The formation of metal cation complexes between o-phenylenediamine with metal ions, Ni2+, Cu2+, Zn2+, Pb2+ and Cr3+ were studied in the dimethylformamide/water(DMF/H2O), acetonitrile/water(AN/H2O) and ethanol/water(Et...The formation of metal cation complexes between o-phenylenediamine with metal ions, Ni2+, Cu2+, Zn2+, Pb2+ and Cr3+ were studied in the dimethylformamide/water(DMF/H2O), acetonitrile/water(AN/H2O) and ethanol/water(EtOH/H2O) binary systems using square wave polarography (SWP) technique. The stoichiometry and stability of the complexes were determined by monitoring the shifts in half-waves or peak potentials of the polarographic waves of metal ions against the ligand concentration. In the most cases, the formation constants of complexes decreased with increasing amounts of H2O, DMF and EtOH in AN/H2O, DMF/H2O and EtOH/H2O binary systems, respectively. The stoichiometry of the complexes was found 1:1. The results obtained show that there is an inverse relationship between the formation constant of the complexes and the donor number of the solvents based on the Gatmann donocity scale. Also, the stability constants show a high sensitivity to the composition of the mixed solvent systems. In most of the systems investigated, Cr3+ cation forms a more stable complex with o-phenylenediamine than other four cations and the order of selectivity of this ligand for cations in pure water is:Cr3+>>Cu2+>Ni2+>Zn2+>Pb2+.展开更多
Three basic conditions for preparation of alternating copolymer with narrow molecular weight distribution were derived from the element kinetic equations of binary radical copolymerization. Using maleimide (MI) and at...Three basic conditions for preparation of alternating copolymer with narrow molecular weight distribution were derived from the element kinetic equations of binary radical copolymerization. Using maleimide (MI) and atropic acid (ATA) as model monomer pairs and dioxane as the solvent the alternating copolymer with molecular weight distribution in the range of 1.09-1.20 was prepared successfully by charger transfer complex (CTC) mechanism in the presence of benzoyl peroxide at 85 °C. The monomer reactivity ratioesr 1(MI) = 0.05±0.01 andr 2(ATA) = 0.03 ± 0.02 were measured. The alternating copolymerization was carried out through formation of a contact-type CTC and then alternating addition of MI and ATA monomers. The molecular weight of the copolymers is nearly independent of the feed ratio in a Iarge range and the polymerization rate dropped with an increase in ATA in feed ratio.展开更多
文摘The formation of metal cation complexes between o-phenylenediamine with metal ions, Ni2+, Cu2+, Zn2+, Pb2+ and Cr3+ were studied in the dimethylformamide/water(DMF/H2O), acetonitrile/water(AN/H2O) and ethanol/water(EtOH/H2O) binary systems using square wave polarography (SWP) technique. The stoichiometry and stability of the complexes were determined by monitoring the shifts in half-waves or peak potentials of the polarographic waves of metal ions against the ligand concentration. In the most cases, the formation constants of complexes decreased with increasing amounts of H2O, DMF and EtOH in AN/H2O, DMF/H2O and EtOH/H2O binary systems, respectively. The stoichiometry of the complexes was found 1:1. The results obtained show that there is an inverse relationship between the formation constant of the complexes and the donor number of the solvents based on the Gatmann donocity scale. Also, the stability constants show a high sensitivity to the composition of the mixed solvent systems. In most of the systems investigated, Cr3+ cation forms a more stable complex with o-phenylenediamine than other four cations and the order of selectivity of this ligand for cations in pure water is:Cr3+>>Cu2+>Ni2+>Zn2+>Pb2+.
基金Project supported by the National Natural Science Foundation of China (Grant No. 29634010-3)Doctor Training Foundation of State Education Ministry of China.
文摘Three basic conditions for preparation of alternating copolymer with narrow molecular weight distribution were derived from the element kinetic equations of binary radical copolymerization. Using maleimide (MI) and atropic acid (ATA) as model monomer pairs and dioxane as the solvent the alternating copolymer with molecular weight distribution in the range of 1.09-1.20 was prepared successfully by charger transfer complex (CTC) mechanism in the presence of benzoyl peroxide at 85 °C. The monomer reactivity ratioesr 1(MI) = 0.05±0.01 andr 2(ATA) = 0.03 ± 0.02 were measured. The alternating copolymerization was carried out through formation of a contact-type CTC and then alternating addition of MI and ATA monomers. The molecular weight of the copolymers is nearly independent of the feed ratio in a Iarge range and the polymerization rate dropped with an increase in ATA in feed ratio.
