Carbonyl bromide analysis

This method is of quite general applicability and the carbonyl compound may be an aldehyde, a ketone, or an ester. Similarly, the halide may be chloride, bromide, or iodide although yields are generally lower with iodides. Alkyl and aryl halides react with equal facility and the alkyl halide may be primary, secondary, or tertiary. A few examples of the yields obtained with a variety of reagents are given in Table I (the yields quoted are obtained by g.l.c. analysis of the reaction mixture using an internal standard ). 

Immunoaffinity chromatography cleanup has also been applied as an ideal and reliable strategy for residue analysis. Immunoaffinity columns prepared by coupling the antibodies to a cyanogen bromide-activated support were used to analyze avermectin BI residues in cattle tissues (359) and ivermectin in sheep serum (376). An immunoaffinity column prepared by an alternative activation/ coupling procedure with carbonyl diimidazole was also employed to analyze ivermectin residues in swine liver (361) since the earlier-reported methods did not work well in the analysis of this matrix. This recent work demonstrated the high specificity of tire antibody-mediated cleanup, but also showed that the immunoaffinity procedures could not always or completely eliminate matrix interference of samples. Therefore, application of additional cleanup steps before or after these procedures is often inevitable. 

On the basis of H-NMR and gas chromatographic analysis, it was shown that the product from aliphatic ketones in each case was a mixture of andZ isomers. Changing the solvent, molar ratio of reactants, reaction temperature, reaction time, or the presence of sodium bromide had little effect on the /Z ratio of reaction products. On the other hand, the structure of the substrate showed a profound effect, especially when a bulky tert-butyl group was adjacent to the carbonyl (see Table III). In this case 99% off olefinic compound was formed stereospecifically (46). 

The analysis in the chapter (p. 1200 reproduced below) shows that we need the thioamide of renzoic acid (thiobenzamide available from Aldrich) and an a-bromoketone. We need these rarticular starting materials because the soft sulfur atom will displace the bromide in a frontier-orbital-controlled Sn2 reaction whilst the hard amino group will attack the ketone in a charge-controlled nucleophilic attack on a carbonyl group. 

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. 

It should be noted that there have been two reports in the literature of RADS apparently being induced by exposures to bromotrifluoromethane (BTM) and bromochlorodifluoromethane (BCDFM), fluorocarbons used in fire extinguishers. I86,87 Both are irritant chemicals, and the effects noted seemingly contradict the observation made above that RADS induced by irritants is always to mixtures of lipophiles and hydrophiles. Both BTM and BCDFM, however, thermally decompose and hydrolyze to haloacids (HC1, HBr, and HF) and their corresponding carbonyl halides (carbonyl chloride, bromide, and fluoride), chemicals that are corrosive to human tissue. In the two studies reported, no analysis of the air inhaled by the injured individuals was carried out. It is strongly suspected that their inju-... 

A modified internal standard method has been developed to determine the compositions of terpolymers of maleic anhydride with styrene and a methacrylate or an acrylate. The method involves IR spectrophotometry of the samples. IR spectra are recorded by means of the potassium bromide technique. The IR analysis is based on integrated absorption of the anhydride and ester carbonyl groups. 9 refs. 

The IR analysis was done on dried potassium bromide pellets containing 0.5 mg sample in 200 mg potassium bromide. The peaks at the wave numbers 11.02 pm and 5.82 pm are the most suitable ones for analysis of epoxy and carbonyl groups, respectively. 

The infrared analysis was performed on dried potassium bromide pellets containing 0.5 mg sample in 200 mg potassium bromide. An infrared spectrum of a methyl methacrylate - glycolymethyacrylate copolymer is shown in Figure 3.7. The peaks at the wave numbers 11.02 and 5.82 jim are the most suitable ones for analysis of epoxy and carbonyl groups, respectively. Using the base line density method, the values of the absorbances at 11.02 and 5.82 xm have been determined in triplicate. The average values of the absorbances, their ratio and the glycidylmethylacrylate mole fraction determined chemically are presented in Table 3.10. 

Formally there are five nonequivalent double bonds and, as a consequence, a number of different coordination modes have been reported [51]. The complexes are usually obtained by reaction of the ligand with metal complexes such as iron carbonyls. For example, the constitution of the dinuclear iron azulene complex 131 has been identified on the basis of its crystal structure analysis [138]. The interesting complex 132 with two azulene moeties was obtained by the reaction of triisopropyliron (from isopropylmagnesium bromide and FeClj) and azulene (Scheme 10.46) [139]. 

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