GB790760A - Recovering trimethylolethane - Google Patents

Abstract

Trimethylolethane is separated from an aqueous solution of trimethylolethane and sodium formate by a process comprising adding to the solution an organic solvent for trimethylolethane, the solvent being a non-solvent for sodium formate, to form a multiphase mixture comprising a liquid aqueous phase containing water and most of the dissolved sodium formate and a liquid organic solvent phase containing the solvent and most of the trimethylolethane, and separating the organic solvent phase from the aqueous phase. Suitable organic solvents comprise alcohols, such as n-propanol and isopropanol. Trimethylolethane may be recovered from the organic solvent phase by, for example, heating the phase in the presence of added water to remove the solvent and to produce an aqueous solution of trimethylolethane from which it is obtained by crystallization. Advantageously the amount of water present during the extraction is insufficient to dissolve all of the sodium formate in the presence of the organic solvent. The extraction may be carried out continuously or otherwise. It is sometimes desirable to add to the starting mixture a mixture of water and the organic solvent rather than the organic solvent alone. For example, an azeotropic mixture of isopropanol or n-propanol and water may be added. This mixture may be obtained, for example, by steam-stripping the propanol-containing phase.