A Mechanistic Approach on the Solvolysis of Cinnamoyl Chloride in the Presence and Absence of Mercuric Chloride Catalyst

The order with respect to water in the solvolysis of cinnamoyl chloride in aqueous acetone and aqueous acetonitrile of lesser water content is H”2.6, favours an addion-elimination mechanism , S N 2 mechanism or a competition between them. Higher enthalpy and lower negative entropy of activation favours S N 2 mechanism. Order with respect to mercuric chloride in the concentration range of 0.001M to 0.0025M is very small, in the range of 0.24, which reveals that mercuric chloride is not involved in the rate determining step of the reaction. The order with respect to water in the presence and absence of mercuric chloride remains the same which indicates that there is no mechanistic change in the presence of the catalyst. The increase in rate of the reaction in presence of catalyst is due to the combined effect of increase in the transition state stabilization and the abstraction of the leaving group from the transition state of the substrate.