Biobutanol recovery from model solutions using potassium pyrophosphate

BACKGROUND: Biobutanol has tremendous advantages over bioethanol, from use as an industrial solvent to a superior next-generation biofuel. In order to compete with synthetic 1-butanol or bioethanol, biobutanol still faces the challenge of developing product recovery methods to reduce production cost over the long term. Here we describe an in situ salting-out technique utilizing potassium pyrophosphate (K4P2O7) as dehydrating agent to form new organic phases in acetone+ 1-butanol+ ethanol (ABE) model solutions. RESULTS: A higher K4P2O7 content resulted in higher distribution coefficients of ABE. A change in temperature led to no appreciable change in the liquid-liquid phase equilibria. More than 90wt% of ABE could be recovered and more than 99.75% of water remained in the bulk aqueous phase. Higher solvent level permits higher recovery of ABE. The linear correlation between the solubility of ABE and the molality of K4P2O7 was demonstrated. CONCLUSION: The salting-out separation technique has potential for the selective recovery of ABE from fermentation broths to reduce the energy consumption in the subsequent distillation. (C) 2016 Society of Chemical Industry