scholarly journals Oxidation of Florfenicol and Oxolinic Acid in Seawater by Ozonation

2020 ◽  
Vol 10 (14) ◽  
pp. 4944
Author(s):  
Homin Kye ◽  
Heegun Oh ◽  
Youmi Jung ◽  
Minhwan Kwon ◽  
Yeojoon Yoon ◽  
...  
Keyword(s):  
Rate Constants ◽  
Marine Ecosystem ◽  
Oxidation Mechanism ◽  
Reaction Rates ◽  
Reaction Rate Constant ◽  
Oxolinic Acid ◽  
Specific Rate ◽  
Marine Aquaculture ◽  
Aquaculture Industry ◽  
Bromide Ions

There has been an increase in the use of antibiotics by the aquaculture industry in marine aquaculture for the prevention of diseases in fish. Antibiotics in the water discharged into the sea without treatment can cause disturbances to the marine ecosystem. Therefore, there is a need for research on how the removal of antibiotics used in aquaculture can be achieved. In this study, the removal of two types of antibiotics (florfenicol, FF, and oxolinic acid, OA) used in the aquaculture industry, by ozonation, was evaluated. Currently, there is a lack of research studies on FF and OA removal from seawater by ozonation. Seawater ozonation shows a significantly different oxidation mechanism as compared to that of freshwater. The high amount of Br− in seawater (60 mg/L) allows for a rapid reaction with ozone to produce bromine (HOBr/OBr−) at a rate of 160 M−1s−1. To predict the removal efficiency of antibiotics by ozone and bromine, the species-specific rate constants for the reaction of FF and OA with ozone and bromine were determined. The predicted removal efficiencies of FF and OA using measured rate constants were verified by the ozonation process in water containing bromide ions in similar concentrations as in seawater. The result for FF indicated less than 10% removal during 20 min, with the rate constants of FF with ozone and bromine being 3.2 M−1s−1 and 3.5 M−1s−1, respectively. However, the removal of OA using ozonation was approximately 99% or higher within 90 s. In the presence of bromide ions, approximately 60% of OA was removed by trace ozone within 15 s, and approximately 30% of OA was removed by the generated bromine after 15 s. Comparing the removability of FF and OA used in aquaculture by ozone, it was observed that FF was more difficult to remove because of its low reaction rate constant. Meanwhile, the reaction rates of OA with ozone and bromine were 2.4 × 103 M−1s−1 and 4.0 × 102 M−1s−1, respectively. At the beginning of the reaction, OA was removed by the trace ozone. Subsequently, OA was removed by the generated bromine after the ozone was decomposed.

scholarly journals HYDROLYSIS AND DEUTERATION OF GLYCYLGLYCINE CATALYZED BY DINUCLEAR [BMXDCu 2]4+ COMPLEX

2007 ◽  
Vol 15 (15) ◽  
pp. 15-27
Author(s):  
Ana Cristina Franzoi ◽  
Gledir T. Stein Martins ◽  
Sérgio Duvoisin Jr. ◽  
Bruno Szpoganicz
Keyword(s):  
Rate Constants ◽  
Kinetic Studies ◽  
Peptide Bond ◽  
Reaction Rates ◽  
Active Species ◽  
Individual Species ◽  
Specific Rate ◽  
First Order ◽  
Parallel Reactions ◽  
Semi Empirical

Kinetic studies of hydrolysis and deuteration of glycylglycine by dinuclear [BMXDCu 2]4+ complexes were following by NMR1H. Two parallel reactions were observed for the ternary system BMXD-Cu 2-Glycylglycine: peptide bond hydrolysis and NCH2 deuteration reactions. The reaction rates show the first-order behavior to the concentration of the ternary [BMXDCu2Glycylglycine] complex. The specific rate constants for the hydrolysis reaction are: KLCu2HGG4+ (L = BMXD and GG = glycylglycine) = 1,8 x 10-6 s-1; KLCu 2GG3+ = 2,3 x 10-6 s-1; KLCu2H-1GG2+, KLCu 2(OH)H-1GG+ and KLCu 2(OH) 2H-1GG = 0, and the specific deuteration rate constants for individual species are: KLCu 2HGG4+ = 3,9 x 10-6 s-1; KLCu 2GG3+ = 4,3 x 10-6 s-1; KLCu2H-1GG2+, KLCu2(OH)H-1GG+ and KLCu2(OH)2H-1GG = 0. The results show that the most active species toward hydrolysis and deuteration reactions are the protonated and non-protonated species, the former being the most reactive species. Semi-empirical calculations for energy minimization showed that the binuclear [BMXDCu 2]4+) complexes adopt the boat-type conformation, in order to accommodate the dipeptide glycylglycine.

Kinetics of esterification of monoisopropylphenols with phosphoryl trichloride

1989 ◽  
Vol 54 (5) ◽  
pp. 1311-1317
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Ján Ilavský
Keyword(s):  
Liquid Phase ◽  
Rate Constants ◽  
Reaction Rates ◽  
Activation Energies ◽  
The Individual ◽  
Kinetics Of

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.

Classical trajectory and statistical adiabatic channel study of the dynamics of capture and unimolecular bond fission. VI. Properties of transitional modes and specific rate constants k(E,J)

2002 ◽  
Vol 117 (9) ◽  
pp. 4201-4213 ◽  
Author(s):  
A. I. Maergoiz ◽  
E. E. Nikitin ◽  
J. Troe ◽  
V. G. Ushakov
Keyword(s):  
Rate Constants ◽  
Classical Trajectory ◽  
Specific Rate

Reactions of the radical cation derived from 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) with amino acids. Kinetics and mechanism

2000 ◽  
Vol 78 (8) ◽  
pp. 1052-1059 ◽  
Author(s):  
C Aliaga ◽  
E A Lissi
Keyword(s):  
Amino Acids ◽  
Radical Cation ◽  
Sulfonic Acid ◽  
Biological Fluids ◽  
Reaction Rates ◽  
Kinetics And Mechanism ◽  
Specific Rate ◽  
Wide Range ◽  
Initial Ph ◽  
Secondary Reactions

Stable free radicals derived from 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) have been extensively employed to monitor the antioxidant capacity of biological fluids and beverages. Besides reacting with typical antioxidants (such as phenols or thiols) these radicals react with a variety of hydrogen or electron donors. The present work reports on the kinetics and mechanism of these radical reactions with several amino acids. Reaction rates notably increase when the pH of the media increases and, when measured under similar conditions, follows the ordercysteine > > tryptophan > tyrosine > histidine > cystineThe kinetics of the process is interpreted in terms of a mechanism comprising an initial pH dependent reversible step, followed by secondary reactions of the substrate derived radical with itself or with another ABTS·+; this simple three-step mechanism leads to very complex kinetic expressions. The specific rate constants of several of the elementary steps were determined by working under a wide range of substrate, radical, and ABTS concentrations. The values obtained for the initial interaction between the ABTS derived radical and the substrate range from 0.5 M–1 s–1 to 1.9 × 106 M–1 s–1 for histidine and cysteine, respectively.Key words: ABTS radical cation, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), amino acids, kinetics.

scholarly journals Reactivity of cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids with diazodiphenylmethane in aprotic solvents

2000 ◽  
Vol 65 (12) ◽  
pp. 839-846
Author(s):  
Jasmina Nikolic ◽  
Gordana Uscumlic ◽  
Vera Krstic
Keyword(s):  
Hydrogen Bond ◽  
Rate Constants ◽  
Kinetic Data ◽  
Linear Regression Analysis ◽  
Spectroscopic Method ◽  
Reaction Rates ◽  
Aprotic Solvents ◽  
Experimental Conditions ◽  
Hydrogen Bond Acceptor ◽  
Protic Solvents

Rate constants for the reaction of diazodiphenylmethane with cyclohex-1-enylcarboxylic acid and 2-methylcyclohex-1-enylcarboxylic acid were determined in nine aprotic solvents, as well as in seven protic solvents, at 30?C using the appropriate UV-spectroscopic method. In protic solvents the unsubsituted acid displayed higher reaction rates than the methyl-substituted one. The results in aprotic solvents showed quite the opposite, and the reaction rates were considerably lower. In order to explain the obtained results through solvent effects, reaction rate constants (k) of the examined acids were correlated using the total solvatochromic equation of the form: log k=logk0+s?*+a?+b?, where ?* is the measure of the solvent polarity, a represents the scale of the solvent hydrogen bond donor acidities (HBD) and b represents the scale of the solvent hydrogen bond acceptor basicities (HBA). The correlation of the kinetic data were carried out by means of multiple linear regression analysis and the opposite effects of aprotic solvents, as well as the difference in the influence of protic and aprotic solvents on the reaction of the two examined acids with DDM were discussed. The results presented in this paper for cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids were compared with the kinetic data for benzoic acid obtained in the same chemical reaction, under the same experimental conditions.

Reaction rates and reaction rate constant conception. One-temperature case

2012 ◽  
Author(s):  
Evgeniy G. Kolesnichenko ◽  
Yuriy E. Gorbachev
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rates ◽  
Reaction Rate Constant

scholarly journals Kinetic Studies on Saponification of Poly(ethylene terephthalate) Waste Powder Using Conductivity Measurements

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Dilip B. Patil ◽  
Vijendra Batra ◽  
Sushil B. Kapoor
Keyword(s):  
Thermodynamic Parameters ◽  
Kinetic Studies ◽  
Frequency Factor ◽  
Reaction Rates ◽  
Reaction Rate Constant ◽  
Activation Entropy ◽  
Constant Frequency ◽  
Free Energy Of Activation ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

Conductometric measurement technique has been deployed to study the kinetic behavior during the reaction of poly(ethylene terepthalate) (PET) and NaOH. A laboratory made arrangement with facility of continuous stirring was used to carry out experiments at desired temperature. With conductometry, the determination of kinetic as well as thermodynamic parameters becomes more simple and faster as compared to gravimetry. Chemical kinetics of this reaction shows that it is a second order reaction with reaction rate constant 2.88×10-3 g−1 s−1 at 70°C. The specific reaction rates of the saponification reaction in the temperature range at various temperatures (50–80°C) were determined. From the data, thermodynamic parameters such as activation energy, Arrhenius constant (frequency factor), activation enthalpy, activation entropy, and free energy of activation obtained were 54.2 KJ g−1, 5.0×106 min−1, 90.8 KJ g−1, -126.5 JK−1 g−1, and 49.9 KJ g−1, respectively.

scholarly journals “Transitivity”: A Code for Computing Kinetic and Related Parameters in Chemical Transformations and Transport Phenomena

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3478 ◽  
Author(s):  
Hugo G. Machado ◽  
Flávio O. Sanches-Neto ◽  
Nayara D. Coutinho ◽  
Kleber C. Mundim ◽  
Federico Palazzetti ◽  
...  
Keyword(s):  
Rate Constants ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
State Theory ◽  
Chemical Transformations ◽  
Graphical Interface ◽  
Arrhenius Behavior ◽  
Reaction Rate Constants ◽  
Kinetic And Thermodynamic Parameters ◽  
Data Documentation

The Transitivity function, defined in terms of the reciprocal of the apparent activation energy, measures the propensity for a reaction to proceed and can provide a tool for implementing phenomenological kinetic models. Applications to systems which deviate from the Arrhenius law at low temperature encouraged the development of a user-friendly graphical interface for estimating the kinetic and thermodynamic parameters of physical and chemical processes. Here, we document the Transitivity code, written in Python, a free open-source code compatible with Windows, Linux and macOS platforms. Procedures are made available to evaluate the phenomenology of the temperature dependence of rate constants for processes from the Arrhenius and Transitivity plots. Reaction rate constants can be calculated by the traditional Transition-State Theory using a set of one-dimensional tunneling corrections (Bell (1935), Bell (1958), Skodje and Truhlar and, in particular, the deformed ( d -TST) approach). To account for the solvent effect on reaction rate constant, implementation is given of the Kramers and of Collins–Kimball formulations. An input file generator is provided to run various molecular dynamics approaches in CPMD code. Examples are worked out and made available for testing. The novelty of this code is its general scope and particular exploit of d -formulations to cope with non-Arrhenius behavior at low temperatures, a topic which is the focus of recent intense investigations. We expect that this code serves as a quick and practical tool for data documentation from electronic structure calculations: It presents a very intuitive graphical interface which we believe to provide an excellent working tool for researchers and as courseware to teach statistical thermodynamics, thermochemistry, kinetics, and related areas.

Solvolyse und Phosphorylierungrseaktionen von Polyphosphorsäureestern / Solvolysis and Phosphorylating Activity of Polyphosphate Esters

1971 ◽  
Vol 26 (7) ◽  
pp. 694-700 ◽  
Author(s):  
Hans Berger
Keyword(s):  
Potentiometric Titration ◽  
Rate Constants ◽  
Reaction Rates ◽  
High Rate ◽  
Catalytic Effects ◽  
Hydrolysis Of

Reaction rates of the ethanolysis and hydrolysis of the phenyl- and methylpolyphosphate-esters and of tetraphenylpyrophosphate were measured by potentiometric titration methods. Exceptionally high rate constants were obtained for the solvolysis of these compounds, some reactions occurring with half-times of less than 10 seconds. The phosphorylating activity of the phenylpolyphosphateester on polyfunctional nucleophilic compounds (SN2P-reaction) was tested and shown to exceed the activity of the conventional agent diphenylphosphoro-chloridate considerably. The catalytic effects of dimethylformamide were measured under several conditions and were shown to be complex solvent phenomena rather than conventional catalysis. The reactivity of the polyphosphate-esters is discussed with respect to their structure as well as the reactivity of P -O -P-bonds as a function of their ligands.

Bisulfite Degrades Aflatoxin: Effect of Temperature and Concentration of Bisulfite

1978 ◽  
Vol 41 (10) ◽  
pp. 774-780 ◽  
Author(s):  
M. P. DOYLE ◽  
E. H. MARTH
Keyword(s):  
Rate Constant ◽  
Aflatoxin B1 ◽  
Reaction Rate ◽  
Reaction Rates ◽  
Reaction Rate Constant ◽  
Effect Of Temperature ◽  
Kcal Mole ◽  
First Order ◽  
Potassium Acid Phthalate ◽  
Acid Phthalate

Bisulfite reacted with aflatoxin B1 and G1 resulting in their loss of fluorescence. The reaction was first order with rate depending on bisulfite (or the bisulfite and sulfite) concentration(s). Aflatoxin G1 reacted more rapidly with bisulfite than did aflatoxin B1. In the presence of 0.035 M potassium acid phthalate-NaOH buffer (pH 5.5) plus 1.3% (vol/vol) methanol at 25 C, the reaction rate constant for degradation of aflatoxin G1 was 2.23 × 10−2h− and that for aflatoxin B1 was 1.87 × 10−2h− when 50 ml of reaction mixture contained 1.60 g of K2SO3. Besides bisulfite concentrations, temperature influenced reaction rates. The Q10 for the bisulfite-aflatoxin reaction was approximately 2 while activation energies for degrading aflatoxin B1 and aflatoxin G1 were 13.1 and 12.6 kcal/mole, respectively. Data suggest that treating foods with 50 to 500 ppm SO2 probably would not effectively degrade appreciable amounts of aflatoxin. Treating foods with 2000 ppm SO2 or more and increasing the temperature might reduce aflatoxin to an acceptable level.

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