A new C 2 symmetric chiral Schiff base compound A with relatively flexible chiral environment was synthesized from L (+) tartaric acid. Its structure was determined by NMR, IR, MS etc, and its preponderant conformatio...A new C 2 symmetric chiral Schiff base compound A with relatively flexible chiral environment was synthesized from L (+) tartaric acid. Its structure was determined by NMR, IR, MS etc, and its preponderant conformation was modeled by CS Chem 3D Program. The results showed that its structure is not in a plane and has a big chiral cavity. It was showed that the complex B has different catalytic performance in asymmetric cyclopropanation of styrene and DMHD (2,5 dimethyl 2,4 hexadiene) with diazoacetate. The catalytic mechanism was also discussed.展开更多
Bi-2-naphthol(BINOL) enantiomers were baseline resolved on HPLC network-polymeric chiral stationary phase (Kromasil CHI-DMB, based on O,O′-di(3,5-dimethylbenzoyl)N,N′-diallyl-L-tartaric diamide). The effects of the ...Bi-2-naphthol(BINOL) enantiomers were baseline resolved on HPLC network-polymeric chiral stationary phase (Kromasil CHI-DMB, based on O,O′-di(3,5-dimethylbenzoyl)N,N′-diallyl-L-tartaric diamide). The effects of the column temperature, the type and the concentration of the polar alcohol modifier in the binary mobile phase on the chiral resolution were examined. The separation value was 1.191 when V(hexane)∶V(2-propanol)=95∶5 was used as mobile phase at a flow rate of 1.0 mL/min at 25 ℃ with retention time being within 14 minutes. The mechanism of the chiral recognition was discussed with the calculated thermodynamic parameters. It is suggested that hydrogen bonding interaction between hydroxyl group of the solute and the CSP play important roles in chiral recognition. The chiral resolution is enthalpy-entropy driven and the enthalpy contribution is greater. 1,1′-Bi-2-naphthyl di-p-toluenesulfonate, 1,1′-bi-2-naphthyl diacetate and 1,1′-bi-2-naphthyl dicinnamate could not be resolved at experiment conditions used.展开更多
This study reports the feasibility of remediation of a heavy metal （HM） contaminated soil using tartaric acid, an environmentally-friendly extractant. Batch experiments were performed to test the factors influencing...This study reports the feasibility of remediation of a heavy metal （HM） contaminated soil using tartaric acid, an environmentally-friendly extractant. Batch experiments were performed to test the factors influencing remediation of the HM contaminated soil. An empirical model was employed to describe the kinetics of riM dissolution/desorption and to predict equilibrium concentrations of HMs in soil leachate. The changes of HMs in different fractions before and after tartaric acid treatment were also investigated. Tartaric acid solution containing HMs was regenerated by chestnut shells. Results show that utilization of tartaric acid was effective for removal of riMs from the contaminated soil, attaining 50%-60% of Cd, 40%-50% of Pb, 40%-50% of Cu and 20%-30% of Zn in the pH range of 3.5-4.0 within 24 h. Mass transfer coefficients for cadmium （Cd） and lead （Pb） were much higher than those for copper （Cu） and zinc （Zn）. Sequential fractionations of treated and untreated soil samples showed that tartaric acid was effective in removing the exchangeable, carbonate fractions of Cd, Zn and Cu from the contaminated soil. The contents of Pb and Cu in Fe-Mn oxide fraciton were also significantly decreased by tartaric acid treatment. One hundred milliliters of tartaric acid solution containing HMs could be regenerated by 10 g chestnut shells in a batch reactor. Such a remediation procedure indicated that tartaric acid is a promising agent for remediation of HM contaminated soils. However, further research is needed before the method can be practically used for in situ remediation of contaminated sites.展开更多
文摘A new C 2 symmetric chiral Schiff base compound A with relatively flexible chiral environment was synthesized from L (+) tartaric acid. Its structure was determined by NMR, IR, MS etc, and its preponderant conformation was modeled by CS Chem 3D Program. The results showed that its structure is not in a plane and has a big chiral cavity. It was showed that the complex B has different catalytic performance in asymmetric cyclopropanation of styrene and DMHD (2,5 dimethyl 2,4 hexadiene) with diazoacetate. The catalytic mechanism was also discussed.
文摘Bi-2-naphthol(BINOL) enantiomers were baseline resolved on HPLC network-polymeric chiral stationary phase (Kromasil CHI-DMB, based on O,O′-di(3,5-dimethylbenzoyl)N,N′-diallyl-L-tartaric diamide). The effects of the column temperature, the type and the concentration of the polar alcohol modifier in the binary mobile phase on the chiral resolution were examined. The separation value was 1.191 when V(hexane)∶V(2-propanol)=95∶5 was used as mobile phase at a flow rate of 1.0 mL/min at 25 ℃ with retention time being within 14 minutes. The mechanism of the chiral recognition was discussed with the calculated thermodynamic parameters. It is suggested that hydrogen bonding interaction between hydroxyl group of the solute and the CSP play important roles in chiral recognition. The chiral resolution is enthalpy-entropy driven and the enthalpy contribution is greater. 1,1′-Bi-2-naphthyl di-p-toluenesulfonate, 1,1′-bi-2-naphthyl diacetate and 1,1′-bi-2-naphthyl dicinnamate could not be resolved at experiment conditions used.
文摘This study reports the feasibility of remediation of a heavy metal （HM） contaminated soil using tartaric acid, an environmentally-friendly extractant. Batch experiments were performed to test the factors influencing remediation of the HM contaminated soil. An empirical model was employed to describe the kinetics of riM dissolution/desorption and to predict equilibrium concentrations of HMs in soil leachate. The changes of HMs in different fractions before and after tartaric acid treatment were also investigated. Tartaric acid solution containing HMs was regenerated by chestnut shells. Results show that utilization of tartaric acid was effective for removal of riMs from the contaminated soil, attaining 50%-60% of Cd, 40%-50% of Pb, 40%-50% of Cu and 20%-30% of Zn in the pH range of 3.5-4.0 within 24 h. Mass transfer coefficients for cadmium （Cd） and lead （Pb） were much higher than those for copper （Cu） and zinc （Zn）. Sequential fractionations of treated and untreated soil samples showed that tartaric acid was effective in removing the exchangeable, carbonate fractions of Cd, Zn and Cu from the contaminated soil. The contents of Pb and Cu in Fe-Mn oxide fraciton were also significantly decreased by tartaric acid treatment. One hundred milliliters of tartaric acid solution containing HMs could be regenerated by 10 g chestnut shells in a batch reactor. Such a remediation procedure indicated that tartaric acid is a promising agent for remediation of HM contaminated soils. However, further research is needed before the method can be practically used for in situ remediation of contaminated sites.
