The Kinetics of Quinoline Hydrodenitrogenation through Reaction Intermediate Products

1975 ◽  
Vol 53 (17) ◽  
pp. 2575-2579 ◽  
Author(s):  
Ahmed Kadry Aboul-Gheit
Keyword(s):  
Order Reaction ◽  
Second Step ◽  
Activation Entropy ◽  
Ammonia Production ◽  
Alumina Catalyst ◽  
High Activation ◽  
Reaction Sequence ◽  
First Order ◽  
The Third ◽  
Kinetics Of

Under petroleum hydrotreating conditions and in the presence of a Co–M–alumina catalyst, quinoline is hydrodenitrogenated through a consecutive first order reaction involving a hydrogénation step followed by two hydrocracking steps. The first step is too fast to measure whereas the second step is the slowest. The ratio of the rate constants of the second to the third step ranges between 0.33 and 0.62 at reaction temperatures between 350 and 400 °C. The second step can be considered responsible for the relatively high activation energy and enthalpy values obtained for the overall reaction. The activation entropy obtained for the overall reaction is −38.2 e.u. mol−1, while the second and the third steps have values of −43.9 and −58.0 e.u. mol−1, respectively. These values indicate the progressive complexity of the steps involved in the reaction sequence as it proceeds towards ammonia production.

scholarly journals The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate

2000 ◽  
Vol 65 (12) ◽  
pp. 857-866
Author(s):  
Mladjen Micevic ◽  
Slobodan Petrovic
Keyword(s):  
Kinetic Data ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Activation Entropy ◽  
Second Order Reaction ◽  
Third Order ◽  
First Order ◽  
Kinetics Of

The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate (soman) was examined with a series of alkoxides and in corresponding alcohols: methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol and 2-ethoxyethanol. Soman reacts with the used alkoxides in a second order reaction, first order in each reactant. The kinetics of the reaction between 1,2,2-trimethylpropyl-methylfluorophosphonate and ethanol in the presence of diethylenetriamine was also examined. A third order reaction rate constant was calculated, first order in each reactant. The activation energy, frequency factor and activation entropy were determined on the basis of the kinetic data.

The Kinetics of Glucose Decomposition with Sulfate Reduction in the Anaerobic Fluidized Bed Reactor

1993 ◽  
Vol 28 (2) ◽  
pp. 135-144 ◽  
Author(s):  
S. Matsui ◽  
R. Ikemoto Yamamoto ◽  
Y. Tsuchiya ◽  
B. Inanc
Keyword(s):  
Sulfate Reduction ◽  
Fluidized Bed ◽  
Kinetic Equations ◽  
Fluidized Bed Reactor ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Glucose Decomposition ◽  
Reaction Equations ◽  
Kinetics Of

Using a fluidized bed reactor, experiments on glucose decomposition with and without sulfate reduction were conducted. Glucose in the reactor was mainly decomposed into lactate and ethanol. Lactate was mainly decomposed into propionate and acetate, while ethanol was decomposed into propionate, acetate, and hydrogen. Sulfate reduction was not involved in the decomposition of glucose, lactate, and ethanol, but was related to propionate and acetate decomposition. The stepwise reactions were modeled using either a Monod expression or first order reaction kinetics in respect to the reactions. The coefficients of the kinetic equations were determined experimentally. The modified Monod and first order reaction equations were effective at predicting concentrations of glucose, lactate, ethanol, propionate, acetate, and sulfate along the beight of the reactor. With sulfate reduction, propionate was decomposed into acetate, while without sulfate reduction, accumulation of propionate was observed in the reactor. Sulfate reduction accelerated propionate conversion into acetate by decreasing the hydrogen concentration.

Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Ionic Strength ◽  
Fractional Order ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Intermediate Complex ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

Bacteriophage Conjugates: The Effect of Coupling Reaction and Specific Antibodies on the Kinetics of Inactivation and Reactivation

1973 ◽  
Vol 28 (1-2) ◽  
pp. 83-90
Author(s):  
Horst Mossmann ◽  
Dietrich K. Hammer
Keyword(s):  
Bacteriophage T4 ◽  
Covalent Binding ◽  
Coupling Reaction ◽  
Order Reaction ◽  
Direct Plating ◽  
Specific Antibodies ◽  
Coupling Process ◽  
First Order ◽  
Kinetics Of ◽  
Critical Site

The reaction of bacteriophage T4 with 1-fluoro-2,4-dinitrobenzene resulted in a covalent binding of 2,4-dinitrophenyl (DNP) determinants to the phage. From the kinetics of inactivation reflecting the coupling process it is concluded that attachment of more than one DNP group to the critical site(s) of the phage is required for inactivation (multi-hit reaction). Contrary to this the neutralization of DNP-T4 by anti-DNP antibody turned out to be a first order reaction, until 80 %> neutralization fitting one-hit kinetics. If compared with native T4, the susceptibility of DNP-T4 to neutralization by anti-T4 antibody is considerably higher, indicating that attachment of DNP groups to T4 amplifies the sensitivity to neutralization by anti-T4. Comparing neutralization kinetics of DNP-T4 and native T4 by anti-DNP-T4 antibody it is suggested that native determinants and DNP groups, as well as determinants resulting from alteration due to the coupling process, all together may contribute as targets for neutralization. Three characteristics strengthen the view that the velocity of T4 conjugates in infecting the host strain is markedly decreased if compared with that of native T4: (a) considerable discrepancy between direct plating and decision technique (b) increasing variety of plaque size and (c) decreased velocity of the first step of reproduction. The kinetics of neutralization observed can be reconciled with a model proposed by Krummel and Uhr. The kinetics of reactivation of neutralized DNP-T4 by the presence cf DNP-BSA has been investigated and the problems involved in the reaction are discussed.

scholarly journals SOLVATION OF THE [Cr(NCS)4(IMIDAZOLE)2] ION IN ETHANOL-WATER MIXTURES

2002 ◽  
Vol 10 (11) ◽  
pp. 63-72
Author(s):  
lon Ganescu ◽  
George Bratulescu ◽  
Ion Papa ◽  
Anca Ganescu ◽  
Alin Barbu ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Order Reaction ◽  
Water Molecules ◽  
Hydrogen Ions ◽  
Second Order Reaction ◽  
Acidic Solutions ◽  
The Third ◽  
Competitive Reactions ◽  
Different Temperatures ◽  
Kinetics Of

Salvation kinetics of [Cr(NCS)4(imidazole)2]- has been studied in ethanol-water mixtures at different temperatures. The first stage of the solvation consists of two competitive reactions: two NCS- ions are exchanged, presumably, by water molecules and simultaneously an imidazole molecule by ethanol, the latter in a second-order reaction, accelerated by hydrogen ions. The exchange of the amine is followed by the substitution of the first two NCS- ions. The third and fourth NCS- ions are substituted only in neutral and slightly acidic solutions. Kinetic parameters have been determined for reactions (1), (2), and (4). The influence of the solvent composition and acidity is discussed

Direct Method for Determining Inorganic Phosphate in Serum with the "CentrifiChem"

1972 ◽  
Vol 18 (3) ◽  
pp. 263-265 ◽  
Author(s):  
John A Daly ◽  
Gerhard Ertingshausen
Keyword(s):  
Inorganic Phosphate ◽  
Direct Method ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Kinetics Of ◽  
A Direct Method

Abstract A direct method was developed for determining inorganic phosphate in serum, which requires only a single reagent addition. The method quantitates the unreduced phosphomolybdate heteropolyacid at 340 nm and is linear to at least 10 mg of phosphate per 100 ml. Only 10 µl of serum is required. The unique blanking capabilities of centrifugal analyzers permit the "on run" elimination of serum and reagent background absorbances, which are automatically subtracted. Data on precision, correlation, and recovery are presented. Kinetics of the reaction were studied, and theoretical limits of automatic blanking when applied to a first-order reaction are discussed.

Studies on the oxidative degradation of paracetamol by a μ-oxo-diiron(III) complex

2020 ◽  
Vol 98 (2) ◽  
pp. 98-105
Author(s):  
Bula Singh ◽  
Ranendu Sekhar Das
Keyword(s):  
Acetic Acid ◽  
Oxidative Degradation ◽  
Active Role ◽  
Order Reaction ◽  
Proton Abstraction ◽  
First Order ◽  
Initial Activation ◽  
Reaction Media ◽  
Kinetics Of ◽  
Reactivity Order

In higher organisms, metalloenzymes like cytochrome P450, containing a Fe(III) metal center, play an active role in metabolism of paracetamol (APAP). Here, we have chosen a mimicking μ-oxo-diiron complex, [Fe(III)2(μ-O)(phen)4(H2O)2]4+ (1, phen = 1,10-phenanthroline), to study spectrophotometrically the kinetics of the redox interactions with APAP. In acidic buffer media (pH = 3.4–5.1), APAP quantitatively reduces 1 following first-order reaction kinetics. Each molecule of 1 accepts two electrons from APAP and is reduced to ferroin [Fe(phen)3]2+. On oxidation, APAP produces N-acetyl-p-benzoquinone imine (NAPQI), which on hydrolysis results in a mixture of benzoquinone, quinone oxime, acetamide, and acetic acid. In reaction media due to successive deprotonations, 1 exists in equilibrium with the species [Fe(III)2(μ-O)(phen)4(H2O)(OH)]3+ (1a) and [Fe(III)2(μ-O)(phen)4(OH)2]2+ (1b) (pKa = 3.71 and 5.28, respectively). The kinetic analyses suggest for an unusual reactivity order as 1 < 1a ≫ 1b. The mechanistic possibilities suggest that although 1 is reduced by concerted electron transfer (ET) – proton transfer (PT) mechanism, 1a and 1b may be reduced by a concerted PT–ET mechanism where a slow proton-abstraction step is followed by a rapid ET process. It seems that the initial activation of the bridging μ-oxo group by a proton-abstraction results in the higher reactivity of 1a.

Development of Torrefaction Kinetics for British Columbia Softwoods

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Jianghong Peng ◽  
Xiaotao T. Bi ◽  
Jim Lim ◽  
Shabab Sokhansanj
Keyword(s):  
British Columbia ◽  
Weight Loss ◽  
Kinetic Model ◽  
Residence Time ◽  
Order Reaction ◽  
First Order Reaction ◽  
Chemical Components ◽  
First Order ◽  
One Step ◽  
Kinetics Of

Torrefaction is a thermal treatment without air or oxygen in the temperature range of 473-573 K. The pyrolysis kinetics of three chemical components (cellulose, hemicelluloses, and lignin) and wood at low temperatures of relevance to torrefaction conditions have been reviewed. A series of thermogravimetric (TG) experiments have been carried out to study the intrinsic torrefaction kinetics of major chemical components and British Columbia (BC) softwoods. The weight loss during BC softwood torrefaction was found to be mainly associated with the decomposition of hemicelluloses, although there was also certain degree of decomposition of cellulose and lignin. The weight loss of the BC softwoods during torrefaction could be approximately estimated from the chemical composition of wood species and the weight loss data for torrefaction of pure cellulose, hemicelluloses, and lignin, respectively. Based on the fitting of the TG curves of BC softwoods and three chemical components, two different torrefaciton models were proposed. The simple one-step (single-stage) kinetic model with the first order reaction can predict the reaction data reasonably well over the long residence time, with the final sample weight being strongly related to the torrefaction temperature. A two-component and one-step first order reaction kinetic model, on the other hand, gave improved agreement with data over short residence time, and can be used to guide the design and optimization of torrefaction reactors over the weight loss range of 0 to 40% at the temperature range of 533-573 K, which covers the typical range of industrially relevant operations.

Kinetics of Cs adsorption/desorption on granite by a pseudo first order reaction model

2007 ◽  
Vol 275 (3) ◽  
pp. 555-562 ◽  
Author(s):  
Shih-Chin Tsai ◽  
Tsing-Hai Wang ◽  
Yuan-Yaw Wei ◽  
Wen-Chun Yeh ◽  
Yi-Lin Jan ◽  
...  
Keyword(s):  
Reaction Model ◽  
Order Reaction ◽  
First Order Reaction ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order ◽  
Adsorption Desorption ◽  
Kinetics Of

Studies in the Vulcanization of Rubber. III—Kinetics of Vulcanization of Rubber with Sulfur and Selenium

1930 ◽  
Vol 3 (4) ◽  
pp. 650-659
Author(s):  
John T. Blake
Keyword(s):  
Molecular Weight ◽  
Order Reaction ◽  
Order Equation ◽  
Second Order Reaction ◽  
Experimental Conditions ◽  
Mathematical Basis ◽  
First Order ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization

Abstract A procedure for the determination of combined selenium in rubber has been evolved. The rate of combination of selenium and rubber has been ascertained under certain conditions and shown to follow a first-order equation. A minimum value for the molecular weight of rubber has been estimated. The formation of hard rubber under chosen experimental conditions has been put on a mathematical basis and has been shown to follow a second-order reaction. The soft- and hard-rubber reactions have been shown qualitatively to be successive reactions and the function of accelerators has been discussed. The theory explains the anomalous results obtained by previous investigators.

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