Oxidation of α-Hydroxy Acids with Quinolinium Dichromate - A Kinetic Study

1993 ◽  
Vol 58 (7) ◽  
pp. 1624-1630 ◽  
Author(s):  
Kailasa Aruna ◽  
Prerepa Manikyamba ◽  
Embar Venkatachari Sundaram
Keyword(s):  
Dielectric Constant ◽  
Acetic Acid ◽  
Bond Cleavage ◽  
Low Dielectric Constant ◽  
Aqueous Acetic Acid ◽  
Hydroxy Acids ◽  
First Order ◽  
Low Dielectric ◽  
Chloro Derivative ◽  
Acid Catalyzed

Oxidation of lactic acid, α-hydroxyphenyllacetic acid and its 4-chloro derivative with quinolinium dichromate (QDC) in 30% (v/v) aqueous acetic acid at 303 K are first order in QDC and first-order in hydroxy acids. The reactions are acid-catalyzed and a medium of low dielectric constant favours the oxidation. The products are the corresponding aldehydes. Thermodynamic parameters are evaluated and a mechanism involving a C-C bond cleavage is proposed.

scholarly journals Kinetics of Oxidation of Benzoin by N. Bromosuccinimide

2005 ◽  
Vol 4 (1) ◽  
pp. 55-61
Author(s):  
R. Sridharan ◽  
N. Mathiyalagan
Keyword(s):  
Dielectric Constant ◽  
Acetic Acid ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Aqueous Acetic Acid ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
First Order Kinetics ◽  
Retarding Effect ◽  
Kinetics Of

Kinetics of Oxidation of Benzoin by N. Bromosuccinimide[NBS] 80% aqueous acetic acid has been investigated. The reaction follows first-order kinetics with respect to both[NBS] and [benzoin]. The effect of varying ionic strength and dielectric constant indicate the reaction is dipole-dipole type. Addition of succinimide(>NH), has a retarding effect on the rate of oxidation. The product of oxidation is benzil. By studying the effect of temparature on the reaction rate, the Arrhenius and the activation parameters have been calculated. A suitable mechanism has been proposed and a rate low explaining the experiment results is derived.

scholarly journals Kinetics of Oxidation of 3-Benzoylpropionic Acid byN-Bromoacetamide in Aqueous Acetic Acid Medium

2011 ◽  
Vol 8 (2) ◽  
pp. 479-482 ◽  
Author(s):  
N. A. Mohamed Farook ◽  
G. A. Seyed Dameem
Keyword(s):  
Dielectric Constant ◽  
Acetic Acid ◽  
Acid Medium ◽  
Main Product ◽  
Reaction Medium ◽  
Aqueous Acetic Acid ◽  
Acetic Acid Medium ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of 3-benzoylpropionic acid (KA) withN-bromoacetamide (NBA) have been studied potentiometrically in 50:50 (v/v) aqueous acetic acid medium at 298 K The reaction was first order each with respect to [KA], [NBA] and [H+]. The main product of the oxidation is the corresponding carboxylic acid. The rate decreases with the addition of acetamide, one of the products of the reaction. Variation in ionic strength of the reaction medium has no significant effect on the rate of oxidation. But the rate of the reaction is enhanced by lowering the dielectric constant of the reaction medium. A mechanism consistent with observed results have been proposed and the related rate law was deduced.

Structire, Properties, and Process Characteristics of Low-K Materials Prepared by PECVD

1999 ◽  
Vol 565 ◽  
Author(s):  
Y. Shimogaki ◽  
S. W. Lim ◽  
E. G. Loh ◽  
Y. Nakano ◽  
K. Tada ◽  
...  
Keyword(s):  
Growth Rate ◽  
Dielectric Constant ◽  
Gas Flow ◽  
Structural Changes ◽  
Silicon Oxide ◽  
Reactive Species ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
Step Coverage ◽  
Low K

AbstractLow dielectric constant F-doped silicon oxide films (SiO:F) can be prepared by adding fluorine source, like as CF4 to the conventional PECVD processes. We could obtain SiO:F films with dielectric constant as low as 2.6 from the reaction mixture of SiH4/N2 O/CF4. The structural changes of the oxides were sensitively detected by Raman spectroscopy. The three-fold ring and network structure of the silicon oxides were selectively decreased by adding fluorine into the film. These structural changes contribute to the decrease ionic polarization of the film, but it was not the major factor for the low dielectric constant. The addition of fluorine was very effective to eliminate the Si-OH in the film and the disappearance of the Si-OH was the key factor to obtain low dielectric constant. A kinetic analysis of the process was also performed to investigate the reaction mechanism. We focused on the effect of gas flow rate, i.e. the residence time of the precursors in the reactor, on growth rate and step coverage of SiO:F films. It revealed that there exists two species to form SiO:F films. One is the reactive species which contributes to increase the growth rate and the other one is the less reactive species which contributes to have uniform step coverage. The same approach was made on the PECVD process to produce low-k C:F films from C2F4, and we found ionic species is the main precursor to form C:F films.

Defect free monolayer and bilayer graphene exfoliated by solvent with low dielectric constant

2020 ◽  
Author(s):  
Vedanki ◽  
Chandrabhan Dohare ◽  
Pawan KumarSrivastava ◽  
Premlata Yadav ◽  
Subhasis Ghosh
Keyword(s):  
Dielectric Constant ◽  
Bilayer Graphene ◽  
Low Dielectric Constant ◽  
Low Dielectric
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