Perhalogenated aromatics

The reaction of the carbanion derived from diethyl methylphosphonate with perhalogenated aromatics may result in substitution of halide to yield perhaloaryl(hetaryl)methylphosphonates, which can be converted into tris- or bis-(perhaloaryl)methanes. Displacement of fluoride ion has been reported in the reaction of dimethoxycarbene with l-fluoro-2,4-dinitrobenzene and with hexafluorobenzene. The hydrodehalogenation of halogenated aryl ketones may be facilitated using hydrogen over a Pt/C catalyst. " ... 

Whereas most disproportionation reactions among the haloalkanes take place catalytically, the emphasis is on thermal disproportionation in the case of the haloalkenes and perhalogenated aromatics. 

Tarasenko, E.A., Artamkina, G.A., Voevodskaya, T.L, Lukashev. N.V., and Beletskaya, LP., Nucleophilic substitution in perhalogenated aromatic compounds by carbanions derived from substituted dialkyl methylphosphonates, Zh. Org. Khim., 34, 1523, 1998 Russ. J. Org. Chem. (Engl. Transl.), 34, 1459, 1998. 

In contrast to the air and moisture sensitivity of most simple arylsilver compounds, perhalogenated aromatic silver compounds are usually stable to water and oxygen. 

Perhalogenated aromatic compounds also yield Grignard reagents on reaction with magnesium e.g.9 (pentachlorophenyl)magnesium chloride is formed from hexachlorobenzene in tetrahydrofuran,119 and (pentafluorophenyl)-magnesium bromide from bromopentafluorobenzene.120... 

Molecular Volume-Kow Relationships Relationships between Kow and different volume parameters have been reported. Leo et al. [41] compare correlations with Bondi and with CPK volume for two classes of apolar molecules (1) alkanes and alkylsilanes, and (2) perhalogenated alkanes and aromatic and haloaromatic compounds. Further, these authors discuss analogous correlations for alkanols and alkylphenols. 

When trialkylphosphites are treated with fluoroalkanoyl chlorides, perhalogenated fluoro-alkenes, perfluorinated aromatics, and other fluorinated alkylating substrates, an Arbuzov reaction takes place and alkyl fluorides are formed as byproducts. The method has been used to prepare 6-fluoro-6-deoxy-l,2 3,4-di-f7-isopropylidenegalactose (1). ... 

Highly efficient oxygenation reactions with ruthenium porphyrin complexes and aromatic 7V-oxides in the presence of strong mineral acids have been described by Hirobe et al. [4], We have recently reported that electron deficient perhalogenated ruthenium porphyrins catalyze the oxygenation of a variety of even unreactive substrates under mild conditions (40 - 65 C) in the presence of 2,6-dichloropyridine A -oxide in aprotic media [5]. Unusually high rates and turnover numbers (TO) were obtained. 

In the synthesis of imidoyl halides from the corresponding cyclic precursors and phosphorus pentachloride elimination, leading to aromatic heterocyclic halides, can occur. However, the imidoyl halides are readily obtained from perhalogenated precursors because elimination is not possible. 

Even under constant contact, POM copolymers are not chemically attacked by organic solvents, such as alcohols, alkalis, esters, ethers, ketones, aliphatic and aromatic hydrocarbons, perhalogenated hydrocarbons, paints, or detergents. At worst, mechanical strength is slightly reduced, while swelling is always minimal [656]. 

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