Insight in the crystallization kinetics of AlPO4-11 molecular sieve using di-isopropylamine as template

The hydrothermal synthesis of aluminophosphate molecular sieve type AlPO4-11 was processed from chemicals containing psueudobohemite, 85% phosphoric acid, water, and di-isopropylamine as templating agent. The crystallization of the samples was studied by taking samples in times from 2 to 74 hours. The obtained white powder products have been characterized by XRD patterns, FT-IR spectra, thermogravimetric data, scanning electron microscopy and pH measurement of the mother liquor. The pore volume, as determined from TG and DTG curves, was ca. 0.17 cm3g-1. The crystallization process of the aluminophosphate exhibited in its initial phase a behavior of first order reaction with a specific velocity constant of ca. 0.25 h-1, as determined from XRD and FT-IR data.

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Thermal and kinetic behaviors of corn stover and polyethylene in catalytic co-pyrolysis

BioResources ◽

10.15376/biores.13.2.4102-4117 ◽

2018 ◽

Vol 13 (2) ◽

pp. 4102-4117

Author(s):

Shaoqing Wang ◽

Xiaona Lin ◽

Zhihe Li ◽

Weiming Yi ◽

Xueyuan Bai

Keyword(s):

Activation Energy ◽

Corn Stover ◽

Compensation Effect ◽

Kinetic Studies ◽

Order Reaction ◽

Kinetic Compensation Effect ◽

Exponential Factor ◽

First Order ◽

Thermogravimetric Data ◽

Kinetics Of

Thermal decomposition characteristics and kinetics of high-density polyethylene (HDPE), corn stover (CS), and their blended mixture (1:1 w/w ratio) during non-catalytic and catalytic co-pyrolysis were studied via thermogravimetric analysis (TGA). The results indicated synergetic interactions between the biomass and the plastics during co-pyrolysis as measured by weight loss (ΔW); this effect was attributed to radical interactions during co-pyrolysis. The pyrolysis catalysts with higher nickel loadings (5%, 10%, and 15%) appreciably diminished the solid residue. Kinetic studies indicated that the pyrolysis was a first-order reaction based on the fitted thermogravimetric data. The activation energy (E) and pre-exponential factor (A) ranged between 26.13 kJ/mol to 392.67 kJ/mol and between 156.24 min-1 to 9.19 x 1023 min-1, respectively. There was a kinetic compensation effect (KCE) observed among the two kinetic parameters. The activation energy (E) decreased for each pyrolysis stage with the presence of a catalyst. The results indicated that catalytic co-pyrolysis could provide great potential for reducing the pyrolysis energy input.

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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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Efficient adsorption of chlorpyrifos onto modified activated carbon by gamma irradiation; a plausible adsorption mechanism

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2020-1765 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Mohamed S. Yahia ◽

Ahmed S. Elzaref ◽

Magdy B. Awad ◽

Ahmed M. Tony ◽

Ahmed S. Elfeky

Keyword(s):

Gamma Irradiation ◽

Area Measurement ◽

Maximum Adsorption Capacity ◽

X Ray Diffraction ◽

X Ray ◽

First Order ◽

Pseudo Second Order ◽

Ft Ir ◽

Pseudo First Order ◽

Kinetics Of

Abstract Commercial Granulated Active Carbon (GAC) has been modified using 10 Gy dose Gamma irradiation (GAC10 Gy) for increasing its ability of air purification. Both, the raw and treated samples were applied for removing Chlorpyrifos pesticide (CPF) from ambient midair. Physicochemical properties of the two materials were characterized by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. The phase formation and microstructure were monitored using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), supported with Energy-Dispersive X-ray (EDX). The Surface area measurement was detected using BET particle size prosometry. Obtained outcomes showed that, the maximum adsorption capacity, given by Langmuir equations, was greatly increased from 172.712 to 272.480 mg/g for GAC and GAC10 Gy, respectively, with high selectivity. The overall removal efficiency of GAC10 Gy was notably comparable to that of the original GAC-sorbent. The present study indicated that, gamma irradiation could be a promising technique for treating GAC and turned it more active in eliminating the pesticides pollutants from surrounding air. The data of equilibrium has been analyzed by Langmuir and Freundlich models, that were considerably better suited for the investigated materials than other models. The process kinetics of CPF adsorbed onto both tested carbon versions were found to obey the pseudo first order at all concentrations with an exception at 70 mg/l using GAC, where, the spontaneous exothermic adsorption of Chlorpyrifos is a strong function for the pseudo-first order (PFO) and pseudo second order (PSO) kinetics.

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

Zeitschrift für Naturforschung C ◽

10.1515/znc-1973-1-215 ◽

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.

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

Canadian Journal of Chemistry ◽

10.1139/cjc-2019-0193 ◽

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.

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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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