A detailed study of the solvolysis of triarylchloroallenes is reported. The rate of disappearance of haloallene was found to equal the rate of appearance of HC1. An increase in solvent polarity results in a marked increase in the rate constant for solvolysis. The m value for triphenylchloroallene in aqueous acetone solutions is found to be 0.69 ± 0.06. No change in rate is observed with a 1250-fold excess of triethylamine added. Addition of 0.10 M LiCl results in a 29 % rate depression while the addition of 0.10 M LiBr results in a slight rate enhancement. The exclusive product of solvolysis of triphenylchloroallene is 1,1,3-triphenylprop-2-yn-l -ol. Substituent effect data yield p = -2.0 against +. The temperature dependence of the rate yields AH* = 20.2 kcal mol-1 and AS* = -10.7 eu. These data are interpreted in terms of a unimolecular reaction proceeding via a chargedelocalized allenyl cation.
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