Silver salt of fatty acid treated with #I_2#/#C Cl_4#. If the ratio of silver salt & iodine is 1:1 then alkyl iodide is formed,if the ratio is 2:1 then ester is formed.Why?

Hunsdiecker's response

The Hunsdiecker reaction is the process of decarboxylating the silver salt of a carboxylic acid with one molar equivalent of either bromine or iodine to form an alkyl halide.

A radical chain reaction is most likely involved in the Hunsdiecker reaction's mechanism.

Step 1: The acyl hypoiodite forms

Step 2: Commencement

Homolyzed acyl hypoiodite is broken down.

Step 3: Transmission

An alkyl radical is created when the acyl radical is decarboxylated.

Step Four: Dissemination

The acyl hypoiodite and the alkyl radical react.

Simonini's response

The Simonini reaction is the process by which two molar equivalents of iodine react with the silver salt of a carboxylic acid to form an ester.

The mechanism most likely involves an ionic substitution with the excess silver salt of the alkyl halide formed in a Hunsdiecker type reaction.

When the ratio of silver salt to iodine is 1:1, alkyl iodide is formed through an SN2 reaction, where the iodine replaces the silver in the fatty acid salt. When the ratio is 2:1, ester is formed through an SN2 reaction as well, but with two moles of iodine per mole of silver salt, leading to the formation of an ester rather than alkyl iodide.