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Predict the products of the following reactions : (i) CH_(3)-CH_(2)-CH_(2)-O-CH_(3)+HBr rarr (ii) (iv) (CH_(3))_(3)C-OC_(2)H_(4)overset(HI)rarr |
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Answer» Solution :(i) Both the alkyl groups ATTACHED to the oxygen atom are primary, therefore, attack of `Br^(-)` ion occurs on the smaller methyl GROUP giving propan-1-ol and bromomethane as the products. `underset("N-Propyl methyl ether")(CH_(3)-CH_(2)-CH_(2)-O-CH_(3))+HBr overset(373K)rarr underset("Propan-1-ol")(CH_(3)-CH_(2)-CH_(2)-OH)+underset("Bromomethane")(CH_(3)-Br)` (ii) `C_(6)H_(5)-O` bond has some double bond character DUE to resonance and hence is STRONGER than `O-C_(2)H_(5)` bond. Therefore, the cleavage takes place at the weaker `O-C_(2)H_(5)` bond to yield phenol and bromoethane as the products.  (iii) `-OC_(2)H_(5)` group is activating as well as o-, p - directing. Therefore, nitration of ethoxybenzene will give a mixture of 2- and 4- ethoxynitrobenzene in which 4 - nitroethoxybenzene dominates due to steric hindrance at 2 - position.  (iv) The reaction follows `S_(N)1` MECHANISM leading to the formation of tert - butyl iodide and ethanol. tery - butyl carbocation is much more stable than ethyl carbocation. Step 1 : 
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