METHOD OF OBTAINING ACETIC ACID Russian patent published in 2008 - IPC C07C51/12 C07C53/08 

FIELD: chemistry.

SUBSTANCE: improved is method of obtaining acetic acid by means of carbonilation of methanol and/or its reaction-able derivative with carbon monoxide in carbonilation reaction zone, which contains liquid reaction medium, including iridium carbonilation catalyst, methyliodide co-catalyst, amount of water within range from 0.1 to 20 wt %, acetic acid, methylacetate, at least one promoter - ruthenium, and stabilising compound, selected from group, which consists of alkali metal iodides, alkali-earth metal iodides, metal complexes, able to generate ions I^-, salts, able to generate I^-, and mixtures of two or more such compounds, molar ratio of promoter to iridium being more than 2 up to 15:1, and molar ratio of stabilising compound to iridium is within range (from more than 0 to 5):1, and where method includes additional stages: a) from said carbonilation reaction zone liquid reaction medium with dissolved and/or carried along carbon monoxide and other gases is drained; b) said drained liquid reaction medium is not obligatory passed through one or several additional reaction zones in order to convert at least part of dissolved and/or carried along carbon monoxide; c) said liquid reaction medium from stage (a) and stage (b) is passed in one or several stages of fast evaporation, in order to form (i) vapour fraction, including condensing components and waste low pressure gas, condensing components contain obtained acetic acid and waste low pressure gas, which contains carbon monoxide and other gases, dissolved and/or carried along with drained liquid reaction medium, and (ii) liquid fraction, including iridium carbonilation catalyst, promoter and acetic acid as solvent; d) from waste low pressure gas condensing components are separated; and e) liquid fraction from stage of fast evaporation is recirculated into carbonilation reactor.

EFFECT: method allows to prevent or reduce loss of catalyst and promoter.

14 cl, 7 tbl, 2 dwg, 32 ex