Kinetics of the Nitrosation of Pyrrolidine and Proline

1974 ◽  
Vol 52 (7) ◽  
pp. 1050-1053 ◽  
Author(s):  
A. Okany ◽  
T. F. Massiah ◽  
L. J. Rubin ◽  
K. Yates
Keyword(s):  
Rate Constants ◽  
Nitroso Compounds ◽  
Meat Processing ◽  
Temperature Range ◽  
Buffer Solutions ◽  
Entropy Of Activation ◽  
Kinetics Of

The kinetics of the nitrosation of pyrrolidine and proline have been investigated in buffer solutions of mildly acidic pH's in the temperature range 40–100 °C. The rate constants were determined and the enthalpy and the entropy of activation were calculated for both reactions. Examples are presented in which are estimated the maximum amounts of nitroso compounds formed under conditions relevant to meat processing.

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.

Kinetics of hydrolyses of o-methylbenzylideneaniline and o-hydroxybenzylideneaniline

1968 ◽  
Vol 46 (9) ◽  
pp. 1589-1592 ◽  
Author(s):  
Alfred V. Willi ◽  
José F. Siman
Keyword(s):  
Hydrogen Bond ◽  
Schiff Base ◽  
Rate Constants ◽  
Experimental Error ◽  
Steric Effect ◽  
Hydrolysis Rate ◽  
Aqueous Methanol ◽  
Buffer Solutions ◽  
Acid Catalyzed ◽  
Kinetics Of

Rates of hydrolysis have been measured for o-methylbenzylideneaniline, o-hydroxybenzylideneaniline, and benzylideneaniline in various buffer solutions in 20% (by volume) aqueous methanol at 29.9 °C. Rate constants for the o-CH3 compound and the unsubstituted Schiff base agree within experimental error which indicates that there is no appreciable rate retarding steric effect. The o-OH group decreases the hydrolysis rate at pH = 5.6 – 6.6 by approximately one power of ten. This effect is caused by the hydrogen bond between the OH group and the azomethine N, which renders the Schiff base less accessible to acid-catalyzed hydrolysis.

scholarly journals The Kinetics of the Reaction C2H5• + HI → C2H6 + I• over an Extended Temperature Range (213–623 K): Experiment and Modeling

2015 ◽  
Vol 229 (10-12) ◽  
Author(s):  
Nicholas Leplat ◽  
Jozef Federič ◽  
Katarína Šulková ◽  
Mária Sudolská ◽  
Florent Louis ◽  
...  
Keyword(s):  
Rate Constants ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Dependent Rate ◽  
Highly Correlated ◽  
Kinetics Of

AbstractThe present study reports temperature dependent rate constantsHighly correlated

scholarly journals Kinetics of the gas-phase reactions of OH radicals with alkanes and cycloalkanes

2003 ◽  
Vol 3 (6) ◽  
pp. 2233-2307 ◽  
Author(s):  
R. Atkinson
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Relative Rate ◽  
Oh Radicals ◽  
Gas Phase Reactions ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Dependent Rate ◽  
Temperature Ranges ◽  
Kinetics Of

Abstract. The available database concerning rate constants for gas-phase reactions of the hydroxyl (OH) radical with alkanes through early 2003 is presented over the entire temperature range for which measurements have been made (~180-2000 K). Measurements made using relative rate methods are re-evaluated using recent rate data for the reference compound (generally recommendations from this review). In general, whenever more than one study has been carried out over an overlapping temperature range, recommended rate constants or temperature-dependent rate expressions are presented. The recommended 298 K rate constants, temperature-dependent parameters, and temperature ranges over which these recommendations are applicable are listed in Table 1.

scholarly journals Kinetics of the gas-phase reactions of OH radicals with alkanes and cycloalkanes

2003 ◽  
Vol 3 (4) ◽  
pp. 4183-4358 ◽  
Author(s):  
R. Atkinson
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Relative Rate ◽  
Oh Radicals ◽  
Reference Compound ◽  
Gas Phase Reactions ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Dependent Rate ◽  
Kinetics Of

Abstract. The available database concerning rate constants for gas-phase reactions of the hydroxyl (OH) radical with alkanes through early 2003 is presented ove the entire temperature range for which measurements have been made (~180–2000 K). Measurements made using relative rate methods are re-evaluated using recent rate data for the reference compound (generally recommendations from this review). In general, whenever more than one study has been carried out over an overlapping temperature range, recommended rate constants or temperature-dependent rate expressions are presented.

Kinetics of acid-catalyzed hydration in aqueous solution of 1-methoxy- and 1-methylthio-2-phenylethyne and some related acetylenes

1987 ◽  
Vol 65 (2) ◽  
pp. 441-444 ◽  
Author(s):  
N. Banait ◽  
M. Hojatti ◽  
P. Findlay ◽  
A. J. Kresge
Keyword(s):  
Aqueous Solution ◽  
Proton Transfer ◽  
Isotope Effect ◽  
Rate Constants ◽  
Acid Catalysis ◽  
The Other ◽  
Buffer Solutions ◽  
Hydronium Ion ◽  
Acid Catalyzed ◽  
Kinetics Of

The rates of conversion of C6H5C≡COCH3 to C6H5CH2CO2CH3 were measured in dilute HClO4/H2O, DCIO4/D2O, and H3PO4–H2PO2−/H2O buffer solutions, and the rates of conversion of C6H5C≡CSCH3 to C6H5CH2COSCH3, C6H5C≡CH to C6H5COCH3, 2,4,6-(CH3)3C6H2C≡CH to 2,4,6-(CH3)3C6H2COCH3, and p-CH3OC6H4C≡CCH3 to p-CH3OC6H4COCH2CH3 were measured in concentrated HClO4/H2O solutions, all at 25 °C. The reaction of C6H5C≡COCH3 showed general acid catalysis and gave the isotope effect [Formula: see text], which indicates that it proceeds through rate-determining proton transfer from catalyst to substrate. The hydronium ion catalytic coefficient for this reaction is [Formula: see text], and those for the other four, in the order given above, are [Formula: see text], and 8.5 × 10−6 M−1 s−1. Relative reactivities based on these rate constants are discussed.

The polymerization of styrene by sulphuric acid - II. The kinetics of polymerization in 1:2-dichloroethane

1961 ◽  
Vol 263 (1312) ◽  
pp. 63-74 ◽  
Keyword(s):  
Rate Constants ◽  
Homogeneous Solution ◽  
The Other ◽  
Chain Reaction ◽  
Individual Values ◽  
Kinetics Of Polymerization ◽  
Temperature Range ◽  
Molecular Weights ◽  
Reaction Theory ◽  
Kinetics Of

The polymerization has been studied in homogeneous solution over the temperature range 0 to 35°C. At the upper temperatures the reactions are very fast; over the whole temperature range they are incomplete, giving limited yields of polymer which depend on the initial acid concentration, but not on that of the monomer. The results are described by the non­-stationary chain reaction theory derived in part I. Individual values of all the rate con­stants are obtained at 25°C, and ratios of rate constants at the other temperatures. The molecular weights are relatively low (< 20000) and determined by transfer rather than true termination processes.

The kinetics of dehydroxylation of kaolinite

Clay Minerals ◽  
1987 ◽  
Vol 22 (4) ◽  
pp. 447-456 ◽  
Author(s):  
S. A. T. Redfern
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Kinetic Analysis ◽  
Rate Constants ◽  
Avrami Equation ◽  
Isothermal Thermogravimetry ◽  
Temperature Range ◽  
Homogeneous Models ◽  
Kinetics Of ◽  
Fraction Method

AbstractThe dehydroxylation of kaolinite has been investigated by isothermal thermogravimetry. Kinetic analysis using the Avrami equation shows that a combination of atomic mechanisms operates throughout the temperature range 734 K to 890 K. An empirical activation energy of 222 kJ mol-1 was calculated from the Arrhenius relationship using rate constants based on diffusion and homogeneous models. The activation energy (Ea) was calculated for a series of degrees of dehydroxylation by the time to a given fraction method, showing an increase in Ea during the early stages of the reaction. The isothermal plots indicate that OH is retained in the final stages of the reaction. The observations are explained in terms of a reaction mechanism in which kaolinite grains dehydroxylate from the edges inwards, parallel to (001).

Oxidation of Hydrazine by Alkaline Ferricyanide in Water-methanol Mixtures

1970 ◽  
Vol 25 (2) ◽  
pp. 188-190 ◽  
Author(s):  
V. K. Jindal ◽  
M. C. Agrawal ◽  
S. P. Mushran
Keyword(s):  
Ion Concentration ◽  
Hydroxide Ion ◽  
First Order ◽  
Order Dependence ◽  
Buffer Solutions ◽  
Entropy Of Activation ◽  
Alkaline Ferricyanide ◽  
Specific Ion Effect ◽  
Kinetics Of

Kinetics of the oxidation of hydrazine by ferricyanide was investigated in water-methanol mixtures using several buffer solutions. The reaction showed first order dependence in both hydrazine and ferricyanide. The order with respect to hydroxide ion concentration was zero. Increase in concentration of methanol had a retarding influence on the rate while the addition of neutral salts showed a specific ion effect. The energy and entropy of activation were calculated as 12.3 kcals. mole-1 and -20.8 cals. deg-1 mole-1 respectively. A suitable mechanism has been proposed which suggests the primary rate determining reaction between N2H4 and Fe (CN)63⊖. Nitrogen was found to be the product of the reaction.

Submerged upflow biotower operation and computer simulation

1994 ◽  
Vol 30 (11) ◽  
pp. 143-146
Author(s):  
Ronald D. Neufeld ◽  
Christopher A. Badali ◽  
Dennis Powers ◽  
Christopher Carson
Keyword(s):  
Computer Simulation ◽  
Benzoic Acid ◽  
Computer Model ◽  
Rate Constants ◽  
Batch Mode ◽  
Operational Conditions ◽  
First Order ◽  
Low Concentrations ◽  
Biological Transformation ◽  
Kinetics Of

A two step operation is proposed for the biodegradation of low concentrations (&lt; 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.

Sign in / Sign up

Export Citation Format

Share Document