Poly (EA-MAn-APTES)/silica hybrid materials were successfully prepared fromEthyl acrylate (EA), maleic anhydride (MAn) and tetraethoxysilane (TEOS) in the presence of acoupling agent 3-aminopropyltriethoxysilane (APTE...Poly (EA-MAn-APTES)/silica hybrid materials were successfully prepared fromEthyl acrylate (EA), maleic anhydride (MAn) and tetraethoxysilane (TEOS) in the presence of acoupling agent 3-aminopropyltriethoxysilane (APTES),by free-radical solution polymerization and insitu sol-gel process. The mass fraction of TEOS varied from 0 to 25%. The hybrid materials werecharacterized by the methods of FT-IR spectra, solvent extraction, scanning electron microscope (SEM), transmission electron microscope (TEM), differential scanning calorimetry (DSC) andthermogravimetric analysis (TGA) measuring apparatus to get their structures, gel contents,morphologies, particle sizes and thermal performances. The results show that the covalent bonds arebetween organic and inorganic phases, gel contents in the hybrid materials are much higher, theSiO_2 phase is well dispersed in the polymer matrix, silicon dioxide exist at nanoscale in thecomposites and have excellent thermal stability.展开更多
Six aminoglucose conjugates were synthesized by the reaction of aminoglucose with 5-fluorou-racil-1-acetic acid or 5-fluorouracil-1-propanoic acid and confirmed by IR, 1H NMR and elemental analyses. Their antitumor ac...Six aminoglucose conjugates were synthesized by the reaction of aminoglucose with 5-fluorou-racil-1-acetic acid or 5-fluorouracil-1-propanoic acid and confirmed by IR, 1H NMR and elemental analyses. Their antitumor activities against A2780 cells and PC-14 cells were also evaluated.展开更多
The vapor-liquid equilibrium of binary mixtures of propyl acetate, butyl acetate and isobutyl acetate with meth- anol has been determined at a constant pressure of 0.6 MPa. Results have been modeled with the Peng-Robi...The vapor-liquid equilibrium of binary mixtures of propyl acetate, butyl acetate and isobutyl acetate with meth- anol has been determined at a constant pressure of 0.6 MPa. Results have been modeled with the Peng-Robinson equation, a traditional cubic equation of state widely employed in chemical industries, as well as with the perturbed-chain statistical associating fluid PC-SAFT theory of Gross-Sadowski. By correlation of the binary inter- action parameters of these equations, the measured vapor-liquid equilibrium data can be accurately predicted. Thus, this work shows that these models are able to represent the experimental data for systems with associating comoounds via hydrogen bonding.展开更多
The diffusion coefficients of aqueous solutions ofglycine, L-alanine, L-valine and L-isoleucine at 298.15 K were determined by holographic interferometry with accuracy and promptness while without disturbance. The den...The diffusion coefficients of aqueous solutions ofglycine, L-alanine, L-valine and L-isoleucine at 298.15 K were determined by holographic interferometry with accuracy and promptness while without disturbance. The density and viscosity of these solutions were also determined. According to original Gordon model, a model for correlating the diffusion coefficients of amino acids in aqueous solutions was developed and applied. The results showed that this model provided significant convenience in correlation of diffusion coefficients for amino acids system.展开更多
The kinetics for production of ethyl levulinate from glucose in ethanol medium was investigated. The experiments were performed in various temperatures （433-473 K） and initial glucose concentrations （0.056-0.168 mo...The kinetics for production of ethyl levulinate from glucose in ethanol medium was investigated. The experiments were performed in various temperatures （433-473 K） and initial glucose concentrations （0.056-0.168 mol·L-1） with extremely low sulfuric acid as the catalyst. The results show that higher temperature can improve the conversion of glucose to ethyl levulinate, with higher yield of ethyl levulinate （44.79%, by mole） obtained at 473 K for 210 min. The kinetics follows a simplified first-order kinetic model. For the main and side reactions, the values of activation energy are 122.64 and 70.97 kJ·mo1-1, and the reaction orders are 0.985 and 0.998, respectively.展开更多
Acrylic acid(AA)and its ester,methyl acrylate(MA),were produced by a green one‐step aldol condensation reaction of dimethoxymethane and methyl acetate.The reaction was conducted over ZSM‐35 zeolites with different c...Acrylic acid(AA)and its ester,methyl acrylate(MA),were produced by a green one‐step aldol condensation reaction of dimethoxymethane and methyl acetate.The reaction was conducted over ZSM‐35 zeolites with different concentrations of Bronsted acid,which were prepared by the sodium ion‐exchange process with H‐form zeolite.The acidic property of HZSM‐35 was studied in detail through infrared experiments.About 51%of all bridging OH groups were distributed in cages,while 23%and 26%,respectively,were distributed in 10‐and 8‐ring channels.The catalytic performance was enhanced by a high concentration of Bronsted acid,indicating that Bronsted acid is an active site for the aldol condensation reaction.The ZSM‐35 zeolite possessing a concentration of Bronsted acid as high as 0.049 mmol/g demonstrated excellent performance with a MA+AA selectivity of up to 73%.展开更多
The racemic phenylalanine has been separated by (R)-mandelic acid through the formation of diastereomeric molecular complex. The crystal of the title chiral complex (C8H8O3 C9H11NO2, Mr = 317.33) belongs to monoclinic...The racemic phenylalanine has been separated by (R)-mandelic acid through the formation of diastereomeric molecular complex. The crystal of the title chiral complex (C8H8O3 C9H11NO2, Mr = 317.33) belongs to monoclinic, space group C2 with a = 19.391(3), b = 5.715(4), c = 15.755(3) ? b = 115.23(1), V = 1579(1) 3, Z = 4, Dc = 1.335 g/cm3, F(000) = 672, m = 0.099 mm-1, R = 0.033 and wR = 0.060 for 1278 observed reflections (I > 2s(I)). The complex consists of (R)-mandelic acid and (R)-phenylalanine in 1:1 molar ratio, and the complex molecules form layered crystal structure by self-assembly through intermolecular H-bonding between carboxyl and carboxylate of the neighboring molecules.展开更多
The effects of different treatments, such as dry heat,wet heat, solvent vapor and ultrasonic, on propertiesof the cyclic oligomers on the surface of polyester fiberare studied. The components of surface oligomers area...The effects of different treatments, such as dry heat,wet heat, solvent vapor and ultrasonic, on propertiesof the cyclic oligomers on the surface of polyester fiberare studied. The components of surface oligomers areanalyzed through Thin-Layer Chromatograph. Theresult shows that: all of the treatment, especially solvent vapor treatment,call significantly increase the content of surface cyclic oligomers.The content of cyclic triIner is increased more considerably than other oligomers. Moreover,the morphology and thedistribution of surface cyclic oligomers are also different from different treatments:Dry heat and wet heat cause larger polygonal solids distributed evenly on the surface of fiber;solvent vapor nlakes fiber surface exhibit irregular rodlike crystal shapes randomly;ultrasonic treatment induces some obscureand smaller deposi^on the surface of fiber.展开更多
Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), ac...Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), acrylate (AA) and methyl acrylate (MAA) were used as reactive cosurfactants. With this process high polymer: surfactant weight ratios (40:1 or greater),relatively concentrated (~30wt. %) latexes and small (~60nm) particle diameters were obtained.Properties of the latexes were characterized by TEM, DSC, dynamic light scattering, and IR spectroscopy.展开更多
The catalytic transformation of cellulose into key building-block or platform chemicals such as 5-hydoxymethylfurfural(HMF),levulinic acid,and lactic acid under mild conditions,has attracted much attention in recent y...The catalytic transformation of cellulose into key building-block or platform chemicals such as 5-hydoxymethylfurfural(HMF),levulinic acid,and lactic acid under mild conditions,has attracted much attention in recent years,as these conversions can be operated without consumption of hydrogen or oxygen and thus are more economical compared to the hydrogenolysis or oxidation of cellulose.This review article highlights recent advances in the development of novel catalysts or catalytic processes for the conversion of cellulose and its derived carbohydrates into HMF,levulinic acid,and lactic acid or their esters under inert atmosphere.We also analyze efficient catalytic systems for HMF production,in particular Lewis acids combined with ionic liquid or biphasic systems.For the formations of levulinic and lactic acids or their esters,we focus on the reactions in aqueous and alcohol media catalyzed by multifunctional catalysts that combine the functions of hydrolysis,isomerization,and dehydration-rehydration or retro-aldol reactions.The reaction mechanism for each process will also be discussed to gain insights into the activation of C–O and C–C bonds in the absence of hydrogen or oxygen.展开更多
Thermo-responsive shape memory hydrogels generally achieve shape fixation at low temperatures,and shape recovery at high temperatures.However,these hydrogels usually suffer from poor mechanical properties.Herein,we pr...Thermo-responsive shape memory hydrogels generally achieve shape fixation at low temperatures,and shape recovery at high temperatures.However,these hydrogels usually suffer from poor mechanical properties.Herein,we present a unique poly(acrylic acid)/calcium acetate shape memory hydrogel with cold-induced shape recovery performances as ultrastrong artificial muscles.Since the acetate groups could form aggregate at high temperatures and thus induce the association of the hydrogel network,the hydrogel can be fixed into a temporary shape upon heating and recover to its original shape in a cold environment.Moreover,a programmable shape recovery process is realized by adjusting the shape fixing time.In addition,the unique shape memory process enables the application demonstration as bio-inspired artificial muscles with an ultrahigh work density of45.2 kJ m^(-3),higher than that of biological muscles(~8 kJ m^(-3)).展开更多
文摘Poly (EA-MAn-APTES)/silica hybrid materials were successfully prepared fromEthyl acrylate (EA), maleic anhydride (MAn) and tetraethoxysilane (TEOS) in the presence of acoupling agent 3-aminopropyltriethoxysilane (APTES),by free-radical solution polymerization and insitu sol-gel process. The mass fraction of TEOS varied from 0 to 25%. The hybrid materials werecharacterized by the methods of FT-IR spectra, solvent extraction, scanning electron microscope (SEM), transmission electron microscope (TEM), differential scanning calorimetry (DSC) andthermogravimetric analysis (TGA) measuring apparatus to get their structures, gel contents,morphologies, particle sizes and thermal performances. The results show that the covalent bonds arebetween organic and inorganic phases, gel contents in the hybrid materials are much higher, theSiO_2 phase is well dispersed in the polymer matrix, silicon dioxide exist at nanoscale in thecomposites and have excellent thermal stability.
文摘Six aminoglucose conjugates were synthesized by the reaction of aminoglucose with 5-fluorou-racil-1-acetic acid or 5-fluorouracil-1-propanoic acid and confirmed by IR, 1H NMR and elemental analyses. Their antitumor activities against A2780 cells and PC-14 cells were also evaluated.
文摘The vapor-liquid equilibrium of binary mixtures of propyl acetate, butyl acetate and isobutyl acetate with meth- anol has been determined at a constant pressure of 0.6 MPa. Results have been modeled with the Peng-Robinson equation, a traditional cubic equation of state widely employed in chemical industries, as well as with the perturbed-chain statistical associating fluid PC-SAFT theory of Gross-Sadowski. By correlation of the binary inter- action parameters of these equations, the measured vapor-liquid equilibrium data can be accurately predicted. Thus, this work shows that these models are able to represent the experimental data for systems with associating comoounds via hydrogen bonding.
基金Supported by the National 973 Program of China (No. 2003CB615701)the National 863 Project of China (No. 2003AA328020)the National Natural Science Foundation of China (No. 200276034)the Educational Ministry Doctor Foundation of China (No 2000005608).
文摘The diffusion coefficients of aqueous solutions ofglycine, L-alanine, L-valine and L-isoleucine at 298.15 K were determined by holographic interferometry with accuracy and promptness while without disturbance. The density and viscosity of these solutions were also determined. According to original Gordon model, a model for correlating the diffusion coefficients of amino acids in aqueous solutions was developed and applied. The results showed that this model provided significant convenience in correlation of diffusion coefficients for amino acids system.
基金Supported by the National Natural Science Foundation of China(21176227)the State Key Laboratory of Motor Vehicle Biofuel Technology(2013011)
文摘The kinetics for production of ethyl levulinate from glucose in ethanol medium was investigated. The experiments were performed in various temperatures （433-473 K） and initial glucose concentrations （0.056-0.168 mol·L-1） with extremely low sulfuric acid as the catalyst. The results show that higher temperature can improve the conversion of glucose to ethyl levulinate, with higher yield of ethyl levulinate （44.79%, by mole） obtained at 473 K for 210 min. The kinetics follows a simplified first-order kinetic model. For the main and side reactions, the values of activation energy are 122.64 and 70.97 kJ·mo1-1, and the reaction orders are 0.985 and 0.998, respectively.
文摘Acrylic acid(AA)and its ester,methyl acrylate(MA),were produced by a green one‐step aldol condensation reaction of dimethoxymethane and methyl acetate.The reaction was conducted over ZSM‐35 zeolites with different concentrations of Bronsted acid,which were prepared by the sodium ion‐exchange process with H‐form zeolite.The acidic property of HZSM‐35 was studied in detail through infrared experiments.About 51%of all bridging OH groups were distributed in cages,while 23%and 26%,respectively,were distributed in 10‐and 8‐ring channels.The catalytic performance was enhanced by a high concentration of Bronsted acid,indicating that Bronsted acid is an active site for the aldol condensation reaction.The ZSM‐35 zeolite possessing a concentration of Bronsted acid as high as 0.049 mmol/g demonstrated excellent performance with a MA+AA selectivity of up to 73%.
基金The work was supported by the National Natural Science Foundation of China (29973036)
文摘The racemic phenylalanine has been separated by (R)-mandelic acid through the formation of diastereomeric molecular complex. The crystal of the title chiral complex (C8H8O3 C9H11NO2, Mr = 317.33) belongs to monoclinic, space group C2 with a = 19.391(3), b = 5.715(4), c = 15.755(3) ? b = 115.23(1), V = 1579(1) 3, Z = 4, Dc = 1.335 g/cm3, F(000) = 672, m = 0.099 mm-1, R = 0.033 and wR = 0.060 for 1278 observed reflections (I > 2s(I)). The complex consists of (R)-mandelic acid and (R)-phenylalanine in 1:1 molar ratio, and the complex molecules form layered crystal structure by self-assembly through intermolecular H-bonding between carboxyl and carboxylate of the neighboring molecules.
文摘The effects of different treatments, such as dry heat,wet heat, solvent vapor and ultrasonic, on propertiesof the cyclic oligomers on the surface of polyester fiberare studied. The components of surface oligomers areanalyzed through Thin-Layer Chromatograph. Theresult shows that: all of the treatment, especially solvent vapor treatment,call significantly increase the content of surface cyclic oligomers.The content of cyclic triIner is increased more considerably than other oligomers. Moreover,the morphology and thedistribution of surface cyclic oligomers are also different from different treatments:Dry heat and wet heat cause larger polygonal solids distributed evenly on the surface of fiber;solvent vapor nlakes fiber surface exhibit irregular rodlike crystal shapes randomly;ultrasonic treatment induces some obscureand smaller deposi^on the surface of fiber.
基金CEM Foundation For N & T Joint Academy (Chinese Education Ministry Foundation for Nankai University and Tianjin University Joint Academy)
文摘Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), acrylate (AA) and methyl acrylate (MAA) were used as reactive cosurfactants. With this process high polymer: surfactant weight ratios (40:1 or greater),relatively concentrated (~30wt. %) latexes and small (~60nm) particle diameters were obtained.Properties of the latexes were characterized by TEM, DSC, dynamic light scattering, and IR spectroscopy.
基金supported by the National Natural Science Foundation of China(21173172,21103143,21033006)the Research Fund for the Doctorial Program of Higher Education(20130121130001)the Program for Changjiang Scholars and Innovative Research Team in University(IRT1036)
文摘The catalytic transformation of cellulose into key building-block or platform chemicals such as 5-hydoxymethylfurfural(HMF),levulinic acid,and lactic acid under mild conditions,has attracted much attention in recent years,as these conversions can be operated without consumption of hydrogen or oxygen and thus are more economical compared to the hydrogenolysis or oxidation of cellulose.This review article highlights recent advances in the development of novel catalysts or catalytic processes for the conversion of cellulose and its derived carbohydrates into HMF,levulinic acid,and lactic acid or their esters under inert atmosphere.We also analyze efficient catalytic systems for HMF production,in particular Lewis acids combined with ionic liquid or biphasic systems.For the formations of levulinic and lactic acids or their esters,we focus on the reactions in aqueous and alcohol media catalyzed by multifunctional catalysts that combine the functions of hydrolysis,isomerization,and dehydration-rehydration or retro-aldol reactions.The reaction mechanism for each process will also be discussed to gain insights into the activation of C–O and C–C bonds in the absence of hydrogen or oxygen.
基金supported by the National Natural Science Foundation of China(51873223 and 22075154)the Natural Science Foundation of Zhejiang Province(LY19B040001)。
文摘Thermo-responsive shape memory hydrogels generally achieve shape fixation at low temperatures,and shape recovery at high temperatures.However,these hydrogels usually suffer from poor mechanical properties.Herein,we present a unique poly(acrylic acid)/calcium acetate shape memory hydrogel with cold-induced shape recovery performances as ultrastrong artificial muscles.Since the acetate groups could form aggregate at high temperatures and thus induce the association of the hydrogel network,the hydrogel can be fixed into a temporary shape upon heating and recover to its original shape in a cold environment.Moreover,a programmable shape recovery process is realized by adjusting the shape fixing time.In addition,the unique shape memory process enables the application demonstration as bio-inspired artificial muscles with an ultrahigh work density of45.2 kJ m^(-3),higher than that of biological muscles(~8 kJ m^(-3)).
