Abstract: Claimed is a process for producing a phosphorus-containing ligand, preferably a diphosphite ligand structure (DLS) such as structure I. The method includes contacting a phosphorochloridite (structure II) with a compound having the structure X—OH (which can be a bisaryl compound), and a tertiary organic amine to provide structure I? and as preferred embodiment structure I.

Abstract: Claimed is a process for producing a phosphorus-containing ligand, preferably a diphosphite ligand structure (DLS) such as structure I. The method includes contacting a phosphorochloridite (structure II) with a compound having the structure X—OH (which can be a bisaryl compound), and a tertiary organic amine to provide structure I? and as preferred embodiment structure I.

Abstract: An aromatic carboxylic acid such as terephthalic acid is produced by the liquid phase oxidation of a precursor thereof, the oxidation being carried out in such a way that substantially all of the aromatic carboxylic acid produced in the course of the reaction is maintained in solution during the reaction.

Abstract: A process for producing pure carboxylic acids by catalytic liquid phase oxidation of a suitable precursor in a solvent in which the oxidation reaction is carried out in a plug flow reaction zone at a high solvent:precursor ratio and reaction conditions sufficient to maintain the pure acid in solution as it is formed, and product produced from such process.

Abstract: Process for removing organic constituents from a high pressure exhaust gas stream in a bromine assisted air oxidation process in which the exhaust gas contains methyl bromide.

Abstract: 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.

Abstract: Purified terephthalic acid is prepared by a process of subjecting an aqueous solution of crude terephthalic acid to hydrogenation to reduce impurities, crystallizing this solution to produce a slurry of purified terephthalic acid in an aqueous liquor, and carrying out an integrated separation washing process.

Abstract: A process for the purification of terephthalic acid is disclosed. A slurry containing crystals in an impurity-containing mother liquor under elevated pressure and temperature conditions is processed to separate the crystals from the mother liquor. The processing comprises highly efficient separation and washing of the crystals under the elevated temperature and pressure conditions in a unit (32) to produce a mass of crystals having a low level of contamination. The washed crystals are reslurried in aqueous medium (vessel 40) and transferred to a secondary separation unit (34) operating under lower pressure and temperature conditions, the transfer being effected by flashing down (in vessel 44) to the lower pressure. The filtrate (41) from unit (34), and optionally wash liquor used in unit (34), is used to establish a recirculating flow whereby the aqueous medium used for reslurrying the crystals prior to pressure let-down is repeatedly re-used.

Abstract: Purified terephthalic acid is prepared by a process of subjecting an aqueous solution of crude terephthalic acid to hydrogenation to reduce impurities, crystallizing this solution to produce a slurry of purified terephthalic acid in an aqueous liquor, and carrying out an integrated separation washing process using a centrifuge having washing facilities.

Abstract: 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.

Abstract: Terephthalic acid is produced by oxidation of para xylene, purified in an aqueous phase and recovered by precipitating a purified product from the aqueous phase, the aqueous phase mother liquor is then cooled or evaporated to produce a further less pure precipitate and a second mother liquor and the less pure precipitate is returned to the reaction medium and/or the water of the second mother liquor is used to dissolve the crude solid and/or the second mother liquor is treated to recover water which is used to wash the precipitate recovered from the aqueous solution. The process produces better yields of terephthalic acid, reduces the use of water and reduces problems in the disposal of polluted waste water.