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Kinetics and product distribution of p‐nitrophenyl phosphate dianion solvolysis in ternary DMSO/alcohol/water mixtures are compatible with metaphosphate formation
Author(s) -
Lima F. S.,
Chaimovich H.,
Cuccovia I. M.
Publication year - 2012
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1856
Subject(s) - chemistry , solvolysis , metaphosphate , alcohol , ternary operation , tert butyl alcohol , phosphate , methanol , hydrolysis , reaction rate constant , inorganic chemistry , medicinal chemistry , organic chemistry , kinetics , physics , quantum mechanics , computer science , programming language
The rate of solvolysis of p‐nitrophenyl phosphate (PNPP) dianion in DMSO/water strongly decreases by increasing water concentration. Addition of linear alcohols (methanol, propanol, butanol, pentanol, and hexanol) at constant DMSO/water molar ratio produced an even sharper rate decrease. Alkyl phosphate formation, resulting from PNPP solvolysis in ternary DMSO/water/alcohol mixtures, increased with alcohol concentration and was essentially temperature independent. Methanol and hexanol were the poorest nucleophiles under all conditions. Activation energies and enthalpies for solvolysis in ternary mixtures were similar and entropies varied with alcohol concentration. Taken together these results can be best interpreted in terms of a dissociative mechanism with the intervention of metaphosphate. Copyright © 2011 John Wiley & Sons, Ltd.