Kinetics of acid-catalyzed hydrolysis of butyn-3-al acetals

Author(s):  
A. N. Volkov ◽  
A. N. Khudyakova
1986 ◽  
Vol 51 (12) ◽  
pp. 2786-2797
Author(s):  
František Grambal ◽  
Jan Lasovský

Kinetics of formation of 1,2,4-oxadiazoles from 24 substitution derivatives of O-benzoylbenzamidoxime have been studied in sulphuric acid and aqueous ethanol media. It has been found that this medium requires introduction of the Hammett H0 function instead of the pH scale beginning as low as from 0.1% solutions of mineral acids. Effects of the acid concentration, ionic strength, and temperature on the reaction rate and on the kinetic isotope effect have been followed. From these dependences and from polar effects of substituents it was concluded that along with the cyclization to 1,2,4-oxadiazoles there proceeds hydrolysis to benzamidoxime and benzoic acid. The reaction is thermodynamically controlled by the acid-base equilibrium of the O-benzylated benzamidoximes.


1997 ◽  
Vol 51 ◽  
pp. 515-520 ◽  
Author(s):  
Martti Lajunen ◽  
Marja Himottu ◽  
Kirsi Tanskanen-Lehti ◽  
Maamar Hamdi ◽  
Suzanne Fery-Forgues ◽  
...  

2018 ◽  
Vol 86 (2) ◽  
pp. 316-328 ◽  
Author(s):  
J. C. Echeverría ◽  
P. Moriones ◽  
G. Arzamendi ◽  
J. J. Garrido ◽  
M. J. Gil ◽  
...  

1983 ◽  
Vol 48 (10) ◽  
pp. 2805-2811 ◽  
Author(s):  
Oldřich Paleta ◽  
Jaroslav Kvíčala ◽  
Václav Dědek

Rates of hydrolysis, kH+, of methyl 2-chloro-2,3,3,3-tetrafluoro-(III), 2,3-dichloro-2,3,3-trifluoro-(IV), 2,2,3-trichloro-3,3-difluoro-(V), 2,3,3,3-tetrafluoro-(VI) and 3-chloro-2,3,3-trifluoropropanoate (VII) were measured in 0.5M-HCl in aqueous methanol (80% vol; 76% wt) at 40, 50 and 60 °C. The relative rate constants, krel (50 °C), (for the propanoate III, kH+ = 4.3 . 10-5 l mol-1 s-1; krel = 100) are 311, 100, 38, 9.4, 44 and 15 for the esters II, III, IV, V, VI and VII, respectively (experimental error ±9%). It was found that krel = αβ where α and β are the following factors for groups in the position 2 and 3: CClF 10, CHF 4.2, CCl2 2.8, CF3 10 and CClF2 3.6. The rate constants obey the isokinetic relationship. For the ester III the dependence of log kobs on logarithm of hydrogen chloride concentration is linear at concentrations 0.08-2.4 mol l-1 which, together with high activation entropy ΔS≠ for the esters III-VII (-167 to -217 J mol-1 K-1), shows that the hydrolysis proceeds by an AAC2 mechanism.


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