 was prepared from polyvinyl alcohol (PVA) and 1-fluro-2,4-dinitrobenzene (DNFB). The PVA-DNP ...A new electrophilic polymer, 2,4-dinitrophenyl ether of polyvinyl alcohol (PVA-DNP), having a degree of substitution of 0.5 was prepared from polyvinyl alcohol (PVA) and 1-fluro-2,4-dinitrobenzene (DNFB). The PVA-DNP polymer was characterized by NMR, IR, and UV-visible spectroscopy. The reaction of PVA-DNP with sodium methoxide was followed by NMR and UV-visible spectroscopy. Evidence of polymer bound spirocyclic SIGMA complex, C-1 and C-3 polymer bound DNP-methoxy SIGMA complexes and the formation and C-1 methoxy complex of 2,4-dinitroanisole was observed.展开更多
Alcohols are selectively and efficiently protected as their tetrahydropranyl ethers in the presence of a catalytic amount of Fe（HSO4）3 in good to high yields. All reactions are performed under mild and completely he...Alcohols are selectively and efficiently protected as their tetrahydropranyl ethers in the presence of a catalytic amount of Fe（HSO4）3 in good to high yields. All reactions are performed under mild and completely heterogeneous reaction conditions.展开更多
Venous system diseases mainly include varicose veins and venous malformations of lower limbs and the genital system.Most of them are chronic diseases that cause serious clinical symptoms to patients and affect their h...Venous system diseases mainly include varicose veins and venous malformations of lower limbs and the genital system.Most of them are chronic diseases that cause serious clinical symptoms to patients and affect their health and quality of life.Sclerotherapy has become the first-line therapy for venous system diseases.However,there are problems such as incomplete fibrosis and vascular recanalization after sclerotherapy,and improper operation will cause serious adverse consequences.Therefore,exploring a safe and effective sclerotherapy strategy is essential for developing clinically successful sclerotherapy.To solve the above problems,we proposed a new sclerotherapy strategy with a dual mechanism of“vascular damage and plasmin(PLA)system inhibition.”We intended to construct a novel cationic surfactant(AEOx-TA)by reacting tranexamic acid(TA),a parent structure,with fatty alcohol polyoxyethylene ether(AEOx)by ester bonds.AEOx-TA could damage vascular endothelium and initiate a coagulation cascade effect to induce thrombus.Furthermore,AEOx-TA could be degraded by esterase and release the parent drug,TA,which could inhibit the PLA system to inhibit the degradation of thrombus and extracellular matrix and promote the process of vascular fibrosis.In addition,such surfactant-based sclerosants have foam-forming properties,and they can be blended with polyvinyl alcohol(PVA)to prepare a highly stable foam formulation(AEOx-TA/P),which can achieve a precise drug delivery and prolonged drug retention time,thereby improving drug efficacy and reducing the risk of ectopic embolism.Overall,the novel cationic surfactant AEOx-TA provides a new avenue to resolve the bottleneck:surfactant sclerosants’efficiency is relatively low in the current sclerotherapy.展开更多
文摘The structure-performance relationship of Cu/Al_(2)O_(3) catalysts in the hydrogenation of diethyl oxalate(DEO)for the synthesis of alcohol ether esters has been investigated by various characterization techniques including XRD,XPS,N2O titration,and 27Al MAS-NMR.The results showed that when the crystal configurations of Al_(2)O_(3) were the same,increasing the specific surface area could effectively refine the size of copper nanoparticles(Cu NPs),and ultimately improve the conversion of DEO.Meanwhile,the smaller size ofγ-Al_(2)O_(3)(HSAl and SBAl)loaded Cu NPs promotes the reaction towards the deep hydrogenation to produce ethanol(EtOH)and ethylene glycol(EG).Besides,the larger size of Cu NPs on the surface of amorphous Al_(2)O_(3)(HTAl and SolAl)resulted in a lower conversion rate,where ethyl glycolate(Egly)is the main product.Despite there are differences in Al^(3+)ionic coordination in Al_(2)O_(3) with different crystal structures,the experimental data showed that the differences in Al^(3+)ionic coordination did not significantly affect the catalytic performance in the hydrogenation reaction.The formation of alcohol-ether ester chemicals is critically dependent on the interactions between Cu sites and acidic sites.Among them,EG and EtOH were dehydrated to form 2-ethoxyethanol via the SN2 mechanism,while Egly and EtOH were reacted to form ethyl ethoxyacetate(EEA)via the SN2 mechanism.This study provides a theoretical basis for the optimization of the coal-based glycol processes to achieve a diversified product portfolio.
基金Project supported by the National Natural Science Foundation Regional Innovation Development Joint Fund(U24A2096)。
文摘Surfactant sodium alcohol ether carboxylate(AEC-9Na)was added to the magnesium sulfate solution in order to enhance the leaching efficiency of ionic rare earth ore,and the mechanism of action for AEC-9Na was elucidated.Under optimal conditions,the addition of AEC-9Na with a mass fraction of 0.03% can enhance the leaching rate by 5.2% and reduce the leaching cycle.Kinetic analysis demonstrates that the leaching process follows the model of internal diffusion control.The analysis of the mass transfer process reveals that the addition of AEC-9Na results in a decrease in the height equivalent to a theoretical plate(HETP)and an improvement in mass transfer efficiency.The addition of AEC-9Na can reduce the thickness of the water layer adsorbed on particles during leaching,which in turn reduces hydration and facilitates penetration of the leaching solution into ore body pores.This improves mass transfer concentration differences during leaching,and facilitates desorption of rare earth ions.Periodic density functional theory(DFT)calculations show that the adsorption of AEC-9Na onto the surface of kaolinite(001)enhances the hydrophilicity of the mineral surface and improves its permeability efficiency.Simultaneously,AEC-9Na forms complexes with hydrated rare earth ions on the kaolinite(001)surface,thereby reducing their adsorption strength on clay minerals.This promotes the exchange and desorption process of magnesium ions to hydrated rare earth ions,ultimately enhancing the mass transfer process for leaching rare earth elements.
文摘Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high condensate content,high temperature,and high salinity)often affect foaming agent performance.In this study,surfactants were screened using an airflow method that closely resembles field treatment method.Notably,alcohol ether sulfates(AE_(n)S)with various polyoxyethylene(EO)units demonstrated exceptional performance in terms of liquid unloading efficiency and foam stability.At 80℃,the unloading efficiency of AE_(n)S with two EO units(AE_(2)S)in a high NaCl mass concentration(up to 200 g/L)and high condensate volume fraction(up to 20%)reached 84%.The dynamic surface tension and interfacial tension measured at the same temperature were used to analyze the influence of the diffusion rate and interfacial characteristics on the AE_(n)S foam,while the viscosity and liquid film thickness measurements reflected the mechanical strength and liquid-carrying capacity.In addition,transmission electron microscopy(TEM)revealed that AE_(2)S formed“dendritic”micellar aggregates at a high NaCl mass concentration,which significantly enhanced the viscosity and stability of the foam.The interactions among AE_(n)S,NaCl,and H2O were analyzed using molecular dynamics,and it was confirmed from a molecular mechanics perspective that a stable structure can form among the three,contributing to the foam stability.These findings demonstrate the significant potential of the AE_(2)S foam for gas well deliquification.
文摘Based on QSPR of alcohol and ether organic compounds in water,geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G＊ level for 73 alcohol and ether organic compounds.Linear relationships between infinite dilution activity coef-ficient（lnγ∞） of alcohols and ethers in water and theoretical descriptors of the molecular structure were established by multiple regression method.The result shows that the parameters derived from molecular electrostatic potential together with molecular surface area can be preferably used to express the quantitative structure-lnγ∞ relationship of alcohols and ethers in water.This reveals that this model has good predictive capabilities（RCV=0.969）.The molecular electrostatic potential has also been proved to have the general applicability in QSPR model of alcohol and ether organic compounds about γ∞ in water.The QSPR model established may provide a new powerful method for predicting γ∞ of organic compounds in aqueous systems.
文摘A new electrophilic polymer, 2,4-dinitrophenyl ether of polyvinyl alcohol (PVA-DNP), having a degree of substitution of 0.5 was prepared from polyvinyl alcohol (PVA) and 1-fluro-2,4-dinitrobenzene (DNFB). The PVA-DNP polymer was characterized by NMR, IR, and UV-visible spectroscopy. The reaction of PVA-DNP with sodium methoxide was followed by NMR and UV-visible spectroscopy. Evidence of polymer bound spirocyclic SIGMA complex, C-1 and C-3 polymer bound DNP-methoxy SIGMA complexes and the formation and C-1 methoxy complex of 2,4-dinitroanisole was observed.
文摘Alcohols are selectively and efficiently protected as their tetrahydropranyl ethers in the presence of a catalytic amount of Fe（HSO4）3 in good to high yields. All reactions are performed under mild and completely heterogeneous reaction conditions.
基金supported by the Shenzhen Natural Science Foundation Project(JCYJ20240813113226035,China)Natural Science Foundation of Top Talent of SZTU(GDRC202305,China)Basic Scientific Research Funding of Education Department of Liaoning Province(JYTMS20231368,China).
文摘Venous system diseases mainly include varicose veins and venous malformations of lower limbs and the genital system.Most of them are chronic diseases that cause serious clinical symptoms to patients and affect their health and quality of life.Sclerotherapy has become the first-line therapy for venous system diseases.However,there are problems such as incomplete fibrosis and vascular recanalization after sclerotherapy,and improper operation will cause serious adverse consequences.Therefore,exploring a safe and effective sclerotherapy strategy is essential for developing clinically successful sclerotherapy.To solve the above problems,we proposed a new sclerotherapy strategy with a dual mechanism of“vascular damage and plasmin(PLA)system inhibition.”We intended to construct a novel cationic surfactant(AEOx-TA)by reacting tranexamic acid(TA),a parent structure,with fatty alcohol polyoxyethylene ether(AEOx)by ester bonds.AEOx-TA could damage vascular endothelium and initiate a coagulation cascade effect to induce thrombus.Furthermore,AEOx-TA could be degraded by esterase and release the parent drug,TA,which could inhibit the PLA system to inhibit the degradation of thrombus and extracellular matrix and promote the process of vascular fibrosis.In addition,such surfactant-based sclerosants have foam-forming properties,and they can be blended with polyvinyl alcohol(PVA)to prepare a highly stable foam formulation(AEOx-TA/P),which can achieve a precise drug delivery and prolonged drug retention time,thereby improving drug efficacy and reducing the risk of ectopic embolism.Overall,the novel cationic surfactant AEOx-TA provides a new avenue to resolve the bottleneck:surfactant sclerosants’efficiency is relatively low in the current sclerotherapy.
