Patent ID: 8829212
Filing Date: 2014-09-09
Classification: C07D,C08G,Y10T

Abstract:
1. An improved method for producing a liquid epoxy resin, which method comprises a) reacting, with water removal, a polyhydric phenol, an epihalohydrin and an alkali metal hydroxide or alkaline earth metal hydroxide, to yield a product slurry that comprises liquid epoxy resin, epihalohydrin, and a precipitated, solid alkali metal halide salt or a precipitated, solid alkaline earth metal halide salt, and b) separating the precipitated alkali metal halide salt or alkaline earth metal salt from the product slurry, wherein the improvement comprises effecting separation of the alkali metal salt or alkaline earth metal salt from the product slurry a) using a filtering basket centrifuge that has an internal slurry feed, a centrifuge basket, and an integral screen, the screen being used with or without at least one of an optional filter cloth or other porous barrier, which screen and optional filter cloth or other porous barrier retains solid material but allows liquid to pass through, said screen being disposed on an outer surface of the centrifuge basket and b) disposing a layer of coarse salt particles having an average particle size within a range of from 100 micrometers to 2000 micrometers on an inner surface of the centrifuge, said coarse salt particles lying atop an inner surface of the screen, or when at least one of the optional filter cloth or other porous barrier is used in conjunction with the screen, atop an inner surface of said optional filter cloth and/or other porous barrier, the coarse salt particles having an average particle size that exceeds that of the precipitated alkali metal salt or alkaline earth metal salt particles contained in the product slurry, whereby the precipitated alkali metal salt or precipitated alkaline earth metal salt forms a layer on a slurry feed side of the layer of coarse salt particles.