A process for the production of a bisphenol comprises reacting a feed comprising a phenol, a ketone and water in the presence of an ion exchange resin catalyst to produce an effluent; determining the para-para bisphenol selectivity of the reaction; and adjusting the concentration of the water in the feed based upon the para-para bisphenol selectivity in the effluent.
A commercial scale continuous process for the production of a bisphenol comprising reacting a phenol and a ketone in the presence of a modified ion exchange resin catalyst, wherein said modified ion exchange resin comprises a crosslinked gellular acid functionalized polystyrene resin modified by neutralization of with a mercapto promoter.