Halides carbon

Of the halogen compounds of carbon, the most important is CCI4, which is widely used as a solvent. However, the fully halogenated compounds are usually considered as derivatives of methane, and they are usually considered as organic in origin. Consequently, they will not be described in much detail here. 

Although it is widely used as a solvent, CC14 is known to constitute health hazards, and its widespread use in dry cleaning has been largely halted. CC14 does not hydrolyze in water as do most covalent halogen compounds. 

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Related to the fixation of C02, electrochemical carbon , which is prepared by converting carbon halides (e.g. polytetrafluoroethylene) to carbon, is recently attracting attention for its technological applicabilities. Non-aqueous electrolyte solutions are often used in the electrochemical carbonization processes [13]. The use of non-aqueous electrolyte solutions is also popular in electrochemical organic syntheses, as is apparent in Ref. [14], although not dealt with in this book. 

In contrast to the inertness of carbon halides, the halides of silicon and phosphorus are extremely reactive with water, to the extent that they must be protected from atmospheric moisture. A clue to the reactivity of these halides is provided hy the somewhat Similar reactivity of acid halides which readily react with water... 

The same relation of reactivity and stability to periodic position is exhibited by such other carbon halides as hexachloroethane CCh CCU and hexabrumoclhane. Brj CBr.i. as well as by hexachloroethylene. CCU -CCI and Itexabromoethylene, CBr = CBr . Carbon also forms halides containing more than one halogen, See also Carbon Tetrachloride. 

Nickel compounds are of great importance industrially and a review is available on the use of nickel in heterogeneous catalysis, electroplating, batteries, pigments, ceramics and hydrogen storage.76 This concerns simple aqua complexes of nickel(II) with anions such as carbonate, halide, hydroxide, nitrate and sulfate. Nickel acetate and formate find similar use, and the acetate is employed in the sealing of anodized aluminum.77 [Ni(NH3)6]Cl2 has been shown to be potentially applicable in heat pumps.78... 

A different approach, based on the use of carbon halides, has been discovered more recently for cobalt and rhodium HNCC carbides, but its extension to other metals has not yet been successful. For cobalt the reaction is conveniently carried out in two different steps first, the well-known chloromethynyl derivative, Cos(( 0)9CCl is prepared (63),... 

Lewis bases often leads to decomposition, and thus rapid hydrolysis in water, unlike carbon halides, which are kinetically more inert. 

Simonet, J., Poizot, P. and Laffont, L. (2006) A copper-palladium alloy usable as cathode material mode of formation and first examples of catalytic cleavages of carbon-halide bonds. J. Electroanal. Chem. 591, 19-26. 

K. Sonogashira, Development of Pd—Cu Catalyzed Cross-Coupling of Terminal Acetylenes with sp2-Carbon Halides, J. Organomet. Chem. 653, 46 49 (2002). 

Sonogashira K (2002) Development of Pd-Cu catalyzed cross-coupling of terminal acetylenes with sp -carbon halides. J Organomet Chem 653(l-2) 46 9... 

Carbon is the basis of organic chemistry there are more compounds of carbon than of any other element except hydrogen and possibly fluorine. However, most of the chemistry of carbon is the province of organic chemistry and thus not covered in this encyclopedia. The inorganic chemistry of carbon discussed in this article, which is an update of an excellent article written previously by professor R. Bruce King (University of Georgia, Athens), includes the allotropic forms of elemental carbon, simple molecular carbon halides and oxides, carbon oxyacids and oxyanions, carbon snlfur derivatives, simple cyano derivatives, and carbon-based molecnlar ladders. 

Covalent hahdes can be prepared by various synthetic routes. The simplest are direct reactions of elemental halogens (equation 9), or hydrogen halides with elements (equation 10) or oxides (equation 11). In other processes, the oxides are reacted with a halogen halide in the presence of carbon to combine with the oxygen (equation 12) or other reactive carbon-halides (equation 13). Exchange of halogens can also take place (equations 14 16). Anhydrous halides can also be obtained by dehydration of metal halide hydrates, using reactants such as thionyl halide, which react with the hydrated water (equation 17). 

Carbon halides, CCI4 and CBr4 react with 62 in ether according to Eq. (84) with the formation of nitrogen and hydrazones (Me3Si)2N—N= CX2, as well as tetrakis(trimethylsilyl)tetrazene, trimethylsilyl halide, and... 

The lower reactivity of Raney Ni towards sulfones allows the chemoselective desulfurization of (4) with Raney W-2, but an appreciable amount of reduction of keto groups was observed. Raney Ni W-2 also tolerates sulfonamides in this work an ionic mechanism was suggested in order to explain the substitution reaction observed. Lactones,keto lactones," and unsaturated lactoneswere tolerated during the desulfurization of sulfide or dithioketal" groups, but deactivated (e.g. by acetone) Raney Ni was generally used. In contrast, carbon-halide bonds are cleaved where the desulfurization is stereoselective only because the product is the thermodynamically more stable d5-lactone (equation 2)." e-" f... 

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