METHOD FOR SEPARATING TRIMETHYLOLPROPANE FROM WATER- SOLUBLE SALTS COMPOSED OF SOLUTION

摘要

PROBLEM TO BE SOLVED: To save on the energy consumption and cause no environmental nuisance problem without the use of a solvent to obtain a colorless triol at a low cost by adopting an electrodialysis method as a separation process, when trimethylolpropane is separated from water-soluble salts composed of a solution. SOLUTION: An electrodialysis device is of a commercial type and has an anion exchange membrane and a cation exchange membrane which are likewise sold on the market. Alternatively the device may have a salt discharger circulation and a salt receiver circulation. A mixture of an aldol adduct obtained by subjecting butyraldehyde and formaldehyde to a basic catalytic action in the presence of a stoichiometric quantity of the base and a polyol which is generated as a crude product under a cannizzaro reaction and salts thereof, for example, is directly supplied to the salt discharger circulation. In addition, the pH value of a salt receiver solution is preferably adjusted to the range of 4-10, and the temperature of the solution is preferably set within the range of 10-50 deg.C. Further the current density is preferably set within the range of 50-750 A/m2.