Detailed Summary
Carboxylic acids are characterized by their functional group –COOH (carboxyl), which influences their reactivity significantly. This section delves into various reactions involving carboxylic acids, each fundamental to organic chemistry.
1. Reduction
Carboxylic acids can be reduced to primary alcohols using reagents like lithium aluminium hydride (LiAlH4) or diborane, with the latter being less reactive toward other functional groups, maintaining selectivity.
2. Decarboxylation
Decarboxylation occurs when carboxylic acids lose carbon dioxide. This reaction can happen when their sodium salts are heated with sodalime (a mixture of sodium hydroxide and calcium oxide). The resulting process provides hydrocarbons with doubled carbons.
Additionally, processes such as Kolbe electrolysis can also facilitate decarboxylation, where the electrolysis of the salts will yield hydrocarbons.
3. Halogenation
Carboxylic acids containing an a-hydrogen can undergo halogenation at their a-position using chlorine or bromine in the presence of red phosphorus, leading to the formation of a-halocarboxylic acids. This is known as the Hell-Volhard-Zelinsky reaction.
The section emphasizes the significance of these reactions in both synthetic and industrial applications, highlighting how reactions involving the –COOH group are essential for further organic transformations.