A KINETIC INVESTIGATION OF THE REACTION OF METHYLMAGNESIUM BROMIDE WITH BENZOPHENONE

1963 ◽  
Vol 41 (5) ◽  
pp. 1329-1343 ◽  
Author(s):  
Norbert M. Bikales ◽  
Ernest I. Becker
Keyword(s):  
Rate Equation ◽  
Rate Constants ◽  
Second Order ◽  
Magnesium Bromide ◽  
Kinetic Investigation ◽  
First Order ◽  
Order Rate ◽  
Entropy Of Activation ◽  
Time Variables ◽  
Order Rate Equation

The reaction of methylmagnesium bromide with benzophenone in tetrahydrofuran was found to be homogeneous and essentially quantitative. The rates of this reaction were measured by following the decrease in absorbance of benzophenone in the ultraviolet as a function of time. Variables examined were concentrations of reactants, magnesium bromide, and temperature. Values were derived for the rate constants, and the energy and entropy of activation. The reaction was found to be initially first order in each reactant, but the rate decreased faster with time than would be predicted from the simple second-order rate equation. The implications of these findings are discussed.

Biosorption of Lignin Compounds Using Biomass Derived from Eichhornia crassipes: Batch Studies

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Renganathan Sahadevan ◽  
Ajit Balaji Kannavadi Devaraj ◽  
Dharmendira Kumar Mahendradas ◽  
Baskar Gurunathan ◽  
Manickam Velan
Keyword(s):  
Rate Equation ◽  
Eichhornia Crassipes ◽  
Second Order ◽  
Isotherm Model ◽  
Batch Studies ◽  
First Order ◽  
Order Rate ◽  
Pseudo Second Order ◽  
Pseudo First Order ◽  
Order Rate Equation

Biosorption of lignin compounds by the Eichhornia crassipes was investigated in batch studies. Batch experiments were conducted to study the effect of initial sorbent dosage, solution pH and lignin compounds concentration. Langmuir and Freundlich adsorption isotherm models were used to represent the equilibrium data. The Freundlich isotherm model was found to be fitted very well with the experimental data when compared to Langmuir isotherm model. The results showed that the equilibrium uptake capacity was found to be increased with decrease in biomass dosage. The lignin compound removal was influenced by the initial lignin compounds concentration. The sorption results were analysed for pseudo first order and pseudo second order kinetic model. It was observed that the kinetic data fitted very well with the pseudo second order rate equation when compared to the pseudo first order rate equation. Sorption results were analyzed for the intra particle diffusion model.

PLATELET AGGREGATION DOES NOT CONFORM TO SIMPLE PARTICLE COLLISION THEORY

1987 ◽  
Author(s):  
Moideen P Jamaluddin
Keyword(s):  
Platelet Aggregation ◽  
Rate Equation ◽  
Rate Constants ◽  
Kinetic Scheme ◽  
Order Type ◽  
Second Order ◽  
Particle Collision ◽  
Collision Theory ◽  
Rate Law ◽  
First Order

Platelet aggregation kinetics, according to the particle collision theory, generally assumed to apply, ought to conform to a second order type of rate law. But published data on the time-course of ADP-induced single platelet recruitment into aggregates were found not to do so and to lead to abnormal second order rate constants much larger than even their theoretical upper bounds. The data were, instead, found to fit a first order type of rate law rather well with rate constants in the range of 0.04 - 0.27 s-1. These results were confirmed in our laboratory employing gelfiltered calf platelets. Thus a mechanism much more complex than hithertofore recognized, is operative. The following kinetic scheme was formulated on the basis of information gleaned from the literature.where P is the nonaggregable, discoid platelet, A the agonist, P* an aggregable platelet form with membranous protrusions, and P** another aggregable platelet form with pseudopods. Taking into account the relative magnitudes of the k*s and assuming aggregation to be driven by hydrophobic interaction between complementary surfaces of P* and P** species, a rate equation was derived for aggregation. The kinetic scheme and the rate equation could account for the apparent first order rate law and other empirical observations in the literature.

THE REDUCTION OF CYTOCHROMEcBY HYDROQUINONE

1963 ◽  
Vol 41 (1) ◽  
pp. 231-237 ◽  
Author(s):  
G. R. Williams
Keyword(s):  
Reaction Mechanism ◽  
Ionic Strength ◽  
Rate Equation ◽  
Second Order ◽  
Order Rate ◽  
Ferricytochrome C ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Order Rate Equation

The kinetics of reduction of ferricytochrome c by hydroquinone have been studied. The reaction does not conform to a simple second-order rate equation and it is demonstrated that the deviations are brought about by the presence of p-quinone, one of the products of the reaction. The accelerating effect of p-quinone is explained tentatively on the basis of an involvement of the semi-quinone. The effects on the reaction of pH, ionic strength, and temperature are reported and used to suggest features of the reaction mechanism.

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.

A kinetic investigation of the effects of molecular complexing on the acidities of some π donor carboxylic acids

1977 ◽  
Vol 55 (6) ◽  
pp. 1028-1038 ◽  
Author(s):  
Allan K. Colter ◽  
R. James Kersting
Keyword(s):  
Carboxylic Acid ◽  
Acrylic Acid ◽  
Carboxylic Acids ◽  
Rate Constants ◽  
Association Constants ◽  
Second Order ◽  
Kinetic Investigation ◽  
Rate Data ◽  
Dihydroxybenzoic Acid ◽  
Order Rate

Rates of reaction of the five π donor acids indole-3-acrylic acid (IAA), indole-5-carboxylic acid (ICA), 3,4,5-trimethoxybenzoic acid (TMBA), 2,4-dihydroxybenzoic acid (DHBA), and 3,4,5-trihydroxybenzoic acid (THBA) with 4-chlorodiphenyldiazomethane (4-ClDDM) in ethanol at 30 °C were measured in the presence of the π acceptors 1,3,5-trinitrobenzene (TNB), benzotrifuroxan (BTF), and 1,2,4,5-tetracyanobenzene (TCNB) and in the absence of acceptor. For 12 of the 13combinations studied, added acceptor produced rate enhancements. The rate data were combined with independently-determined 1:1 acceptor – donor acid association constants to obtain second-order rate constants for reaction of the 1:1 acceptor – donor acid complexes. From the increase in the rate constant resulting from complexation, estimates of the increase in Ka(H2O, 25 °C) produced by complexation were obtained for 13 acceptor – donor acid combinations. Second-order rate constants for reaction of 4-ClDDM with 10 other carboxylic acids and p-toluenesulfonic acid in ethanol at 30°C were also measured and the pattern of reactivity shown to parallel very closely that of diphenyldiazomethane.

THE REDUCTION OF CYTOCHROMEcBY HYDROQUINONE

1963 ◽  
Vol 41 (1) ◽  
pp. 231-237 ◽  
Author(s):  
G. R. Williams
Keyword(s):  
Reaction Mechanism ◽  
Ionic Strength ◽  
Rate Equation ◽  
Second Order ◽  
Order Rate ◽  
Ferricytochrome C ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Order Rate Equation

The kinetics of reduction of ferricytochrome c by hydroquinone have been studied. The reaction does not conform to a simple second-order rate equation and it is demonstrated that the deviations are brought about by the presence of p-quinone, one of the products of the reaction. The accelerating effect of p-quinone is explained tentatively on the basis of an involvement of the semi-quinone. The effects on the reaction of pH, ionic strength, and temperature are reported and used to suggest features of the reaction mechanism.

scholarly journals Preparation and Utilization of Kapok Hull Carbon for the Removal of Rhodamine-B from Aqueous Solution

2006 ◽  
Vol 3 (2) ◽  
pp. 83-96 ◽  
Author(s):  
P. S. Syed Shabudeen ◽  
R. Venckatesh ◽  
S. Pattabhi
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Rate Equation ◽  
Rhodamine B ◽  
Rate Constants ◽  
Diffusion Rate ◽  
Agricultural Waste ◽  
Intraparticle Diffusion ◽  
First Order ◽  
Order Rate

A carbonaceous sorbent prepared from the indegeneous agricultural waste (which is facing solid waste disposal problem) Kapok Hull, by acid treatment was tested for its efficiency in removing basic dyes. Batch kinetic and isotherm experiments were conducted to determine the sorption and desorption of the Rhodamine-B from aqueous solution with activated carbon. The factors affecting the rate processes involved in the removal of dye for initial dye concentration, agitation time, and carbon dose and particle size have been studied at ambient temperature. The adsorption process followed first order rate kinetics. The first-order rate equation by Lagergren was tested on the kinetic data, and isotherm data was analyzed for possible agreement with the Langmuir and Freundlich adsorption isotherm equations. The intraparticle diffusion rate equation from which adsorption rate constants, diffusion rate constants and diffusion coefficients were determined. Intraparticle diffusion was found to be the rate-limiting step. The structural and morphological of activated carbon were characterized by XRD and SEM studies respectively.

Pyrimidine reactions. XI. Amination rates for two chlorodimethylprimidines without solvent

1965 ◽  
Vol 18 (11) ◽  
pp. 1811 ◽  
Author(s):  
DJ Brown ◽  
JM Lyall
Keyword(s):  
Rate Constants ◽  
Second Order ◽  
Arrhenius Parameters ◽  
First Order ◽  
Order Rate

Second-order rate constants, Arrhenius parameters, and isokinetic temperatures are presented for the reactions of 2-chloro-4,6-dimethylpyrimidine and 4-chloro-2,6-dimethylpyrimidine with some n-alkyl-, branched alkyl-, and dialkylamines in the absence of a solvent. The differences between these values and those available for the same reactions in a solvent are briefly discussed. An equation is derived for satisfactorily converting the apparent first-order rate constants previously reported by us into second-order rate constants.

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