The Kinetics of the Acid-Catalyzed Hydrolysis of the Methyl Esters of Cyclo-hexanedicarboxylic Acids1

1961 ◽  
Vol 26 (5) ◽  
pp. 1408-1410 ◽  
Author(s):  
HILTON A. SMITH ◽  
KENNETH G. SCROGHAM ◽  
BILLY L. STUMP
Keyword(s):  
Methyl Esters ◽  
Acid Catalyzed ◽  
Kinetics Of ◽  
Hydrolysis Of

THE TRANSMISSION OF POLAR EFFECTS: PART III. THE KINETICS OF THE ACID-CATALYZED ESTERIFICATION OF 3-SUBSTITUTED ACRYLIC ACIDS AND THE ALKALINE HYDROLYSIS OF THE METHYL ESTERS

1966 ◽  
Vol 44 (6) ◽  
pp. 661-669 ◽  
Author(s):  
Keith Bowden
Keyword(s):  
Alkaline Hydrolysis ◽  
Methyl Esters ◽  
Rate Coefficients ◽  
Steric Effects ◽  
Trans Isomers ◽  
Electrostatic Effect ◽  
Acid Catalyzed ◽  
Acrylic Acids ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate coefficients for the acid-catalyzed esterification in methanol at 35.0° of fourteen 3-substituted acrylic acids have been determined. Rate coefficients have also been determined for the alkaline hydrolysis in 70% v/v dioxin–water at 18.8° of 13 methyl esters and the carbonyl-stretching frequencies of the esters have been examined. The effect of trans-substitution is assessed by use of the Hammett equation. In the alkaline hydrolysis, the transmission of polar effects is approximately 1.9 that of the meta- and para-substituted benzoates. An analysis of the steric effects in the cis-isomers in both reactions shows that the steric effects of the halogeno-substituents in the two reactions differ and an explanation is offered. The application of the Taft–Ingold equation to ortho-substituted benzoates is criticized. The carbonyl-stretching frequencies of the cis-halogeno-esters exhibit a shift of +8 cm−1 compared with the trans-isomers; this shift is attributed to an electrostatic effect.

Cyclization and acid-catalyzed hydrolysis of O-benzoylbenzamidoximes

1986 ◽  
Vol 51 (12) ◽  
pp. 2786-2797
Author(s):  
František Grambal ◽  
Jan Lasovský
Keyword(s):  
Reaction Rate ◽  
Kinetic Isotope ◽  
Acid Base Equilibrium ◽  
Mineral Acids ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Ph Scale ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Derivatives Of

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.

scholarly journals Effect of a Substituent in the Benzene Ring upon the Kinetics of Acid-Catalyzed Hydrolysis of exo-2-Norbornyl Phenyl Ether.

1997 ◽  
Vol 51 ◽  
pp. 515-520 ◽  
Author(s):  
Martti Lajunen ◽  
Marja Himottu ◽  
Kirsi Tanskanen-Lehti ◽  
Maamar Hamdi ◽  
Suzanne Fery-Forgues ◽  
...  
Keyword(s):  
Benzene Ring ◽  
Phenyl Ether ◽  
Acid Catalyzed ◽  
Kinetics Of ◽  
Hydrolysis Of

Kinetics of the acid-catalyzed hydrolysis of tetraethoxysilane (TEOS) by 29Si NMR spectroscopy and mathematical modeling

2018 ◽  
Vol 86 (2) ◽  
pp. 316-328 ◽  
Author(s):  
J. C. Echeverría ◽  
P. Moriones ◽  
G. Arzamendi ◽  
J. J. Garrido ◽  
M. J. Gil ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Nmr Spectroscopy ◽  
29Si Nmr ◽  
Acid Catalyzed ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
29Si Nmr Spectroscopy

scholarly journals The kinetics of hydrolysis of some extended N-aminoacyl-l-arginine methyl esters by human plasma kallikrein. Evidence for subsites S2 and S3

1982 ◽  
Vol 203 (1) ◽  
pp. 149-153 ◽  
Author(s):  
P R Levison ◽  
G Tomalin
Keyword(s):  
Human Plasma ◽  
Methyl Esters ◽  
Plasma Kallikrein ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Rate Limiting Step ◽  
Kinetics Of Hydrolysis ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Hydrolysis Of

Subsites in the S2-S4 region were identified in human plasma kallikrein. Kinetic constants (kcat., Km) were determined for a series of seven extended N-aminoacyl-L-arginine methyl esters based on the C-terminal sequence of bradykinin (-Pro-Phe-Arg) or (Gly)n-Arg. The rate-limiting step for the enzyme-catalysed reaction was found to be deacylation of the enzyme. It was possible to infer that hydrogen-bonded interactions occur between substrate and the S2-S4 region of kallikrein. Insertion of L-phenylalanine at residue P2 demonstrates that there is also a hydrophobic interaction with subsite S2, which stabilizes the enzyme-substrate complex. The strong interaction demonstrated between L-proline at residue P3 and subsite S3 is of greatest importance in the selectivity of human plasma kallikrein. The purification of kallikrein from Cohn fraction IV of human plasma is described making use of endogenous Factor XIIf to activate the prekallikrein. Kallikreins I (Mr 91 000) and II (Mr 85 000) were purified 170- and 110-fold respectively. Kallikrein I was used for the kinetic work.

The acid-catalyzed hydrolysis of phosphinates. III. The mechanism of hydrolysis of methyl and benzyl dialkylphosphinates

1977 ◽  
Vol 55 (21) ◽  
pp. 3740-3750 ◽  
Author(s):  
Khamis A. Abbas ◽  
Robert D. Cook
Keyword(s):  
Methyl Esters ◽  
Mechanism Of Hydrolysis ◽  
Benzyl Esters ◽  
Acid Catalyzed ◽  
Hydrolysis Of

The rates of the acid-catalyzed hydrolysis of methyl dimethyl-, diethyl-, diisopropyl-, and di-tert-butylphosphinate in D2SO4–D2O and of p-methoxybenzyl, p-chlaorobenzyl, p-nitrobenzyl, and benzyl diethylphosphinate in H2SO4 – 70% w/w DMSO-H2O have been studied. The bell-shaped pH-rate profiles, the Bunnett–Olsen Φ (0.91 to 1.28), Bunnett w (2.28 to 3.52) and w* (−0.94 to +0.17), and Yates-McClelland r (0.61 to 2.6) values, and the entropies of activation (−18 to −24 eu) all support an A2 mechanism for the methyl esters. The suggested mechanism for the benzyl esters is a unimolecular hydrolysis (Aa11). This conclusion is supported by the pH-rate profiles, the Φr values (−0.12 to −0.29) and the entropies of activation (−4 to −7 eu). The pKa's of the esters are also reported and they range between −2.4 to −3.3.

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