Renewable plant-based soybean oil methyl esters as alternatives to organic solvents

摘要

The physico-chemical properties of soybean oil methyl ester(SBME),better known as biodiesel,of importance to its use as a solvent in liquid-liquid separations have been examined.Partition coefficients of several organic species between SBME-water have been determined and compared to log P(1-octanol-water).The free energy of transfer of a methylene group has been obtained and the solvent properties of the SBME-water system determined from distribution data of a small solute set using Abraham's generalized solvation equation.Solute distribution behavior is similar to that found for conventional organic solvent-water systems,but is most similar to other vegetable oils such as olive oil.When ionizable solutes are partitioned in the SBME-water system at differing pH,the neutral species show the highest distribution.Partitioning is dependent on the solute's ability to form hydrogen bonds between water and its charged state.Metal ions(e.g.,Fe~(3+),Co~(2+),and Ni~(2+))exhibit moderate partitioning to the SBME phase from water only in the presence of extractants.Actinides(UO_2~(2+),Am~(3+))exhibit significant partitioning to the SBME from aqueous solutions with the use of octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide(CMPO).Soybean oil methyl ester may be a suitable "green" alternative for the replacement of volatile organic solvents in liquid-liquid extractions in selected applications.