71561-71-2Relevant academic research and scientific papers
Suppression of common-ion return by amines: A method to measure rates of fast SN1 reactions
Streidl, Nicolas,Antipova, Anna,Mayr, Herbert
supporting information; experimental part, p. 7328 - 7334 (2010/01/16)
(Chemical Equation Presented) Rate constants for solvolyses of benzhydryl chlorides, which take place on the 10 ms to minute time scale, have been determined in aqueous acetone and acetonitrile by conductometry, using conventional conductometers as well as stopped-flow techniques. Secondary and tertiary amines were used to suppress ion recombination (common-ion return) thus giving access to the ionization rate constants k1. The observed common-ion rate depressions can be rationalized by the correlation equation for electrophile-nucleophile combinations, log k(20 °C) = s(E + N), where electrophiles (here: carbocations) are characterized by the parameter Eand nucleophiles (here: chloride anions and solvents) are characterized by N and s. 2009 American Chemical Society.
KINETICS OF THE PHENOLYSIS OF ACID CHLORIDES IN A PROTON-INERT MEDIUM. NUCLEOPHILIC CATALYSIS BY TERTIARY AMINES
Simanenko, Yu. S.,Savelova, V. A.,Litvinenko, L. M.,Belousova, I. A.,Dadali, V. A.,Zubareva, T. M.
, p. 123 - 131 (2007/10/02)
The kinetics of the reactions of ArOH with acid chlorides (AcX), catalyzed by tertiary amines (B), were studied by UV spectroscopy in methylene chloride (25 deg C): 1) Benzoyl chloride with β-naphthol (B = N-methylimidazole); 2) benzenesulfonyl chloride with p-phenylazophenol (B = 4-dimethylaminopyridine) with the following concentrations 0 >/= 0 >> 0.A nucleophilic mechanism of catalysis with rapid and equilibrium accumulation of the intermediate products, i.e., N-benzoyl-3-methylaminoimidazolium (Ia) and N-phenylsulfonyl-4-dimethylaminopyridinium (Ib) chlorides, is realized in the case of reactions (1) and (2).In the slow stage the intermediates (I) transfer the acyl group not to the free ArOH but to the hydrogen-bonded complexes of ArOH with (I) and with the amines (B), the formation constants of which were determined independently.One of the above-mentioned paths represents the "intramolecular" transfer of the acyl group in the associate ArOH...(I), whereas the second represents bimolecular attack by the intermediate (I) on the complex ArOH...B.In view of the complexing effects an equation was derived for the phenolysis rate which makes it possible to calculate the rate constants for transfer of the acyl group.Thus, the motivating force of the reactions (1) and (2) in the proton-inert medium is proton transfer even in the initial state, while nucleophilic catalysis is realized exclusively in conjunction with general-base assistance on the part of the anion of the intermediate (I) ("intramolecular" catalysis) or on the part of the free base B (intermolecular catalysis) to the transfer of the proton from ArOH in the rate-controlling stage.
NUCLEOPHILIC CATALYSIS IN THE FORMATION OF ESTERS. THE EFFECT OF THE CHARACTERISTICS OF THE MEDIUM
Drizhd, L. P.,Bondarenko, L. I.,Savelova, V. A.,Litvinenko, L. M.,Kirichenko, A. I.,Yakovets, A. A.
, p. 2187 - 2193 (2007/10/02)
The rate constants were determined for the individual stages of nucleophilic catalysis by 4-dimethylaminopyridine in the reaction of 4-dimethylaminobenzoyl chloride with benzyl alcohol in volume mixtures of methylene chloride with benzene (1:1, 1:5, 1:9) at 25 deg C.The corresponding acylpyridinium salt is formed in all the solvents.In the subsequent fast equilibrium stage it forms a complex, which dissociates slowly into the final reaction products.Suggestions are made about the structures of the respective transition states on the basis of the nature of variation in the rate constants of the individual stages as a function of the solvating power of the medium.
