Abstract
The rates of solvolysis of 1-(4-methoxyphenyl)-1-aryl-2,2,2-trifluoroethyl chlorides[I] in a variety of solvents were measured by an electroconductometric method. LArSR relationships (Yukawa-Tsuno eq.)were found to give a linear plot, log(k/ko)=-1.84[σo+0.918(σ+-σo)], in 80% aqueous ethanol. Small |ρ| and r values in comparison with 1-aryl-1-(trifluoromethyl)ethyl tosylate(ρ=-6.09, r=1.59) suggested that the carbocationic charge in the transition state was dispersed by a strong p-π donor, p-methoxy group. Linear mY plots with m 0.90 for all of the substituents in aqueous acetone and m=0.60-0.82 for those of aqueous ethanol indicate that this solvolysis proceeds via an SN1 mechanism with nucleophilic solvent assistance. Thiourea effects and isokinetic temperatures for the rate of solvolysis also can prove the above mechanism.