Thanks, I've got a copy of Schilt on my desk, as well as the Schumacher book. Good for generalities, but I was hoping someone had come across something along the lines of "10-12% perchloric in EtOH is stable until you heat it past 130C." I did in the past find similar data for the ethanol-nitric system. I've asked our reference librarian to look as well, but neither he nor I have been coming up with anything.
You want to get a copy of the book "Perchloric Acid and Perchlorates" by Alfred A Schilt. I obtained my copy from GFS Chemicals, Inc. Page 140 ff has a discussion of the issues related to electropolishing with many literature references.In the absence of specific data, I urge you to have a DSC analysis of the specific mixtures to determine their stability. The thermal data will provide you with the boundaries for safe work.nl------------------------------------------------------------------------------------The information contained in this message is privileged and confidential and protected from disclosure. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message and deleting it from your computer.ACSafety has a new address:NEAL LANGERMAN, Ph.D.ADVANCED CHEMICAL SAFETY, Inc.PO Bs" byox 152329SAN DIEGO CA 92195011(619) 990-4908 (phone, 24/7)We no longer support FAX.Please contact me before sending any packages or courier delivery. The address for those items is:5340 Caminito CachorroSan Diego CA 92105
I was wondering if anyone knows of any actual data about the stability of various perchloric acid-organic solvent mixtures. The mixtures in question are relatively (<10-15%) dilute solutions of perchloric in ethanol, ethylene glycol, butyl Cellosolve, etc. used for electropolishing. I'm having trouble finding literature reports.. Of course, there's plenty of reports (Bretherick's, et.al.) about hazards, but no actual information on how much is too much.
Normally, I would recoil from such mixtures, but perchloric-organic mixtures are pretty extensively used in the metallurgy literature. Just because something has been successfully used without incident, though, does not mean that it was used "safely." It may mean that the lab was lucky.
I've had some problems in the past with other witch's brews used for electropolishing, after which I determined that the literature-reported composition was beyond the actual stability limit for the particular (ethanol-nitric acid) system, so that's kind of sensitized me to this application.
regards,dan=============================Dr. Daniel R. KuespertHomewood Laboratory Safety AdvocateKrieger School of Arts & Sciences/Whiting School of EngineeringThe Johns Hopkins University103G Shaffer Hall3400 North Charles St.Baltimore, MD 21218(410) 516-5525
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