Process for producing acetaldehyde dimethylacetal

A process for producing acetaldehyde dimethylacetal from acetaldehyde and methanol comprising steps of:

• 1) continuously feeding acetaldehyde and methanol to a reactor to which a rectification tower is connected in series to conduct a reaction in the presence of an acid catalyst simultaneously with rectification to withdraw the water by-produced from the bottom of the tower and to recover a distillate containing the acetaldehyde dimethylacetal produced from the top of the tower,
• 2) subjecting the distillate recovered in step (1) to azeotropic distillation in the presence of n-hexane or cyclohexane as an azeotrope former to distill an azeotrope comprising methanol, n-hexane or cyclohexane, and acetaldehyde dimethylacetal from the top of a distillation tower and to recover high purity acetaldehyde dimethylacetal as a bottom,
• 3) bringing the distillate obtained in step (2) into contact with water to extract methanol into the aqueous phase and to recover n-hexane or cyclohexane as a lighter liquid, and
• 4) recycling the n-hexane or cyclohexane recovered in step (3) to step (2) as an azeotrope former and recycling the methanol-rich aqueous phase to step (1).