Production of acrylic and propionic acid and/or their esters, useful as intermediates for e.g. adhesives, comprises catalytic gas-phase oxidation, and work-up to give pure acrylic acid and an acrylic acid by-product which is hydrogenated

摘要

The product mixture from the selective, partial gas-phase oxidation of propane, propene and/or acrolein is worked up by separation to give pure acrylic acid and a by-product mixture containing aldehydes and/or alkanoic acids together with some acrylic acid. Hydrogenation (optionally after esterification) is carried out to give propionic acid and/or its esters. A method for the production of acrylic acid (AA) and propionic acid (PA) and/or their esters involves: (1) selective, partial gas-phase oxidation of propane, propene and/or acrolein on a heterogeneous catalyst in zone 1 (reaction zone), to give a mixture (A) containing acrylic acid as the main product plus aldehydes and/or saturated alkanoic acids; (2) separation in zone 2 (work-up zone) to give (i) AA with a purity of at least 90 wt.% and (ii) a by-product mixture with a total content of aldehydes and/or alkanoic acids (in mol% based on acrylic acid content) which is greater than that of fraction (i); and (3) hydrogenation (optionally after esterification) of the AA in fraction (ii) to give PA and/or its esters.