Solubility products of calcium isosaccharinate and calcium gluconate

Van Loon, LR; Glaus, MA; Vercammen, K

HERO ID

4941471

Reference Type

Journal Article

Year

1999

HERO ID 4941471
In Press No
Year 1999
Title Solubility products of calcium isosaccharinate and calcium gluconate
Authors Van Loon, LR; Glaus, MA; Vercammen, K
Journal Acta Chemica Scandinavica
Volume 53
Issue 4
Page Numbers 235-240
Abstract The solubility products of the calcium salts of two polyhydroxy ligands (PBL), isosaccharinate (ISA) and gluconate (GLUC), were measured. Solubility products of log K-delta,K-O = -6.22+/-0.03 at I = 0 and T = 20+/-1 degrees C for Ca(alpha-ISA)(2), and log K-S,K-O = -3.54+/-0.06 at I = 0 and T = 20+/-1 degrees C for Ca(GLUC)(2) were calculated ignoring the complexation equilibrium: Ca2+ + PHL- reversible arrow CaPHL+. If this complexation reaction is taken into account with log K-1(0) = 1.7, the values of the solubility products are log K-S,K-O = -6.53+/-0.02 at I = 0 For Ca(alpha-ISA)(2) and log K-S,K-O = -4.19+/-0.05 at I = 0 for Ca(GLUC)(2). Both dissolution reactions are endothermic. The standard free enthalpy change (Delta H degrees) for Ca(alpha-ISA)(2) is 40+/-1 kJ mol(-1) and 37+/-4 kJ mol(-1) for Ca(GLUC)(2). The enthalpy was assumed to be constant in the temperature range 7 < T < 90 degrees C. The calculated standard entropy change (Delta S degrees) is 17+/-5 J mol(-1) K-1 for Ca(alpha-ISA)(2) and 60+/-14 J mol(-1) K-1 for Ca(GLUC)(2).
Doi 10.3891/acta.chem.scand.53-0235
Wosid WOS:000079413500001
Url http://actachemscand.org/doi/10.3891/acta.chem.scand.53-0235
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