[Histonet] picric acid
koellingr <@t> comcast.net
koellingr <@t> comcast.net
Sun Feb 5 13:05:54 CST 2012
I whole-heartedly agree with and applaud Amos Brooks playing Devil's advocate. I certainly would never discount the degree of danger with what is a high explosive and would take all due caution using disposal people who know what they are doing. But there is a use for the substance and one needs to separate mystery and uncertainty and incomplete facts and anecdote from actual fact. It is my understanding that while pure, crystalline picric acid might be unstable and shock sensitive (and a danger to a degree), it is the metal or salt picrates that are way, way more dangerous. Thus warnings in chemistry for picric acid; don't use metal spatula's. No metal cans or metal caps. Don't drop on concrete (silica and other things). Don't dispose down drain (lead or other metals). When viewing the chemistry guy in college who "blows up" a minute amount of picric acid on an asbestos pad over a Bunsen burner it is NOT pure picric acid but PA plus Pb (Lead) salt. While artillery shells might have been filled with picric acid they were relatively stable but they became way more unstable if the picric acid reacts with the metal casing or fuse casing (the infamous Halifax Explosion???). Thus the following to my utter dismay. You hear or watch on youtube a "bomb disposal unit"?? blowing up a glass jar of dangerous picric acid they remove from school. In the field right next to a soccer goal post. As a former soccer goalie who used to dive all over the ground my question is; is anyone picking up the thousands of shards of glass from the soccer field? And what about the dispersed picric acid since no chemical reaction is 100% efficient and there must be dangerous picric acid (residue) all over the place. It is not well known but prior to the Trinity blast there was a lot of study of encasing the bomb in an enormous containment vessel called Jumbo. If the lens shaped, multi-firing pin, high explosive nest surrounding the sub-critcal fissionable mass had mis-fired by even a milli-second, the core would have blown to one side instead of attaining criticality by being compressed. As there was very little fissionable grade material on the face of the earth at that point, they wanted to retrieve it "clean it from the environments and re-use it" by containing it. What if they had used Jumbo (it still sits, unused hundreds of yards away from detonation point), while most of it would have vaporized in the successful test, might there not be shards of highly radioactive bits of metal scattered and raining down for hundreds of square miles including on sports fields near towns. Where soccer goalies play?
----- Original Message -----
From: "Amos Brooks" <amosbrooks <@t> gmail.com>
To: histonet <@t> lists.utsouthwestern.edu
Sent: Sunday, February 5, 2012 6:47:12 AM
Subject: [Histonet] picric acid
The largest disaster I know of related to picric acid (among other
things) is one that every one working with it should keep in mind. The
Halifax explosion basically leveled the city of Halifax, Nova Scotia,
Canada in 1917. While they were carrying much more than the 500 ml to 1
gallon that we might use it is worth noting the magnitude of what this
caused. There is a really good Wikipedia article on it here:
This was a terrible disaster and it underscores why we need to be
really conscious of the chemicals we work with, and even the ones we
haven't used in years.
I would also like to play Devil's advocate here though. Yes there are
inherent hazards with many chemicals we work with. But, we also need to be
able use these chemicals in a safe manner. If used safely, these chemicals
can be used for stains that cannot really be replicated with substitutes.
Picro-sirius red is a good example of this.
The solution to hazardous chemicals is not getting rid of them and
burying your head in the sand. It is education and understanding of the
hazards and using them properly.
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