Based on the chiral ligand exchange, the distribution behavior of mandelic acid enantiomers, and the partition of Cu2+ at different pH values were studied in a water/alcohol two-phase system containing Cu2+ and N-n-（...Based on the chiral ligand exchange, the distribution behavior of mandelic acid enantiomers, and the partition of Cu2+ at different pH values were studied in a water/alcohol two-phase system containing Cu2+ and N-n-（dodecyl-L-proline（A）.） The influences of the solvent sort, the pH value, the concentrations of Cu2+ and chiral ligand on the partition coefficient（K） and separation factor（α） were discussed. The experimental results show that the A formed has more stable ternary complex with D-mandelic acid enantiomer than with L-mandelic acid enantiomer. There is an important influence of the pH value on K and α. When the pH values are less than 3.5, the formation of binary complexes is thermodynamically unfavourable. K and α become maximum when pH values are above 3.5 and the molar ratio of the chiral ligand to Cu2+ is 2∶1.展开更多
Distribution behavior of ketoprofen enantiomers was examined in methanol aqueous and organic solvent mixture containing tartaric esters. The influence of length of alkyl chain of tartaric esters, concentration of L-ta...Distribution behavior of ketoprofen enantiomers was examined in methanol aqueous and organic solvent mixture containing tartaric esters. The influence of length of alkyl chain of tartaric esters, concentration of L-tartaric esters and methanol aqueous, kind of organic solvent on partition ratio and separation factors was investigated. The results show that L-tartaric and D-tartaric esters have different chiral recognition abilities. S-ketoprofen is easily extracted by L-tartaric esters, and R-ketoprofen is easily extracted by D-tartaric esters. L-tartaric esters form more stable diastereomeric complexes with S-enantiomer than that with R-enantiomer. This distribution behavior is consistent with chiral recognition mechanism. With the increase of the concentration of tartaric ester from 0 to 0.3 mol/L, partition coefficient K and separation factor a increase. Also, the kind of organic solvent and the concentration of the methanol aqueous have significant influence on K and a.展开更多
The kinetics of the extraction of phenylsuccinic acid(PSA) enantiomers by hydroxypropyl-β-cyclodextrin(HP-β-CD) in a modified Lewis cell was studied,in which HP-β-CD dissolved in 0.1 mol L-1 NaH2PO4/H3PO4 buffer so...The kinetics of the extraction of phenylsuccinic acid(PSA) enantiomers by hydroxypropyl-β-cyclodextrin(HP-β-CD) in a modified Lewis cell was studied,in which HP-β-CD dissolved in 0.1 mol L-1 NaH2PO4/H3PO4 buffer solution(pH = 2.5) was selected as the chiral extractant.PSA enantiomers were extracted from organic phase to aqueous phase in the extraction module.The theory of extraction accompanied by a chemical reaction has been used to obtain the intrinsic kinetics of this extraction module.The different parameters affecting the extraction rate such as agitation speed,interfacial area,initial concentration of PSA enantiomers in organic phase as well as HP-β-CD concentration in aqueous phase were separately studied.The experimental results demonstrate that the extraction reactions are fast.The reactions were found to be first order with respect to PSA and second order with respect to HP-β-CD with forward rate constants of 3.4 × 10-2 m6 mol-2 s-1 for R-PSA and 9.96 × 10?3 m6 mol-2 s-1 for S-PSA.These data will be useful in the design of extraction processes.展开更多
Reactive extraction is an emerging technology for large-scale continuous resolution of drug enantiomers. The enantioselective extraction of R,S-naproxen by hydrophilic HP-β-CD in 1,2-dichloroethane was studied at 5℃...Reactive extraction is an emerging technology for large-scale continuous resolution of drug enantiomers. The enantioselective extraction of R,S-naproxen by hydrophilic HP-β-CD in 1,2-dichloroethane was studied at 5℃. The experimental data were described by a reactive extraction model with a homogeneous aqueous phase reaction of R,S-naproxen with HP-β-CD which couples a complete description of chemical equilibria in aqueous phase with the overall phase equilibria of the system. Important parameters of this model were determined experimentally. The physical distribution coefficients for molecular and ionic NAP were 0.041 and 1.730, respectively. Here we show that the efficiency of extraction depends strongly on two process variables including pH and HP-β-CD concentration. The model predictions are compared graphically with the results of pre- vious experiments and there is a good agreement between each other. By the use of modeling and experiment, an optimized extraction condition with pH of 2.5 and HP-β-CD concentration of 0.1 mol/L was obtained with high enantioselectivity （a） of 1.59 and performance factor （pf） of 0,049. The model gives a good means of predicting enantiomers partitioning over a range of experimental conditions.展开更多
Cellulose tris(4-methylphenylcarbamate), amylosetris(3,5-di-methylphenylcarbamate) and amylose tris (phenylcarbamate) were prepared by the methodreported by Okamoto and were coated onto an aminopropylated mesoporous s...Cellulose tris(4-methylphenylcarbamate), amylosetris(3,5-di-methylphenylcarbamate) and amylose tris (phenylcarbamate) were prepared by the methodreported by Okamoto and were coated onto an aminopropylated mesoporous spherical silica gel. Thesefinal products were used as chiral stationary phases of high performance liquid chromatography forthe eighteen structurally related biphenyl compounds. The resolution was made using normal-phasemethodology with a mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol, 2-pro-panol or1-butanol). The effects of various aliphatic alcohols in the mobile phase were studied. Thestructural features of the solutes that influence then- k′ were discussed. A dominant effect oftrifluoroacetic acid on chiral separation of acidic solutes was noted.展开更多
Based on chiral ligand exchange, the distribution behavior of mandelic acid enantiomers in the two-phase system containing copper ion(Ⅱ)(Cu2+) and N-n-dedecane-L-hydroxyproline (L), was studied. At different pH, the ...Based on chiral ligand exchange, the distribution behavior of mandelic acid enantiomers in the two-phase system containing copper ion(Ⅱ)(Cu2+) and N-n-dedecane-L-hydroxyproline (L), was studied. At different pH, the partition of Cu2+ in the two-phase system containing N-n-dedecane-L-hydroxyproline, was investigated. The formation constant of binary cpmplex(Li2Cu) was obtained by regression. The influence of pH, concentrations of Cu2+ and chiral ligand, and solvents on partition coefficients(K) and separation factor(α), was discussed. The experimental results show that Li forms more stable ternary complex with D-mandelic acid than with L- mandelic acid. There is a large influence of pH on K and α. At low pH values (<3.5), formation of binary complexes is thermodynamically unfavourable. K and α are best when pH values are above 3.5 and the molar ratio of chiral ligand to Cu2+ is 2:1. At the same time, solvents influence K and α very much.展开更多
Distribution behavior of mandelic acid enantiomers was examined in a two-phase aqueous-organic solvent mixture containing L-tartaric esters. The influences of pH, length of alkyl chain of L-tartraic esters, organic so...Distribution behavior of mandelic acid enantiomers was examined in a two-phase aqueous-organic solvent mixture containing L-tartaric esters. The influences of pH, length of alkyl chain of L-tartraic esters, organic solvents and concentrations of phosphate salt on partition coefficient(K) and separation factor(α) were investigated. The results show that L-tartaric esters studied all form more stable diastereomeric complexes with D-enantiomer than with L-enantiomer. With rise of pH, K decrease, but α increase. With addition of length of alkyl chain of L-tartaric esters, K and α decrease. Organic solvents and concentrations of phosphate salt also show a great influence on K and α. K L, K D and α are 2.523, 2.674 and 1.06, respectively, when mandelic acid enantiomers were extracted by di-O-pentyl-L-tartaric ester in n-decanol at pH=2.3.展开更多
基金Project(20376085) supported by the National Natural Science Foundation of China
文摘Based on the chiral ligand exchange, the distribution behavior of mandelic acid enantiomers, and the partition of Cu2+ at different pH values were studied in a water/alcohol two-phase system containing Cu2+ and N-n-（dodecyl-L-proline（A）.） The influences of the solvent sort, the pH value, the concentrations of Cu2+ and chiral ligand on the partition coefficient（K） and separation factor（α） were discussed. The experimental results show that the A formed has more stable ternary complex with D-mandelic acid enantiomer than with L-mandelic acid enantiomer. There is an important influence of the pH value on K and α. When the pH values are less than 3.5, the formation of binary complexes is thermodynamically unfavourable. K and α become maximum when pH values are above 3.5 and the molar ratio of the chiral ligand to Cu2+ is 2∶1.
基金Project(20376085) supportecd by the National Natural Science Foundation of China
文摘Distribution behavior of ketoprofen enantiomers was examined in methanol aqueous and organic solvent mixture containing tartaric esters. The influence of length of alkyl chain of tartaric esters, concentration of L-tartaric esters and methanol aqueous, kind of organic solvent on partition ratio and separation factors was investigated. The results show that L-tartaric and D-tartaric esters have different chiral recognition abilities. S-ketoprofen is easily extracted by L-tartaric esters, and R-ketoprofen is easily extracted by D-tartaric esters. L-tartaric esters form more stable diastereomeric complexes with S-enantiomer than that with R-enantiomer. This distribution behavior is consistent with chiral recognition mechanism. With the increase of the concentration of tartaric ester from 0 to 0.3 mol/L, partition coefficient K and separation factor a increase. Also, the kind of organic solvent and the concentration of the methanol aqueous have significant influence on K and a.
基金supported by the National Natural Science Foundation of China (20976041)Program for New Century Excellent Talents in University,Hunan Provincial Natural Science Foundation of China (10JJ1004)the Open Fund Project of Key Laboratory in Hunan University (09K095)
文摘The kinetics of the extraction of phenylsuccinic acid(PSA) enantiomers by hydroxypropyl-β-cyclodextrin(HP-β-CD) in a modified Lewis cell was studied,in which HP-β-CD dissolved in 0.1 mol L-1 NaH2PO4/H3PO4 buffer solution(pH = 2.5) was selected as the chiral extractant.PSA enantiomers were extracted from organic phase to aqueous phase in the extraction module.The theory of extraction accompanied by a chemical reaction has been used to obtain the intrinsic kinetics of this extraction module.The different parameters affecting the extraction rate such as agitation speed,interfacial area,initial concentration of PSA enantiomers in organic phase as well as HP-β-CD concentration in aqueous phase were separately studied.The experimental results demonstrate that the extraction reactions are fast.The reactions were found to be first order with respect to PSA and second order with respect to HP-β-CD with forward rate constants of 3.4 × 10-2 m6 mol-2 s-1 for R-PSA and 9.96 × 10?3 m6 mol-2 s-1 for S-PSA.These data will be useful in the design of extraction processes.
基金supported by the National Natural Science Foundation of China (20976041)Program for New Century Excellent Talents in University,Hunan Provincial Natural Science Foundation (10JJ1004)+1 种基金Aid Program for Science and Technology Innovative Research Team in Higher Educational Instituions of Hunan Provincethe Open Fund Project of Key Laboratory in Hunan University (09K095)
文摘Reactive extraction is an emerging technology for large-scale continuous resolution of drug enantiomers. The enantioselective extraction of R,S-naproxen by hydrophilic HP-β-CD in 1,2-dichloroethane was studied at 5℃. The experimental data were described by a reactive extraction model with a homogeneous aqueous phase reaction of R,S-naproxen with HP-β-CD which couples a complete description of chemical equilibria in aqueous phase with the overall phase equilibria of the system. Important parameters of this model were determined experimentally. The physical distribution coefficients for molecular and ionic NAP were 0.041 and 1.730, respectively. Here we show that the efficiency of extraction depends strongly on two process variables including pH and HP-β-CD concentration. The model predictions are compared graphically with the results of pre- vious experiments and there is a good agreement between each other. By the use of modeling and experiment, an optimized extraction condition with pH of 2.5 and HP-β-CD concentration of 0.1 mol/L was obtained with high enantioselectivity （a） of 1.59 and performance factor （pf） of 0,049. The model gives a good means of predicting enantiomers partitioning over a range of experimental conditions.
文摘Cellulose tris(4-methylphenylcarbamate), amylosetris(3,5-di-methylphenylcarbamate) and amylose tris (phenylcarbamate) were prepared by the methodreported by Okamoto and were coated onto an aminopropylated mesoporous spherical silica gel. Thesefinal products were used as chiral stationary phases of high performance liquid chromatography forthe eighteen structurally related biphenyl compounds. The resolution was made using normal-phasemethodology with a mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol, 2-pro-panol or1-butanol). The effects of various aliphatic alcohols in the mobile phase were studied. Thestructural features of the solutes that influence then- k′ were discussed. A dominant effect oftrifluoroacetic acid on chiral separation of acidic solutes was noted.
文摘Based on chiral ligand exchange, the distribution behavior of mandelic acid enantiomers in the two-phase system containing copper ion(Ⅱ)(Cu2+) and N-n-dedecane-L-hydroxyproline (L), was studied. At different pH, the partition of Cu2+ in the two-phase system containing N-n-dedecane-L-hydroxyproline, was investigated. The formation constant of binary cpmplex(Li2Cu) was obtained by regression. The influence of pH, concentrations of Cu2+ and chiral ligand, and solvents on partition coefficients(K) and separation factor(α), was discussed. The experimental results show that Li forms more stable ternary complex with D-mandelic acid than with L- mandelic acid. There is a large influence of pH on K and α. At low pH values (<3.5), formation of binary complexes is thermodynamically unfavourable. K and α are best when pH values are above 3.5 and the molar ratio of chiral ligand to Cu2+ is 2:1. At the same time, solvents influence K and α very much.
文摘Distribution behavior of mandelic acid enantiomers was examined in a two-phase aqueous-organic solvent mixture containing L-tartaric esters. The influences of pH, length of alkyl chain of L-tartraic esters, organic solvents and concentrations of phosphate salt on partition coefficient(K) and separation factor(α) were investigated. The results show that L-tartaric esters studied all form more stable diastereomeric complexes with D-enantiomer than with L-enantiomer. With rise of pH, K decrease, but α increase. With addition of length of alkyl chain of L-tartaric esters, K and α decrease. Organic solvents and concentrations of phosphate salt also show a great influence on K and α. K L, K D and α are 2.523, 2.674 and 1.06, respectively, when mandelic acid enantiomers were extracted by di-O-pentyl-L-tartaric ester in n-decanol at pH=2.3.
