National Chemical Laboratory

About: National Chemical Laboratory is a facility organization based out in Pune, Maharashtra, India. It is known for research contribution in the topics: Catalysis & Nanoparticle. The organization has 8891 authors who have published 14837 publications receiving 387600 citations.

Photocatalytic degradation of organochlorine compounds in suspended TiO2

Abstract: Twelve organochlorine solvents which are di-, tri- and tetrachloro derivatives of methane, ethane and ethylene, were photocatalytically degraded on TiO 2 , platinum (Pt)-loaded TiO 2 and TiO 2 with added H 2 O 2 . It was found that for derivatives of the three compounds the degradation rates were in the order Cl 2 > Cl 3 > Cl 4 , and for those containing the same number of Cl substituents the order was ethylene > ethane. During the degradation of each organochlorine solvent, Cl − was liberated simultaneously. On Pt-loaded TiO 2 , Cl − was transformed into ClO 3 − photocatalytically. Stoichiometry for the photocatalytic degradation of dichloroethylene was C 2 H 2 Cl 2 + 2O 2 → 2Cl − + 2CO 2 + 2H + .

Zeolite-encapsulated manganese(III)salen complexes

Abstract: Manganese(III) complexes of [ N , N ′-ethylenebis(salicylidene-aminato)] (salen), [ N , N ′-ethylenebis(5-chloro-salicylidene-aminato)] (Cl 2 Salen), [ N , N ′-ethylenebis(5-bromo-salicylidene-aminato)] (Br 2 Salen) and [ N , N ′-ethylenebis(5-nitro-salicylidene-aminato)] [(NO 2 ) 2 Salen] have been encapsulated in the supercages of zeolite X by the zeolite synthesis method. The catalysts have been characterized by FTIR, UV–Vis and EPR spectroscopic techniques, XRD, SEM, thermal and elemental analysis, as well as nitrogen adsorption and cyclic voltammetric studies. The extent of encapsulation of the Mn(III)Salen complexes in zeolite X varies with the nature of the substituent group on the aromatic ring. While bromo groups enhance encapsulation, substitution with –NO 2 groups decreases the amounts of Mn(III) complexes encapsulated in the cavities of the zeolites. Cyclic voltammetric data indicate that the zeolite matrix facilitates the reduction of Mn(III) to Mn(II), suggesting that it behaves like an electron-withdrawing substituent. The aerobic oxidation of styrene to benzaldehyde, styrene oxide and phenylacetaldehyde over these catalysts is also reported.

Imidazole-Linked Crystalline Two-Dimensional Polymer with Ultrahigh Proton-Conductivity.

Abstract: Proton-exchange membrane fuel cells are promising energy devices for a sustainable future due to green features, high power density, and mild operating conditions. A facile proton-conducting membrane plays a pivotal role to boost the efficiency of fuel cells, and hence focused research in this area is highly desirable. Major issues associated with the successful example of Nafion resulted in the search for alternate proton conducting materials. Even though proton carrier loaded crystalline porous organic frameworks have been used for proton-conduction, the weak host-guest interactions limited their practical use. Herein, we developed a crystalline 2D-polymer composed of benzimidazole units as the integral part, prepared by the condensation of aryl acid and diamine in polyphosphoric acid medium. The imidazole linked-2D-polymer exhibits ultrahigh proton conductivity (3.2 × 10-2 S cm-1) (at 95% relative humidity and 95 °C) in the pristine state, which is highest among the undoped porous organic frameworks so far reported. The present strategy of a crystalline proton-conducting 2D-polymer will lead to the development of new high performing crystalline solid proton conductor.