Iodine reaction with, phosgene

A reaction has an elementary rale law if the reaction order of each species is identical with the stoichiometric coefficient of that species for the reaction as written. For example, the oxidation of nitric oxide presented above has an elementary rate law under this definition, while the phosgene synthesis reaction does not. Another example of this type of reaction with an elementary rate law is the gas-phase reaction between hydrogen and iodine to form hydrogen iodide ... 

A military specification [1394a] suggests the determination of phosgene by reaction of phosgene with a solution of sodium iodide in propanone, and titration of the liberated iodine with sodium thiosulfate (see Section 3.2.1.2), correcting for any free chlorine present. 

The sodium salts of dialkyl l-(alkoxycarbonyl)methylphosphonates. in the presence of a further equivalent of NaH, undergo addition of carbon disulfide in EtjO at room temperature to give alkenedithiolates, which are characterized by protonation, alkylation (Mel, EtI, BnCl), oxidation, and phosgenation. For example, reaction with metliyl iodide provides the dialkyl 1-alkoxycarbonyl-2,2-/7i.v(mcthylthio)vinylphosphonates in good yields (68-75%), whereas room-temperature treatment with acetyl or benzoyl clilonde produces l,3-dithietane-2,4-diylidene-foZ5 [(alkoxycarbo-nyl)methylphosphonates] in moderate yields (18-39%, Scheme 8.23). The same oxidation product is obtained by reaction with iodine. 

The reactions of ferrocenylphosphines and tris(diethylamino)phosphine with iodine lead to the formation of iodotri(organo)phosphonium iodides. The related chlorophosphonium chloride obtained from the reaction of tris(dimethyl-amino)phosphine with phosgene has been used as a dehydrating agent for the preparation of A-protected amino-acid amides. ... 

Dithiocarboxylic acids (118) can be converted into 1,3-dithietans (119) by acid chlorides,iodine, HCl, DCCI, or upon standing for a long time, and they are formally thioketen dimers. The cycloaddition of two C=S groups yields thioketen dimers and (120) from methyl isothiocyanate. Derivatives (121) are prepared by the reaction of dithiocarboxylic acids (118) with phosgene. ... 

Liquid phosgene is assayed by an iodometric method which iavolves the foUowiag reaction (52). The released iodine is titrated with sodium thiosulfate. 

The Sodium Iodide Method. The determination of phosgene by this method, due to the Chemisch-Technischen Reichsanstalt, is carried out by titrating the iodine liberated when a gas mixture containing phosgene but free from acid gases, reacts with a solution of sodium iodide in acetone. The reaction is as follows ... 

Phosgene is an oxidising agent, and iodometric techniques, based upon equation (3.2), have been employed for its determination [425,1148,1255,1357,1604]. The reaction must be carried out under anhydrous conditions (commonly in propanone or methyl ethanoate [1604]), and the iodine determined by conventionai procedures, such as by titration with [S fi 3] Although the usual starch indicator cannot be used in propanone solution, the colour of the generated dliodlne affords a reasonably sharp end-point [1560]. In addition, indications of very smali quantities of phosgene are indicated by the reddish-yellow colour of the liberated diiodine, so that the method can be applied for the trace determination of the gas [1560],... 

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