scholarly journals Aqueous Polymerization of Acrylonitrile with Cerium(IV)-p-Hydroxyacetophenone Redox System

2012 ◽  
Vol 9 (1) ◽  
pp. 359-364
Author(s):  
M. Palanivelu ◽  
K. E. N. Nalla Mohamed ◽  
M. Prem Nawaz
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Sulfuric Acid ◽  
Redox System ◽  
Probable Mechanism ◽  
Effect Of Temperature ◽  
Aqueous Polymerization ◽  
Rate Of Polymerization

Aqueous polymerization of acrylonitrile initiated by Ce(IV)/p-hydroxy acetophenone (Ce(IV) – HAP) was studied in aqueous solution of sulfuric acid at 40°C. The rate of polymerization was investigated at various concentrations of monomer, initiator, activator, sulfuric acid and the effect of temperature of 30-70°C range was studied. The rate of polymerization is governed by the expression Rp = Kp [M]1.44[Ce(IV)]0.55[HAP]0.51. The activation energy of polymerization was found to be 17.9 kJ/mol. A probable mechanism consistent with the observed results is proposed and discussed.

scholarly journals Effect of Temperature and the Organic Phase Content on the Stripping of Mn(II) from a D2EPHA-KEROSENE Pseudo-Emulsion Using a Sulfuric Acid Aqueous Solution

Engineering ◽  
2012 ◽  
Vol 04 (11) ◽  
pp. 723-727
Author(s):  
Jaime Cristobal Rojas-Montes ◽  
Roberto Pérez-Garibay ◽  
Alejandro Uribe-Salas ◽  
Fabiola Nava-Alonso
Keyword(s):  
Aqueous Solution ◽  
Sulfuric Acid ◽  
Organic Phase ◽  
Effect Of Temperature ◽  
Phase Content ◽  
Acid Aqueous Solution

scholarly journals Kinetics of Vinyl Polymerization of Methyl Methacrylate Initiated by Ce(IV)-Vanillin Redox System

2012 ◽  
Vol 9 (1) ◽  
pp. 430-434
Author(s):  
M. Palanivelu ◽  
K. E. N. Nalla Mohamed ◽  
T. Hidayathulla Khan ◽  
M. Prem Nawaz
Keyword(s):  
Sulfuric Acid ◽  
Methyl Methacrylate ◽  
Kinetic Scheme ◽  
Redox System ◽  
Kinetics Of Polymerization ◽  
Rate Of Polymerization ◽  
Reaction Orders ◽  
Higher Temperature ◽  
Increasing Temperature ◽  
Kinetics Of

The kinetics of polymerization of methyl methacrylate initiated by Ce(IV)-Vanillin redox system was studied in aqueous solution of sulfuric acid at 40°C. The rate of polymerization (Rp) and the reaction orders with respect to monomer, initiator and ligand have been determined and found to be 1.5, 0.5 and 0.5 respectively. The effect of concentration of sulfuric acid on the polymerization was also studied. The rate of polymerization was found to increase with increasing temperature 30–60°C and decreases at higher temperature (>60°C). The overall activation energy (Ea) was found to be 36.7 kJ/mol. A suitable kinetic scheme has been proposed.

Nonisochoric Reactor with Constant Feed Rate of One Component

1993 ◽  
Vol 58 (7) ◽  
pp. 1476-1484
Author(s):  
Václav Dušek ◽  
František Skopal
Keyword(s):  
Sulfuric Acid ◽  
Acid Medium ◽  
Feed Rate ◽  
Redox System ◽  
Chemical Reactor ◽  
Constant Volume ◽  
Rate Equations ◽  
Sulfuric Acid Medium ◽  
Constant Feed Rate

For a chemical reactor with constant volume feed rate equations have been derived which describe the time dependences of concentration of the reaction components, and their approximation has been suggested. The applicability of the approximation has been verified on a model redox system Ce(IV)/V(IV) in sulfuric acid medium.

Temperature Effect on the Two-Dimensional Phase Transition Kinetics of Adenine Adsorbed at the Hg Electrode/Aqueous Solution Interface

2003 ◽  
Vol 68 (8) ◽  
pp. 1407-1419 ◽  
Author(s):  
Claudio Fontanesi ◽  
Roberto Andreoli ◽  
Luca Benedetti ◽  
Roberto Giovanardi ◽  
Paolo Ferrarini
Keyword(s):  
Phase Transition ◽  
Aqueous Solution ◽  
Phase Change ◽  
Temperature Effect ◽  
Transition Rate ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Solution Interface ◽  
Phase Transition Kinetics ◽  
Kinetics Of

The kinetics of the liquid-like → solid-like 2D phase transition of adenine adsorbed at the Hg/aqueous solution interface is studied. Attention is focused on the effect of temperature on the rate of phase change; an increase in temperature is found to cause a decrease of transition rate.

Fundamental Measurements of the Friction on an Atomically-Flat Terrace of Au(100) in Sulfuric Acid Solution under Potential Control Using Electrochemical Atomic Force Microscope

2006 ◽  
Vol 512 ◽  
pp. 395-398
Author(s):  
Nobumitsu Hirai ◽  
Tatsuya Tooyama ◽  
Toshihiro Tanaka
Keyword(s):  
Aqueous Solution ◽  
Sulfuric Acid ◽  
Silicon Nitride ◽  
Acid Solution ◽  
Atomic Force Microscope ◽  
Friction Force ◽  
Potential Range ◽  
Potential Control ◽  
Atomic Force ◽  
Atomically Flat

Potential dependence of the friction force between an atomically-flat terrace of Au(100) single crystal and a tip attached to a silicon nitride cantilever of electrochemical atomic force microscope (EC-AFM) have been investigated qualitatively in 0.05 M H2SO4 aqueous solution. It is found that the friction force gains when the potential increases in the potential range between −400 mV and 400 mV vs Hg/Hg2SO4 electrode.

scholarly journals Removal of Chromium from Aqueous Solution Using Modified Pomegranate Peel:Mechanistic and Thermodynamic Studies

2009 ◽  
Vol 6 (s1) ◽  
pp. S153-S158 ◽  
Author(s):  
Tariq S. Najim ◽  
Suhad A. Yassin
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Aqueous Solution ◽  
Adsorption Process ◽  
Batch Process ◽  
The Other ◽  
Water Molecules ◽  
Pomegranate Peel ◽  
Solution Interface ◽  
Adsorbent Surface

Modified pomegranate peel (MPGP) and formaldehyde modified pomegranate peel (FMPGP) were prepared and used as adsorbent for removal of Cr(VI) ions from aqueous solution using batch process. The temperature variation study of adsorption on both adsorbents revealed that the adsorption process is endothermic, from the positive values of ∆H˚. These values lie in the range of physisorption. The negative values of ∆G˚ show the adsorption is favorable and spontaneous. On the other hand, these negative values increases with increase in temperature on both adsorbents, which indicate that the adsorption is preferable at higher temperatures. ∆S˚ values showed that the process is accompanied by increase in disorder and randomness at the solid solution interface due to the reorientation of water molecules and Cr(VI) ions around the adsorbent surface. The endothermic nature of the adsorption was also confirmed from the positive values of activation energy, Ea, the low values of Ea confirm the physisorption mechanism of adsorption. The sticking probability, S*, of Cr(VI) ion on surface of both adsorbents showed that the adsorption is preferable due to low values of S*(0< S*< 1 ), but S*values are lower for FMPGP indicating that the adsorption on FMPGP is more preferable .

THE OXIDATION OF NITRITE AND IODATE IONS BY HYPOCHLORITE IONS

1961 ◽  
Vol 39 (8) ◽  
pp. 1645-1651 ◽  
Author(s):  
M. W. Lister ◽  
P. Rosenblum
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Rate Constant ◽  
Hypochlorous Acid ◽  
Slow Stage ◽  
Iodate Ions

The oxidation of nitrite ions and of iodate ions by hypochlorite ions in aqueous solution has been examined. The oxidation of nitrite is really a reaction of hypochlorous acid, with the slow stage HOCl + NO2− + H2O → H3O+ + Cl− + NO3−. The rate constant is given by log k = 7.36−6450/RT (time in minutes, and the activation energy in calories). The oxidation of iodate is chiefly a reaction of hypochlorite ions, probably ClO− + IO3− → Cl− + IO4−, although the rate is somewhat increased by a higher concentration of hydroxide ions. The rate constant is given by log k = 16.15−26,100/RT. These results are compared with other oxidations by hypochlorite ions, to see if any general trends are apparent.

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