Patent ID: 6046246
Filing Date: 2000-04-04
Classification: B01D,B01J,C12N,G01N,Y10S

Abstract:
A process for the preparation of porous spherical particles of fluorinated polymer adsorbent comprising the steps:(1) forming a water-insoluble solution of organic compounds comprising (a) a monomer selected from C.sub.2-4 alkylene glycol ester of a C.sub.3-6 acrylic acid, (b) a polyfluorinated monomer having ethylenic polymerization functionality, (c) a free radical initiator and (d) a water-insoluble, organic solvent-soluble porogenic material, the weight ratio of monomers (a) and (b) to porogenic material being 0.5-2;(2) with high shear agitation, forming a dilute solution of poly(vinyl alcohol) in water from which any oxygen has been purged with inert gas;(3) with continuing high shear agitation and inert gas purging, rapidly dispersing the water-insoluble solution of organic compounds from step (1) into the dilute aqueous poly(vinyl alcohol) solution from step (2) and adjusting the temperature of the dispersion to 30-90 C. to initiate copolymerization of the monomers, the level of high shear mixing energy being sufficient to disperse the water-insoluble solution of organic compounds in the poly(vinyl alcohol) solution in the form of liquid droplets having an average diameter of no more than 50 micrometers, at least 90% of the droplets being within the range of 20-80 micrometers;(4) continuing the high shear agitation and oxygen purging of the dispersion from step (3) for a time sufficient to effect complete copolymerization of the monomers and particulation of the droplets in the form of finely divided particles by precipitation of the copolymer therein;(5) separating the finely divided copolymer particles from the polymerization reaction medium;(6) extracting the porogenic material from the separated copolymer particles of step (5) by washing the particles with inert organic solvent, thereby forming pores within the copolymer; and(7) drying the porous copolymer particles.