Question

CH3CN and CH3MgBr reaction​

Answer 1

Explanation:

MECHANISM FOR THE REACTION OF RMgX WITH A NITRILE

Step 1:

The nucleophilic C in the organometallic reagent adds to theelectrophilic C in the polar nitrile group. Electrons from the C≡N move to the electronegative N creating an intermediate imine salt complex. addition of Grignard reagent to an nitrile

Step 2:

An acid/base reaction. On addition of aqueous acid, the intermediate salt protonates giving the imine.

Step 3:

An acid/base reaction. Imines undergo nucleophilic addition, but require activation by protonation (i.e. acid catalysis).

Step 4:

Now the nucleophilic O of a water molecule attacks the electrophilicCwith the π bond breaking to neutralise the change on the N.

Step 5:

An acid/base reaction. Deprotonate the O from the water molecule to neutralise the positive charge.

Step 6:

An acid/base reaction. Before the N system leaves, it needs to be made into a better leaving group by protonation.

Step 7:

Use the electrons on the O in order to push out the N leaving group, a neutral molecule of ammonia.

Step 8:

An acid/base reaction. Deprotonation reveals the carbonyl group ofthe ketone product.

Answer 2

On reacting acetonitrile ( CH$_{3}$CN ) with methyl magnesium bromide ( CH$_{3}$MgBr ) followed by hydrolysis , acetone or propanone ( CH$_{3}$COCH$_{3}$ ) is formed .

• This reaction is mainly used to form ketones .

• Methyl magnesium bromide ( CH$_{3}$MgBr ) is a exmple of  Grignard reagent .
• Acetone ( CH$_{3}$COCH$_{3}$ ) is a colorless and flammable liquid . It has a characteristic smell .
• It is used as a solvent in various industries and labs .