Chlorine vapor reagent

Osmium telroxide (osmic acid [CAS 20816-12-0]) Corrosive upon direct contact severe burns may result. Fumes are highly irritating to eyes and respiratory tract. Based on high-dose animal studies, bone marrow injuiy and kidney damage may occur. 0.0002 ppm (as Os) 1 mg/m (as Os) Coloriess to pale yellow solid with a sharp and irritating odor like chlorine. Vapor pressure is 7 mm Hg at20°C (68°F). Not combustible. Catalyst and laboratory reagent. 

Some of the innumerable reagents used in TEC are based on reactions with more or less well-established mechanism. Eor example, sodium iodobismuthate (Dragendorff reagent) is widely used among others for alkaloids and quaternary ammonium compounds, 4-dimethylaminobenzaldehyde for primary amines and amino acids, 2,4-dinitrophenylhydrazine for aldehydes and ketones, ninhydrin for amino acids and some antibiotics, fluorescamine for primary and secondary amines, phosphomolybdic acid for lipids, various steroids, and other compounds, chlorine vapor followed by Kl/starch for amines and amides. More complex is the mechanism of the reactions with some other reagents, containing high concentrations of sulfuric acid, vanillin/sulfuric acid, phosphoric acid, aluminum chloride, antimony(III)... 

Note The TDM reagent can be used everywhere, where o-tolidine is employed. It can also be used on chromatograms, that have already been treated with ninhydrin, Pauly or ammonia perchlorate reagent or with iodine vapor [1]. Water may be used in place of 80% 2-propanol when making up solutions II, III and IV. The chlorine gas atmosphere in the chromatography chamber can also be created by pouring 5 ml hydrochloric acid (ca. 20%) onto 0.5 g potassium permanganate in a beaker such a chlorine chamber is ready for use after 2 min. 

The chlorination of methyl chloroformate in sunlight was first reported by Hentschel, but without a detailed description of either the procedure or the results. The first step of the present procedure for the preparation of trichloromethyl chloroformate utilizes an ultraviolet light source and affords a simple and reproducible way to obtain this reagent. Although trichloromethyl chloroformate may also be synthesized by photochemical chlorination of methyl formate,the volatility of methyl formate causes losses during the reaction and increases the hazard of forming an explosive mixture of its vapor and chlorine gas. The preparation of trichloromethyl chloroformate by chlorination of methyl chloroformate in the dark with diacetyl peroxide as initiator has been reported. However, the procedure consists of several steps, and the overall yield is rather low. 

Elementary chlorine, bromine, and iodine dissolve in many organic solvents, and the variations in the colors among the iodine solutions in various solvents have been a matter of interest to many workers. (Both bromine solutions and solutions of iodine monochloride show analogous variations, but the effect for iodine is by far the most striking.) In completely nonbasic solvents (for example, CCU and CS2) iodine appears violet, the same color as its vapor but as the basicity of the solvent increases, the iodine color shifts toward orange or brown, presumably because the electronic excitation responsible for the iodine color is made more difficult by approach of electron-rich reagents. As the basicity of the solvent increases, the iodine-to-iodine bond weakens in the organic base, pyridine (reaction c, below), many of the I—I bonds are broken, wrhereas... 

Iodine vapor allows nonspecific, usually nondestructive detection of many sub-stances (e.g. surface active agents [129], pharmaceuticals [130, 131], polyethylene glycols [132], see also Table 12). In addition, reactions have also been described with the vapors of bromine [133—135], cyanogen bromide [136], chlorine [137-141, 209], ammonia [147-147] (see also the reagent Ammonia vapor ). 

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