Reactions of Halogen-Containing Compounds

Reactions at a Group liiA or iVA Metal Center 10.3.2.1. Reactions of Halogen-Containing Compounds... 

Reactions of halogen-containing compounds with Ni(CO)4, Fe(CO)s, or Fe3(CO)12 are widely observed. In these reactions, the formation of intermediate a-alkyl complexes by the addition reaction, followed by carbon monoxide insertion to form acyl complexes, is assumed. From these acyl complexes, many useful carbonyl compounds can be synthesized. Compounds having relatively active halogens such as... 

Initial pyrolysis reactions of halogen-containing compounds generally lead to the formation of HX and RX but seldom to the formation of X2, where X is a halogen atom. Detachment of HX from the aliphatic structured macromolecules is accompanied mostly by the formation of unsaturated systems. Transformation of these systems inside the condensed phase causes the formation of a nonvolatile carbonized residue which, in the long run, affects the rate of combustion of the materials. 

The function of halogen-containing compounds as flame retardants has been explained by the radical trap theory. Liberated halogen acid (HX) competes in the above reactions for those radical species that are critical for flame propagation. 

B. Cyclization of Halogen-Containing Compounds 1. The Hofmann-Loeffler Reaction... 

Pyrrole derivatives were used as aromatic partners in photochemical heteroarylation reactions with a number of halogen-containing compounds, for example, the quinone 593 reacts with iV-methylpyrtole to give the corresponding pyrrolyl derivative 594 (Equation 141) <1997J(P1)2369>. This reaction occurs via a charge transfer complex in the ground state. 

Watson, H. B. Reactions of halogens with compounds containing the carbonyl group. Chem. Rev. 1930, 7,173-201. 

Several studies have been concerned with the Michaelis-Arbuzov reactions of halogen-containing imido compounds and which, in addition to their intrinsic interest, are of potential interest for the preparation of more unusual (aminoalkyl)phosphonic acids. Some of the reactions between trialkyl phosphites and imidoyl chlorides are entirely conventional thus, the compounds 163 (R = Me or Ph) give the corresponding esters 164 however, the similar transformation of 165 (R = Ac, PhCO or COOEt) into 166 does not take place ... 

A variety of halogen-containing compounds find uses as refrigerants (Freon), dry-cleaning fluids, and anesthetics, and as solvents in which to carry out organic reactions. 

Figure 7.25 Reaction scheme for combustion of halogen containing compound in...

Although acetonitrile is one of the more stable nitriles, it undergoes typical nitrile reactions and is used to produce many types of nitrogen-containing compounds, eg, amides (15), amines (16,17) higher molecular weight mono- and dinitriles (18,19) halogenated nitriles (20) ketones (21) isocyanates (22) heterocycles, eg, pyridines (23), and imidazolines (24). It can be trimerized to. f-trimethyltriazine (25) and has been telomerized with ethylene (26) and copolymerized with a-epoxides (27). 

DMF can also be manufactured from carbon dioxide, hydrogen, and dimethylamine ia the presence of halogen-containing transition-metal compounds (18). The reaction has also been performed with metal oxides and salts of alkaU metals as promoters (19). 

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