Recherche pétrolière et gazière

Abstrait

A Green approach to the oxidation of some industrially important alcohol using Ammonium meta vanadate in mildly acidic medium

D V Prabhu

Toxic and expensive metals like Osmium,Chromium and Ruthenium in different oxidation states have been exhaustively used as catalysts for organic reactions.The use of these metals is hazardous to the environment and hence should be reduced as far as possible.We have successfully used less toxic and cheaper transition metal ions of the first series to catalyze the oxidation of some industrially important alcohols by Ammonium meta vanadate under mildly acidic conditions. Some of the alcohols oxidized are: 1)Acyclic alcohols –The primary alcohols, Nerol,Citronellol and Geraniol are used in the preparation of perfumes. 2) Cyclic alcohols-The secondary alcohols, Cyclopentanol.Cyclohexanol and Cyclooctanol are used in the manufacture of polymers,plasticizers and pharmaceuticals. 3)Substituted ethanols-2-Chloroethanol,2- Butoxyethanol and 2-Phenoxyethanol are used in the preparation of varnishes,crop protection chemicals and industrial cleaners. The oxidation was studied under first order kinetic conditions with respect to the inorganic oxidant and the progress of oxidation was monitored iodometrically.From the variation of oxidation rate with temperature (303-313K), the thermodynamical activation parameters of the oxidation process were evaluated and interpreted.The sequences of oxidation rates of alcohols has been explained on the basis of their steric,isomeric and structural characteristics. Transition metal ions ,Mn(II),Co(II) and Ni(II) have been used to catalyze the oxidation of alcohols.For each alcohol under study ,the sequence of catalytic efficiencies of the metal ion catalysts has been determined. The oxidation rates of all alcohols studied varied linearly with the metal ion catalyst concentration. A suitable reaction mechanism has been suggested for the oxidation of alcohols using Ammonium meta vanadae in acidic medium.