Question

What is the most suitable catalyst for reducing vinyl cyanide $(CH=CHCN)$ to propanenitrile?

• A. $H_2/Ni$
• B. $H_2/Pt$
• C. $(P{h}_{3}P{)}_{3}RhCl$ (Wilkinson's catalyst)
• D. $LiAl{H}_4$

Answer 1

The correct option is C $(P{h}_{3}P{)}_{3}RhCl$ (Wilkinson's catalyst)

Wilkinson's catalyst catalyzes the hydrogenation of alkenes.

The mechanism of this reaction involves the initial dissociation of one or two $triphenylphosphine$ ligands to give $14-$ or $12-electron$ complexes, respectively, followed by oxidative addition of $H_2$ to the metal. Subsequent π-complexation of an alkene, intramolecular hydride transfer (olefin insertion), and reductive elimination results in extrusion of the alkane product.

Here vinyl cyanide undergoes hydrogenation to form propanenitrile using Wilkinson' catalyst.