Document gDpN8vmZK7ZN2Q70ZXrNKb6eQ

hit documem it the property of M O N S A N T O C O M P A N Y . It containi C O N F ID E N T IA L IN F O R M A T IO N which must not be reproduced, rivaled :o unauthorized perioni or sent outside ths Company without proper uthorization. The recipient i* responsible for its safekeeping end estruction. DISTRIBUTION ' W I T H D E T A I L S _____________________________________ *D. c . Armstrong - WOK *K. od Bergen, Jr . - G .0 . *0. DeGarmo - S o . 2nd -D. Ta?;*tDill - G.O T7T1 L. Gossage - G.O. XT.?L w Keller - So . 2nd *D. K n:, p XuT . p -Il. E Lynch/H. J. Horner - WGK Richard - G. 0 . C ^ Savare/T.- -- t-cn " - C-. On-rVJGX S . Tnonpscn TITLE entachlorcphenol/Santobrite Dioxin Studies (continued ir or?. eport Ho. J242-2, 8-15-70, S.H. Vogel) 3BJECTIVE ! Measure dioxin concentrations and formation races in process, product, and end-use pentachlorophenol/santobrite streams. . Evaluate effectiveness of various' routes of pentachlorophenol dioxin removal and suppression. antohrite and pentachlorophenol (penta) each slowly increase in ioxin content when held at elevated temperatures. Solutions of enta (cyclosol-53)j 3.s well as aqueous santcbrite solutions, also ncrease slowly in dioxin content when held at elevated temperatures, n each case, the formation rate increases with temperature. Typical emperatures however, in 'end-use processes are quite moderate (3~0-220F) . ormaticn rates at these temperatures are very meager. For this reason, ioxin build-up in treating plant oils cr their sludges is negligible. inished penta and santcbrite contain at least three different dioxins exa. h e p t a , and-octa chlorcdibenzodioxin. Octachlorocibenzodiozin OCDD) is the major dioxin present. Other lov;er chlorinated dioxins ave not been detected in finished penta cr santcbrite. Trace amounts 4 1 ppm) of 2,3,7s3-t etrachloroditenzodicxin (TCDD) however, have been etected at the"dichlor,r stage of penta chlorination. Ultimately urther chlorination transforms TODD to the higher chlorinated ioxins (hexa-octa). TCDD if present in penta is <-0.5 pom which is the etecticn limit of our test. s m e n t i o n e d ^ o ' 1v* ^ j. V-- w ------t--- W, **l *Kz r\ n penta are formed curing the final stages G rmation can be suppressed considera bly by of ch usinm a: ta 1 4 O of dioxins o r i n a t on. This milder chlorination Confidant??.! -Subject to Protective. Order COU SO Progress Report 'echnology Department 090171 Page 2 WGK 11/15/71 :onditions. Keeping the batch heat history as low as possible, --_ 3speclally In the later stages of chlorination.Is most essential. jOW heat history, coupled with increased hydrogen ion concentration luring, chlorination, suggests further benefit in dioxin suppression. Increased hydrogen ion concentration is effected by addition of 'small amounts of or by chlorination under mild pressure (increases -iCl concentration in the mass).' lab tests have confirmed chlorine is the initiator in dioxin formation, ./hen-free chlorine in molten penta is eliminated, dioxin formation is stopped. Introduction of small amounts of chlorine scavengers to molten penta just after chlorination, effectively prevents further dioxin formation. Phenol and para chlorophenol are examples of such scavengers. Para chlorophenol is currently being used in the plant in conjunction with KOI/MOT additives. Subsequently, all normal penta production at this time is dioxin stabiized during the molten hold period. Dioxins, as w e l l as other impurities in penta. can be removed by various purif ici cion techniques"! "Fractional distillation, solvent gxlrcfgtTon from soiui,. ubntachlornnhpna^P or* Tpcrvstallization are each effective purification schemes. Fractionation however appears to be the most economical means of purification. Future Plans and Recommendations123*S. 1. Continue to periodically monitor dioxin levels in Monsanto and competitive penta. 2. Determine if dioxin formation during chlorination can be suppressed by: a. Chlorinating under pressure. b. Chlorinating in presence of mineral acids. - c. Chlorinating in presence of solvent at reduced temperatures. d. Chlorinating in presence of chlorine radical scavengers. e. Chlorinating in presence of increased chloride icn concentration. 3. -Continue to provide analytical support for penta purification "research. S. K. Vogel dy