Elimination of hydrogen halide from organic

The elimination of hydrogen halide from organic halides under basic conditions generates alkenes and is a fundamental reaction in organic chemistry. It is sometimes carried out with a base in aqueous media.14 In contrast, the corresponding Hofmann-type eliminations of quaternary ammonium hydroxides are frequently carried out in aqueous media,15 which will be covered in Chapter 11. 

The absence so far of unequivocal proof of carbene formation by a-elimination of hydrogen halide from organic halides and related reactions using hydroxide and alkoxide ions or weaker bases suggests that more detailed investigations of some reported carbenoid reactions may be justified. Thus carbenoid behaviour in the reaction between benzal chloride and potassium t-butoxide in the presence of olefins seems to be critically dependent upon the nature of the solvent (McElvain and Weyna, 1959 Cawley and Westheimer, 1960) and the reaction temperature (Hodgkins et al., 1964). 

Elimination of hydrogen halide from haloalkanes to produce alkenes is an important process in organic synthesis and industry. Realization of this reaction under PTC conditions requires continuous transfer of base (OH anions) into the organic phase ... 

There are many examples of jS-elimination of hydrogen halide from gem-dihalocyclopropanes, promoted by organic anions, generated in PTC system. Usually, these eliminations are followed by further reactions (eqs. 160-162). 

The -elimination of hydrogen halides HX from organic halogen compounds yields olefins or acetylenes, depending on the structure of the starting substance and the number of HX molecules which have split off, viz. 

An elimination reaction is one in which the elements of a small molecule, such as water or a hydrogen halide, are removed from an organic molecule and not replaced. 

Halogenoalkanes also undergo elimination reactions. An elimination reaction involves the loss of a small molecule from the original organic molecule. In the case of halogenoalkanes, this small molecule is a hydrogen halide, such as HCl or HBr. 

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