Document QJBrV66LJgOz2N4e3GmqpDa9L

35) Discussion of the hydrolysis of PFBS SANITIZED ..+ DEC 0 9 2003 Discussion of the Rate of Hydrolysis Perfluorobutane Sulfonate 1 'j3M Environmental Laboratory, St Paul, MN, 7/22/02 Based on hydrolysis studies of perfluorooctanesulfonate (PFOS) and the mechanism of hydrolytic decomposition of sulfonates, it is a reasonable proposition that/-k'FBqis as resistant to hydrolysis as PFOS. Hydrolysis is a reaction between some species, Rx, with water that results in the substitution of X with OH. While hydrocarbon based sulfonates as a rule are resistant to hydrolysis in the traditional sense, they may undergo an elimination reaction mediated by ' water to below. form sulfuric In the case of acid and olefins via rupture of the carbon-sulfur perfluorinated sulfonates, molecular mechanics bond as shown calculations have shown that the C-S bonds are always weaker than the other bonds in the molecule,' making rupture of that bond the most thermodynamically probable. These two facts imply that if hydrolysis were to occur in a perfluorinated sulfonate, it would occur via C- S bond cleavage. ' Hydrolytic degradation of sulfonates: A hydrolysis study on perfluorooctane sulfonate (PFOS) was conducted at 50C over a 49 day time period. In that study, loss of PFOS was monitored over time at pHs 1.5, 3, 5, 7, 9 and 1 1. The results showed no detectable loss of the initial concentration of PFOS and an environmental half-life of greater than 41 years3 As$FB$and PFOS share the same fiinctionality and the same types of chemical bonds, ifhydrolysis reactions were to occur, they should occur via the same mechanism and at approximately the same rate. 1. Harris, Judith C.; Rate of Hydrolysis in Handbook of Chemical Properly Estimation ibfethods, Environmental Behavior of Organic Compounds; Warren J. Lyman, William F. Reehl, David H. Rosenblatt. Eds. McGraw Hill New York 1982, pp 7-4 2. Dixon, David A.; Fluorochemical Decomposition Processes jM Internal Report, Battelle Memorial Institute - Pacific Northwest Division, April 27,2000, pp 3 (See Public EPA Administrative Record, File AR-226) ? J. Hatfield, T.L. Hydrolysis Reactions of Perfltiorooctane Sulfonate (PFOS), 3M Environmental Laboratory Report W 1878 March 27,2001 (See Public EPA Administrative Record, File AR-226) 1