Document 93Vk4BmR6DzmZawYZXe4X6a3e

V INTERNAL CORRESPONDENCE--------- MAR 1 (1 1977 R. K WHEtlEH. JR. CHEMICALS AND PLASTICS * P. O. BOX 8361. SOUTH CHARLESTON, WEST VIRGINIA 253C3 To (Name) Divikioft location Dr. D. R. Montgomery Texas City Copy *0 Mr. M. E. Eisenhour, 515 Mr. R. L. Frantz, 515 Dr. K. L. Hoy, 511 Dr. J. B. Saunby, 701 Dr. W. R. Manning, 511 Dr. C. E. Moyer, 515 -/Mr. R. N. Wheeler, 514 Data Originating Dtpt. Subject March 8, 1977 Research and Development Removal of Residual VC1 via Redox Initiator Systems Dear Don: In a recent conversation with Dr. Moyer, I reviewed some of our current efforts in the removal of residual VC1 from our latices via redox polymerization. With latices containing both vinyl chloride and vinyl acetate, we have no difficulty in going below 10 ppm on the resin basis. With VCI/VCI2 latices in which the residual vinylidine chloride is quickly used, we can readily get below 100 ppm and probably-to the 10 ppm level.- The technique is the use of a redox system over a periodof time up to 8 hours. Our redox system is comprised of t-butyl hydro peroxide and erythorbic acid activated with ppm quantities of EDTA-complexed iron. If your system is acidic, you should not need the EDTA. The recipe: Oxidant Solution: 350 parts water, 14.4 parts TBHP (Trigonox A-W70) 1.5 parts of 0.844 FeSO^7H2O/I.156 EDTA/200 H2O at pH 9.1 Reductant Solution; 300 parts water, 21 parts erythorbic acid neutralized to operating pH. Feed: 0.03 parts oxidant, 0.023 parts reductant per minute per phr. UCC 032725 Dr. D. R. Montgomery Page 2 March 8, 1977 Several points come to mind: 1. Studies should be done either with or without blowdown, but with care to exclude oxygen. Con tamination with air appears to interfere with the redox polymerization more than would be expected. 2. High-speed agitation should be maintained such that VC1 will be removed from the vapor phase. Since the rapid removal of the VC1 will also lead to a vacuum in perhaps a half-hour, some nitrogen should be added to hold the pressure above atmo spheric, again to prevent the possibility of introducing air into the reactor. 3. We have successfully operated this redox system from 40 to 85C, but these temperatures are above the glass transition temperature of our products. In your case you should test at conditions both above and below the transition temperature because of differences in diffusion of VC1 from the particle. Since your particles are much larger than ours, the success of the redox system for you is in question both in the removal of VC1 and possible damage to resin porosity. Neverthe less, the advantages of completely avoiding your vacuum stripping system via this technique could be highly significant. RJH/d UCC 032726