PROCESSES FOR PRODUCTION OF DIHYDROXYDIPHENYL SULFONE ISOMERIC MIXTURES

WIPO Patent Application WO/2003/070695

A1

The invention provides processes for producing high-quality dihydroxydiphenyl sulfone isomeric mixtures which little cause color development (color formation) in non-image areas when used in thermal recording paper as the developer; and such dihydroxydiphenyl sulfone isomeric mixtures. Specifically, a process for the production of dihydroxydiphenyl sulfone isomeric mixtures, characterized by subjecting a solution or suspension of a crude isomeric mixture comprising 2,4’-dihydroxydiphenyl sulfone and 4,4’-dihydroxy- diphenyl sulfone in an organic solvent to cooling and filtration successively; a process for the production of dihydroxydiphenyl sulfone isomeric mixtures, characterized by mixing a solution or suspension of a crude isomeric mixture comprising 2,4’- dihydroxydiphenyl sulfone and 4,4’-dihydroxydiphenyl sulfone in an organic solvent with an aqueous basic solution to extract the isomeric mixture into the aqueous basic solution, removing the resulting organic solvent layer by liquid-liquid separation, adding an acid to the resulting aqueous basic solution to precipitate crystals, and recovering the crystals by filtration; and dihydroxydiphenyl sulfone isomeric mixtures obtained by the processes.

OI FUMIO (JP)
YANASE NORIO (JP)
NATE NOBUYUKI (JP)

PCT/JP2003/001836

August 28, 2003

February 20, 2003

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KONISHI CHEM IND (JP)
OI FUMIO (JP)
YANASE NORIO (JP)
NATE NOBUYUKI (JP)

C07C315/00; C07B61/00; C07C315/04; C07C315/06; C07C317/22; (IPC1-7): C07C315/00; C07C317/22

JPH06107622A	1994-04-19
EP0755920A1	1997-01-29

Saegusa, Eiji (1-7-1 Doshomachi, Chuo-k, Osaka-shi Osaka, JP)

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