Ethylene exchange in PtCl(C5H7O2)(π-C2H4)

1970 ◽  
Vol 48 (24) ◽  
pp. 3802-3806 ◽  
Author(s):  
C. E. Holloway ◽  
J. Fogelman
Keyword(s):  
Activation Energy ◽  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Kcal Mole ◽  
First Order ◽  
First Order Kinetics ◽  
Solvent Dependence ◽  
Kinetics Of

The kinetics of exchange of free with complexed ethylene in the system PtCl(acac)(π-C2H4) have been investigated over a temperature and concentration range by proton magnetic resonance. First order kinetics are observed with respect to each component with no solvent dependence of rate. The activation energy and entropy are 2.7 kcal mole−1 and −36 cal deg−1 mole−1, respectively. A five coordinate intermediate is suggested, with complete retention of configuration at the platinum.

scholarly journals The dissociation energy of the C-N bond in benzylamine

1949 ◽  
Vol 198 (1053) ◽  
pp. 285-292 ◽  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Dissociation Energy ◽  
Heat Of Formation ◽  
Molar Ratio ◽  
Kcal Mole ◽  
First Order ◽  
First Order Kinetics ◽  
Permanent Gases ◽  
Kinetics Of

The kinetics of the thermal decomposition of benzylamine were studied by a flow method using toluene as a carrier gas. The decomposition produced NH 3 and dibenzyl in a molar ratio of 1:1, and small quantities of permanent gases consisting mainly of H 2 . Over a temperature range of 150° (650 to 800° C) the process was found to be a homogeneous gas reaction, following first-order kinetics, the rate constant being expressed by k = 6 x 10 12 exp (59,000/ RT ) sec. -1 . It was concluded, therefore, that the mechanism of the decomposition could be represented by the following equations: C 6 H 5 . CH 2 . NH 2 → C 6 H 5 . CH 2 • + NH 2 •, C 6 H 5 . CH 3 + NH 2 •→ C 6 H 5 . CH 2 • + NH 3 , 2C 6 H 5 . CH 2 •→ dibenzyl, and the experimentally determined activation energy of 59 ± 4 kcal./mole is equal to the dissociation energy of the C-N bond in benzylamine. Using the available thermochemical data we calculated on this basis the heat of formation of the NH 2 radical as 35.5 kcal./mole, in a fair agreement with the result obtained by the study of the pyrolysis of hydrazine. A review of the reactions of the NH 2 radicals is given.

Vulcanization of Elastomers. 23. The Chemical Kinetics of Vulcanization Reactions and The Physical Properties of The Vulcanizates. I

1960 ◽  
Vol 33 (2) ◽  
pp. 335-341
Author(s):  
Walter Scheele ◽  
Karl-Heinz Hillmer
Keyword(s):  
Activation Energy ◽  
Physical Properties ◽  
Chemical Kinetics ◽  
Kcal Mole ◽  
First Order ◽  
Equilibrium Swelling ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization ◽  
Limiting Value ◽  
Good Agreement

Abstract As a complement to earlier investigations, and in order to examine more closely the connection between the chemical kinetics and the changes with vulcanization time of the physical properties in the case of vulcanization reactions, we used thiuram vulcanizations as an example, and concerned ourselves with the dependence of stress values (moduli) at different degrees of elongation and different vulcanization temperatures. We found: 1. Stress values attain a limiting value, dependent on the degree of elongation, but independent of the vulcanization temperature at constant elongation. 2. The rise in stress values with the vulcanization time is characterized by an initial delay, which, however, is practically nonexistent at higher temperatures. 3. The kinetics of the increase in stress values with vulcanization time are both qualitatively and quantitatively in accord with the dependence of the reciprocal equilibrium swelling on the vulcanization time; both processes, after a retardation, go according to the first order law and at the same rate. 4. From the temperature dependence of the rate constants of reciprocal equilibrium swelling, as well as of the increase in stress, an activation energy of 22 kcal/mole can be calculated, in good agreement with the activation energy of dithiocarbamate formation in thiuram vulcanizations.

THE NON-ENZYMATIC HYDROLYSIS OF ADENOSINE DIPHOSPHATE

1957 ◽  
Vol 35 (12) ◽  
pp. 1496-1503 ◽  
Author(s):  
K. A. Holbrook ◽  
Ludovic Ouellet
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Enzymatic Hydrolysis ◽  
Inorganic Phosphate ◽  
Adenosine Diphosphate ◽  
Hydrogen Ions ◽  
Kcal Mole ◽  
First Order ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of the non-enzymatic hydrolysis of adenosine diphosphate in aqueous solution have been studied at pH 3.5 to 10.5 and temperatures from 80° to 95 °C. The reaction has been followed by measuring colorimetrically the inorganic phosphate liberated according to the over-all reaction[Formula: see text]The reaction has been found to be first order with respect to ADP concentration and to be catalyzed by hydrogen ions. From rate studies at pH 8.0 an activation energy of 24.2 kcal./mole was derived. A mechanism is proposed to account for the observed facts and the mechanism for the hydrolysis of adenosine triphosphate is also discussed.

scholarly journals Temperature and pH effects on the kinetics of 2-aminophenol auto-oxidation in aqueous solution

2003 ◽  
Vol 1 (3) ◽  
pp. 233-241 ◽  
Author(s):  
Dumitru Oancea ◽  
Mihaela Puiu
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Aqueous Solution ◽  
Ph Effects ◽  
Influence Of Temperature ◽  
First Order ◽  
Incremental Methods ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetics Of

AbstractThe kinetics of the auto-oxidation of 2-aminophenol (OAP) to 2-amino-phenoxazin-3-one (APX) was followed in air-saturated aqueous solutions and the influence of temperature and pH on the auto-oxidation rate was studied. The kinetic analysis was based on a spectrophotometric method following the increase of the absorbance of APX. The process follows first order kinetics according to the rate law—d[OAP]/dt=k′[OAP]. The experimental data, within the pH range 4–9.85, were analyzed using both differential and incremental methods. The temperature variation of the overall rate constant was studied at pH=9.85 within the range 25–50°C and the corresponding activation energy was evaluated.

THE NON-ENZYMATIC HYDROLYSIS OF p-NITROPHENYL PHOSPHATE

1958 ◽  
Vol 36 (4) ◽  
pp. 686-690 ◽  
Author(s):  
K. A. Holbrook ◽  
Ludovic Ouellet
Keyword(s):  
Activation Energy ◽  
Enzymatic Hydrolysis ◽  
Ionic Species ◽  
Kcal Mole ◽  
First Order ◽  
Colorimetric Measurement ◽  
Nitrophenyl Phosphate ◽  
Ph Range ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of the non-enzymatic hydrolysis of p-nitrophenyl phosphate have been studied in aqueous solution in the pH range 2.6 to 9.0 and at temperatures from 68.0°to 82.0 °C. The reaction has been followed by colorimetric measurement of the nitrophenol produced by the reaction[Formula: see text]The reaction is first order with respect to p-nitrophenyl phosphate and has an activation energy of 26.0 kcal./mole at pH 2.6. An explanation has been proposed in terms of the different rates of hydrolysis of the various ionic species of the ester present in solution.

The effect of temperature on the aggregation kinetics of partially bare gold nanoparticles

RSC Advances ◽  
2016 ◽  
Vol 6 (85) ◽  
pp. 82138-82149 ◽  
Author(s):  
Anushree Dutta ◽  
Anumita Paul ◽  
Arun Chattopadhyay
Keyword(s):  
Activation Energy ◽  
Gold Nanoparticles ◽  
Effect Of Temperature ◽  
Aggregation Kinetics ◽  
Temperature Dependent ◽  
Colloidal Aggregation ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of ◽  
Bare Gold

Temperature dependent aggregation reaction of partially bare gold nanoparticles showed a first order kinetics and prevalence of reaction limited colloidal aggregation with an activation energy equal to 36.2 ± 3.0 kJ mol−1.

scholarly journals Temperature Effects Associated with the Adsorption of Neodymium Ions onto Activated Charcoal

2005 ◽  
Vol 23 (5) ◽  
pp. 399-406 ◽  
Author(s):  
Riaz Qadeer
Keyword(s):  
Activation Energy ◽  
Activated Charcoal ◽  
Temperature Effects ◽  
Adsorption Process ◽  
First Order ◽  
First Order Kinetics ◽  
Charcoal Adsorption ◽  
Increasing Temperature ◽  
Kinetics Of ◽  
Activated Charcoal Adsorption

The temperature dependence of the kinetics of the adsorption of neodymium ions from aqueous solution onto activated charcoal has been studied. The results obtained indicate that a form of equilibration appears to be attained after ca. 30 min although further very slow changes may occur over a much longer period. The adsorption process is controlled by the diffusion of neodymium ions into the pores of the activated charcoal. Adsorption follows first-order kinetics with an activation energy of 13.09 kJ/mol. Values of the equilibrium constant for the adsorption of neodymium ions onto activated charcoal increase with increasing temperature, thereby indicate the endothermic nature of the process.

Hydrogenation Kinetics of N-Ethylcarbaozle as a Heteroaromatic Liquid Organic Hydrogen Carrier

2014 ◽  
Vol 953-954 ◽  
pp. 981-984 ◽  
Author(s):  
Ming Yang ◽  
Yuan Dong ◽  
Han Song Cheng
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
Hydrogen Pressure ◽  
Reaction Rate ◽  
Hydrogenation Reaction ◽  
First Order ◽  
First Order Kinetics ◽  
Hydrogenation Kinetics ◽  
Hydrogen Carrier ◽  
Kinetics Of

The catalytic hydrogenation kinetics of N-ethylcarbazole over 5 wt% Ru/Al2O3 was investigated at various temperatures. The results shows that the hydrogenation reaction was exothermic and high temperature is unfavorable for the reaction rate. Fully hydrogenation was achieved within 1 hour under the best reaction temperature of 170 °C. The kinetics of N-ethylcarbazole follows the first-order kinetics in terms of the reactant concentration but independent of hydrogen pressure, which was maintained as a constant in the reaction process. The apparent activation energy of N-ethylcarbazole hydrogenation reaction at 150-180 °C was found to be 71.2 kJ/mol.

An Experimental Study of the Coking Process

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Somayeh Ebrahimi ◽  
Jafarsadegh Moghaddas
Keyword(s):  
Activation Energy ◽  
Coke Formation ◽  
Nitrogen Atmosphere ◽  
Fuel Oil ◽  
Effective Parameters ◽  
Pyrolysis Kinetics ◽  
Exponential Factor ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of

The coking process includes two dynamic and isothermal steps. In this process, some factors control the coke formation kinetics. In this research, effects of some important and effective parameters of feed on the quality of petroleum coke were studied. Two hydrocarbon residue feeds; Cracked Fuel Oil (CFO) and Styrene Monomer Tar (SMTAR) were used at 500°C with atmospheric pressure of nitrogen used as an inert gas. Rate of weight loss and gas evolution from these feeds were considered by data of thermal analysis TG (thermogravimetry) and DTG (derivative thermogravimetry). Based on the results, CFO was assigned as the better feed. After selecting better feed, simultaneous thermogravimetry-differential analysis (TG-DTA) was used to study the pyrolysis kinetics of CFO. Samples were heated in a TG-DTA apparatus in nitrogen atmosphere at a temperature range of 37-600°C. The activation energy (Ea) and pre-exponential factor (A) were calculated from the experimental results by using a three stage Arrhenius-type kinetic model and showed that CFO pyrolysis kinetics at temperature ranges 37-285, 320-450 and 467-600°C follows first, second and first order kinetics, respectively. Attentive to temperature increase and reaction progress, activation energy and pre-exponential factor indicated different values at each stage. Also, kinetics of the isothermal step of coke formation was studied during heating of CFO. Samples were reacted in a tube furnace at 450°C and with nitrogen atmosphere. The kinetics of coke formation for petroleum residue was followed by solvent extraction (insolubility in hexane (HI), toluene (TI)) and a development of TI approximate to apparent first order kinetics. The rate constant at this temperature was calculated and it was also observed that the coke formation had been started at a temperature below 450°C.

scholarly journals Kinetics of the decomposition and the estimation of the stability of 10% aqueous and non-aqueous hydrogen peroxide solutions

2014 ◽  
Vol 27 (4) ◽  
pp. 213-216 ◽  
Author(s):  
Maria Zun ◽  
Dorota Dwornicka ◽  
Katarzyna Wojciechowska ◽  
Katarzyna Swiader ◽  
Regina Kasperek ◽  
...  
Keyword(s):  
Activation Energy ◽  
Hydrogen Peroxide ◽  
Decomposition Rate ◽  
Aqueous Hydrogen Peroxide ◽  
Decomposition Rate Constant ◽  
First Order ◽  
First Order Kinetics ◽  
C 30 ◽  
The Stability ◽  
Kinetics Of

Abstract In this study, the stability of 10% hydrogen peroxide aqueous and non-aqueous solutions with the addition of 6% (w/w) of urea was evaluated. The solutions were stored at 20°C, 30°C and 40°C, and the decomposition of hydrogen peroxide proceeded according to first-order kinetics. With the addition of the urea in the solutions, the decomposition rate constant increased and the activation energy decreased. The temperature of storage also affected the decomposition of substance, however, 10% hydrogen peroxide solutions prepared in PEG-300, and stabilized with the addition of 6% (w/w) of urea had the best constancy.

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