| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for highly purifying acrylic acid from an aqueous solution of crude acrylic acid while polymerization of acrylic acid is prevented. SOLUTION: The method for purifying acrylic acid, in production of acrylic acid by catalytically oxidizing propylene and/or acrolein with molecular oxygen, comprises dehydration of crude acrylic acid aqueous solution, which solution is obtained by cooling the oxidation reaction gas and/or by absorbing the gas in water or by moreover removing aldehydes therefrom by stripping, in an azeotropic dehydration distillation column by using an azeotropic agent having≤130°C boiling point, wherein the crude acrylic acid aqueous solution supplied to the the column contains 40-80 wt.% acrylic acid, 1-5 wt.% acetic acid and 20-60 wt.% water and, in the bottom solution, azeotropic agent concentration is kept≥5 wt.% but≤30 wt.% and water content is kept 0.04-0.5 wt.% (except 0.05-0.3 wt.%). The theoretical plates of the azeotropic dehydration column and an acetic acid separation distillation column are 5-20. COPYRIGHT: (C)2005,JPO&NCIPI
|
