Abstract

STUDY OF SEMICONDUCTOR PHOTOCATALYSED OXIDATION OF ?-HYDROXY BUTYRIC ACID USED AS COSMETIC AND HYPOGLYCEMIC ACTION.

Pushkar Raj Meena*

ABSTRACT

In the last century, scientists have made rapid and significant advances in the field of semiconductor physics. Semiconducting materials have been the subject of great interest due to their numerous practical applications, and they provide fundamental insights into the electronic processes involved. TiO2 P25 (70% anatase, 30% rutile) is the most employed photocatalytic semiconductor because of its chemical inertness, photostability, low cost, and non-toxicity.[5] Anatase form has been successfully used for photo- catalytic treatment of contaminants due to its faster electron transfer when exposed to UV radiation. Heterogeneous photocatalysis is one typical example of AOPs for the degradation of pharmaceuticals and other organic pollutants in water.[10-13] When TiO2 is exposed to UV light, electrons in the uppermost valence band will jump to the conduction band and create conduction band electrons and valence band holes. In most instances, the valence band holes and conduction band electrons simply recombine liberating heat or light, a process known as recombination. 2-Hydroxybutyrate, the conjugated base of 2-hydroxybutyric acid, is produced in mammalian tissues (principally hepatic) that catabolize L-threonine or synthesize glutathionine.The oxidative stress or detoxification demands can dramatically increase the rate of hepatic glutathione synthesis. α-Hydroxybutyrate may be useful as an early indicator of insulin resistance in non diabetic subject.[17,18] Moreover; elevated serum α-hydroxybutyrate predicts worsening glucose tolerance. α-ketobutyrate is produced by amino acid catabolism (threonine and methionine) and glutathione anabolism (cysteine formation pathway) and is metabolized to propionyl-CoA and carbon dioxide.[20] In this part of research the photoproduct was characterized as α-ketobutyric acid in the practical circumstances i.e. by TiO2 sensitized in visible light. The water was taken as solvent and the concentration of α-hydroxy acid was taken as 1.47 X 10-2 M to 4.90 X 10-2 ( i.e. 1.5 gms to 5.0 gms per liter), as such concentrations are already taken by Bard et al. who reported the alcohol as photoproduct by decarboxylation. He reported this photoproduct at wavelengths in the range of from about 2,200A0 to about 4,000A0 (i.e. UV light), but here the visible light (4000A0 to 7500A0) is used.

Keywords: ?-hydroxybutyric acid, ?-ketobutyric acid, Titanium dioxide, Photooxidation.