Trihalides, reactions

Alkylmercury anions, 11 370-371 Ai-Alkyl-A-nitrosohydroxylamine, 34 355-356 Alkylphosphazo trihalides reactions of, 14 70-77 spectral properties of, 14 78-80 syntheses of, 14 59-77 X-ray studies on, 14 80-81 Alkylphosphonofluoridous esters, 13 4(K), 401 Alkylphosphorimidic trichloride, nomenclature of, 14 3, 4... 

Noncombustible gas bums with fuels, hydrocarbons, or when heated with hydrogen. Nitric oxide reacts violently with carbon disulfide vapors, producing green luminous flame with fluorine, it produces a pale yellow flame. It explodes when mixed with ozone, chlorine monoxide, or a nitrogen trihalide. Reactions with many pyrophoric metals produce incandescence. Reaction with amorphous boron produces brilliant flashes. 

White and red phosphorus combine directly with chlorine, bromine and iodine, the red allotrope reacting in each case at a slightly higher temperature. The reactions are very vigorous and white phosphorus is spontaneously inflammable in chlorine at room temperature. Both chlorine and bromine first form a trihalide ... 

A complete set of trihalides for arsenic, antimony and bismuth can be prepared by the direct combination of the elements although other methods of preparation can sometimes be used. The vigour of the direct combination reaction for a given metal decreases from fluorine to iodine (except in the case of bismuth which does not react readily with fluorine) and for a given halogen, from arsenic to bismuth. 

Reaction with phosphorus trihalides (Section 4 13) Phosphorus trichloride and phosphorus tribromide convert alcohols to alkyl halides... 

Section 19 16 Halogenation at the a carbon atom of carboxylic acids can be accom plished by the Hell-Volhard-Zehnsky reaction An acid is treated with chlorine or bromine m the presence of a catalytic quantity of phospho rus or a phosphorus trihalide... 

With tetiaaiyltin compounds, the reaction can proceed further to the aryltin trihalides ... 

Some of the general reactions for the boron trihalides where X represents Cl, Br, or 1 and X a different halogen, ate... 

Addition to the Double Bond. Chlorine, bromine, and iodine react with aHyl chloride at temperatures below the inception of the substitution reaction to produce the 1,2,3-trihaLides. High temperature halogenation by a free-radical mechanism leads to unsaturated dihalides CH2=CHCHC1X. Hypochlorous and hypobromous acids add to form glycerol dihalohydrins, principally the 2,3-dihalo isomer. Dehydrohalogenation with alkah to epicbl orobydrin [106-89-8] is ofgreat industrial importance. 

Hell-Volhard-Zelinsky reaction (Section 19.16) The phosphorus trihalide-catalyzed a halogenation of a carboxylic acid ... 

The importance of the trihalides as industrial chemicals stems partly from their use in preparing crystalline boron (p. 141) but mainly from their ability to catalyse a wide variety of organic reactions.BF3 is the most widely used but BCI3 is employed in special cases. Thus, BF3 is manufactured on the multikilotonne scale whereas the production of BCI3 (USA, 1990) was 250 tonnes and BBr3 was about 23 tonnes. BF3 is shipped in steel cylinders containing 2.7 or 28 kg at a pressure of 10-12 atm, or in tube trailers... 

Many other routes are now available but the most used involve the reaction of Grignard reagents or lithium alkyls on orthoborates or boron trihalides ... 

Many of the trihalides of As, Sb and Bi hydrolyse readily but can be handled without great difficulty under anhydrous conditions. AsFs and SbFs are important reagents for converting non-metal chlorides to fluorides. SbFs in particular is valuable for preparing organofluorine compounds (the Swans reaction) ... 

Despite this, they are good solvents for chloride-ion transfer reactions, and solvo-acid-solvo-base reactions (p. 827) can be followed conductimetri-cally, voltametrically or by use of coloured indicators. As expected from their constitution, the trihalides of As and Sb are only feeble electron-pair donors (p. 198) but they have marked acceptor properties, particularly towards halide ions (p. 564) and amines. 

The trihalides of As, Sb and Bi are strong halide-ion acceptors and numerous complexes have been isolated with a wide variety of compositions. They are usually prepared by direct reaction of the trihalide with the appropriate... 

N-Bridged tellurium-containing heterocycles are exemplified by derivatives of l,4-tellurazine[2,3-g/i]carbazole 107 and heterocycle 108. One-pot reaction of A-propargylcarbazole with tellurium tetrahalides under conditions of the two-phase tellurohalogenation (Section n,B,l) leads to halogenomethylene derivatives 107 (90KGS126). The reaction proceeds as the spontaneous electrophilic cycliza-tion of initially formed tellurium trihalides 109. 

The formulated mechanism is supported by the finding that no halogen from the phosphorus trihalide is transferred to the a-carbon of the carboxylic acid. For instance, the reaction of a carboxylic acid with phosphorus tribromide and chlorine yields exclusively an a-chlorinated carboxylic acid. In addition, carboxylic acid derivatives that enolize easily—e.g. acyl halides and anhydrides—do react without a catalyst present. 

The hydrolysis of 106 was studied in some detail and led to the isolation and structural characterization of a rare example of a titanoxane derivative with a planar Ti2(p-G)2 core 108 [111]. The formation of complex 108 can be contrasted with the hydrolysis reaction of the trihalides in the Cp and Cp series giving rise... 

A very useful route to monoalkyltin trihalides involves the reaction of stannous bromide with alkyl bromides in the presence of 5 mol % of a trialkylantimony compound (47). A typical example is shown in the following equation. 

For single crystals, the same method is applied, using an excess of metal and of halogen. After reaction, the mixture of the sulfide halide and the halide is heated to a temperature slightly above the melting point of the respective halide. Perfect, small crystals for X-ray determination are formed. The excess of the trihalide is removed by treatment with anhydrous alcohol 92, 93, 96). CeSI may also be prepared from the sulfides 68, 93) CeSCl is formed by reaction 4 92). 

Wells et al. characterized group 13-stibine adducts by single crystal X-ray structure analyses first in 1997 [35]. The solid state structures of three borane-stibine adducts of the type X3B—Sb(Tms)3 (X = Cl 6, Br 7, I 8), obtained by reaction of boron trihalides BX3 and Sb(Tms)3 in n-pentane, were determined. 

This reaction is similar to the previous one. The utility of the method is limited by the lack of availability of trihalides, though these compounds can be prepared by addition of CCI4 and similar compounds to double bonds (15-44) and by the free... 

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