Question

Hello,

How could we make the reaction of 2-chloro-2-methylpropane with NaI in acetone go faster? Be specific about what changes you would make the experimental procedure?

Thanks in advance!

Answer 1

Above reaction consist of 2-chloro-2-methylpropane, which involve nucleophillic substitution at the tertiary carbon hence the reaction is S_N1 (3 degree carbon favors S_N1 mechanism due to stable carbocation formation). We can make the reaction go faster by doing following changes.

1.) BY USING POLAR PROTIC SOLVENT like methanol or ethanol as these solvent stabilize  the carbocation by solvating them hence decreasing the activation barrier for the reaction so reaction proceeds at a faster rate.

2.) BY USING A INERT SILVER ION SOURCE such as silver nitrate (nitrate will not act as nucleophile) which would precipitate the chloride as AgCl , which is by product in the reaction. Hence according to the LE CHATELIER PRINCIPLE reaction goes in forward reaction as one of the product is being consumed so rate of substitution increases.