Optimized ion exchanger beds for the synthesis of bisphenol A

In an ion exchange bed for producing bisphenol A from phenol and acetone in a fixed bed reactor containing gel-form or macroporous sulfonic acid ion exchanger resins, the improvement comprising providing the resin as a two-layer bed wherein:

• the lower layer of the bed comprises an unmodified resin having a low degree of crosslinking, less than or equal to 2%, and comprises 75 to 85% of the bed volume as a whole;
• and
• the upper layer of the bed, which comprises 15 to 25% of the bed volume as a whole, comprises either
• a resin having a higher degree of crosslinking than the lower bed, from equal to or greater than 2% to less than or equal to 4%, in which 1 to 25 mol % of the sulfonic acid groups are optionally covered with species containing alkyl-SH groups by ionic fixing, or
• a resin having a low degree of crosslinking, less than or equal to 2%, in which 1 to 25 mol % of the sulfonic acid groups are covered with species containing alkyl-SH groups by ionic fixing.