Investigation of some 1-3-diols for the requirements of solvent extraction of boron: 2,2,6-trimethyl-1,3 heptanediol as a potential boron extractant

Eighteen 1,3-diols were synthesized and their structure and distribution ratio for the solvent extraction of boron were studied. Diols with a high distribution ratio $(D_{B(OH)_3} > 10)$ were investigated for the requirements of solvent extraction of boron. Their extraction capacity, and solubility in aqueous phase and in organic diluents were investigated by comparison to -ethyl-1,3-hexanediol (EHD), which is widely used as a boron extractant. Among a series of 1,3 diols, 1-benzyl-2,2-dimethyl-1,3-propanediol (4a) and 2,2,6-trimethyl-1,3-heptanediol (3a) were found to have very low solubility in the aqueous phase compared to the others. IPD (3a) was found to have a high solubility in aliphatic diluents such as kerosene. IPD,which has good solubility properties for the solvent extraction of boron, was studied in detail, including dependence of pH, diol concentration, and stripping facility, and in various organic diluents.