Subject: Re: Phosgene in Japanese incident?
From: nreitzel@lonestar.jpl.utsa.edu (Norman L. Reitzel   )
Date: Apr 20 1995
Newsgroups: sci.chem

In article <mfein.14.0026E2BA@aplcomm.jhuapl.edu>
mfein@aplcomm.jhuapl.edu (Matt Feinstein) writes:

>	It says in my newspaper that the Japanese think phosgene was used in 
>the most recent gas attack in Yokohama.. But the report also says that the gas 
>had a 'sharp, foul odor'.  I thought that phosgene has a flowery odor.  Am I 
>wrong?  Is there another gas that would be synthesized along with phosgene 
>that would produce a foul odor?

Phosgene has a flowery sweet odor only when very dilute.  A strong whiff 
is quite reminiscent of HCl, and is plenty sharp.  However, I wonder 
about the reports, also.  I've managed to catch whiffs of phosgene odor 
in a good functioning fume hood, but a good lungfull is quite lethal, but 
the lethality is delayed.  Since we haven't heard any follow-up articles 
about exposes persons dropping dead, I can't help wonder if the stuff 
wasn't some less lethal active halide, like say benzyl bromide.  That 
stuff is easy to make (one of my age-14 projects) and it sure enough is 
sharp and foul, and a -dandy- lachrymator as well (ask my parents).

  ------------------------------------------------------------------------
  Norman L. Reitzel, Jr.       |    "When you live beside the graveyard,
  nreitzel@lonestar.utsa.edu   |     you can't cry for every funeral."
  Blue Water Ventures, dba.    |                     Russian Proverb
  ------------------------------------------------------------------------

From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: WELDING GALVANIZED
Date: Sun, 27 Sep 1998 20:12:33 GMT

On 27 Sep 1998 04:05:45 GMT, "Don Foreman"
<foreman_don@htc.honeywell.com> wrote:

>Beg to differ, please.  Not phosgene.  Phosgene can be generated by teflon
>or freon when subjected to high temps, but not galvanized steel.  Welding
>galvanized generates zinc fumes -- also not good, but not phosgene by any
>means.

Perhaps (but not likely) from freon (depends on which freon and what
conditions) but no way from teflon.

Phosgene COCl2 sometimes referred to as carbon oxychloride is produced
by passing a mixture of carbon monoxide and chlorine over a catalyst.
Teflon does not contain chloride and it would take some pretty exotic
chemistry to produce phosgene from a freon.

The fumes probably will be zinc oxide which is also not good for the
lungs. In addition zinc is not good for the weld either. It is best to
remove the zinc first or braze.

Muriatic acid will remove the zinc (both inside the tube and outside).


>Cautions of ventilation still definitely apply.

Absolutely.