GB1237298A - Production of terephthalic and/or isophthalic acid - Google Patents

Abstract

1,237,298. Preparation of terephthalic and/or isophthalic acid. CELANESE CORP. 16 April, 1969 [16 April, 1968], No. 19327/69. Heading C2C. A continuous process for the liquid phase oxidation with gaseous oxygen of m-xylene and/or p-xylene to obtain isophthalic acid and/or terephthalic acid comprises, maintaining in a reactor, in substantially uniform admixture, a body of liquid-solid slurry comprising, besides isophthalic acid and/or terephthalic acid, xylene and its intermediate oxidation products, acetaldehyde, acetic acid and a dissolved cobalt salt catalyst, continuously feeding into said slurry the xylene, at least 0À2 part by weight of acetaldehyde and from 3-15 parts by weight of acetic acid per part by weight of the xylene fed, a soluble cobalt compound, in quantity sufficient to provide 0À1 to 2À5 weight per cent of cobalt metal based on the combined weight of the xylene, acetic acid and acetaldehyde, and at least 3À25 moles of oxygen per mole of xylene, withdrawing from the reactor spent gas and sufficient of the slurry to maintain substantially constant the quantity in the reactor and recovering isophthalic acid and/or terephthalic acid as product from the withdrawn slurry, the oxidation being carried out at a temperature of from 120‹ to 140‹ C. under a gauge pressure of at least 95 1b. p.s.i. and so as to maintain an average residence time in the reactor such that at least 98À6% by weight of the xylene fed is oxidized to isophthalic acid and/or terephthalic acid and intermediate oxidation products, with xylene and the intermediate oxidation products forming less than 3% by weight of the slurry.