Corante

About this Author
DBL%20Hendrix%20small.png College chemistry, 1983

Derek Lowe The 2002 Model

Dbl%20new%20portrait%20B%26W.png After 10 years of blogging. . .

Derek Lowe, an Arkansan by birth, got his BA from Hendrix College and his PhD in organic chemistry from Duke before spending time in Germany on a Humboldt Fellowship on his post-doc. He's worked for several major pharmaceutical companies since 1989 on drug discovery projects against schizophrenia, Alzheimer's, diabetes, osteoporosis and other diseases. To contact Derek email him directly: derekb.lowe@gmail.com Twitter: Dereklowe

Chemistry and Drug Data: Drugbank
Emolecules
ChemSpider
Chempedia Lab
Synthetic Pages
Organic Chemistry Portal
PubChem
Not Voodoo
DailyMed
Druglib
Clinicaltrials.gov

Chemistry and Pharma Blogs:
Org Prep Daily
The Haystack
Kilomentor
A New Merck, Reviewed
Liberal Arts Chemistry
Electron Pusher
All Things Metathesis
C&E News Blogs
Chemiotics II
Chemical Space
Noel O'Blog
In Vivo Blog
Terra Sigilatta
BBSRC/Douglas Kell
ChemBark
Realizations in Biostatistics
Chemjobber
Pharmalot
ChemSpider Blog
Pharmagossip
Med-Chemist
Organic Chem - Education & Industry
Pharma Strategy Blog
No Name No Slogan
Practical Fragments
SimBioSys
The Curious Wavefunction
Natural Product Man
Fragment Literature
Chemistry World Blog
Synthetic Nature
Chemistry Blog
Synthesizing Ideas
Business|Bytes|Genes|Molecules
Eye on FDA
Chemical Forums
Depth-First
Symyx Blog
Sceptical Chymist
Lamentations on Chemistry
Computational Organic Chemistry
Mining Drugs
Henry Rzepa


Science Blogs and News:
Bad Science
The Loom
Uncertain Principles
Fierce Biotech
Blogs for Industry
Omics! Omics!
Young Female Scientist
Notional Slurry
Nobel Intent
SciTech Daily
Science Blog
FuturePundit
Aetiology
Gene Expression (I)
Gene Expression (II)
Sciencebase
Pharyngula
Adventures in Ethics and Science
Transterrestrial Musings
Slashdot Science
Cosmic Variance
Biology News Net


Medical Blogs
DB's Medical Rants
Science-Based Medicine
GruntDoc
Respectful Insolence
Diabetes Mine


Economics and Business
Marginal Revolution
The Volokh Conspiracy
Knowledge Problem


Politics / Current Events
Virginia Postrel
Instapundit
Belmont Club
Mickey Kaus


Belles Lettres
Uncouth Reflections
Arts and Letters Daily
In the Pipeline: Don't miss Derek Lowe's excellent commentary on drug discovery and the pharma industry in general at In the Pipeline

In the Pipeline

« Silent Mutations and Noisy Ones | Main | The State of the State of the Art »

August 4, 2004

Things I Won't Work With: A Nasty Condensed Gas

Email This Entry

Posted by Derek

If you cool things down enough, you can turn almost anything into a liquid (or into a solid, if you're really insane about it.) Chemists use liquid ammonia fairly often, for example, though it's been some years now since I've needed any. People outside the field think of the aqueous solution of ammonia gas (household ammonia) when you say "liquid ammonia", but I'm talking about the pure stuff. Cool the gas down below about -33 C, and you'll condense it out to a clear liquid that's sort of like a thinner version of water.

It's easy enough to do, with an ammonia tank and a condenser full of dry ice. But once, over twenty years ago, I had a chance to see someone use one of those rigs to condense something a bit more exotic: pure hydrogen cyanide. That's another one that people confuse with the aqueous solution. But pure HCN has a fairly high boiling point, for such a small molecule, and condensing out is no problem - as long as you have more nerve than you have sense.

The fellow doing it was down the hall from me in graduate school, and he was doing an obscure reaction which forms a geminal dinitrile, which themselves are rather obscure compounds. (That's probably because this bug-eyed route is the best way to make 'em.) He was dressed in full suit and respirator gear, for which he'd had to get trained. Everyone else had cleared out of the lab, but someone was watching him at all times from the hallway, just in case.

I thought to myself, "When am I going to get the chance to see pure liquid HCN again?", and went down to see, ready to bail out if anything started going wrong. It looked just like ammonia, clear drops rolling down the cold condenser and dripping into the round-bottom flask below. But there was enough HCN in there to kill off the lot of us, if (im)properly handled.

I've worked with plenty of cyanide since then, and even plenty of reactions that have produced small whiffs of HCN vapor. (As I think I've mentioned, it doesn't smell as much like almonds as it's said to, in my opinion.) But I doubt very much if I've worked with enough of it to match the amount that I saw in that flask, that day - there must have been a couple of moles of it in there. A lifetime supply that was, in many sense of the word. . .

Comments (8) + TrackBacks (0) | Category: Things I Won't Work With


COMMENTS

1. Harry on August 5, 2004 7:57 PM writes...

Oddly enough I used to know a fellow that actually made pure HCN on a kilo basis. He had one customer that bought about 25kg/year.

As you might expect he made it quite simply by adding Sufuric Acid to Sodium Cyanide and condensing the resulting HCN. He actually purified it as he made it by allowing the condensate to reflux in a 10 plate Oldershaw column, and then taking off only the pure HCN.

Like you, I made a point to watch this once from a a safe distance. It was fascinating albeit a bit macabre to watch HCN refluxing.

He actually made the stuff for years with no trouble, but I recall thinking that no matter what he was charging, it wasn't enough.

BTW I really enjoy the lab tales- I've been in the custom Organic synthesis business for over 20 years, so we have some experiences in common.

Have you ever handled organoselenium compounds?

They have the most aweful odors I have ever experienced, putting mercaptans and diamines like cadaverine to shame.

Permalink to Comment

2. Chris Hoess on August 5, 2004 9:07 PM writes...

Hmmm. I seem to recall that the Org. Synth. prep for HCN recommends that the operator smoke during the procedures, as the tobacco apparently sensitizes you to the almond odor and lets you detect leaks at a much lower level. Times have changed...

Permalink to Comment

3. The Novice Chemist on August 6, 2004 10:46 AM writes...

Whoa! Got a reference for that Org Syn prep? That would be one for the group room lunch table.

Permalink to Comment

4. Stewart on August 6, 2004 7:30 PM writes...

Sure enough, it's right there. Org. Synth. Coll Vol. 1, p. 314. Available on the web at http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0314
The original reference for the smoking suggestion is given as Gattermann, Ann. 357, 318 (1907).

Permalink to Comment

5. Derek W on August 7, 2004 3:55 AM writes...

Its also amusing (frightening) to me that ammonia was used as a refrigerant early on. Worked ok, I guess, unless there was a leak. (Google "icy ball" for one example.)

One page notes how this low-tech approach is being recommended for modern day use in third world countries.

Permalink to Comment

6. hound on August 7, 2004 6:45 PM writes...

unfortunately i remember standing too close to a bottle of ammonia i opened while it was on the shelf. Instant immune system failure and sinus infection.this happedened once working with CCl4 also.
I'll take your word on the almond odor;)
My vote for worst odors - either pyridine or carbon tetrachloride.

Permalink to Comment

7. hound on August 7, 2004 6:52 PM writes...

derek, i believe one might have to admit that perhaps ammonia would be safer to the ozone if leaked than other refrigerants.

Permalink to Comment

8. Lawrence B. Ebert on August 13, 2004 1:27 AM writes...

Of the mention of ammonia as a refrigerant, recall that Einstein and Szilard got a patent in the area. Motivated by a news story stating the ammonia refrigerant leaked from a home refrigerator and killed a family, Leo Szilard and Albert Einstein believed that their knowledge of thermodynamics and engineering would be useful in improving refrigerators. The device they designed was actually manufactured, but then freons came.

Permalink to Comment


EMAIL THIS ENTRY TO A FRIEND

Email this entry to:

Your email address:

Message (optional):




RELATED ENTRIES
XKCD on Protein Folding
The 2014 Chemistry Nobel: Beating the Diffraction Limit
German Pharma, Or What's Left of It
Sunesis Fails with Vosaroxin
A New Way to Estimate a Compound's Chances?
Meinwald Honored
Molecular Biology Turns Into Chemistry
Speaking at Northeastern