Iodide, potassium reaction rates with alkyl halides

Table 2.11. Reaction Rates of Alkyl Halides with Potassium Iodide...

The structure of the halide is critically important because for a Sn2 reaction, as shown in Table 2.11. This table gives the rate for reaction for the reaction of alkyl halides with potassium iodide. As the steric bulk around the carbon being attacked by iodide increase, the rate of reaction slows, which can be directly correlated with an increase in activation energy required to achieve the pentacoordinate transition state, 56. With tertiary halides, the steric bulk imposes a large energy barrier for formation of 56, making the rate of S]q2... 

---