Kinetic Study of the Epimerization of 1,1,1-Trichloro-2-hydroxy-3-methyl-4-hexanone

1973 ◽  
Vol 51 (19) ◽  
pp. 3182-3186 ◽  
Author(s):  
Eberhard Kiehlmann ◽  
Fred Masaro ◽  
Frederick J. Slawson
Keyword(s):  
Activation Energy ◽  
Acetic Acid ◽  
Kinetic Study ◽  
Glacial Acetic Acid ◽  
Initial Reaction ◽  
First Order ◽  
Kinetically Controlled ◽  
Different Temperatures ◽  
Pseudo First Order

The acetate-catalyzed epimerization of 1,1,1-trichloro-2-hydroxy-3-methyl-4-hexanone has been studied in glacial acetic acid as solvent at five different temperatures. The reaction follows pseudo first-order, reversible kinetics and is associated with an activation energy of 24.0 ± 0.4 kcal/mol. Rate and product studies have shown that epimerization occurs by an enolization–ketonization pathway rather than dehydration–rehydration or retroaldol–aldolization. The ratio of diastereomeric ketols formed by condensation of 2-pentanone and 2-heptanone with chloral does not change as a function of time while the stereochemistry of the chloral addition to cyclohexanone is kinetically controlled during the initial reaction period.

Catalytic performance of cerium-modified ZSM-5 zeolite as a catalyst for the esterification of glycerol with acetic acid

2020 ◽  
Vol 18 (9) ◽  
Author(s):  
Priyanka Gautam ◽  
Sanghamitra Barman ◽  
Amjad Ali
Keyword(s):  
Activation Energy ◽  
Acetic Acid ◽  
Process Parameters ◽  
Reaction Temperature ◽  
Zeolite Catalyst ◽  
Catalytic Performance ◽  
Order Reaction ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order

AbstractEsterification of glycerol with acetic acid was carried out over cerium-modified ZSM-5 zeolites to synthesize monoacetin (MA) and diacetin (DA). The modified zeolite catalyst was characterized. The effect of reaction process parameters such as acetic acid to glycerol mole ratio (1–11), reaction temperature (30–120 °C), and catalyst weight (2–8 wt %) on the selectivity of the product was investigated. At 120 °C reaction temperature, 8 wt % catalyst, and 9:1 acetic acid to glycerol mole ratio, about 98.32% conversion of glycerol were obtained. This reaction follows pseudo-first-order reaction kinetics and the activation energy was found to be 63.72 kJ mol−1.

scholarly journals Permanganatic oxidation of neomycine sulphate salt in basic media: a kinetic study

2019 ◽  
Vol 9 (1) ◽  
pp. 159-164
Author(s):  
Narayan V. Lawale ◽  
Bhagwan Singh Dobhal ◽  
Sandip Singh Gaur ◽  
Rajendra Pardeshi
Keyword(s):  
Kinetic Study ◽  
Order Reaction ◽  
First Order Reaction ◽  
Pseudo First Order Reaction ◽  
Reaction Conditions ◽  
First Order ◽  
Alkaline Permanganate ◽  
Different Temperatures ◽  
Alkaline Conditions ◽  
Pseudo First Order

Permanganatic oxidation of Neomycine sulphate salt has been studied at different temperatures using spectrophotometer under alkaline conditions. The effect of variation of substrate Neomycine sulphate salt (NS), oxidant (KMnO4) and NaOH was studied under pseudo first order reaction conditions. The effect of different salts and solvents on oxidation of NS was also studied. The reaction was found to be first order with respect to oxidant, substrate and NaOH.. Keywords: Neomycine sulphate salt (NS), KMnO4 , permanganatic  oxidation, alkaline permanganate

The kinetic study of the addition of tetrachloromethane to styrene in the presence of copper complexes

1987 ◽  
Vol 52 (7) ◽  
pp. 1758-1763 ◽  
Author(s):  
Li Gwang Hun ◽  
Lubomír Nondek
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Kinetic Study ◽  
Copper Complexes ◽  
Catalytic Mechanism ◽  
First Order ◽  
First Order Kinetics ◽  
Experimental Activation Energy ◽  
Pseudo First Order ◽  
Kinetics Of

Kinetics of the addition of tetrachloromethane to styrene catalyzed by copper-amine complexes was studied. The pseudo-first order kinetics in respect to styrene and the catalyst was observed at an excess of tetrachloromethane. The reaction mechanism involving a catalytic cycle compatible with the kinetic observations is proposed. The experimental activation energy, being about 104 kJ mol-1, indicates a catalytic mechanism.

scholarly journals Kinetics and Mechanism of the Change of the 4-Nitrobenzylthio-System into 4,4′-Diformylazoxybenzene in Alkaline Dioxane-Water Media

1985 ◽  
Vol 40 (11) ◽  
pp. 1128-1132
Author(s):  
Y. Riad ◽  
Adel N. Asaad ◽  
G.-A. S. Gohar ◽  
A. A. Abdallah
Keyword(s):  
Acetic Acid ◽  
Sodium Hydroxide ◽  
Rate Constants ◽  
Main Product ◽  
Reaction Medium ◽  
Aqueous Dioxane ◽  
Proton Abstraction ◽  
First Order ◽  
Water Media ◽  
Different Temperatures

Sodium hydroxide reacts with α -(4-nitrobenzylthio)-acetic acid in aqueous-dioxane media to give 4,4'-diformylazoxybenzene as the main product besides 4,4'-dicarboxyazoxybenzene and a nitrone acid. This reaction was kinetically studied in presence of excess of alkali in different dioxane-water media at different temperatures. It started by a fast reversible a-proton abstraction step followed by two consecutive irreversible first-order steps forming two intermediates (α -hydroxy, 4-nitrosobenzylthio)-acetic acid and 4-nitrosobenzaldehyde. The latter underwent a Cannizzaro's reaction, the products of which changed in the reaction medium into 4,4'-diformylazoxybenzene and 4,4'-dicarboxyazoxybenzene. The rate constants and the thermodynamic parameters of the two consecutive steps were calculated and discussed. A mechanism was put forward for the formation of the nitrone acid.Other six 4-nitrobenzyl, aryl sulphides were qualitatively studied and they gave mainly 4,4'-diformylazoxybenzene beside 4,4'-dicarboxyazoxybenzene or its corresponding azo acid.

Kinetic study of dye removal using TiO2 supported on polyethylene terephthalate by advanced oxidation processes through neural networks

2019 ◽  
Vol 79 (6) ◽  
pp. 1134-1143 ◽  
Author(s):  
Ada Azevedo Barbosa ◽  
Ramon Vinicius Santos de Aquino ◽  
Naiana Santos da Cruz Santana Neves ◽  
Renato Falcão Dantas ◽  
Marta Maria Menezes Bezerra Duarte ◽  
...  
Keyword(s):  
Kinetic Study ◽  
Polyethylene Terephthalate ◽  
Advanced Oxidation Processes ◽  
Dye Removal ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Order Model ◽  
Oxidation Processes ◽  
First Order ◽  
Pseudo First Order

Abstract This work investigated the efficiency of polyethylene terephthalate (PET) as support material for TiO2 films in the photocatalytic degradation of red Bordeaux and yellow tartrazine dyes. The optimum operating conditions were determined by a factorial design, which resulted after 180 min of treatment in degradations of 99.5% and 99.1% for the UVC/H2O2/TiO2Sup and solar/H2O2/TiO2Sup systems, respectively. For the kinetic study, the experimental data fitted to the pseudo-first-order model and the calculated kinetic constants (k) values were 0.03 min−1 for the UVC/H2O2/TiO2Sup system and 0.0213 min−1 for the system solar/H2O2/TiO2Sup. It was verified that TiO2 supported in the PET remained with high degradation efficiency even after five cycles of reuse, indicating a good stability of the photocatalyst in the support. A significant reduction of TOC content was also observed along the reaction time. The phytotoxicity bioassay with Lactuca sativa demonstrated that after treatment with UVC/H2O2/TiO2Sup and solar/H2O2/TiO2SUP, an increase in IC50 and consequently lower toxicity was observed.

Kinetics and Activation Parameters for the Alkaline Aqueous Rearrangement of Trichorfon [O,O-Dimethyl-(2,2,2-Trichloro-1-Hydroxyethyl) Phosphonate] to Dichlorvos [O,O-Dimethyl-O-(2,2-Dichloroethenyl)Phosphate]

2001 ◽  
Vol 36 (3) ◽  
pp. 589-604 ◽  
Author(s):  
Julian M. Dust ◽  
Christopher S. Warren
Keyword(s):  
Activation Energy ◽  
High Pressure ◽  
Activation Parameters ◽  
Base Catalysis ◽  
Rearrangement Product ◽  
Exponential Factor ◽  
First Order ◽  
Pseudo First Order ◽  
Order Plot ◽  
Kinetics Of

Abstract The kinetics of the alkaline rearrangement of O,O-dimethyl-(2,2,2-trichloro-1- hydroxyethyl)phosphonate, (trichlorfon, 1), the active insecticidal component in such formulations as Dylox, was followed at 25±0.5°C by high pressure liquid chromatography (UV-vis detector, 210 nm). The rearrangement product, O,Odimethyl- O-(2,2-dichloroethenyl)phosphate (dichlorovos, 2), which is a more potent biocide than trichlorfon, undergoes further reaction, and the kinetics, consequently, cannot be treated by a standard pseudo-first-order plot. A two-point van't Hoff (initial rates) method was used to obtain pseudo-first-order rate constants (kѱ) at 25, 35 and 45°C: 2.6 × 10-6, 7.4 × 10-6 and 2.5 × 10-5 s-1, respectively. Arrhenius treatment of this data gave an activation energy (Ea) of 88 kJ·mol-1 with a pre-exponential factor (A) of 5.5 × 109 s-1. Kinetic trials at pH 8.0 using phosphate and tris buffer systems show no buffer catalysis in this reaction and indicate that the rearrangement is subject to specific base catalysis. Estimates are reported for pseudo-first-order half-lives for trichlorfon at pH 8.0 for environmental conditions in aqueous systems in the Corner Brook region of western Newfoundland, part of the site of a recent trichlorfon aerial spray program.

STUDIES ON THE FORMATION OF HEXAMINE

1952 ◽  
Vol 30 (9) ◽  
pp. 687-693 ◽  
Author(s):  
T. R. Ingraham ◽  
C. A. Winkler
Keyword(s):  
Activation Energy ◽  
Acetic Acid ◽  
Acid Solution ◽  
Induction Period ◽  
Ammonium Nitrate ◽  
Sodium Acetate ◽  
Glacial Acetic Acid ◽  
Initial Rate ◽  
Acetic Acid Solution ◽  
Rate Data

Rate curves have been determined for the reaction of ammonium nitrate with formaldehyde in glacial acetic acid solution at 25 °C., 35 °C., 45 °C., and 55 °C. over a range of Initial mole ratios (formaldehyde: ammonia) of 0.75:1 to 9.0:1. Data obtained at 25 °C. show a definite induction period in the formation of hexamine. The length of the induction period is not changed by increasing ammonium nitrate concentrations above the theoretical (1.5:1), but may be appreciably shortened by initial additions of excess formaldehyde or of sodium acetate. From 35 °C. upward, the induction period is not apparent. The order of the reaction with respect to formaldehyde has been determined from initial rate data, and an activation energy calculated. The reactions in general appear analogous to those found in slightly acid aqueous systems.

Aromatic oxidation by cobaltic acetate in acetic acid

1969 ◽  
Vol 47 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Koichiro Sakota ◽  
Yoshio Kamiya ◽  
Nobuto Ohta
Keyword(s):  
Activation Energy ◽  
Electron Transfer ◽  
Acetic Acid ◽  
Bond Energy ◽  
Hydrogen Abstraction ◽  
Steric Factor ◽  
Benzyl Acetate ◽  
Kcal Mole ◽  
First Order ◽  
Reversible Electron Transfer

A detailed kinetic study of oxidation of toluene and its derivatives by cobaltic acetate in 95 vol% acetic acid is reported. The reaction was found to be profoundly affected by a steric factor and rather insensitive to the C—H bond energy. The order of reactivities of various alkylbenzenes is quite reversal to that of hydrogen abstraction reactions. The reaction was of first-order with respect to toluene, of second-order with respect to cobaltic ion and of inverse first-order with respect to cobaltous ion. The oxidation by cobaltic ion seems to proceed via an initial reversible electron transfer from toluene to cobaltic ion, yielding [Formula: see text] which is oxidized into benzyl acetate by another cobaltic ion. The apparent activation energy for toluene was found to be 25.3 kcal mole−1, and the same activation energy was found for ethylbenzene, cumene, diphenylmethane, and triphenylmethane.

scholarly journals Isotherm, Thermodynamic, and Kinetics Studies of Iodide Adsorption on The Al_SBA-16 Mesoporous Nanomaterial as Radiopharmaceutical Vehicle Candidate

2020 ◽  
Vol 21 (1) ◽  
pp. 27
Author(s):  
Maria Christina Prihatiningsih ◽  
Sri Sundari Retnoasih ◽  
Athanasia Elra Andjioe ◽  
Noor Anis Kundari ◽  
Edy Giri Rachman Putra
Keyword(s):  
Activation Energy ◽  
Hypothesis Testing ◽  
Research Work ◽  
P Value ◽  
Testing Time ◽  
Order Model ◽  
First Order ◽  
Pseudo First Order ◽  
In Vitro Stability

In order to investigate the potential of Al_SBA-16 Mesoporous Nanomaterial as a candidate for radiopharmaceutical vehicles, the studies of kinetics, thermodynamic, and in vitro stability of Iodide adsorption onto the nanomaterial have been carried out. The adsorption study was conducted at different temperature, time, and iodide concentration and observed with spectrophotometric techniques. The isotherm adsorption was fitted with Langmuir and Freundlich model and the thermodynamic parameters were determined at temperatures of 293K, 301K, 308K, and 313K. Moreover, the adsorption kinetics was analyzed in terms of pseudo first order model for Al_SBA-16 Mesoporous Nanomaterial and Iodide and pseudo second order in overall reaction. The activation energy was determined by using Arrhenius equation, meanwhile, the in vitro stability testing was conducted in phosphate buffer saline at pH variation for 5.5 to 7.0, and at temperature variation for 20C to 45C and at testing time variation for 6 to 48 hours. The result indicate that the adsorption obeys the Langmuir isotherm model and has a tendency to be chemical adsorption with a value of H was -116.641 kJ/mol and the nature of spontaneous reactions. The adsorption process followed the pseudo-first-order model and the apparent activation energy was 41.26 kJ/mol. In the present research work, the in vitro stability data were evaluated using P-Value and the theory of Hypothesis Testing or Fisher's significance test. The result of hypothesis testing show that, the adsorption of iodide onto Al_SBA-16 Mesoporous Nanomaterial were highly stable under the experimental conditions adopted.

scholarly journals Optimization, Kinetics, Thermodynamic and Arrhenius Model of the Removal of Ciprofloxacin by Internal Electrolysis with Fe-Cu and Fe-C Materials

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2110
Author(s):  
Tra Huong Do ◽  
Xuan Linh Ha ◽  
Thi Tu Anh Duong ◽  
Phuong Chi Nguyen ◽  
Ngoc Bich Hoang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Ph Value ◽  
Arrhenius Model ◽  
First Order ◽  
Chemical Plating ◽  
First Order Kinetics ◽  
Internal Electrolysis ◽  
Plating Method ◽  
Rapid Removal ◽  
Pseudo First Order

The ciprofloxacin (CIP) removal ability of a Fe-Cu electrolytic material was examined with respect to pH (2–9), time (15–150 min), shaking speed (100–250 rpm), material mass (0.2–3 g/L), temperature (298, 308, 323) and initial CIP concentration (30–200 mg/L). The Fe-Cu electrolytic materials were fabricated by the chemical plating method, and Fe-C materials were mechanically mixed from iron powder and graphite. The results show that at a pH value of 3, shaking time 120 min, shaking speed 250 rpm, a mass of Fe-Cu, Fe-C material of 2 g/L and initial CIP concentration of 203.79 mg/L, the CIP removal efficiency of Fe-Cu material reached 90.25% and that of Fe-C material was 85.12%. The removal of CIP on Fe-Cu and Fe-C materials follows pseudo-first-order kinetics. The activation energy of CIP removal of Fe-Cu material is 14.93 KJ/mol and of Fe-C material is 16.87 KJ/mol. The positive ΔH proves that CIP removal is endothermic. A negative entropy of 0.239 kJ/mol and 0.235 kJ/mol (which is near zero and is also relatively positive) indicated the rapid removal of the CIP molecules into the removed products.

Sign in / Sign up

Export Citation Format

Share Document