摘要:
The complexation of Ca2+ by alpha-isosaccharinic acid (alpha-ISA) was determined by measuring the solubility of Ca(alpha-ISA), as a function of pH. In the pH range between 12 and 12.8, the observed increase of the total concentration of Ca in solution with increasing pH is explained by the complexation reaction:Ca2+ + alpha-ISA(-) = Ca(alpha-ISA(-H))(0) + H+with log K-CaISAo(o)=-10.4 (s=0.2) at I=0. In addition to this complexation reaction, another complex is postulated:Ca2+ + alpha-ISA(-) reversible arrow Ca(alpha-ISA)(+)with log K-CaISA+(o)=1.70. A value for the solubility product of Ca(B-ISA), is calculated: log K-sol(o)=-6.36 (s=0.1) at I=0.