Imperial Chemical Industries Limited

Invista North America S.a.r.l.

E.i. Dupont De Nemours and Company

Alan Macpherson Ure

John Arthur Turner

Eric Hindmarsh

William David Parten

Antony Peter John Limbach

The present invention provides a process for the production of an aromatic dicarboxylic acid comprising the catalytic oxidation of a hydrocarbon precursor in an organic solvent, comprising the steps of: i) separating a vent gas from an oxidation stage into an organic solvent-rich liquid stream and a water-rich vapor stream in a distillation stage; and ii) separating an aqueous purification mother liquor comprising organic compounds from purified aromatic dicarboxylic acid crystals in a separation stage, characterized in that the process further comprises the steps of: iii) transferring the aqueous purification mother liquor from the separation stage to an extraction stage; iv) extracting said organic compounds from the aqueous purification mother liquor by contacting the aqueous purification mother liquor at a temperature of at least 90&#xb0; C. with an organic liquid in the extraction stage to form an aqueous phase and an organic phase, wherein the concentration of said organic compounds in the aqueous phase is lower than the concentration of said organic compounds in the aqueous purification mother liquor; and v) transferring the aqueous phase to said distillation stage. The present invention further provides an apparatus for carrying out the process.

Paraxylene extraction of purification mother liquor with heat integration

Disclosed is a process for the separation of water from a liquid phase medium containing an aliphatic carboxylic acid using azeotropic distillation in the presence of an entrainer. The entrainer, water, and organics are subsequently separated, wherein the entrainer is recycled back to the azeotropic distillation column and organics recycled back to the oxidation reactor.

Dehydration of acetic acid by azeotropic distillation in the production of an aromatic acid

Disclosed are processes and systems for the production of aromatic carboxylic acids, such as purified terephthalic acid. The processes result in reduced volatile aromatic monocarboxylic acid contamination throughout various stages of the PTA process when compared to known processes. This permits the various effluent streams to be recycled back to several stages in the production process, which allows for the efficient production of pure PTA at a lower cost.

Production of aromatic carboxylic acids

Embodiments of the present disclosure include methods or processes for purifying CTA, systems for purifying CTA, methods or processes for cooling mother liquor streams, systems for cooling mother liquor streams, methods or processes for treating mother liquor solids, systems for treating mother liquor solids, and the like.

Methods, processes, and systems for treating and purifying crude terephthalic acid and associated process streams

Dehydration of acetic acid by azeotropic distillation in the production

A terephthalic acid slurry in acetic acid is produced by oxidising p-xylene in acetic acid, removing water by evaporation of a stream of water and acetic acid, and returning acetic acid to the oxidation step. The terephthalic acid is separated from the reaction medium in a first zone to leave a deposit on a band, the deposit is washed with a first aqueous medium in a second zone, removed from the band in a third zone, and admixed with a second aqueous medium. Reaction medium is passed from the first zone to the oxidation step and terephthalic acid is recovered, preferably after further purification.

Process for the production of terephthalic acid

A terephthalic acid slurry in acetic acid is produced by oxidizing p-xylene in acetic acid, removing water by evaporation of a stream of water and acetic acid, and returning acetic acid to the oxidation step. The terephthalic acid is separated from the reaction medium in a first zone to leave a deposit on a band, the deposit is washed with a first aqueous medium in a second zone, removed from the band in a third zone, and admixed with a second aqueous medium. Reaction medium is passed from the first zone to the oxidation step and terephthalic acid is recovered, preferably after further purification.

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Cleveland, United Kingdom

Alan Macpherson Ure