| 摘要 |
PURPOSE:To obtain lactones having high purity by hydrogenating dicarboxylic acids in liquid phase in the presence of a ruthenium catalyst and distilling the resultant crude lactones under specific condition to obtain purified product. CONSTITUTION:A dicarboxylic acid, dicarboxylic acid anhydride or dicarboxylic acid ester is hydrogenated in a solvent comprising ether or polyether in the presence of a ruthenium catalyst. The reaction product is distilled with an ordinary distillation column and crude lactone is distilled out from the column top. The crude lactam is distilled at a column bottom temperature of <=150 deg.C while keeping the residence time of the bottom liquid in the column to <=6hr. The lower limit of the column bottom temperature is >=20 deg.C and that of the residence time of the bottom liquid is about 30min. |
