Aqueous media

Synthesis of 1, 2-disubstituted benzimidazoles by reaction of N-substituted benzene-1,2-diamine with different aldehydes was developed. This greener procedure proceeds with the help of oxygen in water at 60oC. The advantages of proposed method are catalyst-free conditions in water, short reaction time and excellent yields.

8p tocectocec 25-05-2020 10 1   Download

An ecofriendly methods for the synthesis of medicinally important class of heterocyclic scaffold, pyrazole 4-carbonitrile derivatives by one pot three component reaction of malononitrile, phenyl hydrazine and aromatic aldehyde has been achieved at room temperature.

8p tocectocec 25-05-2020 13 1   Download

Kinetic study of oxidation of toluidine blue (TB+) by periodate was carried out in aqueous medium and also in the cetyl trimethyl ammonium bromide (CTAB) reverse micellar medium. In both the media reaction obeys first order kinetics with respect to each of the reactants.

8p tocectocec 25-05-2020 11 2   Download

In aqueous media, muscle pyruvate kinase is highly selective for K + over Na + . We now studied the selec-tivity of pyruvate kinase in water/dimethylsulfoxide mix-tures by measuring the activation and inhibition constants of K + and Na + , i.e. their binding to the monovalent and divalent cation binding sites of pyruvate kinase, respect-ively [Melchoir J.B. (1965) Biochemistry4, 1518–1525]. In 40% dimethylsulfoxide theK0.5 appfor K + and Na + were 190 and 64-fold lower than in water.Kiappfor K + and Na +decreased 116 and 135-fold between 20 and 40% dimethylsulfoxide. The ratios of Kiapp/K0.

9p fptmusic 16-04-2013 34 2   Download

A comprehensive study of the hydration mechanism of an enzyme in non-aqueous media was done using molecular dynamics simulations in five organic solvents with different polarities, namely, hexane, 3-pentanone, diisopropyl ether, ethanol, and acetonitrile.

13p galaxyss3 19-03-2013 61 4   Download

The realm of aqueous organometallic catalysis incorporates many more reactions and catalysts than discussed in the preceeding chapters. However, these were not investigated in so much detail as, for instance, hydrogenation or hydroformylation; some of them are mentioned only here and there. An attempt is made to give a representative sample of these studies.

13p boyminsk 10-06-2010 132 14   Download

Catalytic oxidation of organic compounds is an extremely important field of chemistry, spanning the range from biological oxidations to large scale industrial production of commodity chemicals. However, many of these transformations can hardly be classified as organometallic reactions, since the catalysts (often simple metal salts) and the intermediates can be rather regarded as coordination complexes than organometallic compounds.

7p boyminsk 10-06-2010 105 19   Download

The annual production of various polymers can be measured only in billion tons of which polyolefins alone figure around 100 million tons per year. In addition to radical and ionic polymerization, a large part of this huge amount is manufactured by coordination polymerization technology. The most important Ziegler-Natta, chromium- and metallocene-based catalysts, however, contain early transition metals which are too oxophilic to be used in aqueous media.

19p boyminsk 10-06-2010 155 17   Download