The Separation2,3-Butanediol From Fermentation Broth By Reactive-extraction

2,3-Butanediol is an important chemical and potential fuels, which is widely used as raw material in chemical industry, food industry and aerospace industry. Now biotechnology makes it possible to produce2,3-butanediol from fermentation broth in commercial scale. However the high boiling point and high hydrophilicity of2,3-butanediol and complex of fermentation broth make separation2,3-butanediol directly from fermetantion broth very hard, which limits the use of bio-based2,3-butanediol.In this paper, an effective separation process has been studied. An innovative process including reactive-extraction and hydrolysis has been presented, which can effective recover2,3-butanediol from fermentation broth. The main contents and conclusions are as follows:(1) Conversional distillation process for2,3-butanediol fermentation broth is high energy-consuming and hard to get pure product, due to the high boiling point and high hydrophilicity of2,3-butanediol and the complex of fermentation broth. An innovation reactive-extraction and hydrolysis couple process has been provided in this paper to separate2,3-butanediol from fermentation broth. The process contains pretreatment, reactive-extraction, hydrolysis and purification. In the reactive-extraction unit,2,3-butanediol reacts with aldehyde to form corresponding acetal which is extracted into the organic phase in sequence. Due to the high selectivity of reaction, effective separation of2,3-butanediol has been achieved. The reactive-extraction and hydrolysis couple process requires less solution and less energy.(2) Pretreatment is used to remove cells and proteins from fermentation broth to avoid emulsion in reactive-extraction. Flocculation and membrane separation have been studied. Feasible pretreatment has been chosen for the following separation process.(3) The thermodynamics and kinetic study of2,3-butanediol-acetaldehyde,2,3-butanediol-propionaldehyde,2,3-butanediol-n-butylaldehyde have been studied to provide basic data for reactive-extraction and process development.(4) Reactive-extraction condition selection have been done for2,3-butanediol-acetaldehyde-cyclohexane system,2,3-butanediol-propionaldehyde system and2,3-butanediol-n-butylaldehyde sytem. The results have revealed that reactive-extraction can extracted95%of2,3-butanediol from fermentation broth with less solution.(5) Hydrolysis is studied in the paper. The results reveal that with feasible hydrolysis conditions, hydrolysis rate can be over90%.(6) Finally, using2,3-butanediol solution with10%mass concentration as raw material, the final concentration of2,3-butanediol can be over99%, the total recover rate of2,3-butanediol is more than90%. That means the new process can effective separate and purify2,3-butanediol from fermentation broth. And compared the results of three reactive-extraction system, the n-butyl aldehyde system is the most feasible system to run the process.The innovative process for separation and purification of2,3-butanediol from fermentation broth has been depicted in this paper. This research provides the experimental data for the industrial application.