Patent ID: 6858759
Filing Date: 2005-02-22
Classification: C07C

Abstract:
1. A method for the manufacture of bisphenols comprising: introducing a combined feed stream comprising a feed stream and a recycle stream into a reactor system comprising at least one reactor containing a catalytic proportion of an acid catalyst and wherein the combined feed stream comprises a carbonyl compound and an amount of greater than or equal to about 60 wt % phenol, wherein the weight percents are based on the total weight of the combined feed stream; removing from the reactor system a reactor effluent; splitting the reactor effluent into a crystallization feed stream and an effluent recycle stream; extracting from said crystallization feed stream a bisphenol adduct, remainder comprising a mother liquor stream; dehydrating said mother liquor stream and said effluent recycle stream in a dehydrator wherein excess water and carbonyl compound are removed; and recycling the dehydrated mother liquor and the dehydrated effluent recycle stream back to the combined feed stream to effect improved production of p,p-bisphenol, along with increased reactor selectivity and reduced promoter quantities.