Manufacturing method of butanol

PROBLEM TO BE SOLVED: To provide a method for producing butanol, comprising a process of eliminating impurities contained in a solution containing the butanol. SOLUTION: This method for producing the butanol is provided by comprising a process A of filtering the butanol-containing solution through a nano-filtering membrane and recovering the butanol-containing liquid from a permeation side, and a process B of increasing the butanol concentration by passing the obtained butanol-containing solution in the process A through a reverse osmosis membrane. COPYRIGHT: (C)2010,JPO&INPIT