Regeneration of acidic ion exchangers
AssigneeBayer MaterialScience AG
InventorsMichael Prein, Christian Münnich, Ulrich Blaschke
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Abstract
The invention relates to a method for regenerating acidic cation exchangers, which are used as catalysts in the reaction of phenols with aldehydes or ketones to give bisphenols, in particular to give bisphenol A, with acids, with the proviso that, in the method according to the invention, these cation exchangers experience very little mechanical damage due to swelling processes during the regeneration process.
Claims14
A method for regenerating a deactivated or partly deactivated acidic cation exchanger comprising washing an ion exchange catalyst taken out of operation with a mixture comprising phenol and acid, wherein the water content of said mixture is increased by the gradient method.
A method for regenerating a deactivated or partly deactivated acidic cation exchanger comprising
- a) washing an ion exchange catalyst bed with from 1 to 4 bed volumes (BV) of a mixture of phenol and acid;
- b) washing said ion exchange catalyst bed with from 0.25 to 4 BV of a mixture of phenol and acid during which water is added to said mixture such that the water content of said mixture is increased by the gradient method from 0% by weight of water to 1% by weight of water;
- c) washing said ion exchange catalyst bed with from 0.25 to 4 BV of a mixture of phenol and acid during which water is added to said mixture such that the water content of said mixture is increased by the gradient method from 1% by weight of water to 5% by weight of water;
- d) washing said ion exchange catalyst bed with a mixture of phenol and from 5 to 25% by weight of water, until the electrical conductivity of said mixture is less than 50 μS/cm to obtain a washed ion exchange catalyst bed;
- and
- e) dewatering said washed ion exchange catalyst bed with phenol until the residual water content in the said phenol is less than 1% by weight;
- wherein
- said ion exchange catalyst bed has been taken out of operation;
- the acid content of the mixtures used in steps a), b), and c) is less than 10% by weight and greater than 0% by weight;
- the BV corresponds to the volume of said ion exchange catalyst bed;
- and
- the temperature of said ion exchange catalyst bed is in the range of from 45° C. to 90° C.
Dependencies are inferred from the claim text.