From: Eugene Ngai <eugene_ngai**At_Symbol_Here**COMCAST.NET>
Subject: Re: [DCHAS-L] Safety with Hydrogen-Filled Balloons
Date: Thu, 4 Apr 2019 19:53:39 -0400
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 00ac01d4eb41$a0dfcc50$e29f64f0$**At_Symbol_Here**comcast.net
In-Reply-To <5CC9AB53-5C63-4530-AEFB-6F461C373E77**At_Symbol_Here**wisc.edu>


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

 

From: TILAK CHANDRA <tilak.chandra**At_Symbol_Here**wisc.edu>
Sent: Thursday, April 4, 2019 2:10 PM
To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**princeton.edu>
Cc: eugene_ngai**At_Symbol_Here**comcast.net
Subject: Re: [DCHAS-L] Safety with Hydrogen-Filled Balloons

 

Hi Craig:

 

Thank you for your note. The balloon was not only filled with the hydrogen, perhaps they also filled it with oxygen. Small balloon will not cause this type of injury. There are other news articles available about this incident.

 

I will send you more information on this.

 

Regards,

 

Tilak

Sent from my iPhone


On Apr 4, 2019, at 12:48 PM, Craig Merlic <merlic**At_Symbol_Here**chem.ucla.edu> wrote:

Colleagues,

 

Following up on the explosion at IIT-Bombay which injured a professor and 2 interns:

https://www.hindustantimes.com/mumbai-news/explosion-at-iit-bombay-injures-professor-2-interns/story-i8UkvjMhnKnDeLyjKUj8iM.html

 

And the dramatic acetylene balloon explosion:

http://www.esdjournal.com/static/Kansas/dauer%20truck.htm

 

This raises questions about the very common synthetic technique used in research labs of using hydrogen-filled party balloons for small scale reduction reactions at atmospheric pressure.   Researchers often fill party balloons with 1-5 liters of hydrogen at a regular gas cylinder, sometimes walk through the lab to their hood, and then connect the balloon to a reaction flask.  (All that in contrast with hydrogenation under pressure in a Parr reactor using fixed high pressure lines.)

 

  1. Have there been reports of explosions when using hydrogen-filled balloons for lab reduction reactions?
  2. What safety precautions should be followed when balloons are used?

 

I can envision a number of things to do to avoid or discharge static electricity, but wonder if others have experience in this.

 

Thanks,

Craig Merlic

 

Professor of Chemistry

UCLA Department of Chemistry and Biochemistry

Executive Director 

UC Center for Laboratory Safety

http://cls.ucla.edu

Los Angeles, CA  90095-1569

Voice:  310-825-5466

 

 

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