Phosgene, or Carbonyl Chloride

This reaction can also be brought about without the influence of solar radiation by means of catalysts such as platinum sponge, vegetable carbon, animal charcoal, etc. 

Phosgene was employed for the first time as a war gas in December, 1915. It was used throughout the war alone or mixed with chlorine by emission from containers, while shells were also used which contained the same mixture or one including metallic chlorides as stannic chloride or other war gases such as chloro-picrin, diphosgene, diphenylchloroarsine, etc.  

In the laboratory, phosgene may be easily prepared by treating chloroform with chromic acid mixture  

Either Erdmann s method, based on the reaction between 

Preparation from Oleum and Carbon Tetrachloride loo ml. carbon tetrachloride are placed in a flask, A (Fig. i), fitted with a stopper through one of whose three holes passes a tap-funnel, B, containing 120 ml. oleum (80% free SO3), while a thermometer and a reflux condenser pass through the other two holes. The flask A is gently heated, while fuming sulphuric acid is allowed to enter drop by drop from the tap-funnel, and when this comes into contact with the carbon tetrachloride it reacts according to the equation  

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Chloroform was formerly used in medicine as an anaesthetic. One disadvantage for this purpose is the ready oxidation which chloroform undergoes on exposure to light and air, generating the poisonous phosgene, or carbonyl chloride, COCU- This is counteracted by storing the liquid in dark amber-... 

Among the halogen derivatives of acid radicles especial interest attaches to phosgene or carbonyl chloride because of its great toxic properties, and it was used in the war of 1914-18. 

It burns in air with a blue flame and formation of carbon dioxid it forms explosive mixtures with air and oxygen it is oxidized to carbon dioxid by cold chromic acid. It is a valuable reducing agent, and is used for the reduction of metallic oxids at a red heat. Ammoniacal solutions of the cuprous salts absorb it readily. Being non-saturated, it unites readily with O to form COs, and with Cl to form COCI3, the latter a colorless, suffocating gas, known as phosgene, or carbonyl chlorid. 

Phosgene, or carbonyl chloride, is produced by reacting anhydrous chlorine with high purity carbon monoxide over an active carbon catalyst. The chemical reaction is... 

Phosgene (or carbonyl chloride) is obtained by the action of chlorine on carbon monoxide at about 200 C in the presence of charcoal as catalyst ... 

The more general preparations of A-acyltriazoles and A-acylbenzotriazoles have utilized acid chlorides in reactions with 2-trimethylsilyl-l,2,3-triazole, l-(trimethylsilyl)benzotriazole 133 or l-(tributylstannyl)benzotriazole. Thus 133 reacts with phosgene or sulfuryl chloride to give 1,1-carbonyl- 134 and l,l-sulfonyl-di(benzotriazole) 135. Treatment of 134 with an alkanol affords 1-alkoxycarbonylbenzotriazoles 136. 

The following is a selective list of some typical suppliers (USA and Western Europe) who are currently, or who have recently, produced research quantities of phosgene, isotopically-labelled phosgene, carbonyl difluoride or carbonyl chloride fluoride, for laboratory research or small-scale development studies. This list is always in a state of flux, but it is hoped that it will at least provide some useful starting points in the search for a supplier. Convenient laboratory syntheses of these materials are give in Appendix A5. 

Preparation of Arylcarboxylic Acids and Derivatives. The general Friedel-Crafts acylation principle can be successfully appHed to the preparation of aromatic carboxyUc acids. Carbonyl haUdes (phosgene, carbonyl chloride fluoride, or carbonyl fluoride) [353-50-4] are diacyl haUdes of carbonic acid. Phosgene [75-44-5] or oxalyl chloride [79-37-8] react with aromatic hydrocarbons to give aroyl chlorides that yield acids on hydrolysis (133) ... 

Carbazole-9-carbonyl chloride [73500-82-0J M 300.0, m 100-103 , 103.5-104.5 . Recrystd from C6H6. If it is not very pure (presence of OH or NH bands in the IR) dissolve in pyridine, shake with phosgene in toluene, evaporate and recrystallise the residue. Carry out this experiment in a good fume cupboard as COCI2 is very TOXIC, and store the product in the dark. It is moisture sensitive. The amide has m 246.5-247 , and the dimethylaminoethylamide hydrochloride has m 197-198 . [Weston et al. J Am Chem Soc IS 4006 1953.]... 

Tndecanedione, 47, 95 Tnethylamine, 46, 18 dehydrobromination of o-bromo-y-butyrolactone with, 46, 23 dehydrobromination of or.a -dibromo-dibenzyl ketone, 47, 62 dehydrochlormation of cyclohexane-carbonyl chloride, 47, 34 in synthesis of nicotinic anhydride with phosgene, 47, 90 Tnethyl orthoformate, condensation with N,N diphenylethylene-diaminc, 47,14... 

PHOSGENE Carbonyl chloride, Chloroformyl chloride Poisonous Gas or Liquid, Class A 4 0 0 ... 

Chlorodifluoroamine has been prepared by reaction of difluoro-amine with boron trichloride,1 phosgene (carbonyl chloride),2 or hydrogen chloride 2 treating a mixture of sodium azide and sodium chloride with fluorine 3 reaction of chlorine trifluoride with ammonium fluoride 4 reaction of chlorine with diflu oro-amine in the presence of potassium fluoride 5 and photolysis of tetrafluorohydrazine and sulfinyl chloride (thionyl chloride).6... 

Phenoxazine is easily acylated with acetic anhydride or on heating with acyl chlorides in benzene.12-71,75 A very convenient method is the reaction of phenoxazine with phosgene to give phenoxazine-10-carbonyl chloride (37).73- 76 This acyl chloride is very stable it is not decomposed by short boiling in water or methanol, and gives phenoxazine only with hot sodium hydroxide. On prolonged boiling... 

SAFETY PROFILE Varies widely, Sodium chloride (table salt) has very low toxicity, while carbonyl chloride (phosgene) is lethal in small doses. Therefore, see specific entries. When heated to decomposition or on contact with acids or acid fumes, they evolve highly toxic chloride fumes. Some organic chlorides decompose to yield phosgene. 

Phosgene (CG, Carbonyl or chloroformyl chloride, Carbon oxychloride). COCI2, mw 98.92 colorl, highly toxic gas suffocating odor when much diluted with air there is an odor reminiscent of moldy hay fr pt —127.76°, bp 8.2°, d 1.392g/cc at 19/4°. SI sol in w and slowly hydrolyzed by it freely sol in benz, toluene, gl acet acid, and most liq hydrocarbons. Can be prepd by passing a mixt of carbon monoxide and chlorine over activated carbon, or by other methods described in Refs 1 8... 

The ethylidene, or unsymmetrical di-halogen substitution products of ethane, are not of much importance, because they do not easily undergo reaction. They are prepared by the reactions just described, viz., from aldehyde by the action of phosphorus penta-chloride, -bromide, or -iodide. Also by the action of phosphorus chlor-bromide, PCl3Br2, or of carbonyl chloride (phosgene), COCI2. They may also be made by the further halogenation of the mono-halogen ethanes ... 

Carbonyl Chloride.—The simplest proof of the constitution of the hypothetical substance carbonic acid, H2CO3, is through the synthesis of its salts and esters from carbonyl chloride or phosgene, COCI2. This latter compound is the product of the reaction of the lower oxide of carbon, viz., carbon monoxide, CO, with chlorine in the sunlight or in the presence of a carbon catalyser. 

The maiin domain of oxidation with dimethyl sulfoxide is the conver-sionofprimary alcoholsinto aldehydes andofsecondaryalcoholsintoketones. These reactions are accomplished under very mild conditions, sometimes at temperatures well below 0 °C. The reactions require the presence of acid catalysts such as acetic anhydride [713, 1008, 1009], trifluoroacetic acid [1010], trifluoroacetic anhydride [1011, 1012, 1013], trifluorometh-anesulfonic acid [1014], phosphoric acid [1015, 1016], phosphorus pentox-ide [1006, 1017], hydrobromic acid [1001], sulfur trioxide [1018], chlorine [1019, 1020], A -bromosuccinimide [997], carbonyl chloride (phosgene) [1021], and oxalyl chloride (the Swem oxidation) [1022, 1023, 1024], Dimethyl sulfoxide also converts sufficiently reactive halogen derivatives. into aldehydes or ketones [998, 999] and epoxides to a-hydroxy ketones at -78 °C [1014]. 

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