Kinetics of the Acid-catalyzed Isomerization of Neoabietic Acid in Anhydrous Ethanol

Kinetics of formation of 2-imino-4-thiazolidone from S-ethoxycarbonylmethylisothiouronium chloride has been studied in aqueous buffers and dilute hydrochloric acid. The reaction is subject to general base catalysis, the β value being 0.65. Its rate limiting step consists in acid-catalyzed splitting off of ethoxide ion from dipolar tetrahedral intermediate. At pH < 2 formation of this intermediate becomes rate-limiting; rate constant of its formation is 2 . 104 s-1.

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Cyclization and acid-catalyzed hydrolysis of O-benzoylbenzamidoximes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19862786 ◽

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.

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Kinetic modelling of reactions for the synthesis of 2-methyl-5-ethyl pyridine

Reaction Chemistry & Engineering ◽

10.1039/d1re00085c ◽

2021 ◽

Author(s):

Emanuele Moioli ◽

Leo Schmid ◽

Peter Wasserscheid ◽

Hannsjoerg Freund

Keyword(s):

Kinetic Modelling ◽

Acid Catalyst ◽

Acid Catalyzed ◽

Catalyzed Reactions ◽

Kinetics Of

The kinetics of the acid catalyzed reactions of acetaldehyde ammonia trimer (AAT) and paraldehyde (para) to 2-methyl-5-ethyl pyridine (MEP) in the presence of an acid catalyst were investigated systematically. A...

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Meso tetrakis ortho-, meta-, and para-N-alkylpyridiniopor-phyrins: kinetics of copper(II) and zinc(II) incorporation and zinc porphyrin demetalation

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424603000197 ◽

2003 ◽

Vol 07 (03) ◽

pp. 139-146 ◽

Cited By ~ 6

Author(s):

Peter Hambright ◽

Ines Batinić-Haberle ◽

Ivan Spasojević

Keyword(s):

Aqueous Solution ◽

Ionic Strength ◽

Effective Charge ◽

Methyl Ethyl ◽

Ionic Strength Dependence ◽

Zinc Porphyrin ◽

Cationic Porphyrin ◽

Strength Dependence ◽

Acid Catalyzed ◽

Kinetics Of

The relative reactivities of the tetrakis( N -alkylpyridinium- X - yl )-porphyrins where X = 4 (alkyl = methyl, ethyl, n -propyl) , X = 3 (methyl) , and X = 2 (methyl, ethyl, n -propyl, n -butyl, n -hexyl, n -octyl) were studied in aqueous solution. From the ionic strength dependence of the metalation rate constants, the effective charge of a particular cationic porphyrin was usually larger when copper(II) rather than zinc(II) was the reactant. The kinetics of ZnOH + incorporation and the acid catalyzed removal of zinc from the porphyrins in 1.0 M HCl were also studied. In general, the more basic 4- (para-) and 3- (meta-) isomers were the most reactive, followed by the less basic 2- (ortho-) methyl to n -butyl derivatives, with the lipophilic ortho n -hexyl and n -octyl porphyrins the least reactive.

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Kinetics of the acid-catalyzed isomerization of phenylbutenes in glacial acetic acid

Journal of the American Chemical Society ◽

10.1021/ja00759a034 ◽

1972 ◽

Vol 94 (4) ◽

pp. 1247-1249 ◽

Cited By ~ 4

Author(s):

R. S. Schwartz ◽

H. Yokokawa ◽

E. W. Graham

Keyword(s):

Acetic Acid ◽

Glacial Acetic Acid ◽

Acid Catalyzed ◽

Kinetics Of

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High field 1H NMR Studies of Sol-Gel Kinetics

MRS Proceedings ◽

10.1557/proc-73-157 ◽

1986 ◽

Vol 73 ◽

Cited By ~ 7

Author(s):

Bruce D. Kay ◽

Roger A. Assink

Keyword(s):

Equilibrium Distribution ◽

Sol Gel ◽

Nmr Studies ◽

H Nmr ◽

Rate Limiting Step ◽

Rate Of Hydrolysis ◽

Acid Catalyzed ◽

Product Species ◽

Rate Limiting ◽

Kinetics Of

ABSTRACTHigh resolution 1H NMR spectroscopy at high magnetic fields is employed to study the reaction kinetics of the Si(OCH3)4:CH3OH:H2O sol-gel system. Both the overall extent of reaction as a function of time and the equilibrium distribution of species are measured. In acid catalyzed solution, condensation is the rate limiting step while in base catalyzed solution, hydrolysis becomes rate limiting. A kinetic model in which the rate of hydrolysis is assumed to be independent of the adjacent functional groups is presented. This model correctly predicts the distribution of product species during the initial stages of the sol-gel reaction.

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