Acetic acid is produced while inhibiting an increased concentration or production of
hydrogen iodide in a
carbonylation reactor or
corrosion of the
carbonylation reactor.A production process of
acetic acid comprises a
reaction step for continuously allowing
methanol to react with
carbon monoxide in the presence of a catalyst
system comprising a
metal catalyst (e.g., a
rhodium catalyst), an ionic
iodide (e.g.,
lithium iodide), and
methyl iodide in a
carbonylation reactor; and in the process, (i) the concentration of the
metal catalyst is maintained at not less than 860 ppm on the basis of weight, the concentration of water is maintained at 0.8 to 15% by weight, the concentration of
methyl iodide is maintained at not more than 13.9% by weight, and the concentration of
methyl acetate is maintained at not less than 0.1% by weight, in a whole
liquid phase in the reactor, and / or (ii) the concentration of the
metal catalyst is maintained at not less than 660 ppm on the basis of weight, the concentration of water is maintained at 0.8 to 3.9% by weight, the concentration of the ionic iodide is maintained at not more than 13% by weight, the concentration of
methyl iodide is maintained at not more than 13.9% by weight, and the concentration of
methyl acetate is maintained at not less than 0.1% by weight, in a whole
liquid phase in the reactor.