Kinetics and Mechanisms of the Acid-catalysed Hydrolysis of Tertiary Butyl Acetate

1962 ◽  
Vol 15 (3) ◽  
pp. 467 ◽  
Author(s):  
KR Adam ◽  
I Lauder ◽  
VR Stimson
Keyword(s):  
Rate Constants ◽  
Butyl Acetate ◽  
Arrhenius Equation ◽  
Aqueous Acetone ◽  
Energy Of Activation ◽  
Kcal Mole ◽  
Tertiary Butyl ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of the acid-catalysed hydrolysis of tertiary butyl acetate in water, in aqueous acetone, and in aqueous dioxan, over a range of temperature have been studied. The Arrhenius equation is not obeyed. In 40% water-60% acetone the energy of activation varies from 26-29 kcal mole-1 for temperatures 48-97 �C. This is due presumably to simultaneous hydrolyses via the AAL1 and the AAC2 mechanisms. By combination of oxygen-18 tracer results and kinetic results the rate constants for reactions by these mechanisms in water have been separated. The observed percentage of alkyl-oxygen fission in water varies from 85 at 25 �C to 97 at 60 �C. Rate constants for reactions by the AAL1 and the AAC2 mechanisms are expressed by the equations : k (sec-1 l mole-1) = 10l6.l exp (-27500/RT), and k (sec-1 l mole-1) = 107.9 exp (-l73OO/RT),respectively. However, the parameters of the latter equation may contain considerable errors because the extent of reaction by the AAC2 mechanism is small. In water and in 80% water-20% acetone, tertiary butyl acetate undergoes an uncatalysed solvolytic reaction, involving presumably the BAL1 mechanism. The variation of the rate of this reaction with temperature is expressed by the equation, k (sec-1) = 1012.3 exp (-26800/RT).

scholarly journals KINETICS OF THE REACTIONS BETWEEN ISOPROPYL CUMENE AND TERTIARY BUTYL CUMENE HYDROPEROXIDES AND IRON(II) IN DILUTE AQUEOUS SOLUTIONS IN THE ABSENCE OF OXYGEN

1952 ◽  
Vol 30 (12) ◽  
pp. 985-993 ◽  
Author(s):  
R. J. Orr ◽  
H. Leverne Williams
Keyword(s):  
Free Radicals ◽  
Rate Constants ◽  
Arrhenius Equation ◽  
Cumene Hydroperoxide ◽  
Bimolecular Reaction ◽  
Probable Error ◽  
Tertiary Butyl ◽  
Rate Of Reaction ◽  
Dilute Aqueous Solutions ◽  
Kinetics Of

From studies of the rate of reaction at 11°, 15°, 20°, and 26 °C. it was deduced that the bimolecular reaction between iron(II) and isopropyl cumene hydroperoxide is represented by[Formula: see text]At 0 °C. the radical induced oxidation of iron(II) due to inability of the monomer to remove the free radicals became appreciable. Addition of up to 7.5% methanol did not change the rate appreciably. The effect of traces of oxygen was negligible. Rate constants were measured at 15°, 9°, and 0 °C. for the reaction between iron(II) and the tertiary butyl cumene hydroperoxide. The average probable error in the determinations was 5.4%. From the data, the Arrhenius equation was determined as[Formula: see text]Comparison of the equations measured for cumene hydroperoxide, isopropyl cumene hydroperoxide, and tertiary butyl cumene hydroperoxide and iron(II) has been made. Changes in the constants have been explained qualitatively. The iodometric method of analysis when applied to tertiary butyl cumene hydroperoxide must be modified for accurate results. It is believed that the heating necessary in the presence of water decomposes the hydroperoxide.

Influence of the Polarity of the Medium on the Alkaline Hydrolysis of n-Butyl Acetate in Hydroalcoholic Mixtures

1977 ◽  
Vol 32 (5) ◽  
pp. 496-500
Author(s):  
M. S. Celdrán ◽  
M. V. Ramón ◽  
P. Martínez
Keyword(s):  
Reaction Mechanism ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Butyl Acetate ◽  
Activation Energies ◽  
Free Energies ◽  
Kinetics Of ◽  
Hydrolysis Of

Abstract The kinetics of the alkaline hydrolysis of n-butyl acetate have been studied in water and in hydroalcoholic mixtures. The rate constants, activation energies, frequency factors, entropies, Gibbs free energies and enthalpies of activation have been determined. The radii of the activated com­ plexes have been calculated and related to their degree of solvation. A possible reaction mechanism is formulated.

Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1229-1236 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Acidic Medium ◽  
Measured Data ◽  
Molar Ratios ◽  
Starting Solution ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

KINETICS OF THE AQUEOUS ALKALINE HOMOGENOUS HYDROLYSIS OF HIGH EXPLOSIVE 1, 3,5,7-TETRAAZA- 1, 3,5,7-TETRANITROCYCLOOCTANE (HMX)

1994 ◽  
Vol 30 (3) ◽  
pp. 53-61 ◽  
Author(s):  
Harro M. Heilmann ◽  
Michael K. Stenstrom ◽  
Rolf P. X. Hesselmann ◽  
Udo Wiesmann
Keyword(s):  
Temperature Dependence ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Elevated Temperatures ◽  
Second Order ◽  
Order Rate ◽  
Subsequent Calculation ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Order Rate Equation

In order to get basic data for the design of a novel treatment scheme for high explosives we investigated the kinetics for the aqueous alkaline hydrolysis of 1,3,5,7-tetraaza-1,3,5,7-tetranitrocyclooctane (HMX) and the temperature dependence of the rate constants. We used an HPLC procedure for the analysis of HMX. All experimental data could be fit accurately to a pseudo first-order rate equation and subsequent calculation of second-order rate constants was also precise. Temperature dependence could be modeled with the Arrhenius equation. An increase of 10°C led to an average increase in the second-order rate constants by the 3.16 fold. The activation energy of the second-order reaction was determined to be 111.9 ±0.76 kJ·moJ‒1. We found the alkaline hydrolysis to be rapid (less than 2.5% of the initial HMX-concentration left after 100 minutes) at base concentrations of 23 mmol oH‒/L and elevated temperatures between 60 and 80°C.

Stability of the Nerve Gas Antidote BIS (4-Hydroxyiminomethyl-1-Pyridinomethyl) Ether Dichloride (Toxogonin®)

1968 ◽  
Vol 2 (9) ◽  
pp. 234-243 ◽  
Author(s):  
Inga Christenson
Keyword(s):  
Aqueous Solution ◽  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Rate Constants ◽  
Kinetics Of Hydrolysis ◽  
Dilute Aqueous Solution ◽  
Nerve Gas ◽  
Ph Range ◽  
Kinetics Of ◽  
Hydrolysis Of

The products and kinetics of hydrolysis of the nerve gas antidote bis(4-hydroxyiminomethyl - 1 - pyridinemethyl) ether dichloride (Toxogonin ®) have been investigated. A survey of these studies is given: The hydrolytic reactions were studied in the pH range 1 M hydrochloric acid to 1 M sodium hydroxide at 25, 45, 75 and 85° C. Rate constants were determined in dilute aqueous solution, generally with an initial Toxogonin concentration of 0.01 mg per ml. In addition, a report is given concerning two-year storage of 25 percent (w/v) Toxogonin solutions at pH 2.5, 3.0 and 3.5. The solutions were stored in glass or polypropylene ampuls at 5, 15, 25 and 45°C. At 5 and 15C° decomposition was negligible, at 25 and 45 °C average decomposition was 1.5 percent and 3.3 percent, respectively.

KINETICS OF THE OXIDATION OF URANIUM (IV) BY IRON (III) IN AQUEOUS SOLUTIONS OF PERCHLORIC ACID

1955 ◽  
Vol 33 (12) ◽  
pp. 1780-1791 ◽  
Author(s):  
R. H. Betts
Keyword(s):  
Electron Transfer ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Perchloric Acid ◽  
Rate Constants ◽  
Kcal Mole ◽  
Kinetics Of Oxidation ◽  
Temperature Coefficients ◽  
Kinetics Of ◽  
Rate Controlling Step

The kinetics of oxidation of uranium (IV) by iron (III) in aqueous solutions of perchloric acid have been investigated at four temperatures between 3.1 °C. and 24.8 °C. The reaction was followed by measurement of the amount of ferrous ion formed. For the conditions (H+) = 0.1–1.0 M, ionic strength = 1.02, (FeIII) = 10−4–10−5 M, and (UIV) = 10−4–10−5 M, the observed rate law is d(Fe2+)/dt = −2d(UIV)/dt[Formula: see text]K1 and K2 are the first hydrolysis constants for Fe3+ and U4+, respectively, and K′ and K″ are pseudo rate constants. At 24.8 °C., K′ = 2.98 sec.−1, and K″ = 10.6 mole liter−1 sec−1. The corresponding temperature coefficients are ΔH′ = 22.5 kcal./mole and ΔH″ = 24.2 kcal./mole. The kinetics of the process are consistent with a mechanism which involves, as a rate-controlling step, electron transfer between hydrolyzed ions.

scholarly journals The kinetics of mutarotation in solution

1940 ◽  
Vol 176 (966) ◽  
pp. 352-367 ◽  
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Reducing Sugars ◽  
Arrhenius Equation ◽  
Energy Of Activation ◽  
A Value ◽  
Temperature Ranges ◽  
Velocity Coefficient ◽  
Kinetics Of ◽  
True Energy

The kinetics of the mutarotation of representative reducing sugars from the pentose, hexose and disaccharide series have been investigated polarimetrically over wide temperature ranges in aqueous solution. The dependence of the velocity coefficient, k , upon temperature is fairly well reproduced by an equation of the form ln k = C + ( J/R ) ln T - E/RT . The true energy of activation, E , is found to be some 6000 calories greater than the apparent value afforded by the Arrhenius equation at room temperature. J/R has a value of — 10, which is identified as the number of oscillators contributing to the activation. The constants C, J and E of this equation are discussed, with reference to many reactions, in terms of a theory of unimolecular reactions in solution.

Vulcanization of Elastomers. 40. Vulcanization of Natural Rubber and Synthetic Rubber with Sulfur in Presence of Sulfenamides. III

1965 ◽  
Vol 38 (1) ◽  
pp. 189-203 ◽  
Author(s):  
W. Scheele ◽  
J. Helberg
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
Rate Constants ◽  
Sulfur Concentration ◽  
Kcal Mole ◽  
Synthetic Rubber ◽  
Chemical Constitution ◽  
Induction Times ◽  
Kinetics Of

Abstract Vulcanization of natural rubber with sulfur was studied in presence of six sulfenamides, to determine the effect of the chemical constitution of the sulfenamide on sulfur decrease and on crosslinking. The results can be condensed as follows: (1) The kinetics of sulfur disappearance is in every respect qualitatively independent of the chemical constitution of the sulfenamide. (2) For the sulfenamides investigated, the smallest and largest rate constants for sulfur decrease differed only by a factor of two. (3) Greater differences are encountered in the induction times for sulfur decrease and for crosslinking. The latter are notably longer than those for sulfur disappearance. (4) The same activation energy, 23 kcal/mole, is derived from the temperature dependence of the induction times for all the sulfenamides. (5) The dissociation of sulfenamides in solution and their reaction with mercaptobenzothiazole were investigated further. The results provide the basis for a proposed reaction mechanism, which is presented in detail and can account for a number of the features typical of sulfenamide-accelerated vulcanization. (6) The drop in sulfur concentration goes at practically the same rate, if one introduces, instead of N, N-dicyclohexyl-2-benzothiazolesulfenamide, the corresponding ammonium mercaptide in equimolar concentration.

scholarly journals Pyrolysis of azetidinones. Part 2. Kinetics and mechanism of thermolysis of β-lactams and β-thiolactams

2016 ◽  
Vol 94 (9) ◽  
pp. 788-793 ◽  
Author(s):  
Nouf S. Al-Hamdan ◽  
Alya M. Al-Etaibi ◽  
Rasha F. Al-Bashir ◽  
Yahia A. Ibrahim ◽  
Nouria A. Al-Awadi ◽  
...  
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Kinetics And Mechanism ◽  
Energy Of Activation ◽  
The Novel ◽  
Temperature Range ◽  
Entropy Of Activation ◽  
Kinetics Of ◽  
Thermolysis Reaction

The kinetics of the gas-phase thermolysis reaction of seven β-lactams and their thione analogues were investigated over the temperature range 533–603 K for the β-lactams and 463–542 K for the β-thiolactams. The average values of the energy of activation (Ea) (kJ mol−1) and Arrhenius log A (s–1) were, respectively, 170.8 ± 18.6 and 12.4 ± 1.6 for the lactams and 131.7 ± 18.2 and 11.0 ± 2.0 for the thione analogues. The entropy of activation (ΔS#) was negative for of the substrates and slightly positive for three. The rate constants (k) (s−1) were calculated for 510 K and compared for the two series of azetidinones. The effects of substituents on rates and the novel role played by the C=O and C=S moieties on the relative reactivities of the cyclic amides are rationalized on the basis of a formal retro[2+2]cycloaddition mechanism used earlier to explain the products of the gas-phase thermolysis reaction of the present azetidinones.

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