Elements phosgene

The oxidative carbonylation of amines to give ureas is at present one of the most attractive ways for synthesizing this very important class of carbonyl compounds via a phosgene-free approach. Ureas find extensive application as agrochemicals, dyes, antioxidants, resin precursors, synthetic intermediates (also for the production of carbamates and isocyanates), and HIV-inhibitors. Many transition metals (incuding Au [244], Co [248,253-255], Cu [242], Mn [249,256-258], Ni [259], Rh [246,247,260-262], Ru [224,260,263] and especially Pd [219,225,226,264-276], and, more recently, W [277-283]) as well as main-group elements (such as sulfur [284-286] and selenium [287— 292]) have been reported to promote the oxidative carbonylation of amines, usually under catalytic conditions. In some cases, carbamates and/or oxamides are formed as byproducts, thus lowering the selectivity of the process. 

Elemental composition C 12.14%, 0 16.17%, Cl 71.69%. Phosgene can be analyzed by GC using FID or a balogen-specific detector or by GC/MS. Ambient air may be collected in a metal container placed in an argon bath or condensed into any other type cryogenically cooled trap. Alternatively, the air may be collected in a Tedlar bag. The sampled air may be sucked by a condensation mechanism into tbe GC column. 

Note Carbon-, sulfur-, nitrogen-, and phosphorus-containing solvents will evolve oxides of their constituent elements, including CO, on combustion, and these gases are toxic and probably irritants if a fire involving such materials is encountered. Some chlorinated solvents can form phosgene (carbonyl chloride) in fires. 

Phosgene, COClg, is made by mixing carbon monoxide with chlorine in the sunlight or in the presence of a catalyst. Write the equation for this reaction, assigning oxidation numbers to the elements in the reactants and th product. What do you think the electronic structure of phosgene is ... 

If only the simplest compounds of carbon are considered (marsh gas, methyl chloride, carbon tetrachloride, chloroform, carbonic acid, phosgene gas, carbon disulfide, prussic acid, etc.), it is striking that the amount of carbon which the chemist has known as the smallest possible, as the atom always combines with four atoms of a monatomic, or two atoms of a diatomic element that in general, the sum of the chemical units of the elements which are bound to one atom of carbon is equal to 4. This leads to the view that carbon is tetratomic (or tetrabasic). ... 

Phosgene contains three elements, each of which possesses an isotope with a non-zero nuclear spin. Thus, phosgene has been studied by C, O, and nuclear magnetic... 

As seen in Chapter 6, phosgene is thermodynamicaliy stable under standard conditions with respect to its elements. Equation (8.1), and with respect to dissociation. Equation (8.2). 

The thermal dissociation of phosgene into carbon monoxide and elemental chlorine. Equation (8.2), is the reverse of the reaction used widely, either thermally, catalytically or photochemlcally promoted, for the synthesis of phosgene (see Section 5.1). Thus, much of the chemistry relevant to this Section has already been covered in Chapters 5 and 6. Much of the early work, both kinetic and thermodynamic, was marred by a lack of appreciation of the importance of high purity, and the fact that the system takes a very long time to come... 

It is remarkable how pooriy documented, on the whole, are the reactions of phosgene with the main group elements. There are very few classical studies of the reactivity of the elements with phosgene at low temperature, although the number of purely physical investigations are increasing. 

Davy reported that elemental arsenic and antimony both react with phosgene, upon heating, to produce their respective chlorides and carbon monoxide [467]. Phosphorus, however, can be sublimed in an atmosphere of phosgene without any reaction occurring [467]. 

Reactions of phosgene with Group 4, Group 5 and Group 6 elements... 

From the reactions of phosgene with fluorides of the main group elements... 

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