Halogens interhalogen compounds

In a series of seven recent publications, these Italian authors21-27 reported isobutylene homo- and copolymerizations using alkylaluminum coinitiators in the presence of halogen, interhalogen compounds and alkyl halide initiators. The following conclusions21 are reported in the first paper. 

Halogenation Interhalogen compounds are good halogenatig agent. 

Nonsolvating solvents may be used for nonelectrolyte molecular species such as rare gases, halogens, interhalogen compounds, and some metal halide complexes. 

INTER HALOGEN COMPOUNDS AND POLYHALIDES There are four types of interhalogen compound ... 

Sihcon and boron bum ia fluorine forming siUcon tetrafluoride [7783-61-17, SiF, and boron trifluoride [7637-07-2] respectively. Selenium and tellurium form hexafluorides, whereas phosphoms forms tri- or pentafluorides. Fluorine reacts with the other halogens to form eight interhalogen compounds (see Fluorine compounds, inorganic-halogens). 

J. E. Ellis and G. Iveson, The Application of Gas-Eiquid Chromatography to the Analysis of Volatile Halogen and Interhalogen Compounds, Gas Chromatography, Butterworths, London, 1956 pp. 300—309. 

The interhalogen compounds are the bromine- and iodine-base materials. It is the larger, more positive halogen that is the reactive portion of the interhalogen molecule during the disinfection process. Although only used on a limited basis at present, there are members of this class that show great promise as environmentally safe disinfectants. 

Two approaches that have been investigated recently for disinfection are mixtures of bromine and chlorine, and mixtures containing bromide or iodide salts. Some evidence exists that mixtures of bromine and chlorine have superior germicidal properties than either halogen alone. It is believed that the increased bacterial activity of these mixtures can be attributed to the attacks by bromine on sites other than those affected by chlorine. The oxidation of bromide or iodide salts can be used to prepare interhalogen compounds or the hypollalous acid in accordance with the following reaction ... 

Interhalogen compounds are compounds of two different halogens that have, with few exceptions, the general formula XX . Examples include BrCI, C1F, and IF5. Use I ewis structures to explain why n is always an odd number. 

The halogens form compounds among themselves. These interhalogens have the formulas XX, XX 5, XX 5, and XX 7, where X is the heavier (and larger) of the two halogens. Only some of the possible combinations have been synthesized (Table 15.5). They are all prepared by direct reaction of the two halogens, the... 

Of these, (a), (c), (d), and (e) can all function as greenhouse gases. 2.113 All halogens have an odd number of valence electrons (7). As a consequence interhalogen compounds of the type XX will be extremely reactive radicals unless the total number of halogens is an even number, which can only be achieved if n is odd. Look at IC12 vs. IC13 as examples ... 

Interhalogen compounds, hardly surprisingly, add to alkenes very much as do the halogens themselves, and the following order of reactivity has been observed ... 

Hydrogen peroxide (H2O2) Interhalogen compounds Halogen oxides (OF2, CI2O, CI2O7) Halogens (F2, CI2, Br2)... 

Carbon monoxide is a highly flammable and poisonous gas. Its flammable limits in air are 12.5 to 74.2% by volume, and the autoignition temperature 700°C. It explodes when exposed to flame. Reactions with interhalogen compounds, such as, bromine pentafluoride or halogen oxides can cause explosion. It forms explosive products with sodium or potassium that are sensitive to heat and shock. 

Fluorine also reacts with other halogens, forming interhalogen compounds. While with bromine and iodine it reacts vigorously at ordinary temperatures, with chlorine the reaction occurs at 200°C. Such interhalogen products with these halogens include iodine heptafluoride, bromine trifluoride, bromine pentafluoride, and chlorine trifluoride. Metalloid elements, such as arsenic, silicon, selenium, and boron also inflame in a stream of fluorine, forming fluorides. 

A very large number of complexes of pyridines and quinolines with all the halogens and interhalogen compounds are known, and as they have been enumerated elsewhere (74HQ14-S2)407,77HC(32-1)319) just a few examples are illustrated (Scheme 14). Treatment of pyridine with chlorine or bromine in the presence of aluminum chloride yields 4-pyridylpyridinium salts (equation 29), but rather curiously the action of iodine chloride on pyridinium hydrochloride at 250 °C produces the 2-isomer (51 equation 30). 

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