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.

Esterification of renewable levulinic acid to ethyl levulinate biodiesel catalyzed by highly active and reusable desilicated H-ZSM-5

Abstract: BACKGROUND In the near future, fossil fuel will have limitations in terms of availability and also great concerns over its environmental impact. New routes and related technologies based on renewable feedstocks can overcome most of these problems associated with fossil fuel. Among current biodiesel sources, ethyl levulinate (EL) biodiesel obtained from catalytic esterification of renewable levulinic acid (LA) with ethanol has received a great deal of attention. The use of desilicated H-ZSM-5 (DH-ZSM-5) as heterogeneous acid catalyst for EL biodiesel production in a closed system (under autogeneous pressure) was studied. RESULTS The effect of reaction parameters such as ethanol to LA molar ratio (4:1 to 10:1), catalyst to LA ratio (0.10–0.25), speed of agitation (100–400 rpm), particle size (53–355 µm), reaction temperature (363–403 K) and reaction time (7 h) was investigated to maximize LA conversion. CONCLUSION Levulinic acid conversion reached 95% over DH-ZSM-5 and the catalyst was reusable for up to six cycles. This LA conversion and the catalyst reusability values are higher than others reported in the literature. A pseudo-homogeneous (P-H) kinetic model indicated that reaction rate constants increased with increasing molar ratio, catalyst to LA ratio and reaction temperature. The activation energy decreased from 73.14 to 21.08 kJ mol-1 when increasing the catalyst to LA ratio from 0.10 to 0.25, which implies a kinetically controlled reaction. © 2013 Society of Chemical Industry

Gas diffusion in microporous media in knudsen''s regime

Abstract: A diffusion equation for gas permeation through microporous media in the Knudsen regime was obtained theoretically, considering the potential energy between a gas molecule and the solid surface of pores. The equation as a function of temperature contains four parameters, all of which have physical meanings. The most significant of these parameters is the effective potential energy e*, by which the gas diffusion equation as a function of temperature is characterized. Permeabilities of He, H2, CO, N2, O2, Ar, and CO2 through a microporous Vycor glass membrane were measured in the temperature range from 300 K to 950 K. The validity of the diffusion equation obtained was verified experimentally and was shown to express well the previous data. For helium in particular, diffusion is almost gas-phase flow, with no adsorbed flow except at very low temperature. However, the diffusion is affected by the interaction energy between the gas molecules and the solid surface in the pores.

Fluorinated Metal–Organic Frameworks: Advantageous for Higher H2 and CO2 Adsorption or Not?

Abstract: The synthesis, structure, and gas adsorption properties of three new metal-organic frameworks (MOFs) designed from isonicotinic acid (INA) and its fluorinated analogue 3-fluoroisonicotinic acid (FINA) along with Co(II) as the metal center have been reported. Co-INA-1 ([Co(3)(INA)(4)(O)(C(2)H(5)OH)(3)][NO(3)]·C(2)H(5)OH·3H(2)O; INA=isonicotinic acid) and Co-INA-2 ([Co(INA)(2)]·DMF) are structural isomers as are Co-FINA-1 ([Co(3-)(FINA)(4)(O)(C(2) H(5) OH)(2)]·H(2)O; FINA=3-fluoroisonicotinic acid) and Co-FINA-2 ([Co(FINA)(2)]·H(2)O), but the most important thing to note here is that Co-INA-1 and Co-FINA-1 are isostructural as are Co-INA-2 and Co-FINA-2. The effect of partial introduction of fluorine atoms into the framework on the gas uptake properties of MOFs having similar structures has been analyzed experimentally and computationally in isostructural MOFs.

Influence of Pd doping on morphology and LPG response of SnO2

Abstract: In the present study nanocrystalline pristine and Pd-doped SnO 2 (Pd:SnO 2 ) with various mol% Pd have been synthesized by a modified Pechini citrate route. Transmission electron microscopy and X-ray powder diffraction studies were used to characterize the morphology, crystallinity, and structure of the SnO 2 and Pd:SnO 2 . The response of the pristine SnO 2 and Pd:SnO 2 was studied towards different reducing gases. The 1.5 mol% Pd doping showed an enhanced response of 75 and 95% towards LPG at as low as 50 and 100 °C, respectively, which were quite large high value as compared with pristine SnO 2 (38 and 35% at 50 and 100 °C, respectively). Structural characterization revealed that Pd doping reduced the crystallite size of SnO 2 and helps in the formation of distinct spherical nanospheres at a calcinations temperature of 500 °C. Thus the increase in LPG response can be correlated with the spherical morphology, a decrease in the crystallite size (11 nm) due to doping with Pd as compared with the pristine SnO 2 (26 nm) and main role of Pd as a catalyst.