Document 0dyGL0odzeLy4m6a37QJV96n

a C U v*-- pVc^/7 / BY tephen H. Vogel PROGRESS REPORT ORGANIC C H EM IC ALS QIVISION TECHNOLOGY DEPARTMENT (D. ?.. Dill) FOR ETLJ August, 1970 November, 1973 Yes R E P O R T NO. DATE A II/I5/7: , G. Krummrich J O B NOS. R & D 090171 ill document ii the property of M O N SA N T O COMPANY. Il contains C O N F ID E N T IA L IN F O R M A T IO N which must not be reproduced, vealed to unauthorized persons or sent outside the Company without proper authorization. Tha recipient is responsible for its ufeVwping and -structi on. DISTRIBUTION WITH D E T A I L S "D. c . Armstrong ~ WOK *K. <7 cs Bergen, Jr. - G.O. *0, *Z) * DeC-armo - So. 2nd ?... Dill - G.O. $ ^ L. Gossage - G.O. K D.1 9 E . Keller - So. 2nd "D. K. Lynch/H. J . Horner - WGK *W i R. Richard - G . O . C ^ wraLT> > ?.. Savage/?.- Dalt-crr-*G-.Oo^V/OK E. S. Tr.onpscn - " a TITLE entachlorcD'nenol/Santobrite Dioxin Studies (continued rom 11.G sport :-;o. 4 2 4 2 - 2 , 8-15-70, S.K. Vogel) ' BJECTI VE Measure dioxin concentrations and formation rates in process, product, and end-use pentachlorophenol/santobrite streams. Evaluate effectiveness of various routes of pentachlorophenol cioxin removal and suppression. arv : antotrice ana pentachlorophenol (penta) each slowly increase in ioxin content when held at elevated temperatures. Solutions of er.ta (cyclosol-53)s 2-S well as aqueous santobrite solutions, also nereise 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*0-220 P) . ormaticn rates at these temperatures are very meager. ?cr this reason, ioxin build-up in treating plant oils or their sludges is negligible, inishea penta and santobrite contain at least three different dioxins exa. hepta, and*octa chlorcditenzocioxin. Octachloroditenzodiozin 3CDD) is the major dioxin present, Other lower chlorinated dioxins ave not been detected in finished penta cr santobrite. Trace amounts 1 ppm) of 2,3,7,8-tetrachioroditenzodioxin (TCDD) however, have been etected at the':dichlor" stage of penta chlorination. Ultimately arther chlorination transforms TCDD to the higher chlorinated ioxins (hexa-ccta). TCDD if present in penta is ^0.5 pom which is the etection limit of our test. s mentioned in our previous report, the S t i w L O w 3 i..G v s of dxoxins n penta are formed during the final sta es of chlorination. This ormation can be suppressed considerably oy uoinm milder chlorination Corii.o.,t-I!. .;!- ".Mor to ProtectivaOrdi C 0 1 T Sf Progress Report Technology Department R&D 090171 Page 2 WGK 11/15/71 conditions. Keeping the batch heat history as. low as possible, r. especially in the later stages of chlorination.is most essential. Low heat history, coupled with increased hydrogen ion concentration during, 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 HC1 concentration in the mass).' Lab tests have confirmed chlorine is the initiator in dioxin formation. When-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 stabilized during the molten hold period. Dioxins, as well as other impurities in penta, can be removed by various purification techniques. Fractional distillation, solvent extraction from sodium pentachlorcphenate solution, or recrystallization are each effective purification schemes. Fractionation however appears to be the most economical means of purification. future Plans and Recommendations 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 ion concentration. 3. .-.Continue .to .provide analytical support for penta purification "research. - .... S. K. Vomer dy C c.r. :?-'t;ect to Protective Ordi er1