APPARATUS FOR AND METHOD OF PRODUCING AROMATIC CARBOXYLIC ACIDS

摘要

A reactor for the oxidation of a precursor to an aromatic carboxylic acid or ester thereof in a liquid phase reaction mixture is disclosed. The reactor (1) comprises an elongate vessel, substantially vertical in use, having an upper mixing element (5) and a lower mixing element (3), characterised in that the upper mixing element (5) is an axial pumping impeller and the lower mixing element (3) is a radial pumping impeller. A process of producing a carboxylic acid or ester thereof in a reactor of the invention is also disclosed. In use, the configuration of mixing elements leads to three highly turbulent mixing zones. In a preferred embodiment of the process of the present invention oxidant, from one inlet, and solvent, precursor and catalyst, are introduced directly into a mixing zone. The highly turbulent mixing zones lead to rapid mass transfer suppressing the formation of unwanted, coloured by-products and reduced reactor fouling.