From: ILPI Support <info**At_Symbol_Here**ILPI.COM>
Subject: [DCHAS-L] Acetylene balloons. Was: Re: [DCHAS-L] Safety with Hydrogen-Filled Balloons
Date: Thu, 4 Apr 2019 23:26:30 -0400
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 64928197-129D-4B94-87A5-CD3B452ADB2F**At_Symbol_Here**
In-Reply-To <00ac01d4eb41$a0dfcc50$e29f64f0$**At_Symbol_Here**>

Second hand story as told to me by one of the participants who I will presume wishes to remain anonymous.

A pair of bored chemists had the great idea to fill a Matt's beer ball with stoichiometric acetylene and oxygen at the lab.  A brief history of the beer ball which I imagine most on the list have never heard of:

Anyhow, they were headed off to the woods to set the thing off and one of the duo was carrying it under his arm like a basketball.  Perhaps it had something to do with having run a Pd-catalyzed hydrogenation earlier in the day and the residue acted as a catalyst, perhaps it was static discharge, or perhaps maybe the oxygen and acetylene suddenly realized their activation barrier wasn't as high as they thought, but for whatever reason the thing went off while it was under the guy's arm.

He apparently had a giant purple bruise that ran from his armpit down his hip.  I doubt they sought medical attention given the circumstances.  Lucky there was no lasting damage or blown eardrums.

Try something like that nowadays and you're likely to get visits from several agencies that have 3 letter abbreviations!

Rob Toreki

Safety Emporium - Lab & Safety Supplies featuring brand names
you know and trust.  Visit us at
esales**At_Symbol_Here**  or toll-free: (866) 326-5412
Fax: (856) 553-6154, PO Box 1003, Blackwood, NJ 08012

On Apr 4, 2019, at 7:53 PM, Eugene Ngai <eugene_ngai**At_Symbol_Here**COMCAST.NET> wrote:

This now makes sense that air was mixed with the H2. I believe if it was only H2 it would have popped and flashed
Acetylene balloons are more dangerous than H2 because Acetylene is unstable. It can explosively decompose, this is the reason why special solid filled cylinders are used. The larger the diameter or pressure of the system the quicker it transitions to a detonation.
The energy of decomposition is higher than the oxidation reaction.
Eugene Ngai
Chemically Speaking LLC

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