In this study, we modified microcrystalline cellulose by cross-linking it with epichlorohydrin to obtain a rapid and efficient adsorbent for the removal of Reactive Blue 4 dye from aqueous solution. Evidences of the c...In this study, we modified microcrystalline cellulose by cross-linking it with epichlorohydrin to obtain a rapid and efficient adsorbent for the removal of Reactive Blue 4 dye from aqueous solution. Evidences of the cross-linking of the microcrystalline cellulose were obtained by Fourier transform infrared spectroscopy, X-ray diff raction, Brunauer–Emmett–Teller analysis, thermogravimetric analysis, and scanning electron microscopy. We investigated the eff ects of adsorbent dosage, p H, initial dye concentration, temperature, and contact time on the dye adsorption capacity. The results showed that the adsorption equilibrium time was just 20 min and the maximum adsorption capacity was 69.79 mg/g. The adsorption isotherm data fitted the Langmuir isotherm model well, and the adsorption kinetics data followed the pseudo-second-order kinetic model. The results of the thermodynamic analysis suggest that the adsorption process was spontaneous and exothermic. Recyclability experiments demonstrated the good reusability of this adsorbent. Electrostatic interaction was found to dominate the adsorption process.展开更多
1 INTRODUCTIONIn literature,most matrices of affinity chromatography for urokinase(EC 3.4.99.26)purification were prepared by cyanogen bromide activation.However,theseadsorbents usually suffered from the drawback of l...1 INTRODUCTIONIn literature,most matrices of affinity chromatography for urokinase(EC 3.4.99.26)purification were prepared by cyanogen bromide activation.However,theseadsorbents usually suffered from the drawback of leakage of the ligand,particularly inalkaline medium,because of the instability of the isourea linkage between the ligandand the spacer or agarose.Moreover,the positively charged imido group of theN-substituted isourea derivative and the hydrophobicity of the spacers might promotenonspecific adsorption.On the contrary,the adsorbents prepared by the method展开更多
The aim of this study was to develop a simple and derivatization free method for the Quantification of S-Epichlorohydrin in R-Epichlorohydrin by using a gas chromatography coupled with flame ionization detector (FID)....The aim of this study was to develop a simple and derivatization free method for the Quantification of S-Epichlorohydrin in R-Epichlorohydrin by using a gas chromatography coupled with flame ionization detector (FID). Enantiopure epichlorohydrin was a valuable epoxide key starting material for preparing optically active Rivaroxaban. The enantiomeric separations of S-Epichlorohydrin and R-Epichlorohydrin were achieved on Gamaa-Dex-225 (30 meters × 0.25 mm I.D, 0.25 μm) column with a total run time of 30 min. Nitrogen was used as a carrier gas with constant pressure 25.0 psi. The critical experimental parameters such as, column selection, flow rate, injection volume and diluent were studied and optimized. Excellent correlation coeffient between peak responses and concentrations was >0.9998. The recoveries of S-Epichlorohydrin spiked in R-Epichlorohydrin were in the range from 98.2% to 102.8%. Limit of quantitation for S-Epichlorohydrin was sufficiently lower than limits specified by ICH. The method has validated as per International Conference on Harmonization (ICH) guidelines. A precise, accurate, linear and robust Gas Chromatography method was developed for the quantification of S-Epichlorohydrin in R-Epichlorohydrin for Rivaroxaban.展开更多
Different proportions of β-cydodextrin and epichlorohydrin were used to prepare a group of β-cyclodextrin polymers. The relationship between the reaction extent and the molar ratios of reactants was discussed accord...Different proportions of β-cydodextrin and epichlorohydrin were used to prepare a group of β-cyclodextrin polymers. The relationship between the reaction extent and the molar ratios of reactants was discussed according to the results of ~1H-NMR, ^(13) C-NMR spectra and elemental analysis. Especially, high resolution ~1H-NMR spectra were usd for studying the reaction active sites and the extent of reaction. The solubility of oil soluble drugs in water was largely improved in the presence of water-soluble β-cyclodextrin polymer.展开更多
Copolymerization of carbon dioxide with epichlorohydrin was successfully carried out by usingNd(P_(204))_3-Al(i-Bu)_3 as catalyst (P_(204))=(RO)_2 POO--,R=CH_3 (CH_2),CH(C_2H_5) CH_2--). Addi-tion of carbonyl compound...Copolymerization of carbon dioxide with epichlorohydrin was successfully carried out by usingNd(P_(204))_3-Al(i-Bu)_3 as catalyst (P_(204))=(RO)_2 POO--,R=CH_3 (CH_2),CH(C_2H_5) CH_2--). Addi-tion of carbonyl compounds into the catalyst decreased the carbon dioxide content of the copoly-mer to some extent. Compared to nonpolar solvents, ethereal and moderate polar solvents werefavourable to obtaining higher carbon dioxide content copolymer. The coincidence of these resultswith the assumed copolymerization scheme clearly indicated that the copolymerization proceeds via coordinate anionic mechanism.展开更多
novel complex composed of chitosan(CS) and neodymium(Nd ) was preparedand the ring opening polymerization of epichlorohydrin(ECH) with a new catalyticsystem comprising this new rare earth polymer complex(CS . Nd) has ...novel complex composed of chitosan(CS) and neodymium(Nd ) was preparedand the ring opening polymerization of epichlorohydrin(ECH) with a new catalyticsystem comprising this new rare earth polymer complex(CS . Nd) has been suc-cessfully carried out for the first time. It has been found that the new catalytic sys-tem composed of CS . Nd-AI (i-Bui,-methyl benzoxylate( Ⅲ) is an excellent cata-lyst for the polymerization of epichlorohydrin which shows a catalytic activity 60times higher tlian that of conventional rare earth catalyst. Under the following re-action conditions : Nd - 1 ×10￣(-6) mo1/g monomer, A1/Nd= 60 molar ratio , Ⅲ/A1=-0. 6 molar ratio, the monomer conversion and PECH molecular weight are as highas 92.9% and 28. 2 × 10￣5 respectively and the polymer prepared has a low crys-tallinity. The kinetics investigation revealed that the polymerization has a short in-duction period of several minutes and the rate of polymerization is of first orderwith respect to the monomer concentration and the catalyst concentration. The acti-vation energy of the polymerization reaction was found to be 25. 5 kJ/mol which islower than that of conimon rare earth catalvst.展开更多
The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin. Certain amount of pre-crosslinking agent was added to form chitosan gels by tra...The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin. Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization. Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads. The effects of reaction conditions, such as crosslinking time, the amount of crosslinking agent and the NaOH concentration, on the physical properties of the chitosan beads were investigated. The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde. The capacity for copper ions is as high as 40mg/g. The beads have good mechanical strength and can be reused.展开更多
Epichlorohydrin (ECH) was polymerized with a rare earth catalytic system: Nd (i-OPr)_3-Al (i-Bu)_3. The effects of Al/Nd molar ratio, solvents, the polymerization time and temperature,the aging time and temperature of...Epichlorohydrin (ECH) was polymerized with a rare earth catalytic system: Nd (i-OPr)_3-Al (i-Bu)_3. The effects of Al/Nd molar ratio, solvents, the polymerization time and temperature,the aging time and temperature of the catalyst preparation were studied. The results showed thatat a low Al/Nd molar ratio (4) of the Nd(i-OPr)_3-Al(i-Bu)_3 system ECH polymerized at a lowtemperature (248K) with a high conversion. The average molecular weight ofpolyepichlorohydrin (PECH) ranged from 1×10~5 to 3×10~5.展开更多
文摘In this study, we modified microcrystalline cellulose by cross-linking it with epichlorohydrin to obtain a rapid and efficient adsorbent for the removal of Reactive Blue 4 dye from aqueous solution. Evidences of the cross-linking of the microcrystalline cellulose were obtained by Fourier transform infrared spectroscopy, X-ray diff raction, Brunauer–Emmett–Teller analysis, thermogravimetric analysis, and scanning electron microscopy. We investigated the eff ects of adsorbent dosage, p H, initial dye concentration, temperature, and contact time on the dye adsorption capacity. The results showed that the adsorption equilibrium time was just 20 min and the maximum adsorption capacity was 69.79 mg/g. The adsorption isotherm data fitted the Langmuir isotherm model well, and the adsorption kinetics data followed the pseudo-second-order kinetic model. The results of the thermodynamic analysis suggest that the adsorption process was spontaneous and exothermic. Recyclability experiments demonstrated the good reusability of this adsorbent. Electrostatic interaction was found to dominate the adsorption process.
基金Supported by the National Natural Science Foundation of China.
文摘1 INTRODUCTIONIn literature,most matrices of affinity chromatography for urokinase(EC 3.4.99.26)purification were prepared by cyanogen bromide activation.However,theseadsorbents usually suffered from the drawback of leakage of the ligand,particularly inalkaline medium,because of the instability of the isourea linkage between the ligandand the spacer or agarose.Moreover,the positively charged imido group of theN-substituted isourea derivative and the hydrophobicity of the spacers might promotenonspecific adsorption.On the contrary,the adsorbents prepared by the method
文摘The aim of this study was to develop a simple and derivatization free method for the Quantification of S-Epichlorohydrin in R-Epichlorohydrin by using a gas chromatography coupled with flame ionization detector (FID). Enantiopure epichlorohydrin was a valuable epoxide key starting material for preparing optically active Rivaroxaban. The enantiomeric separations of S-Epichlorohydrin and R-Epichlorohydrin were achieved on Gamaa-Dex-225 (30 meters × 0.25 mm I.D, 0.25 μm) column with a total run time of 30 min. Nitrogen was used as a carrier gas with constant pressure 25.0 psi. The critical experimental parameters such as, column selection, flow rate, injection volume and diluent were studied and optimized. Excellent correlation coeffient between peak responses and concentrations was >0.9998. The recoveries of S-Epichlorohydrin spiked in R-Epichlorohydrin were in the range from 98.2% to 102.8%. Limit of quantitation for S-Epichlorohydrin was sufficiently lower than limits specified by ICH. The method has validated as per International Conference on Harmonization (ICH) guidelines. A precise, accurate, linear and robust Gas Chromatography method was developed for the quantification of S-Epichlorohydrin in R-Epichlorohydrin for Rivaroxaban.
基金The project is supported by National Natural Science Foundation of China
文摘Different proportions of β-cydodextrin and epichlorohydrin were used to prepare a group of β-cyclodextrin polymers. The relationship between the reaction extent and the molar ratios of reactants was discussed according to the results of ~1H-NMR, ^(13) C-NMR spectra and elemental analysis. Especially, high resolution ~1H-NMR spectra were usd for studying the reaction active sites and the extent of reaction. The solubility of oil soluble drugs in water was largely improved in the presence of water-soluble β-cyclodextrin polymer.
文摘Copolymerization of carbon dioxide with epichlorohydrin was successfully carried out by usingNd(P_(204))_3-Al(i-Bu)_3 as catalyst (P_(204))=(RO)_2 POO--,R=CH_3 (CH_2),CH(C_2H_5) CH_2--). Addi-tion of carbonyl compounds into the catalyst decreased the carbon dioxide content of the copoly-mer to some extent. Compared to nonpolar solvents, ethereal and moderate polar solvents werefavourable to obtaining higher carbon dioxide content copolymer. The coincidence of these resultswith the assumed copolymerization scheme clearly indicated that the copolymerization proceeds via coordinate anionic mechanism.
文摘novel complex composed of chitosan(CS) and neodymium(Nd ) was preparedand the ring opening polymerization of epichlorohydrin(ECH) with a new catalyticsystem comprising this new rare earth polymer complex(CS . Nd) has been suc-cessfully carried out for the first time. It has been found that the new catalytic sys-tem composed of CS . Nd-AI (i-Bui,-methyl benzoxylate( Ⅲ) is an excellent cata-lyst for the polymerization of epichlorohydrin which shows a catalytic activity 60times higher tlian that of conventional rare earth catalyst. Under the following re-action conditions : Nd - 1 ×10￣(-6) mo1/g monomer, A1/Nd= 60 molar ratio , Ⅲ/A1=-0. 6 molar ratio, the monomer conversion and PECH molecular weight are as highas 92.9% and 28. 2 × 10￣5 respectively and the polymer prepared has a low crys-tallinity. The kinetics investigation revealed that the polymerization has a short in-duction period of several minutes and the rate of polymerization is of first orderwith respect to the monomer concentration and the catalyst concentration. The acti-vation energy of the polymerization reaction was found to be 25. 5 kJ/mol which islower than that of conimon rare earth catalvst.
基金The Natural Science Foundation of China (No. 20025617)
文摘The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin. Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization. Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads. The effects of reaction conditions, such as crosslinking time, the amount of crosslinking agent and the NaOH concentration, on the physical properties of the chitosan beads were investigated. The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde. The capacity for copper ions is as high as 40mg/g. The beads have good mechanical strength and can be reused.
基金This work is supported by the National Natural Science Foundation of China
文摘Epichlorohydrin (ECH) was polymerized with a rare earth catalytic system: Nd (i-OPr)_3-Al (i-Bu)_3. The effects of Al/Nd molar ratio, solvents, the polymerization time and temperature,the aging time and temperature of the catalyst preparation were studied. The results showed thatat a low Al/Nd molar ratio (4) of the Nd(i-OPr)_3-Al(i-Bu)_3 system ECH polymerized at a lowtemperature (248K) with a high conversion. The average molecular weight ofpolyepichlorohydrin (PECH) ranged from 1×10~5 to 3×10~5.
