Bromoform compounds

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

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. 

Condensation of vinyl chloride with formaldehyde and HCl (Prins reaction) yields 3,3-dichloro-l-propanol [83682-72-8] and 2,3-dichloro-l-propanol [616-23-9]. The 1,1-addition of chloroform [67-66-3] as well as the addition of other polyhalogen compounds to vinyl chloride are cataly2ed by transition-metal complexes (58). In the presence of iron pentacarbonyl [13463-40-6] both bromoform [75-25-2] CHBr, and iodoform [75-47-8] CHl, add to vinyl chloride (59,60). Other useful products of vinyl chloride addition reactions include 2,2-di luoro-4-chloro-l,3-dioxolane [162970-83-4] (61), 2-chloro-l-propanol [78-89-7] (62), 2-chloropropionaldehyde [683-50-1] (63), 4-nitrophenyl-p,p-dichloroethyl ketone [31689-13-1] (64), and p,p-dichloroethyl phenyl sulfone [3123-10-2] (65). 

Chlorine. Chlorine is a weU known disinfectant for water and wastewater treatment, however, it can react with organics to form toxic chlorinated compounds such as the tribalomethanes bromodichloromethane, dibromochloromethane, chloroform [67-66-3] and bromoform [75-25-2]. Chlorine dioxide [10049-04-4] may be used instead since it does not produce the troublesome chlorinated by-products as does chlorine. In addition, by-products formed by chlorine dioxide oxidation tend to be more readHy biodegradable than those of chlorine, however, chlorine dioxide is not suitable for waste streams containing cyanide. 

The toxicity of chlorine residuals to aquatic life has been well documented. Studies indicate that at chlorine concentrations in excess of 0.01 mg/1, serious hazard to marine and estuarine life exists. This has led to the dechlorination of wastewaters before they are discharged into surface water bodies. In addition to being toxic to aquatic life, residuals of chlorine can produce halogenated organic compounds that are potentially toxic to man. Trihalomelhanes (chloroform and bromoform), which are carcinogens, are produced by chlorination. 

Molecular complexation or clathration was observed somewhat earlier using similar compounds referred to by MacNicol and Wilson as hexa-hosts ". These compounds formed clathrates with carbon tetrachloride, toluene, dioxane, bromoform and a num-... 

The radical addition of bromoform to ketensilylacetals has been described, initiated with AIBN or Et3B (ref. 12). The reaction yields polyfunctional silicon-containing compounds of CHBr2C(R)CBr(OR )OSiR type or products of their conversions (hydrolysis, fragmentation of R etc.). 

The following compounds were determined by this procedure chloroform bromoform 1,1,1-trichloroethane 1,1,2,2-tetrachloroethane trichloroethylene benzene carbon tetrachloride toluene bromodichloromethane chlorobenzene 1,1,2-trichloroethane o,p-xylene tetrachloroethylene o,p-chlorotoluene 1,2-dibromoethane and fluorobenzene (used as an internal standard). 

Undiluted halogen compounds of the aliphatic series, such as ethyl bromide, chloroform, bromoform, and the like, should not be brought into contact with metallic sodium or potassium thus they must not be dried with these metals since very violent explosions may occur as a result of detonation (Staudinger). 

With the exception of the parent compounds, where the Michael adducts are isolated, acrylic esters [see, e.g. 6,7,31,105,111 ] and nitriles [6,7], and vinyl ketones [26, 113, 115] generally yield the cyclopropanes (Table 7.6) under the standard Makosza conditions with chloroform. Mesityl oxide produces a trichlorocyclopropy-lpropyne in low yield (10%) [7]. When there is no substituent, other than the electron-withdrawing group at the a-position of the alkene, further reaction occurs with the trichloromethyl anion to produce spiro systems (35-48%) (Scheme 7.12) [7, 31]. Under analogous conditions, similar spiro systems are formed with a,p-unsaturated steroidal ketones [39]. Generally, bromoform produces cyclo adducts with all alkenes. Vinyl sulphones are converted into the dichlorocyclopropane derivatives either directly or via the base-catalysed cyclization of intermediate trichloromethyl deriva-... 

The data also indicate that there was a net increase from the influent concentration to the effluent concentration for the following compounds trichlorofluoromethane, bromoform. 

Dibromomethane [74-95-3] (methylene bromide), CH2Br2, is a similar liquid, mp — 52.7° C, bp 96.9°C, Water solubility is 1.17 g/100 g at 15°C. It is prepared by the same methods as bromochloromethane, allowing the reaction to proceed to completion. A laboratory preparation involves removing a bromine from bromoform using sodium arsenite (86). The compound is used as a solvent, as a gauge fluid, and in producing pesticides. Both of these dihalomethanes can be used as dense, readily volatile media for mineral and salt separations. 

The halogen compounds used were methylene dichloride, chloroform, carbon tetrachloride, ethylene dichloride, ethyl bromide, ethylene dibromide, bromoform, methyl iodide, and ethyl iodide. The hydrocarbons selected for their interesting combustion properties were hexane, 2-methylpentane, 2,2-dimethylbutane, hex-l-ene, heptane, methylcyclo-hexane, isooctane, diisobutylene, benzene, toluene, m-xylene, and ethylbenzene. 

Flame Studies. The effects of ethylene dibromide, bromoform, and chloroform on flame speeds of several hydrocarbons were examined. These studies were carried out with 5% molar concentration of the halogen compounds in each hydrocarbon. All the experiments were carried out under identical conditions, and the results reported in Table I are the mean of at least three separate determinations. 

Sulphuric Acid, Chlorine, and Organic Bromine Compounds (Bromoform Carbon Tetrabromide). — 5 gm. of bromine dissolve without turbidity of any kind in 100 cc. of wat r after adding, by drops, 20 cc. of ammonia water. Evaporate to dryness the solution of ammonium bromide thus obtained, and test for ... 

Broiiiofonu is made by reaction of acetone or eLhyl alcohol with sodium hypobromite carbon tetrabromide by reaction of CS2 plus bromine Br2 in the presence of iron, heated or by one reaction of bromoform with aqueous hypobromite solutions. Use is made of the diazo-reaction to introduce bromine into aryl compounds. 

The following qualitative observations on the action of liquid ammonia on organic compounds are mainly by E. C. Franklin and C. A. Kraus, those in brackets are by G. Gore. Aliphatic compounds.—Halides methyl iodide, m. chloroform, reacts, and m. bromoform, m. iodoform, v.s., ethyl bromide and iodide, s. ethylene bromide, s. ethylidene chloride, m. isobutyl bromide, s. amyl bromide, s.s. tribromomethane, v.s. nitrotriohloromethane, m. perehloroethane (n.s.) perchloroethylene (m.) dichloroacetylene (s.). Alcohols methyl, m. ethyl, m. propyl, m. normal butyl,... 

E. Peligot said that after being melted, the peroxide requires a much lower temp, for its solidification, for at —16° the compound remains liquid, and J. Fritzsche said that it can be re-solidified only at —30° because a little nitric acid has been formed, and this also accounts for the turbidity of the cooling liquid. For the fusion curve with nitric oxide, vide supra, nitrogen trioxide. P. Pascal studied the f.p. of binary systems of nitrogen peroxide with bromoform, chloroform, carbon tetrachloride, bromobenzene, methyl iodide, chloropicrin, and camphor. 

The oxidation rates for bromoform were slower than the oxidation rates of unsaturated chlorinated aliphatic compounds, including the TCE. Because the hydroxylation rate constant of TCE is 109 Mr1 s 1 and the hydrogen abstraction of bromoform is 1.1 x 108 M 1 s aromatics and alkenes react more rapidly by hydroxyl addition to double bonds than does the more kinetically difficult hydrogen atom abstraction. No oxidative destruction of chloroform by Fenton s reagent was experimentally observed an explanation for this is that both H202 and Fe2+ have rate constants about one magnitude higher with respect to hydroxyl radicals than chloroform. 

The absence of chromatographic separation makes MIMS a fast technique. It is advantageous in some applications where only select compounds are to be detected or the total concentration of a mixture is to be determined. For instance, the total concentration of trihalomethanes (THMs, including chloroform, bromoform, bromodichloromethane, and dibromo-chloromethane) in drinking water can be determined by MIMS in less than... 

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