INTEGRATED OXIDATION OF ISOMERIC XYLENE MIXTURE TO ISOMERIC PHTHALIC ACID MIXTURE AND SEPARATION OF MIXTURE OF ISOMERIC PHTHALIC ACIDS INTO INDIVIDUAL ISOMER PRODUCTS

摘要

Liquid phase oxidation of isomeric xylene mixture with molecular oxygen-containing gas (e.g. air or oxygen gas) in the presence of aqueous or acetic acid reaction media and catalysis provided by one or more heavy metals (metals of about 50 to about 200 atomic weight) or by a side-chain oxidation initiator or promotor (bromine source, or acetaldehyde or methylenic ketone) provides oxidation effluent containing mixture of isomeric phthalic acids for product crystallization and reaction media displacement from concentrate of said effluent by contact of the concentrate with water in a single step, preferably conducted with a vertical column of water, thereby producing aqueous acetic acid for feed to acetic acid recovery and recycle to oxidation and aqueous slurry of mixture of isomeric phthalic acids as feed for separation into individual phthalic acid isomer products. Iso- and tere-phthalic acids in particular are separated from mixtures of the same by crystal size classification.