Recovery of acetic acid

An acetic acid separation process comprising:

• providing a first process stream comprising acetic acid and greater than 250 ppm of propionic acid;
• separating at least a portion of the propionic acid from the acetic acid within the first process stream to provide an acetic acid product stream comprising acetic acid, less than 500 ppm of water and less than 250 ppm of propionic acid and a bottoms stream comprising propionic acid and acetic acid;
• contacting the bottoms stream with methanol in the presence of an acid catalyst selected from mineral acids, ion exchange resins, acidic zeolites, heteropolyacids and combinations thereof to form a methanolysis product stream comprising methyl acetate and methyl propionate;
• and
• separating at least a portion of the methyl acetate from the methyl propionate within the methanolysis product stream to form an overhead stream comprising methyl acetate and a bottoms stream comprising methyl propionate.

An acetic acid separation process comprising:

• providing a first process stream comprising acetic acid and greater than 250 ppm of propionic acid;
• separating at least a portion of the propionic acid from the acetic acid within the first process stream to provide an acetic acid stream comprising acetic acid, less than 500 ppm of water and less than 250 ppm of propionic acid and a bottoms stream comprising propionic acid and acetic acid;
• reacting the bottoms stream to form a product stream comprising components of respectively lower boiling points than corresponding components in the bottoms stream;
• and
• separating components of the product stream to form an overhead stream comprising one or more acetates and a bottoms stream comprising one or more propionates.