ACID HALIDE THEORY

IUPAC names alkanoyl halides by replacing the -oic acid ending with an equal number of carbons per -oil . In addition, the word acid is replaced by the corresponding halogen, named as salt.

alkanoyl halides nomenclature 1

[1] Methanoyl chloride

[2] Ethanoyl bromide

[3] Propanoyl iodide

Alkanoyl halides react with water at room temperature to form carboxylic acids.

hidrolisis-haluros-alcanoilo

The reaction of alkanoyl halides with alcohols produces esters. The equilibria of this reaction are favored by eliminating the hydrochloric acid with a base (tertiary amine, pyridine)

reaccin-haluros-alcanoilo-alcoholes

Amines and ammonia react with alkanoyl halides to form amides. The reaction is favored with an excess of amine, in order to eliminate the hydrochloric acid released in the reaction.

 

reaccion-haluros-alcanoilo-amidas

Magnesium organometallics at -78°C react with alkanoyl halides to form ketones. It is necessary to work at a low temperature to avoid adding a second equivalent of organometallic, in which case the product obtained would be an alcohol.

 

reaccion-haluros-alcanoilo-organometalicos

Alkanoyl halides are reduced to alcohols with the lithium aluminum reductant

 
reduccion-haluros-alcoholes

The reduction of alkanoyl halides can be stopped at the aldehyde using modified hydrides. From lithium aluminum hydride lithium tri(tert-butoxy)aluminum hydride can be prepared. This modified hydride allows reduction of acid halides to aldehydes.

 

Synthesis of the reductant: the reductant is obtained by reaction between lithium aluminum hydride and tert-butanol
 
reduccion-haluros-aldehidos

Alkanoyl halides are reduced to aldehydes with hydrogen and a palladium poisoned catalyst.

reduccion-rosenmund