I have read of apparatus to use perchloric acid on a small scale in a non-perchloric hood. I have not used them nor, in good conscience, suggest that they be used. Our laboratory is fortunate to have a perchloric acid hood although we currently don't use it much. I don't believe there is a minimum where you can 'ignore' the safety concerns, especially if heating the acid. Use of cold or dilute perchloric acid does not result in any hazardous vapors or gases and does not require a hood at all. I know it has been used in titrations of organic compounds (an aniline assay in a job 30 yrs ago, D2896-05 Standard Test Method for Base Number of Petroleum Products by Potentiometric Perchloric Acid Titration, etc) but no heating was involved. I have heard of people using perchloric acid for wet oxidation of oils. I do remember one thing said - when it starts to go wrong, run. I know I don't know what 'wrong' would be and I probably wouldn't recognize it until too late. I definitely wouldn't use an oil bath to heat perchloric acid. What if, somehow, the vessel containing the acid broke? If that were to happen, it's too late to run. You may wish to review this link at GFS Chemical: http://www.gfschemicals.com/TechnicalLibrary/Questions-About-Perchloric- Acid.asp The information contained in this e-mail message and any attachments may be confidential. It is intended only for the use of the individual or entities named above. If the reader of this message is not 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 e-mail at the originating address. Peter Lazarski National Grid USA Lab. & Testing Svcs., Bldg. 1 7437 Henry Clay Blvd. Liverpool, NY 13088 (315)460-2114 -----Original Message----- From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of Gordon Miller Sent: Monday, November 14, 2005 8:41 PM To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU Subject: [DCHAS-L] Questions About Perchloric Acid I have one good question and two dumb ones. They are: What is a good chemistry and design for a scrubber to be used to control emissions of perchloric acid from small scale heating operations done in common hoods? Is there a quantity of perchloric acid that is so small that it can be handled without benefit of a special hood, even if heated (Is there a de minimis quantity)? What is the derivation of the NFPA 45 requirement that HClO4 not be heated by flame or in an oil bath? I can guess, but I don't know. Please advise. "Inquiring minds want to know." Gordon Miller Lawrence Livermore National Laboratory P.O. Box 808 (L-379) Livermore, California 94550 (925) 423-8036 Fax (925) 422-5176 miller22**At_Symbol_Here**llnl.gov **** For your information: Granite State Electric, Massachusetts Electric, Nantucket Electric, Narragansett Electric, and Niagara Mohawk are each doing business under the name National Grid. **** This e-mail and any files transmitted with it, are confidential to National Grid and are intended solely for the use of the individual or entity to whom they are addressed. If you have received this e-mail in error, please reply to this message and let the sender know.
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