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The Influence of solvent and crown polyethers on the nucleophilic reactivity of potassium tert ‐Butylperoxide, potassium tert ‐Butoxide, and some other oxygen bases
Author(s) -
Curci Ruggero,
di Furia Fulvio
Publication year - 1975
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550070304
Subject(s) - chemistry , nucleophile , reactivity (psychology) , toluene , solvation , solvent , medicinal chemistry , oxygen , substrate (aquarium) , base (topology) , 18 crown 6 , polymer chemistry , inorganic chemistry , organic chemistry , ion , catalysis , medicine , mathematical analysis , oceanography , alternative medicine , mathematics , pathology , geology
The rates of reaction of t ‐BuOOK, t ‐BuOK, n ‐BuOOK, and p ‐MeC 6 H 4 OKwith p ‐nitrophenyl diphenylphosphinate 1 and with p ‐nitrophenyl benzoate 2 have been measured in toluene both in the absence and in the presence of crown polyether dicyclohexyl‐18‐crown‐6 3a . The rates of nucleophilic displacementon 1 by HOO − , t ‐BuOO − , and some “nonalpha” oxyanions in water have also been determined. Solvent transfer from water to toluene results in increasing the nucleophilic reactivity of the t ‐butyl hydroperoxide anion. Rate ratios Q Qa are given which allow one to estimate the enhanced reactivity of t ‐BuOO − (an α‐nucleophile) compared to oxygen nucleophiles of comparable base strength toward 1 and 2 . These are for substrate 1 , Q α (water) ≃ 6.5 and Q α (toluene) ≃ 2.7; for substrate 2 , Q α (water) ≃ 5.5 and Q α (toluene) ≃ 5. The hypothesis is advanced that solvation is not a major factor in determining the α‐effect of the t ‐butylhydroperoxide anion.