Halide formation

Table 2.6 Reaction steps in hydrogen halide formation...

For all three halates (in the absence of disproportionation) the preferred mode of decomposition depends, again, on both thermodynamic and kinetic considerations. Oxide formation tends to be favoured by the presence of a strongly polarizing cation (e.g. magnesium, transition-metal and lanthanide halates), whereas halide formation is observed for alkali-metal, alkaline- earth and silver halates. 

Alkyl oxalyl chlorides, reactions, 228 Aryl nickel halides, formation, 227 3-Arylpropanenitriles, preparation, 229... 

The enthalpy AHN2 for ester (halide) formation is given by... 

The United States Geological Survey (FEDRIP 1996) is conducting a study on the Mississippi River and its major tributaries focused on the transport and degradation of organic substances. Experiments will be conducted at 12 stations to determine the THM and organic halide formation potentials. The results will be summarized in a chapter on water purification by-products in a Report to Congress on the Mississippi River. 

Benzyl alcohol readily undergoes the reactions characteristic of a primary alcohol, such as esterification and etherification, as well as halide formation. In addition, it undergoes ring substitution. In the presence of acid, polymerization is observed, and the alcohol can be thermally dehydrated to toluene [108-88-3], Catalytic oxidation over copper oxide yields benzaldehyde benzoic acid is obtained by oxidation with chromic acid or potassium permanganate. Catalytic hydrogenation of the ring gives cyclohexylmethanol [100-49-2]. 

Alkyl halide formation from an alcohol and a hydrogen halide affords an important example of a reaction wherein the C-O bond of the alcohol is broken ... 

Halide formation proceeds at a useful rate only in the presence of strong acid, which can be furnished by excess hydrogen bromide or, usually and more economically, by sulfuric acid. The alcohol accepts a proton from the acid to give an alkyloxonium ion, which is more reactive in subsequent displacement with bromide ion than the alcohol (by either SN2 or SN1 mechanisms) because H20 is a better leaving group than eOH ... 

The reaction is closely related to alkyl halide formation under strongly acidic conditions, whereby conversion of the alcohol to an oxonium salt is a first step ... 

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