Acetic Acid → Acetic Anhydride

Participants

Reaction Steps

The bulk of unreacted carbon monoxide and hydrogen is circulated by means of a gas recirculation pump 2, whilst a fraction thereof is allowed to issue from the system via a scrubbing stage 3. Fresh carbon monoxide and hydrogen are introduced into the gas under circulation via a conduit 4 in metered proportions corresponding to the conversion rate. Fresh methyl acetate and/or dimethylether are supplied in quantities corresponding to the conversion rate via a conduit 5 opening into the upper portion of the scrubbing stage 3 and introduced into the reactor 1 through a conduit 6. The reaction mixture issues from the reactor 1 through a conduit 7. The distilling column 8 is used to effect the separation of non volatile constituents of the catalyst system, which are recycled to the reactor 1 via conduits 9 and 6. Condensate obtained through conduit 10 is subjected to distillative treatment in a work-up stage which does not form part of the present process. Unreacted feed material and an acetic acid proportion corresponding to that contained in the catalyst system are recycled to the reactor 1. 1,1-Diacetoxyethane and acetic anhydride are obtained together with acetic acid as the reaction products. They are analyzed by gas-chromatography and NMR-spectroscopy and ultimately separated from each other by customary fractional distillation.

Provenance & Evidence