Bioactive epoxides and hydroperoxides derived from naturally monoterpene geranyl acetate.

Geranyl acetate (1) was oxidized thermally and photochemically using (mcpba, H2O2) respectively to obtain (E)-5-(3, 3-dimethyloxiran-2-yl)-3-methylpent-2-enyl acetate (2) and 3-(2-(3, 3-dimethyloxiran-2-yl) ethyl)-3-methyloxiran-2-yl) methyl acetate (3). On the other hand, photooxygenation of 1 with tetraphenyl porphin (TPP) as a photo sensitizer gave corresponding acitic acid 2,6-bis-hydroperoxy-7-methyl-3-methylene-oct-7-enyl-ester (4), acitic acid 7-hydroperoxy-3,7-dimethyl-octa-2,5-dienyl ester (5) and Acitic acid 3-hydroperoxy-7-methyl-3,7-dimethyl-octa-1,6-dienyl ester (6). Antifungal studies were carried out on geranyl acetate and its derivatives. Studies on the antifungal activity especially Microsporum gypsum, Trichophyton vercossum and Candida tropicalis showed that geranyl acetate, its epoxide and hydroperoxide derivatives have good antifungal action.

Zinc Oxide-Multi Walled Carbon Nanotubes Nanocomposites for Carbon Monoxide Gas Sensor Application.

Zinc oxide (ZnO)/multi walled carbon nanotubes (MWCNTs) composites based sensors with different ZnO concentrations were fabricated to improve carbon monoxide (CO) gas sensing properties in comparison to the sensors based on bare MWCNTs. To study the structure, morphology and elemental composition of the resultant products, X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and Energy dispersive X-ray spectroscopy (EDS) were carried out. It has been observed that as the concentration of ZnO is increased more and more ZnO nanoparticles in the form of nodes get attached to MWCNTs resulting the reduction in average diameter of MWCNTs. The typical response of ZnO/MWCNTs composites based gas sensors for different CO concentrations (40, 100, 140 and 200 ppm) was studied by using very advanced sensing setup attached to I-V measurement system. Different sensing parameters such as: resistive response, sensitivity and response time were estimated at room temperature for all the fabricated sensors. The results indicated that the sensor based on nanocomposite which has 30 mg ZnO dispersed on 20 mg MWCNTs showing highest sensitivity and fastest response. All the sensors showed response times ranging from 8 to 23 seconds. The sensing mechanism behind the sensors based on ZnO/MWCNTs nanocomposites for CO gas at room temperature is also discussed in the present report.

Glucose sensor based on copper oxide nanostructures.

CuO spheres composed of finely arranged nanobricks were synthesized by simple and facile hydrothermal process and used as efficient electron mediators for the fabrication of highly sensitive non-enzymatic glucose sensor. The CuO spheres were synthesized at low-temperature of -30 degrees C and characterized in terms of their morphological, compositional, and structural properties. The morphological investigations revealed that the synthesized CuO powder possess spherical shapes and made of several CuO nanobricks. The detailed structural characterizations exhibited that the synthesized CuO spheres are nanocrystalline and possessing monoclinic structure. The fabricated glucose sensor based on CuO spheres exhibits a high sensitivity of -164.2523 microA mM(-1) cm(-2) and experimental detection limit of -39 microM with a quick response time of -10.0 s. The presented work shows that the easily prepared CuO nanomaterials can be used as efficient electron mediators for the fabrication of high sensitive non-enzymatic glucose sensors.

Photocatalytic oxidation of phenolic pollutants and hydrophobic organic compounds in industrial wastewater using modified nonosize titanium silicate-1 thin film technology.

Nanocrystalline Titanium Silicate-1 (TS-1) with attractive physical and chemical properties is being explored for the degradation of phenol. A fully dispersible nanocrystalline zeolite TS-1 was prepared. The catalyst was characterized by DLS, XRD, TEM and BET analyses. XRD analysis confirmed that the diffraction pattern of the NPs (CP-0) was very similar to that of amorphous silica and the aged concentrated precursor sample CP-48 showed peaks characteristic of MFI. TEM analysis confirmed that the size of the crystal is about 30 nm. The photocatalytic oxidation of phenol was studied over nanocrystalline Titanium silicate-1 thin film flow reactor. The experimental parameters such as aeration, flow rate, solution pH and phenol concentration were optimized. The degradation efficiency of choro-substituted phenols are compared at optimum conditions. In addition, photocatalytic degradation efficiency of simulated phenolic waste water was studied. The results are significant, as the method adopted here can be extended for the treatment and purification of waste water and air using nanocrystalline Titanium silicate-1 thin film flow reactor.

Hierarchical zeolite beta: an efficient and eco-friendly nanocatalyst for the Friedel-Crafts acylation of toluene.

P-Methyacetophenone, the acylated product of toluene finds a wide range of applications in the flavors and fragrance industry. It is typically produced on an industrial scale by Friedel-Crafts acylation of toluene with acetic anhydride using homogeneous, corrosive and polluting acid catalysts such as aluminium chloride. The pollution problems related to this process such as the disposal of catalyst and treatment of acidic effluent needs to be replaced by a green process. The current work reports on the activity of hierarchical zeolite Beta in the liquid phase acylation of toluene with acetic anhydride. The liquid phase reactions were carried out in the temperature range of 60-140 degrees C in an autoclave. The effect of various reaction parameters such as time-on-stream (TOS), mole ratio of reactants, catalyst loading, and reaction temperature on the rates of reaction has been investigated. Under the optimum reaction conditions the performance of hierarchical zeolite Beta was compared with nanocrystalline zeolite Beta. It was found that hierarchical zeolite Beta catalyst exhibit higher activity, which is due to the hierarchical porosity and to the nano size of the Beta zeolite catalyst particles allows faster diffusion of the products out of the catalyst.

Synthesis and characterizations of Cd-doped ZnO multipods for environmental remediation application.

Well-crystalline Cd-doped ZnO multipods were synthesized by simple and facile hydrothermal process by using zinc chloride, cadmium chloride, hexamethylenetetramine and ammonium hydroxide at low-temperature. The synthesized materials were characterized in terms of their morphological, structural, compositional and optical properties. The morphological investigations done by field emission scanning electron microscopy (FESEM) reveal that the synthesized products are multipods shaped and grown in high density. The structural and compositional properties, observed by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) attached with FESEM and Fourier transform infrared (FTIR) spectroscopy exhibit that the synthesized multipods are well-crystalline and possessing wurtzite hexagonal phase pure Cd-doped ZnO. The as-synthesized Cd-doped ZnO multipods exhibited good optical properties as was confirmed by UV-vis. spectroscopy. Finally, the as-synthesized Cd-doped ZnO multipods were used environmental remediation application. For this, the synthesized multipods were used as an effective photocatalyst for the photocatalytic degradation of acridine orange (AO) which exhibit -92.4% degradation within 90 min. This work demonstrates that doped ZnO materials could be used as efficient photocatalyst for the photocatalytic degradation of various organic dyes and chemicals.