Carbonyl bromide properties

Analogues of phosgene, such as carbonyl bromide have been studied at various times, 1 but experiments on the chemical and particularly toxicological properties have only been carried out in the last few years. ... 

Only a few of the physical properties of COBrF have been measured. Carbonyl bromide fluoride (relative molecular mass 126.91) is a colourless gas, with an odour similar to, but distinguishable from, phosgene [1195]. The melting point at atmospheric pressure of COBrF has been reported as -120 2 C [1196a], and the boiling point as -20.6 "C [1196a]. Its critical temperature occurs at +124 C, and its critical pressure is ca. 6.18 MPa [656a,1751]. 

The only solid state property on record for carbonyl bromide fluoride is its melting point -120 i 2 C [1196a]. 

Partial oxidations [104,105] of polysaccharides is commonly done, both during stmctural analysis and to modify their properties. Oxidation introduces both carbonyl and carboxylate functions at different positions, and especially in alkaline systems, can result in chain cleavage, i. e., depolymerization [108]. Oxidation using sodium hypochlorite by itself [109] or in combination with sodium bromide [110] is practiced in the starch industry, both to introduce specific properties into the product and for depol)merization. This oxidation is non-specific. 

The bis-acetonitrile complexes 55-63 were not active for either TH or DH of acetophenone in /PrOH/KOtBu. However, the monocarbonyl complexes 67, 68, 70 and 73 with the correct steric and electronic properties at phosphorus " " and nitrogen, " as defined in Section 8.3.2.1 were active for TH but not DH as long as they were first activated with KOfBu in /PrOH. The complexes 67 and 73 with bromide and acetonitrile trails to carbonyl provided the same ATH activity and selectivity. The bromide complexes were easiest to prepare and were used for most of the catalyst testing. 

There has been considerable effort devoted to optimizing the conditions for the polymerization and the final conversion step [2, 10]. The temperature for the conversion can be dramatically lowered to 100-115 °C by using a bromide [12] or a dodecylphenylsulfonate counterion [13] instead of a chloride. Performing the conversion under an inert atmosphere improves the optical properties of the PPV as traces of oxygen have been shown to induce formation of carbonyl defects during the conversion [14]. 

Esterification of the ketoacid (39) with diazomethane afforded the ketoester (40). This, on treatment with sodium hydride and diethyl carbonate in 1,2-dimethoxyethane, furnished (41) whose NMR spectrum was rather complicated, probably due to contamination with a small amount of tautomer. Reduction of the free carbonyl group with sodium borohydride led to the formation of alcohol whose tosyl derivative on heating with lithium bromide and lithium carbonate in dimethylformamide gave the diester (42). Its spectroscopic properties were identical with those of the one reported [20]. As the diester (42) has already been converted to warburganal (12), the present route for the diester (42) constitutes a formal total synthesis of warburganal. 

While the physical properties of the metal carbonyls are distiiiatly different from those of both carbon monoxide and the particular metal, much of the chemical behavior of the carbonyls is typical of that of the metal and of carbon monoxide. Thus, nickel carbonyl reacts vigorously with bromine to form nickel bromide and hberate carbon monoxide ... 

Data in Table V illustrate the production of acetic acid from 1/1 syngas. A variety of ruthenium-containing precursors - coupled with cobalt halide, carbonate and carbonyl compounds - at different initial Co/Ru atomic ratios, have been found to yield the desired carboxylic acid when dispersed in tetrabutylphosphonium bromide. In a more detailed examination of the ruthenium-cobalt-iodide melt catalyst system, we have followed the generation of acetic acid and its acetate esters as a function of catalyst composition and certain operating parameters, and examined the spectral properties of these reaction products, particularly with regard to the presence of identifiable metal carbonyl species. 

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