By means of acid-base potentiometric titration and the advanced BEST computer program developed by Martell et al., the deprotonation constants of four inhibitors[Aminotrimethylenephosphoinic acid(ATMP), 2-phosphino-tu...By means of acid-base potentiometric titration and the advanced BEST computer program developed by Martell et al., the deprotonation constants of four inhibitors[Aminotrimethylenephosphoinic acid(ATMP), 2-phosphino-tutane-1,2,4-tricarboxylic acid(PBTCA), polyacrylic acid(PAA, M_w=2000), poly(maleic, acrylic) acid(PMAAA, M_w=3000)], and the stability constants of the complexes of these inhibitors with Ca 2+ have been determined. And the distribution curves of ATMP at different pH values in aqueous solutions have also been given out. The result of this study can be applied to explaining the inhibition mechanism.展开更多
In this paper the Bi? ligand(pyridine 2 carboxylic acid) system was studied by direct current sampled polarography (DC _ TAST) at a fixed ratio of total ligand to total metal concentration and changing pH. The polarog...In this paper the Bi? ligand(pyridine 2 carboxylic acid) system was studied by direct current sampled polarography (DC _ TAST) at a fixed ratio of total ligand to total metal concentration and changing pH. The polarographic experimental complex formation curve (ECFC) and the theoretical complex formation curve (TCFC) were used for modelling the metal ligand system and optimizing stability constants. The ECFC, in which experimental parameters of polarography are included (a shift in a half wave potential and a variation in a diffusion controlled limiting current), appears to be a characteristic function for a particular metal ligand system. The TCFC is a theoretical curve calculated for the designed metal ligand model from mass balance equation. Five bismuth complexes MHL, ML, ML2, ML3 and ML3(OH) with their stability constants as logβ 7.54± 0.10, 7.50± 0.02, 13.91± 0.04, 18.15± 0.03 and 26.75± 0.02, respectively, are reported.展开更多
本文用示差脉冲极谱技术研究Pb(Ⅱ) 络合剂(β N 三丙酸)体系。依据实验得到的极谱峰电位的移动随溶液pH值的变化关系曲线,建立合适的金属络合物体系模型。用计算机分析程序,通过求解体系的质量平衡方程及拟合实验络合物形成曲线,优化...本文用示差脉冲极谱技术研究Pb(Ⅱ) 络合剂(β N 三丙酸)体系。依据实验得到的极谱峰电位的移动随溶液pH值的变化关系曲线,建立合适的金属络合物体系模型。用计算机分析程序,通过求解体系的质量平衡方程及拟合实验络合物形成曲线,优化得到金属络合物的稳定常数。计算机分析结果表明,在所研究的pH值范围内,溶液中存在四种金属络合物:PbH2L+、PbHL、PbL-、PbL(OH)2-,其稳定常数(logβ)分别为:16.23±0.04、12.42±0.01、4.11±0.05、9.43±0.02。展开更多
The dissociation constants of polyepoxysuccinic acid(PESA)were investigated in this study.Based on the potentiometric titration and the BEST program,the dissociation constants of PESA were determined.Considering the c...The dissociation constants of polyepoxysuccinic acid(PESA)were investigated in this study.Based on the potentiometric titration and the BEST program,the dissociation constants of PESA were determined.Considering the complexity of the dissociation of PESA in aqueous solution,several models were constructed to simulate the dissociation process of PESA.By comparison,the dissociation constants of PESA were obtained with model 4.The species distribution of PESA in aqueous solution as a function of pH was also presented according to the experimental and calculation results.It showed that the H_(2)L model with five basic structure units to describe the dissociation of PESA was reasonable,and the relevant constants had less error and better matching between the experimental and calculation data.The corresponding values of pK_(ai) were 4.68 and 4.92,respectively,for H2L at 35℃ with ionic strength of 0.1 mol/L.展开更多
文摘By means of acid-base potentiometric titration and the advanced BEST computer program developed by Martell et al., the deprotonation constants of four inhibitors[Aminotrimethylenephosphoinic acid(ATMP), 2-phosphino-tutane-1,2,4-tricarboxylic acid(PBTCA), polyacrylic acid(PAA, M_w=2000), poly(maleic, acrylic) acid(PMAAA, M_w=3000)], and the stability constants of the complexes of these inhibitors with Ca 2+ have been determined. And the distribution curves of ATMP at different pH values in aqueous solutions have also been given out. The result of this study can be applied to explaining the inhibition mechanism.
文摘In this paper the Bi? ligand(pyridine 2 carboxylic acid) system was studied by direct current sampled polarography (DC _ TAST) at a fixed ratio of total ligand to total metal concentration and changing pH. The polarographic experimental complex formation curve (ECFC) and the theoretical complex formation curve (TCFC) were used for modelling the metal ligand system and optimizing stability constants. The ECFC, in which experimental parameters of polarography are included (a shift in a half wave potential and a variation in a diffusion controlled limiting current), appears to be a characteristic function for a particular metal ligand system. The TCFC is a theoretical curve calculated for the designed metal ligand model from mass balance equation. Five bismuth complexes MHL, ML, ML2, ML3 and ML3(OH) with their stability constants as logβ 7.54± 0.10, 7.50± 0.02, 13.91± 0.04, 18.15± 0.03 and 26.75± 0.02, respectively, are reported.
文摘本文用示差脉冲极谱技术研究Pb(Ⅱ) 络合剂(β N 三丙酸)体系。依据实验得到的极谱峰电位的移动随溶液pH值的变化关系曲线,建立合适的金属络合物体系模型。用计算机分析程序,通过求解体系的质量平衡方程及拟合实验络合物形成曲线,优化得到金属络合物的稳定常数。计算机分析结果表明,在所研究的pH值范围内,溶液中存在四种金属络合物:PbH2L+、PbHL、PbL-、PbL(OH)2-,其稳定常数(logβ)分别为:16.23±0.04、12.42±0.01、4.11±0.05、9.43±0.02。
基金This work was supported by the Key Technologies Research and Development Program of the Eleventh-Five Year Plan of China(Grant No.2006BAJ08B02)the Innovation Project of Talented Scientific Youth of Fujian Province in 2008 Year(No.2008F3096).
文摘The dissociation constants of polyepoxysuccinic acid(PESA)were investigated in this study.Based on the potentiometric titration and the BEST program,the dissociation constants of PESA were determined.Considering the complexity of the dissociation of PESA in aqueous solution,several models were constructed to simulate the dissociation process of PESA.By comparison,the dissociation constants of PESA were obtained with model 4.The species distribution of PESA in aqueous solution as a function of pH was also presented according to the experimental and calculation results.It showed that the H_(2)L model with five basic structure units to describe the dissociation of PESA was reasonable,and the relevant constants had less error and better matching between the experimental and calculation data.The corresponding values of pK_(ai) were 4.68 and 4.92,respectively,for H2L at 35℃ with ionic strength of 0.1 mol/L.
