| 摘要 |
PURPOSE: To highly dehydrate a substance, essentially a condensation mixture, by continuously carrying out an azeotropic distillation by using an org. solvent which can form an azeotrope having minimal boiling point with water but can not be mixed with water. CONSTITUTION: Continuous dehydration is carried out by using an org. solvent having a density higher than that of water in the reaction mixture in direct esterification, direct acetal formation or direct ketal formation processes which are simultaneously performed while the reaction proceeds. The org. solvent used is prepared from a short-chain alcohol as the starting material and is used in at most 10 mol.% excess amt. The org. solvent can form an azeotrope having the minimal boiling point with water but can not be mixed with water. As for the org. solvent which can form an azeotrope having the lowest boiling point but can not be mixed with water, aromatic hydrocarbons can be used, and benzene, toluene or halogenated aliphatic hydrocarbons are preferably used. |
