Methods for producing acetic acid

A method for producing acetic acid while inhibiting by-production of acetaldehyde by increasing carbon monoxide partial pressure or methyl acetate content, comprising the steps of:

• continuously reacting methanol with carbon monoxide in the presence of a rhodium catalyst which is a rhodium complex soluble in the reaction mixture under reaction conditions or can form the rhodium complex, an iodide salt, methyl iodide, methyl acetate, and water;
• producing acetic acid at a production rate of 11 mol/L·hr or more;
• keeping the acetaldehyde content of a reaction mixture to 500 ppm or less;
• and
• keeping the production rate of acetaldehyde to 1/1500 or less of the production rate of acetic acid,
• wherein the reaction is carried out at a carbon monoxide partial pressure in a gaseous phase of a reactor of 1.05 MPa or more and at a methyl acetate content of the reaction mixture of 2 to 10 percent by weight and at water content of the reaction mixture of 3 percent by weight or less and at a hydrogen partial pressure in the gaseous phase of the reactor of 70 kPa or less.