Semi-continous method for producing 4,4'-dihydroxydiphenylsulfone
AssigneeBASF SE
InventorsGunther Pabst, Jurgen Kast
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Abstract
The invention relates to a semi-continuous method for producing 4,4-dihydroxydiphenylsulfone, comprising the following steps: (a) reacting phenol with a sulfonating agent; (b) suspending the resulting crude product in hot water which is at least 40° C. and which is free from inert organic solvents and can contain residual amounts of unreacted phenol, and filtering off the product; and (c) returning the resulting waste streams containing the educt and/or product to the production process. Step (b) is carried out using the crude product and water in a weight ratio of 85:15 to 55.45.
Claims9
A semicontinuous process for the preparation of 4,4′-dihydroxydiphenyl sulfone, comprising the following steps:
- (a) reaction of phenol with a sulfonating agent,
- (b) suspension of the resulting crude product in water heated to at least 40° C., which is free of inert organic solvents and can contain residual amounts of unreacted phenol, and filtration of the product, and
- (c) recycling of the resulting educt-containing and/or product-containing waste streams into the preparative process,
- wherein, in carrying out step (b), the crude product and water are used in a weight ratio of 85:15 to 55:45.
Dependencies are inferred from the claim text.