Method for producing acetic acid

A method for producing acetic acid, comprising at least one step selected from

• a carbonylation reaction step that satisfies the following operating conditions (i) and
• an evaporation step or a distillation step that satisfies the following operating conditions (ii) in an acetic acid production process:
• (i) operating conditions involving a hydrogen partial pressure of more than 1 kPa and less than 500 kPa (absolute pressure), a carbon dioxide partial pressure of not less than 2 kPa and less than 70 kPa (absolute pressure), and an operating temperature of more than 175° C. and not more than 250° C.;
• and
• (ii) operating conditions involving a hydrogen partial pressure of not less than 0 kPa and not more than 5 kPa (absolute pressure), a carbon dioxide partial pressure of not less than 0 kPa and less than 20 kPa (absolute pressure), and an operating temperature of more than 100° C. and not more than 250° C., wherein
• the acetic acid production process has at least one distillation step,
• a column top fraction of a distillation column in the at least one distillation step is recycled to the carbonylation reaction step that satisfies the operating conditions (i), the evaporation step that satisfies the operating conditions (ii), and/or the distillation step that satisfies the operating conditions (ii) positioned upstream from the distillation step associated with the distillation column, and
• the carbonylation reaction step that satisfies the operating conditions (i) or the evaporation step or the distillation step that satisfies the operating conditions (ii) decomposes formic acid in the column top fraction.