Bromine-oxygen compounds

Chlorine and Bromine Oxidizing Compounds. The organo chlorine compounds shown in Table 6 share chemistry with inorganic compounds, such as chlorine/77< 2-3 (9-j5y and sodium hypochlorite/7 )< /-j5 2-5 7. The fundamental action of chlorine compounds involves hydrolysis to hypochlorous acid (see Cm ORiNE oxygen acids and salts). 

Iodine forme, with oxygen, compounds of various degrees of oxidation, the lowest being iodic oxide—10, and iodous acid—IOs the highest iodic acid—TOe,- and periodic acid—IOT. The latter three constitute salts with the metallic bases, which ore called iodites, iodates, and byperiodates respectively. To enter into a description of the processes by which they are prepared, would not be warranted by the uses whioh they serve —namely, of forming the links of analogy between iodine and chlorine, bromine, et cetera. 

Regarding ozonation processes, the treatment with ozone leads to halogen-free oxygenated compounds (except when bromide is present), mostly aldehydes, carboxylic acids, ketoacids, ketones, etc. [189]. The evolution of analytical techniques and their combined use have allowed some researchers to identify new ozone by-products. This is the case of the work of Richardson et al. [189,190] who combined mass spectrometry and infrared spectroscopy together with derivatization methods. These authors found numerous aldehydes, ketones, dicarbonyl compounds, carboxylic acids, aldo and keto acids, and nitriles from the ozonation of Mississippi River water with 2.7-3 mg L 1 of TOC and pH about 7.5. They also identified by-products from ozonated-chlorinated (with chlorine and chloramine) water. In these cases, they found haloalkanes, haloalkenes, halo aldehydes, haloketones, haloacids, brominated compounds due to the presence of bromide ion, etc. They observed a lower formation of halocompounds formed after ozone-chlorine or chloramine oxidations than after single chlorination or chlorami-nation, showing the beneficial effect of preozonation. 

Fluorine also differs from its congeners in its apparent inability to form oxy-acids and oxy-salts. On the other hand, there are some fluorine-oxygen compounds that have no chlorine, bromine, or iodine homologs. Among these are fluorine nitrate, FONO2 fluorine perchlorate, FOCIO3 ... 

Oxidizer Chemical substance that causes oxygen to combine with another chemical substance examples include oxygen and hydrogen peroxide Ozone depletion Destruction of the stratospheric ozone layer that protects the Earth from harmful effects of ultraviolet radiation. Depletion of ozone layer is due to the breakdown of certain chlorine- and/or bromine-containing compounds (chlorofluorocarbons or halons), which break down when they reach the stratosphere and then catalytically destroy ozone molecules Ozone layer Protective layer in the atmosphere, about 15 miles above the ground. The ozone layer absorbs some of the sun s ultraviolet rays, thereby reducing the amount of potentially harmful radiation that reaches the Earth s surface PAHs Polycyclic aromatic hydrocarbons... 

None of the oxygen compounds of bromine has found important practical use. 

See Barium perchlorate Alcohols Bromine Alcohols Chlorine Methanol Chromium trioxide Alcohols Hydrogen peroxide Oxygenated compounds Lead perchlorate Methanol Nitric acid Alcohols (reference 6)... 

Compound A, stable to oxygen and to alkaline hydroperoxide below 100°, reacts with anhydrous trimethylamine N-oxide under liberation of about 9 mol (CH3)3N per mol of A. Bromine reacts with neat compound A or CCI4 solutions of A to give HBr and various brominated C2B3 compounds. Compound A does not react with nitric acid up to 85°. Compound A is also stable toward pyridine at room temperature, and it shows no reaction with metallic sodium on heating in the absence of any solvent at < 150°. 

Alben (1980) chlorinated a coal-tar leachate that contained many polycyclic aromatic hydrocarbons and demonstrated that many hydrocarbons were significantly reduced in concentration. Oxygenated compounds, such as dibenzofuran (17), were formed, together with low concentrations of chlorinated and brominated derivatives of naphthalene and fluorene. Chlorinated polycyclic compounds have been demonstrated to occur in drinking water samples (Shiriashi et al., 1985), including mono-and dichloro derivatives of naphthalene, fluorene, dibenzofuran, phenanthrene, fluoranthene, and fluorenone (Figure 5.3). 

Maleic acid and its esters are isomerized by irradiation of their solutions in the presence of various alkyl bromides, sometimes bromine itself. The C-Br (or Br-Br) bond is sonolyzed to bromine atoms, which add reversibly to the double bond.56 Geometric stabilization of the adduct radical and then elimination of bromine produces fumaric compounds (Fig. 13). When the initiator is bromine, oxygen inhibits the reaction (R = H or CH3), an argument in favor of a radical chain process with the initiation step, the cleavage of the Br2 molecule, occurring in the cavitation bubble. The lifetime of the bromine atoms is s, which at the... 

Fig. 1.9 Schematic presentation of the chemical interactions in the stratosphere. At the start of my scientific career only the OX and some of the HX reactions had been taken into account. Note that OX stands for the odd oxygen compounds, HX for H, OH, HO2 and H2O2 NX for N, NO, NO2, NO3, N2O5, HNO3 and HNO4 and CIX for all inorganic chlorine compounds. Cl, CIO, CI2O2, CIONO2, HCl, OCIO and CI2. Not included are the bromine compounds which likewise play a significant role in stratospheric ozone depletion...

Laser isotope separation techniques have been demonstrated for many elements, including hydrogen, boron, carbon, nitrogen, oxygen, sHicon, sulfur, chlorine, titanium, selenium, bromine, molybdenum, barium, osmium, mercury, and some of the rare-earth elements. The most significant separation involves uranium, separating uranium-235 [15117-96-1], from uranium-238 [7440-61-1], (see Uranium and uranium compounds). The... 

The unique chemical behavior of KO2 is a result of its dual character as a radical anion and a strong oxidizing agent (68). The reactivity and solubiHty of KO2 is gready enhanced by a crown ether (69). Its usefiilness in furnishing oxygen anions is demonstrated by its appHcations in SN2-type reactions to displace methanesulfonate and bromine groups (70,71), the oxidation of benzyHc methylene compounds to ketones (72), and the syntheses of a-hydroxyketones from ketones (73). 

An asymmetric synthesis of estrone begins with an asymmetric Michael addition of lithium enolate (178) to the scalemic sulfoxide (179). Direct treatment of the cmde Michael adduct with y /i7-chloroperbenzoic acid to oxidize the sulfoxide to a sulfone, followed by reductive removal of the bromine affords (180, X = a and PH R = H) in over 90% yield. Similarly to the conversion of (175) to (176), base-catalyzed epimerization of (180) produces an 85% isolated yield of (181, X = /5H R = H). C8 and C14 of (181) have the same relative and absolute stereochemistry as that of the naturally occurring steroids. Methylation of (181) provides (182). A (CH2)2CuLi-induced reductive cleavage of sulfone (182) followed by stereoselective alkylation of the resultant enolate with an allyl bromide yields (183). Ozonolysis of (183) produces (184) (wherein the aldehydric oxygen is by isopropyUdene) in 68% yield. Compound (184) is the optically active form of Ziegler s intermediate (176), and is converted to (+)-estrone in 6.3% overall yield and >95% enantiomeric excess (200). 

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