Oxidation of aliphatic alcohols by triethylammonium chlorochromate in non-aqueous medium – A kinetic and mechanistic study

AbstractThe oxidation of some aliphatic alcohols by triethylammonium chlorochromate (TriEACC) in dimethyl sulfoxide leads to the formation of the corresponding carbonyl compounds. The reaction is first order with respect to TriEACC. The reaction exhibited Michaelis–Menten type kinetics with respect to alcohol. The reaction is catalyzed by hydrogen ions. The hydrogen-ion dependence has the form: kobs=a+b[H+]. The oxidation of [1,1-2H2] ethanol (MeCD2OH) exhibits a substantial primary kinetic isotope effect. Oxidation of aliphatic alcohol was studied in 19 different organic solvents. The solvent effect has been analysed using Kamlet’s and Swain’s multi-parametric equation. A suitable mechanism has been proposed

Melamine trisulfonic acid as an efficient catalyst for the synthesis of 2,6-dimethyl-4-substituted-1,4-dihydropyridine-3,5-diethyl/dimethylcarboxylate derivatives via Hantzsch reaction in solvent free condition

AbstractA facile and highly efficient one-pot synthesis of 1,4-dihydropyridine derivatives (1,4-DHPs) is reported via three component condensation reaction of aldehydes, ethyl acetoacetate or methyl acetoacetate and ammonium acetate using environmentally benign melamine trisulfonic acid (MTSA) as a catalyst in solvent free condition at 60°C. The method presented here is applied to the tenets of green chemistry to the generation of biologically interesting products under solvent-free media that is less expensive and less toxic than those with organic solvents. Also, the catalyst is recyclable and could be reused without significant loss of activity. Even after three runs for the reaction, the catalytic activity of MTSA was almost the same as that of the freshly used catalyst.The method also offers several advantages including high yields and simple work-up procedure

Kinetics and Mechanism of Oxidation of Aromatic Aldehydes by Imidazolium Dichromate in Aqueous Acetic Acid Medium

The kinetics of oxidation of benzaldehyde (BA) and para-substituted benzaldehydes by imidazolium dichromate (IDC) has been studied in aqueous acetic acid medium in the presence of perchloric acid. The reaction is first order each in [IDC], [Substrate] and [H+]. The reaction rates have been determined at different temperatures and the activation parameters calculated. Electron withdrawing substituents are found to increase the reaction and electron releasing substituents are found to retard the rate of the reaction and the rate data obey the Hammett relationship. The products of the oxidation are the corresponding acids. The rate decreases with the increase in the water content of the medium. A suitable mechanism is proposed

Synthesis and in vitro antimicrobial evaluation of 5-amino-7-aryl-6-cyano-4H- pyrano[3,2,b]pyrrole derivatives catalyzed by reusable ZrOCl2•8H2O

An efficient synthesis of a new series of 5-amino-7-aryl-6-cyano-4H-pyrano[3,2-b]pyrrole derivatives from the reaction of 3-hydroxypyrrole, malononitrile, and various aromatic aldehydes using ZrOCl2·8H2O, an environmentally friendly catalyst under a thermal solvent-free green procedure is described. This simple protocol offer advantages such as shorter reaction times, simple work-up and excellent yield. The catalyst ZrOCl2·8H2O can be reused. The reusability of the catalyst has been studied for the synthesis of 5-amino-7-aryl-6-cyano-4H-pyrano[3,2-b]pyrrole. All the compounds were screened for their antibacterial and antifungal activity.KEY WORDS: ZrOCl2·8H2O, Pyranopyrrole, Malononitrile, 3-Hydroxypyrrole, Solvent-freeBull. Chem. Soc. Ethiop. 2014, 28(1), 91-100.DOI:http://dx.doi.org/10.4314/bcse.v28i1.11<w:LsdExc

Oxidation of Methionine by Tripropylammonium Fluorochromate-A Kinetic and Mechanistic Study

The kinetics of oxidation of methionine (Met) by tripropylammonium fluorochromate (TriPAFC) has been studied in the presence of chloroacetic acid in aqueous acetic acid medium. The reaction is first order with respect to methionine, TriPAFC and acid. The reaction rate has been determined at different temperatures and activation parameters calculated. With an increase in the amount of acetic acid in its aqueous mixture, the rate increases. The reaction does not induce polymerization of acrylonitrile. A suitable mechanism has been proposed

Kinetics and Mechanism of Oxidation of some α -Hydroxy Acids by Tripropylammonium Fluorochromate in Aqueous Acetic Acid Medium

Abstract: The oxidation of some α-hydroxy acids like glycolic, lactic and mandelic acids by tripropylammonium fluorochromate (TriPAFC) have been studied in aqueous acetic acid medium. The oxidation leads to the formation of the corresponding oxo acids. The reaction is first order with respect to TriPAFC, hydroxy acids and [H + ] and the reaction is catalyzed by hydrogen ions. The reaction has been studied in different percentage of acetic acid-water mixture. A suitable mechanism has been proposed

Correlation analysis of reactivity in the oxidation of some organic diols by tripropylammonium fluorochromate in non-aqueous media

The kinetics of oxidation of some organic diols by tripropylammonium fluorochromate (TriPAFC) have been studied in dimethylsulfoxide (DMSO). The main product of oxidation is the corresponding hydroxy aldehydes. The reaction is first order with respect to TriPAFC and exhibited Michaelis-Menten type kinetics with respect to organic diols. The reaction is catalyzed by hydrogen ions. The hydrogen ion dependence has the form: kobs = a + b[H+]. Various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of isokinetic relationship. Oxidation of diols was studied in 18 different organic solvents. The rate data are showing satisfactory correlation with Kamlet–Taft solvotochromic parameters (α, β and π∗). A suitable mechanism of oxidation has been proposed

Kinetics and Mechanism of Oxidation of Aromatic Aldehydes by Imidazolium Dichromate in Aqueous Acetic Acid Medium

The kinetics of oxidation of benzaldehyde (BA) and para-substituted benzaldehydes by imidazolium dichromate (IDC) has been studied in aqueous acetic acid medium in the presence of perchloric acid. The reaction is first order each in [IDC], [Substrate] and [H+]. The reaction rates have been determined at different temperatures and the activation parameters calculated. Electron withdrawing substituents are found to increase the reaction and electron releasing substituents are found to retard the rate of the reaction and the rate data obey the Hammett relationship. The products of the oxidation are the corresponding acids. The rate decreases with the increase in the water content of the medium. A suitable mechanism is proposed

Succinimide-N-sulfonic acid: An efficient and recyclable catalyst for the one-pot synthesis of tetrahydrobenzo[c]acridine-8(7H)-one derivatives

Synthesis of substituted 10,10-dimethyl-7-phenyl-9,10,11,12-tetrahydrobenzo[c]acridin-8(7H)-one derivatives proceeded by the one-pot reaction of aromatic aldehydes, 5,5-dimethylcyclohexane-1,3-dione (dimedone) and 1-naphthylamine, in the presence of Succinimide-N-sulfonic acid (SuSA) has been reported. Simplicity of operation, high yields, easy work-up and a wide range of substrate applicabilities are the key advantages of this methodology. Furthermore, the catalyst can be recovered conveniently and reused efficiently