From: NEAL LANGERMAN <neal**At_Symbol_Here**>
Subject: Re: [DCHAS-L] Perchloric acid-organic mixtures
Date: Thu, 5 Jun 2014 09:35:36 -0700
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: 01b101cf80dc$2e9c0110$8bd40330$**At_Symbol_Here**

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.






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:



PO Bs” byox 152329


011(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 Cachorro

San Diego CA 92105



From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Dan Kuespert
Sent: Thursday, June 05, 2014 7:21 AM
Subject: [DCHAS-L] Perchloric acid-organic mixtures


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, 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.






Dr. Daniel R. Kuespert

Homewood Laboratory Safety Advocate

Krieger School of Arts & Sciences/Whiting School of Engineering

The Johns Hopkins University

103G Shaffer Hall

3400 North Charles St.

Baltimore, MD 21218

(410) 516-5525


Previous post   |  Top of Page   |   Next post

The content of this page reflects the personal opinion(s) of the author(s) only, not the American Chemical Society, ILPI, Safety Emporium, or any other party. Use of any information on this page is at the reader's own risk. Unauthorized reproduction of these materials is prohibited. Send questions/comments about the archive to
The maintenance and hosting of the DCHAS-L archive is provided through the generous support of Safety Emporium.