Process for monitoring a continuous acetic acid and/or methyl acetate production

Abstract

A continuous preparative process, including monitoring production, for acetic acid, methyl acetate or a mixture thereof, by carbonylation, in an industrial installation, of methanol or a carbonylatable derivative of methanol with carbon monoxide in a liquid phase in the presence of water and a homogeneous catalyst system. In a reaction zone I, the carbonylation is carried out in the liquid phase at a temperature of 150 to 250° C., under a pressure of 5·10 to 200·10 Pa and with venting of part of a gaseous canopy above a liquid phase level in said reactor. Then, in a vaporization or flash zone II, a liquid originating from the zone I at a pressure below that of zone I is partially vaporized to form a liquid fraction which is recycled into the reactor, and in a purification zone III, a vaporized fraction originating from flash zone II is distilled on a distillation column. At an outlet of the column, the product is recovered, other constituents of the vaporized fraction being at least partially recycled into said reactor. In the process, the reactor temperature and feed rate of the methanol or carbonylatable derivative in said reactor are brought under control of the carbon monoxide feed rate and of at least one of the parameters defining the composition of the reaction medium, or of the venting or of both the reaction medium and of the venting.