Process for producing high-purity...

Details Process for producing high-purity... Process for producing high-purity...

2003-09-22

2008-11-25

Eyler, Yvonne (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Sulfur containing

Reexamination Certificate

active

07456321

ABSTRACT:
The present invention provides a process for producing 4,4′-dihydroxydiphenylsulfone of very high purity. In particular, the present invention provides a process for producing 4,4′-dihydroxydiphenylsulfone of high purity comprising the steps of subjecting phenol in combination with a sulfonating agent or phenolsulfonic acid to a dehydration reaction in the presence of an aromatic nonpolar solvent while suspending the resulting dihydroxydiphenylsulfone therein, mixing the reaction suspension with a polar solvent to at least partially dissolve the dihydroxydiphenylsulfone, and precipitating 4,4′-dihydroxydiphenylsulfone.

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