Reaction Kinetics of In Situ Methanolysis of Jatropha curcas Seeds

In-situ methanolysis of Jatropha curcas had been investigated at various reaction temperatures along with reaction time. Increasing reaction temperature enhanced the yield of biodiesel and shortened the reaction completion. According to shrinking core model, the mechanism of in-situ methanolysis of Jatropha curcas was chemical reaction control with the first-order reaction. The constant of the first-order reaction rate in the range of 5.15×10-9 to 8.78×10-9 m·s-1 and Arrhenius activation energy of 22.66 kJ⋅mol-1 were obtained.

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Leaching Kinetics of Atrazine and Inorganic Chemicals in Tilled and Orchard Soils

International Agrophysics ◽

10.2478/intag-2014-0012 ◽

2014 ◽

Vol 28 (2) ◽

pp. 231-237 ◽

Cited By ~ 2

Author(s):

Lech W. Szajdak ◽

Jerzy Lipiec ◽

Anna Siczek ◽

Artur Nosalewicz ◽

Urszula Majewska

Keyword(s):

Reaction Rate ◽

Inorganic Compounds ◽

Model Performance ◽

Order Reaction ◽

First Order Reaction ◽

Order Kinetic ◽

Time Data ◽

First Order ◽

Concentration Changes ◽

Reaction Constants

Abstract The aim of this study was to verify first-order kinetic reaction rate model performance in predicting of leaching of atrazine and inorganic compounds (K+1, Fe+3, Mg+2, Mn+2, NH4 +, NO3 - and PO4 -3) from tilled and orchard silty loam soils. This model provided an excellent fit to the experimental concentration changes of the compounds vs. time data during leaching. Calculated values of the first-order reaction rate constants for the changes of all chemicals were from 3.8 to 19.0 times higher in orchard than in tilled soil. Higher first-order reaction constants for orchard than tilled soil correspond with both higher total porosity and contribution of biological pores in the former. The first order reaction constants for the leaching of chemical compounds enables prediction of the actual compound concentration and the interactions between compound and soil as affected by management system. The study demonstrates the effectiveness of simultaneous chemical and physical analyses as a tool for the understanding of leaching in variously managed soils.

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

Water Science & Technology ◽

10.2166/wst.1993.0092 ◽

1993 ◽

Vol 28 (2) ◽

pp. 135-144 ◽

Cited By ~ 3

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.

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

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19921451 ◽

1992 ◽

Vol 57 (7) ◽

pp. 1451-1458 ◽

Cited By ~ 6

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.

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Determination of exothermic batch reactor specific model parameters

MATEC Web of Conferences ◽

10.1051/matecconf/201929201063 ◽

2019 ◽

Vol 292 ◽

pp. 01063

Author(s):

Lubomír Macků

Keyword(s):

Rate Constant ◽

Reaction Rate ◽

Batch Reactor ◽

Specific Model ◽

Reaction Rate Constant ◽

Order Reaction ◽

First Order Reaction ◽

Model Parameters ◽

Reactor Model ◽

First Order

An alternative method of determining exothermic reactor model parameters which include first order reaction rate constant is described in this paper. The method is based on known in reactor temperature development and is suitable for processes with changing quality of input substances. This method allows us to evaluate the reaction substances composition change and is also capable of the reaction rate constant (parameters of the Arrhenius equation) determination. Method can be used in exothermic batch or semi- batch reactors running processes based on the first order reaction. An example of such process is given here and the problem is shown on its mathematical model with the help of simulations.

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

Journal of the Serbian Chemical Society ◽

10.2298/jsc0012857m ◽

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.

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

Clinical Chemistry ◽

10.1093/clinchem/18.3.263 ◽

1972 ◽

Vol 18 (3) ◽

pp. 263-265 ◽

Cited By ~ 194

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.

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Development of Torrefaction Kinetics for British Columbia Softwoods

International Journal of Chemical Reactor Engineering ◽

10.1515/1542-6580.2878 ◽

2012 ◽

Vol 10 (1) ◽

Cited By ~ 10

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.

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

Journal of Radioanalytical and Nuclear Chemistry ◽

10.1007/s10967-007-7045-y ◽

2007 ◽

Vol 275 (3) ◽

pp. 555-562 ◽

Cited By ~ 15

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

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Kinetics and Mechanism of Oxidation of Selenium(IV) by Permanganate Ion in Aqueous Perchlorate Solutions

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19930538 ◽

1993 ◽

Vol 58 (3) ◽

pp. 538-546 ◽

Cited By ~ 10

Author(s):

Refat M. Hassan ◽

Sahr A. El-Gaiar ◽

Abd El-Hady M. El-Summan

Keyword(s):

Reaction Mechanism ◽

Reaction Rate ◽

Oxidation Process ◽

Selenium Dioxide ◽

Order Reaction ◽

Acid Solutions ◽

First Order ◽

Acid Catalyzed ◽

Mechanism Of Oxidation ◽

Kinetics Of

The kinetics of permanganate oxidation of selenium dioxide in perchloric acid solutions at a constant ionic strength of 2.0 mol dm-3 has been investigated spectrophotometrically. A first-order reaction in [MnO4-] and fractional order with respect to selenium(IV) were observed. The reaction rate was found to be pH-independent at lower acid concentrations ([H+] < 0.5 mol dm-3) and was acid-catalyzed beyond this range. Addition of Mn2+ and F- ions leads to the prediction that MnO4- is the sole reactive species in the oxidation process. A tentative reaction mechanism consistent with the reaction kinetics has been proposed.

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