03-24-02 04:16
No 287158
Extract from patent GB538028 (Improvements in and relating to the manufacture of Thionyl Chloride) :
It is know that thionyl chloride can be prepared by reacting phosgene with sulphur dioxide in the presence of a cataylst such as charcoal when the main products are carbon dioxide and thionyl chloride.
PHOSGENE IS VERY TOXIC (TEN TIMES AS TOXIC AS CHLORINE GAS)
Phosgene is formed with HCl when chloroform is oxidised (this happens on standing in air, particularly in sunlight)
2CHCl3 + O2 = 2COCl2 + 2HCl
Umm, how interesting !!
(Hive Photographer)
03-24-02 09:30
No 287231
PHOSGENE IS VERY TOXIC (TEN TIMES AS TOXIC AS CHLORINE GAS)
This one is then ten times less toxic and gives you two valuable products:
1) PCl3 + Cl2 -> PCl5
2) PCl5 + SO2 -> POCl3 + SOCl2
(Official Hive Translator)
03-24-02 10:53
No 287262
Dear Elementary!
I don't know what you see as the best method of utilization of SOCl2, but! But!
Would you mind sharing w/me a way of converting CHCl3 into phosgene?
See, COCl2 can bee used in Vilsmeier formylations - actually, it's better than SOCl2.
Antoncho
(Hive Bee)
03-24-02 16:01
No 287312
This procedure avoids having to use phos' chlorides, that are very difficult for some individuals to aquire
Umm, how interesting !!
(Hive Bee)
03-24-02 16:11
No 287313
"Would you mind sharing w/me a way of converting CHCl3 into phosgene?"
This is only an idear, but the know oxidation of CHCl3 by exposure to air (normally combated by adding small amounts of ethanol to CHCl3) could possibly be accelerated by the addition of dilute hydrogen peroxide solution.
EDIT : this would not work because the water in the hydrogen peroxide solution would hydrolize the phosgene. A dry oxidising agent in a appropriate solvent would be called for probably !
(BTW) does anyone know of a chemical test for phosgene ?
Ref :
Oxidation of CH3Cl
This can be prevented by storing chloroform in dark glass bottles with well fitting stoppers. Sometimes about 1% of alcohol is added to convert any phosgene into harmless ethyl carbonate.
Umm, how interesting !!
(Distinctive Doe)
03-24-02 17:32
No 287319
Warning this is DANGEROUS
Subject: Re: How concentrate 30 % H2O2 to 90 % H2O2
From: nreitzel@lonestar.jpl.utsa.edu (Norman L. Reitzel )
Date: Feb 29 1996
Newsgroups: sci.chem
In article <31330953.0@news-feed.tfi.be> P. COCKS <> writes:
>Is it possible with a litle chem lab to concentrate
>H2O2?
>What are the dangers of 90 % H2O2 ?
>Can it explode spontanously ?
You can concentrate 30% H2O2 to 90% by drying it in a dessicator over concentrated sulfuric acid. Use a 4:1 ratio of acid to peroxide.
The 90% peroxide is -quite- explosive unless it is -absolutely- pure.
Worse, it sets things on fire on contact. If you plan on doing this thing, go to a Library first, and read the article on hydrogen peroxide in _Preperative Inorganic Chemistry_.
I'll make that patent clickable
Patent GB538028
Those who give up essential liberties for temporary safety deserve neither liberty nor safety
(Old P2P Cook)
03-24-02 18:53
No 287340
Vogel gives a procedure for producing phosgene by dripping carbon tetrachloride into 100% sulfuric acid at 120-130°C and absorbing the phosgene into toluene.
3CCl4 + 2H2SO4 __> 3COCl2 + 4HCl + S2O5Cl2
Vogel comments: "the resulting phosgene is absorbed in the toluene, whilst the hydrogen chloride passes on."
The trouble with phosgene is that while it is extremely toxic by inhalation it does not have an unpleasant or choking odor nor any immediate effects. It is very easy to breathe fatal amounts without knowing it.
The only time that I have worked with phosgene was incidentaly when it was produced as a decomposition product while distilling oxalyl chloride at atmospheric pressure.
(Hive Bee)
03-24-02 19:43
No 287349
Using Sodium Chlorate might work.
3CHCl3 + NaClO3 -> 3COCl2 + NaCl + 3HCl
Umm, how interesting !!
(Newbee)
03-24-02 20:00
No 287351
Elementary:(BTW) does anyone know of a chemical test for phosgene ?
silver nitrate solution
(Old P2P Cook)
03-24-02 20:49
No 287362
Elementary:(BTW) does anyone know of a chemical test for phosgene ?
From the Merck Index, see the end of the listing for preparation of the indicator paper.
Monograph number: 7491
Title: Phosgene.
CAS Registry number: [75-44-5]
CA name(s): Carbonic dichloride;
Additional name(s): carbonyl chloride; chloroformyl chloride.
Molecular formula: CCl2O
Molecular weight: 98.92
Composition: C 12.14%, Cl 71.68%, O 16.17%.
Line formula: Cl2C=O.
Literature references: Prepn from chlorine + carbon monoxide: Whitehouse, U.S. pat. 1,231,226 (1917); Peacock, U.S. pat. 1,360,312 (1921); Bradner, U.S. pat. 1,457,493 (1923); Douthitt, U.S. pat. 2,847,470 (1958 to Texas Co.); from carbon monoxide + nitrosyl chloride: Williams, U.S. pat. 1,746,506 (1930 to du Pont Ammonia Corp.); from carbon tetrachloride + oleum: Murphy, Reuter, Aust. Chem. Inst. J. Proc. 15, 144 (1948). Toxicology: S. A. Cucinell, Arch. Environ. Health 28, 272 (1974). Review: E. E. Hardy in Kirk-Othmer Encyclopedia of Chemical Technology vol. 17 (Wiley-Interscience, New York, 3rd ed., 1982) pp 416-425.
Properties: Colorless, highly toxic gas; suffocating odor; when much diluted with air there is an odor reminiscent of moldy hay. Condenses at =0 deg to a clear, colorless, fuming liquid. d40 1.432. mp -118 deg. bp760 8.2 deg. Vapor press at 20 deg: 1215 mm. Slightly sol in water and slowly hydrolyzed by it; freely sol in benzene, toluene, glacial acetic acid and most liq hydrocarbons.
Melting point: -118
Boiling point: 8.2
Density: 1.432
Caution: Insidious poison as it is not irritating immediately, even when fatal concns are inhaled. May cause severe pulmonary edema (may be quickly fatal) or pneumonia. Inhalation of high concns causes choking, constricted feeling in chest, coughing, painful breathing, bloody sputum. Vapors strongly irritating to the eyes, cf. Patty's Industrial Hygiene and Toxicology vol. 2C, G. D. Clayton, F. E. Clayton, Eds. (Wiley-Interscience, New York, 3rd ed., 1982) pp 4126-4128. Note: Paper soaked in alcoholic or carbon tetrachloride soln contg 10% of a mixture of equal parts of p-dimethylaminobenzaldehyde and colorless diphenylamine, then dried, will turn from yellow to deep orange in the presence of approx the max allowable concn of phosgene, and should always be used where the generation of this gas is possible or suspected.
USE: For the prepn of many organic chemicals; as a war gas.
(Newbee)
03-26-02 20:19
No 288175
BTW:
3CCl4 + 2H2SO4 --> 3COCl2 + 4HCl + S2O5Cl2
you can do other nice things with CCl4:
6S + CCl4 -> CS2 + 2S2Cl2
(Stranger)
03-26-02 22:50
No 288252
ClearLight's first attraction to chemistry was working through prentiss's Chemicals in War, in which the synthesis of major lacrimators was done and inflicted on the local football hoods as a teen on a military base...( couch story later )...however Phosgene has a very insidious method of attack.. smelling slightly like new mown hay, it quickly dulls the olfactory organs. The compound absorbs on the lung tissues, where upon contact with H20 hydrolizes into interstital HCl! The effects appear 8-10 hours after exposure when the lungs start to fill up with liquid, drowing the victim. Death can occur as quickly as 10 minutes from onset of symptoms. Tobacco will have a metallic taste if you've been exposed to phosgene... somewhere around 15-20 mg/m3/min was what I recall the lethal dose was...
Infinite Radiant Light - THKRA
(Hive Bee)
03-26-02 23:15
No 288258
Post 180231 (FloridaAlchemist: "Thionyl Chloride Prep", Chemistry Discourse)