Nucleophilic substitution reactions at high pressure

Abstract

The rates of e number of nucleophilic substitution reactions have been measured over a range of pressures to 3000 atm. Reactions where ions are produced in the rate-determining step are accelerated 4.0-4.6 times, while where there is no change in the number of ions, the acceleration is by a factor of 2.25. In the solvolysis of isopropyl bromide, which proceeds by simultaneous S_Nl, S_N2, and E2 mechanisms, of differing electrical type, it is shown that high pressures favour the S_N1 mechanism.