Question

Explain decarboxylation with an example.

Answer 1

Hint: The decarboxylation is a process of transformation of a carboxylic acid group into alkane by the replacement of a carboxyl group with a hydrogen atom. This process is marked by the release of the carbon dioxide gas with effervescence.

Complete step by step answer:
Decarboxylation is a chemical reaction in which there is a removal of a carboxyl group and a release of carbon dioxide (\[C{O_2}\] ) takes place. Generally, decarboxylation refers to a reaction involved in carboxylic acids, where there is a removal of a carbon atom from the carbon chain. The exact reverse process, which is the first occurring chemical step in photosynthesis, is called carboxylation which is defined as the addition of \[C{O_2}\] to a compound. Enzymes that catalyze decarboxylations are called decarboxylases or, simply carboxy-lyases.
The example of a decarboxylation process is:
$RCOOH \to R - H + C{O_2} \uparrow $
Decarboxylation is one of the oldest known organic conversions. It is one of the processes assumed to accompany destructive distillation and pyrolysis (thermal decomposition of substances). Metal salts, especially copper compounds, facilitate the reaction via the intermediacy of metal carboxylate complexes. Decarboxylation of aryl carboxylates can generate the equivalent of the corresponding aryl anion, which in turn can undergo cross coupling reactions.
There are numerous decarboxylation reactions. One such is the Kolbe’s electrolysis decarboxylation reaction whose reaction is as follows:
$2R - COOH\xrightarrow{{2{e^ - }}}R - R + 2C{O_2}$

Note:
There are many other decarboxylation reactions in organic chemistry such as Barton decarboxylation which is a form of reductive decarboxylation where there is a transformation of a carboxylic acid into a thio hydroxamate ester. Similarly some more reactions include Kochi reaction and Hunsdiecker reaction.