Bromoform acidity

Here, the initial carbon-bromine distance is 3.6 A, compared to an equilibrium C—Br bond length of 1.97 A in bromoformic acid [143]. 

Possible Role of BrCOOH. The possibility that the nearby Br atom plays a role chemically through an interaction involving all species seems reasonable, but at this point is speculative. Since the photolysis of HBr involves n—a electronic excitation, the biradical HBr can interact with the CO2 n orbitals to form bromoformic acid in a symmetry-allowed, concerted way. This can result in a short-lived, highly excited bromoformic acid intermediate, as shown schematically in Figure 30. The term bromoformic acid is used here to indicate an electronic interaction that may assist the overall chemical transformation leading to OH. The nuclei are initially very far from their BrCOOH equilibrium positions, and may even avoid the equilibrium structure completely in the reaction. 

It is better not to remove the lower bromoform layer in a separatory funnel, but to do so entirely by steam distillation complete oxidation of the ketone id thus ensured. The weight of recovered bromoform may be somewhat smaller (100-105 g.), but the yield of pure acid is increased to 36 g. The steam distillation must be carefully watched as a solid (carbon tetrabromide) may crystallise in the condenser this can easily be removed by turning ofi the water supply when the solid will soon melt and pass on into the distillate. 

Polybromo compounds (bromoform, s-tetrabromoethane) react similarly at 50°, but simple polychloro compounds (chloroform, carbon tetrachloride and trichloroacetic acid) do not. 

Tribromoacetic acid [75-96-7] (Br CCOOH), mol wt 296.74, C2HBr302, mp 135°C bp 245°C (decomposition), is soluble in water, ethyl alcohol, and diethyl ether. This acid is relatively unstable to hydrolytic conditions and can be decomposed to bromoform in boiling water. Tribromoacetic acid can be prepared by the oxidation of bromal [115-17-3] or perbromoethene [79-28-7] with fuming nitric acid and by treating an aqueous solution of malonic acid with bromine. 

Removal of Refractory Organics. Ozone reacts slowly or insignificantly with certain micropoUutants in some source waters such as carbon tetrachloride, trichlorethylene (TCE), and perchlorethylene (PCE), as well as in chlorinated waters, ie, ttihalomethanes, THMs (eg, chloroform and bromoform), and haloacetic acids (HAAs) (eg, trichloroacetic acid). Some removal of these compounds occurs in the ozone contactor as a result of volatilization (115). Air-stripping in a packed column is effective for removing some THMs, but not CHBr. THMs can be adsorbed on granular activated carbon (GAG) but the adsorption efficiency is low. 

In the known absence of bromoform, iodoform, chloral, and other halogenated methanes, the formation of phenyhsonitrile with aniline provides a simple and faidy sensitive but nonspecific test for the presence of chloroform, the carbylamine test. Phenyhsonitrile formation is the identification test given in the British Pharmacopoeia. A small quantity of resorcinol and caustic soda solution (10% concentration) added to chloroform results in the appearance of a yellowish red color, fluorescing yeUow-green. When 0.5 mL of a 5% thymol solution is boiled with a drop of chloroform and a small quantity of potassium hydroxide solution, a yellow color with a reddish sheen develops the addition of sulfuric acid causes a change to brilliant violet, which, diluted with water, finally changes to blue (33). 

VV -values for bromoform and pyrrole, acidic liquids, against poly(vinyl chloride), an acidic polymer, and dimethyl sulfoxide, a predominantly basic liquid, against polyfmethyl methacrylate), a basic polymer, but large values for the acidic liquids against PMMA and the basic liquid against PVC. 2-Iodoethanol, a bifunctional liquid, showed appreciable -values with both polymers. Despite these results in line with expectations, other results based on wettability measurements are not so clear-cut. For example, Vrbanac [94] found significant apparent acid-base interactions of various aromatic liquids against poly(ethylene), presumably a neutral substrate. 

The reaction of methyl ketones with a calculated amount of BTMA Br3 in aq. sodium hydroxide at room temperature and subsequent acid hydrolysis gave carboxylic acids together with bromoform in good yields. Aliphatic and aromatic methyl ketones have usually been reacted (Fig. 30) (ref. 38). 

Curtis GP, M Reinhard (1994) Reductive dehalogenation of hexachloroethane, carbon tetrachloride, and bromoform by anthrahydroquinone disulfonate and humic acids. Environ Sci Technol 28 2393-2401. 

When the reaction with substituted benzaldehydes is conducted in the presence of ammonia, the a-amino carboxylic acids are formed [11], The corresponding reaction involving bromoform is less effective and, for optimum yields, the addition of lithium chloride, which enhances the activity of the carbonyl group, is required. In its absence, the overall yields are halved. The reaction of dichlorocarbene with ketones or aryl aldehydes in the presence of secondary amines produces a-aminoacetamides [12, 13] (see Section 7.6). 

Methanoic acid, see Formic acid Methanoic acid, methyl ester, see Methyl formate Methenyl chloride, see Chloroform Methenyl tribromide, see Bromoform... 

Ethanediol monoformate, see 1,4-Dioxane Ethanesulfonic acid see Ethyl sulfide Ethanethiol, see Parathion, Phorate Ethanol, see Bromoform, Butane, 1-Butene,... 

Hydracrylic acid, see p-Propiolactone Hydrazobenzene, see Aniline Hydriodic acid, see Methyl iodide Hydrobromic acid, see Bromodichloromethane, Bromoform, Methyl bromide, Metobromuron Hydrochloric acid, see Alachlor. Aldrin, Benzyl chloride, a-BHC, p-BHC, Bis (2-chloroethyl) ether, Bis(2-chloroisopropyl) ether, Bromacil. Bromodichloromethane, Carbon tetrachloride, Chloroethane, Chloroform, o-Chloronitrobenzene. Chloropicrin, Chloroprene, p-Chloronitrobenzene, 2,4-D, see Dalanon-sodium. p.p -DDD, p,p -DDT, Dicamba. 1,1-Dichloroethane, 1,1-Dichloroethylene, fratts-l,2-Dichloroethylene, s/m-Dichloromethyl ether, 2.3-Dichloronitrobenzene. 3.4-Dichloronitrobenzene. 1,2-Dichloropropane, cis-1,3-... 

Methamidophos, see Acephate Methane, see Acetaldehyde, Benzoic acid, 7 Bromobenzoic acid. 3-Bromobenzoic acid. 4-Bromobenzoic acid. Bromoform, Carbatyl, Catechol, 2-Chlorobenzoic acid. 3-Chlorobenzoic acid. Chloroform, Dibromochloromethane, 2,5-Dichlorobenzoic acid. 1,2-Dichloroethane, Ethylamine, Ethyl bromide. Ethylene dibromide, Ethylenimine, Formic acid, Hydroqninone, 4 Hvdroxvbenzoic acid. Indole, 2-Iodobenzoic acid. 3 lodobenzoic acid. Methyl bromide, 4-Iodobenzoic acid. 2-Methylphenol, 4-Methylphenol, Phenol, Prorocatechuic acid. Svringic acid. Svringaldehvde. TCDD, Tetrachloroethylene, Toluene, Trichloroethylene, Vanillin. Vanillic acid. Vinyl chloride... 

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