FORMATION OF NEUTRAL COMPLEXES OF BORIC-ACID WITH 1,3-DIOLS IN ORGANIC-SOLVENTS AND IN AQUEOUS-SOLUTION

From solubility measurements in organic media and extraction experiments, the values of the stability constants of neutral 1:1 complexes (HBL) formed between boric acid (HB) and 1,3-diols (L) have been obtained in aqueous solution (K-c(w)) and in organic solvents (K-c(s)). The values of the partition coefficients of the diols (P-L) and the complexes (P-HBL) between water and the organic solvents have also been calculated. Generally, the addition of a diol to an aqueous solution of borax is accompanied by a decrease of pH due to the prevailing formation of borate species but, in the case of 2-methyl-2,4-pentanediol, the pH increased, in agreement with the formation of a single neutral complex. It is shown that a modification of a previous potentiometric procedure yields simultaneously the values of the stability constants of the neutral and anionic complexes in aqueous solution.