Process for cleaning bisphenol crystallizer

In a method for producing a bisphenol comprising the steps of reacting a first reactant stream containing phenol and a second reactant stream containing a ketone or aldehyde to produce a product mixture containing the bisphenol;

• feeding the product mixture as a slurry to a crystallizer to produce crystals of a 1:1 bisphenol:phenol adduct;
• and recovering the adduct, the improvement comprising periodically cleaning the crystallizer using a method comprising the steps of:
• (a) draining from 20 to 80% of the slurry from the crystallizer;
• (b) replacing the drained slurry stream with a solvent comprising phenol, thereby forming a diluted slurry;
• (c) increasing the temperature in the crystallizer to a temperature at which the crystallized bisphenol is dissolved in the diluted slurry, and then rapidly cooling the diluted slurry to a temperature of 45 to 55° C.;
• and
• (d) adding a seed slurry containing solid bisphenol at a concentration of at least 5% , said seed slurry having a temperature of 45 to 55° C., until conditions are established at which bisphenol crystals added to the crystallizer do not redissolve.