Reactive extraction of lactic acid with mixed tertiary amine extractants

The mixture of tripropylamine (TPA) and trioctylamine (TOA) dissolved in 1-octanol/n-heptane was used in the reactive extraction of (L+)lactic acid in aqueous solution. Maximum distribution coefficients were obtained in the range from 6:4 to 8:2 weight ratio of TPA/TOA at 5% (w/w) lactic acid in aqueous phase and their extraction efficiencies were above 90%. By introducing TPA into TOA, the third phase formation could be overcome, thereby, the settling time is shorter than in the case of TOA only.