Mitsui Petrochemical Industries, Ltd.

Mitsui Chemicals, Inc.

Etsuro Okamoto

Hiroshi Suzuki

Toshiyuki Sakata

Ryoichi Yamamoto

Shigeru Isayama

Hideaki Iwata

Norio Murashige

Shizu Suzuki

Process for producing aromatic dicarboxylic acid

A method for recovering crystals from a crystal-containing slurry, which comprises supplying the slurry to a rotary filter having a rotating cylindrical filter medium, filtering the supplied slurry in a filtering region to retain the crystals on the filter medium and washing the filter cake formed on the rotating filter medium repeatedly in a plurality of washing regions by spraying a washing liquid onto the cake in each region by supplying any one of washing regions on the aft side in the rotating direction of the filter medium with the spent washing liquid of the washing region adjacent to said one washing region on the fore side in the rotating direction.

Method for recovering crystals from slurry with wash water recycle means

It is contemplated by the present invention to produce a high quality aromatic carboxylic acid by a liquid phase oxidation of an alkylbenzene by contacting it with a molecular oxygen-containing gas in a solvent containing a lower aliphatic carboxylic acid, under exclusion of any acceleration of decomposition of the solvent molecules and danger of explosion accident. The process for producing an aromatic carboxylic acid according to the present invention by a liquid phase oxidation of an alkylbenzene by contacting the alkylbenzene with a molecular oxygen-containing gas in a solvent containing a lower aliphatic carboxylic acid comprises supplying the alkylbenzene and the solvent to a reactor, supplying, as the molecular oxygen-containing gas, a high oxygen content gas containing molecular oxygen at a concentration higher than that of air to the reactor, circulating at least a part of the reactor exhaust gas as such or after having been separated from the condensable components thereof to the liquid layer in the reactor and thereby oxidizing the alkylbenzene to the aromatic carboxylic acid.

Process and apparatus for producing aromatic carboxylic acid

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Kuga-Gun, Japan

Etsuro Okamoto