Efficient recovery of bio-based 1,2,4-butanetriol by using boronic acid anionic reactive extraction

Effective isolation of 1,2,4-butanetriol (BT) from the fermentation broth with low BT concentration was achieved based on anionic reactive extraction with a combined extractant consisted of boronic acid carrier and trioctylmetylammonium Aliquat® 336 (A336) dissolved in the organic phase. The influence of various diluents, pH values, the ratio of phenylboronic acid derivatives (PBAD) to BT (α PBAD/BT ), and A336 to BT (β A336/BT ) on extraction property was investigated in detail. For model BT solutions, satisfactory extraction efficiency of 92% was obtained under the conditions of α PBAD/BT  = 1.5, β A336/BT  = 2, with dichloromethane as a diluent. Aqueous hydrochloric acid solutions were employed to strip BT from the organic phase. For actual fermentation broth, the extraction and stripping efficiency under the optimum conditions were 74% and 69%, respectively. Besides, compared with the original fermentation broth, 1,2,4-butanetriol has been concentrated by 4.6 times with the reactive extraction coupled hydrolysis.