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Previous by Date: Subject: Dental Schools and silica Date: Mon, 20 Sep 2010 16:21:35 -0400 Author: "Wawzyniecki Jr, Stefan" |
Next by Date: Subject: Re: Peroxide Question Date: Mon, 20 Sep 2010 18:45:41 -0500 Author: Andrew Stice |
Our waste handler won't accept bottles over 10ppm peroxide, therefore that's my limit. Karen Smith, CSMM Chemical Hygiene Officer/ Lab Coordiantor Whitman College 345 Boyer Ave. Walla Walla, WA 99362 509 527-5272 On Sep 20, 2010, at 12:10 PM, Johnson, Amy Carr wrote: > Here is a link to the article from which the excerpt below was taken > regarding safe levels of peroxides http://www.bnl.gov/esh/cms/PDF/peroxides.pdf > > > > =93Kelly (7) reviewed the literature to determine the minimum > hazardous concentration of peroxides in solution > with organic solvents. Peroxide concentration of 100 ppm has been > widely used as a control point, but lacks > scientific justification and is probably based on the practical > detection limit of the potassium iodide method. Kelly > reported great disparity (range 50-10,000 ppm as hydrogen peroxide) > between various references. There was little > agreement between authors and none provided supporting data. The > highest level (10,000 ppm) was found in a > National Safety Council publication (16). However, the NSC > publication included no supporting references for the > latter statement or the NSC recommendation for administrative > control value of 100 ppm. > The Material Safety Data Sheet for diethyl ether cautions against > concentrating ether containing peroxide level > above 100 ppm (10). Presumably, instability and hazard increase with > concentration such that at some point, the > solution spontaneously explodes. Kelly suggested that it is likely > that the control concentration of 100ppm, in some > cases may be overly conservative by at least an order of magnitude. > This may apply to the chemicals listed in Table > 1-B unless the unstable materials are concentrated as result of > solvent evaporation (7). > Kelly (7) stated that "theoretically, explosion should be impossible > for most solutions of <1% peroxides." > However, to rationally establish a safe/hazard concentration is > complicated by a number of factors. For example, > some of the liquid may remain on the threads and cap when > peroxidized liquids are dispensed from glass containers > with screw-caps or with ground-glass stoppers. As the solvent > evaporates, the peroxide can be concentrated to > dangerous levels within in the threads of the cap. Thus, a volatile > solvent containing relatively low peroxide > contamination could explode because of peroxide concentration at the > cap (3, 7). Dilute solutions of most > peroxidizable chemicals or solutions in solvents with low volatility > (B.P. > 300 o C or V.P. <0.1 mm Hg at 20 o C) > usually do not pose a peroxide hazard and are not likely to > concentrate. Thus, it is usually unnecessary to treat such > solutions as peroxide hazards (3, 5). > Some of the peroxidation products of the chemicals in Group A (Table > 1) are less structurally stabile than those > in Group B. Thus even peroxide concentrations of less than 100 ppm > should be considered very hazardous. > Unstabilized isopropyl ether can readily form highly unstable > peroxides. Even low small concentrations produced > through solvent evaporation are very dangerous and may explode on > shaking (33). The temperature and > concentration at which explosion of peroxides of isopropyl ether > becomes probable has never been authoritatively > stated (20).=94 > > Hope this helps- > From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**list.uvm.edu] On > Behalf Of Bill Galdenzi > Sent: Friday, September 17, 2010 9:17 AM > To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU > Subject: [DCHAS-L] Peroxide Question > > All, > > I have a question: What concentration of peroxide do you folks use > for your =93acceptable=94 level? What is the basis for this level? > > Thanks for your help. > > Bill Galdenzi > Environmental, Health, and Safety > Boehringer-Ingelheim Pharamceuticals > (203) 778-7759 > bill.galdenzi**At_Symbol_Here**boehringer-ingelheim.com >
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