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

Kinetic studies of the reactions between isocyanates and carboxylic acids

1994 ◽  
Vol 6 (3) ◽  
pp. 235-239 ◽  
Author(s):  
Hong Xiao ◽  
Han X Xiao ◽  
Kurt C Frisch ◽  
Nelson Malwitz
Keyword(s):  
Carboxylic Acids ◽  
Reaction Kinetic ◽  
Arrhenius Plot ◽  
Kinetic Studies ◽  
Isobutyric Acid ◽  
Phenyl Isocyanate ◽  
Order Reaction ◽  
Second Order Reaction ◽  
Different Temperatures ◽  
Kinetics Of

Reaction kinetic studies between isocyanates and carboxylic acids were undertaken to evaluate the kinetic parameters. Various isocyanates (phenyl isocyanate, cyclohexyl isocyanate) and carboxylic acids (acetic acid, n-butyric acid, isobutyric acid, dimethylbutyric acid and benzoic acid) were used to study the kinetics of the reactions at different temperatures and in different solvents. It was found that these reactions followed the rate law of second-order reaction. From the Arrhenius plot, the activation energies of these reactions were computed.

Kinetics of the reaction between hexamethylenediisocyanate and 1-pentanol

1983 ◽  
Vol 48 (11) ◽  
pp. 3279-3286
Author(s):  
Slavko Hudeček ◽  
Miloslav Bohdanecký ◽  
Ivana Hudečková ◽  
Pavel Špaček ◽  
Pavel Čefelín
Keyword(s):  
Liquid Chromatography ◽  
Rate Constants ◽  
Reversed Phase ◽  
Order Reaction ◽  
Second Order ◽  
Second Order Reaction ◽  
Reversed Phase Liquid Chromatography ◽  
Consecutive Reactions ◽  
Phase Liquid ◽  
Kinetics Of

The reaction between hexamethylenediisocyanate and 1-pentanol in toluene was studied by means of reversed-phase liquid chromatography. By employing this method, it was possible to determine all components of the reaction mixture including both products, i.e. N-(6-isocyanate hexyl)pentylcarbamate and N,N'-bis(pentyloxycarbonyl)hexamethylenediamine. Relations for the calculation of kinetic constants were derived assuming a competitive consecutive second-order reaction. It was demonstrated that the reaction involved in this case is indeed a second-order reaction, and the rate constants of the first and second consecutive reactions were determined.

scholarly journals Degradation Kinetics of Anthocyanins in Shalgam Beverage

2019 ◽  
Vol 7 (2) ◽  
pp. 282
Author(s):  
Adnan Bozdoğan ◽  
Kurban Yaşar
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Half Life ◽  
Degradation Kinetics ◽  
Production Method ◽  
Order Reaction ◽  
Different Temperatures ◽  
Traditional Production ◽  
Effects Of Temperature ◽  
Kinetics Of

This research was performed to elucidate the effects of temperature on the degradation kinetics of anthocyanins in shalgam beverage. Shalgam beverage was produced according to traditional production method. Then, it was kept at three different temperatures (65°C, 75°C, and 85°C) for 12 hours, and the relevant quantities of anthocyanins were determined thereafter. The research revealed that degradation of the anthocyanins was well described with a 1st-order reaction kinetics model and the R2 values varied in the range of 0.9059-0.9715. Activation energy of the reaction was determined to be 48537 Joule/mole. The half-lives of anthocyanins at 65°C and 75° C, and 85°C were found to be 138.63, 136.72, and 51.57, respectively. Compared the half-life periods at different temperatures, anthocyanins were found to be more resistant at 65°C and 75°C than at 85°C.

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.

scholarly journals Translocation of Cations During Sorption of Copper in the System Solution - Algae (Spirogyra sp.)/Translokacja Kationów Podczas Procesu Sorpcji Miedzi W Układzie Roztwór - Glony (Spirogyra Sp.)

2014 ◽  
Vol 21 (3) ◽  
pp. 425-433
Author(s):  
Małgorzata Rajfur ◽  
Andrzej Kłos ◽  
Jan Kříž
Keyword(s):  
Order Reaction ◽  
Static System ◽  
Second Order Reaction ◽  
System Solution ◽  
Fixed Proportion ◽  
Pseudo Second Order ◽  
The Difference ◽  
Kinetics Of ◽  
Copper Cations ◽  
Solution Volume

Abstract Kinetics of the sorption of copper cations in Spirogyra sp. algae was analysed, together with the accompanying processes of hydrogen cations sorption and releasing to the solution the cations bonded in the algae: Na+, Mg2+, K+ and Ca2+. It was established that, in a static system, at the fixed proportion of algae mass to the solution volume, these processes occur simultaneously, however presumably the quantity of the released salts influences the parameters of heterophase equilibrium of ion exchange. In the experiment conditions, the quantity of the released cations was nearly 10 times larger than the quantity of the sorbed cations. The equilibrium parameters, determined from the model of pseudo second order reaction, were compared with the parameters obtained after 30 min of the process duration, ie at relatively stable indications of measuring equipment. On the example of the sorbed copper, the difference is approximately 8%. It was confirmed that the solution conductivity is a good parameter for the estimation of the state close to equilibrium.

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.

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.

KINETICS AND MECHANISMS OF THE THERMAL DECOMPOSITION OF ACETALDEHYDE: I. THE UNINHIBITED REACTION

1964 ◽  
Vol 42 (8) ◽  
pp. 1851-1860 ◽  
Author(s):  
M. Eusuf ◽  
K. J. Laidler
Keyword(s):  
Order Reaction ◽  
Second Order ◽  
Small Extent ◽  
Kinetic Behavior ◽  
Third Order ◽  
The Third ◽  
Rate Of Reaction ◽  
Ethane Formation ◽  
Kinetics Of ◽  
Initial Process

The kinetics of the uninhibited decomposition of acetaldehyde have been reexamined. The initial rates of the decomposition of pure acetaldehyde show strict three-halves-order dependence at temperatures from 480 to 525 °C, and the activation energy is 47.6 kcal per mole. Foreign gases, which decrease the rate of reaction, cause a significant increase in order. The rate of ethane formation is second order in acetaldehyde, and Trenwith has found the hydrogen formation to be second order in acetaldehyde. The results are shown to be consistent only with a mechanism involving second-order initiation and the third-order reaction 2CH3 + M → C2H6 + M as the terminating step. The rate of the initiation process is increased only to a small extent by the addition of inert foreign gases; it is suggested that the initial process may be CH3CHO + CH3CHO → CH3CHOH + CH3CO, with a subsequent breakdown of CH3CHOH into CH3CHO + H. The mechanism is shown to account for the overall kinetic behavior and for the formation of the minor products.

scholarly journals KINETIKA FOTODEGRADASI METHYLENE BLUE MENGGUNAKAN KOMPOSIT Ag3PO4/Ag/HAp TULANG IKAN KAKAP MERAH (Lutjanus sp.)

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Stoflly E. M. Pangajow ◽  
Audy Wuntu ◽  
Meiske S. Sangi
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Reaction Kinetics ◽  
Fish Bone ◽  
Order Reaction ◽  
Kinetics Model ◽  
Light Radiation ◽  
Second Order Reaction ◽  
Bone Powder ◽  
Kinetics Of

ABSTRAKTujuan dari penelitian ini untuk mengkaji kinetika fotodegradasi methylene blue (MB) menggunakan komposit Ag3PO4/Ag/HAp tulang ikan kakap merah (Lutjanus sp.).  Serbuk tulang ikan yang dikalsinasi hingga 1000ºC dan direaksikan dengan AgNO3 dengan rasio mol 5:1 (Ag:HAp) dan dihasilkan komposit Ag3PO4/Ag/HAp. Larutan MB diinteraksikan dengan komposit dengan variasi waktu 5-180 menit dibawah radiasi cahaya tampak. Konsentrasi MB yang tersisa ditentukan ditentukan dengan spektrofotometer UV-Vis dan data yang diperoleh dianalisis dengan model kinetika reaksi orde ke-1 dan ke-2. Hasil penelitian menunjukkan bahwa fotodegradasi MB oleh komposit Ag3PO4/Ag/HAp mengikuti model kinetika fotodegradasi orde ke-2. ABSTRACT The purpose of this research was to study the kinetics of methylene blue (MB) photodegradation using composite Ag3PO4/Ag/HAp bone fish of red snapper (Lutjanus sp.). Fish bone powder which was calcined to 1000ºC and reacted with AgNO3 with mole ratio of 5 : 1 (Ag: HAp) and produced Ag3PO4/Ag/HAp composite. MB solution was interacted with composites with variation of time 5-180 minutes under visible light radiation. The remaining MB concentrations determined were determined by a UV-Vis spectrophotometer and the data obtained were analyzed with first and second order reaction kinetics model. The results showed that MB photodegradation by Ag3PO4/Ag/HAp composites followed the 2nd order photodegradation kinetics model. 

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