| 摘要 |
PROBLEM TO BE SOLVED: To produce acetic anhydride in which the deterioration of quality due to thermal history or entrainment is suppressed. SOLUTION: This distillation purifying equipment for acetic anhydride is obtained by composing a reboiler 1 additionally installed in a distillation column 2 of a naturally falling film evaporator(FFE) and respectively installing a baffle 16 on the outflow side and a baffle 17 on the inflow side near the wall surface connected to a reboiled gas feed line 15 in the reboiler 1 or a distillation column 2. Thereby, the deterioration of quality due to the thermal history or entrainment can be suppressed to purify and recover the high-quality acetic anhydride improved in hue [American Public Health Association(APHA)] from conventional 8-10 to 5-7.
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