Machhindra K. Lande

Scolecite as an efficient heterogeneous catalyst for the synthesis of 2,4,5-triarylimidazoles

Natural scolecite has been found as an effective catalyst for the one-pot synthesis of 2,4,5-triarylimidazole derivatives via a three component reaction using benzil or benzoin, aldehydes and ammonium acetate. This method provides several advantages such as being environmentally benign, reusable, possessing high yields with increased variations of the substituents in the product and preparative simplicity.

Preparation, Characterization, and Catalytic Application of a Nanosized Ce1MgxZr1-xO2Solid Heterogeneous Catalyst for the Synthesis of Tetrahydrobenzo[b]pyran Derivatives

A series of Ce1MgxZr1-xO2 mixed metal oxides with different molar ratios were prepared by simple co-precipitation and were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, temperature- programmed desorption of CO2, and N2 adsorption techniques. The prepared materials were tested for catalytic activity by the synthesis of tetrahydrobenzo[b]pyran derivatives using a three component reaction (aromatic aldehydes, malononitrile, and dimedone) in an ethanol medium. The best catalytic activity was obtained with Ce1Mg0.6Zr0.4O2. The particle size or crystallite size was estimated using the Debye-Scherrer equation. The addition of magnesium oxide into the ceria-zirconia lattice resulted in the formation of nanosized particles ranging from 5.41 to 9.78 nm. This work describes the catalytic behavior of magnesium oxide in mixed metal oxide systems.

Photodegradation of Molasses by a MoO3-TiO2 Nanocrystalline Composite Material

A MoO3-TiO2 nanocrystalline composite material was prepared by a simple sol-gel method. The synthesized material was characterized by X-ray diffraction, scanning electron microscopy with an electron dispersion spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. Melanoidin is a dark brown pigment found in wastewater from the sugar industry and it pollutes water. This polluted water is generally referred to as molasses and it undergoes fermentation and is solely responsible for water, soil, and air pollution. The synthesized catalytic material was found to be effective in degrading molasses under UV-visible radiation. Analysis of treated and untreated molasses was carried out by measuring its color, chemical oxygen demand, biological oxygen demand, pH, and total dissolved solid. Results from these analyses indicate the effective photodegradation of the molasses. This methodology has several advantages such as high photocatalytic activity, non-toxicity, cleanliness, and reusability of the catalytic material.

ZnO-beta zeolite: as an effective and reusable heterogeneous catalyst for the one-pot synthesis of polyhydroquinolines

Abstract ZnO-beta zeolite, an inexpensive and mild catalyst, has been used for the synthesis of polyhydroquinolines in excellent yields from the one-pot four-component condensation of aldehydes, dimedone, ethyl acetoacetate, and ammonium acetate in ethanol at room temperature. The remarkable advantages offered by this method are a green catalyst, mild reaction conditions, simple work-up procedures, much faster reactions, and excellent yield of products. Furthermore, the catalyst could be reused several times keeping its initial activity in recycled reactions.

Synthesis and characterizations of NiTiO3 nanoparticles prepared by the sol–gel process

Nanocrystalline nickel titanate (NiTiO3) composite powders were prepared by the sol–gel process combined with a surfactant-assisted template method. The resulting powders were calcined at different temperatures ranging from 150°C to 750°C for 2 h in air. The results revealed that a pure hexagonal phase of NiTiO3 could be obtained at the low temperature of 750°C. The phase evolution of NiTiO3 was investigated by X-ray diffraction patterns, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Particle size and morphology were studied by transmission electron microscopy.

ZnO-beta zeolite mediated simple and efficient method for the one-pot synthesis of quinoxaline derivatives at room temperature

A rapid and an efficient one-pot method for the synthesis of quinoxalines catalysed by ZnO-beta zeolite at room temperature is described. This environmentally benign method provides several advantages over methods that are currently employed such as a simple work-up, mild reaction conditions, good to excellent yields, and a process to recover and reuse the catalyst for several cycles with consistent activity.

Photocatalytic activity and characterization of sol-gel-derived Cr(III)-doped TiO2-coated active carbon composites

Cr(III)-doped, TiO2-coated active carbon (Cr–TiO2/AC) were prepared by a sol–gel method. The effect of supports, including TiO2 and active carbon (AC), on the molecular structure and photocatalytic activity of chromium oxide for complete decomposition of EDTA has been examined with respect to the content of Cr on the catalyst surface. The photocatalytic activity of the Cr–TiO2/AC composites was evaluated in the decomposition of EDTA solution under UV irradiation. The results indicate that Cr–TiO2/AC has a higher efficiency in decomposition of EDTA than TiO2, TiO2/AC or active carbon. This was attributed to the different functions of active carbon and chromate species. (1) Nanosize TiO2 particles on composites were not reunited, possible because active carbon retards transformation of anatase into rutile and decreases the crystallite size. (2) Production of high concentrations of organic compound near Cr–TiO2. (3) Carbon in active carbon causes some of the TiO2 to reduce to Ti3+ ions, which prevents electron–hole pair recombination. (4) Formation of polychromate species, with a stronger redox capability, on the surface of TiO2/AC. It was found that the addition of Cr to TiO2 sol could suppress the grain growth of TiO2 crystals and increase the hydroxyl content on the surface of TiO2/AC. The photocatalytic efficiency and activity of the composites remained good, even after three cycles.

Densities and viscosities of propylene carbonate with aromatic hydrocarbons (benzene, 1,4-dimethylbenzene and ethylbenzene) at 288.15, 298.15 and 308.15 K

Densities and viscosities of the binary mixtures of propylene carbonate with benzene, 1,4-dimethylbenzene and ethylbenzene were measured over the entire mole fraction range at 288.15, 298.15 and 308.15 K. Using the experimental values of densities and viscosities the excess molar volumes and viscosity deviations were calculated. The results were fitted by Redlich–Kister equation. The results were discussed in terms of intermolecular interactions.

Mesolite: An Efficient Heterogeneous Catalyst for One-Pot Synthesis of 2-Amino-4H-chromenes

Abstract An efficient and environmentally benign method for one-pot three-component synthesis of 2-Amino-4H-chromenes has been developed by cyclocondensation of benzaldehyde, malononitrile and resorcinol using newly modified mesolite-type natural zeolite as green catalyst. The catalyst was structurally modified by sulfuric acid treatment and characterized by X-ray diffraction, FT-IR, NH3-TPD, SEM-EDS and BET. This method offers several advantages over the reported methods such as simple and inexpensive modification of catalyst, mild reaction conditions, excellent yield and reusability of catalyst.

Preparation, Characterizations of TS-1 Zeolite: An Effective Solid Acid Catalyst for the Synthesis of 1, 3, 5-Triaryl-2-Pyrazolins

ABSTRACT A clean and efficient method has been developed for the synthesis 1, 3, 5-triaryl-2-pyrazoline derivatives via cyclocondensation of chalcone and phenyl hydrazine using TS-1 as solid heterogeneous reusable catalyst. The catalyst was synthesized by the hydrothermal method under autogenous pressure. The prepared catalyst was characterized by Powder-X-ray diffraction (XRD), Fourier-transform infrared spectroscopy spectroscopy, scanning electron microscope-Energy dispersive spectroscopy (EDAX) and Brunauer–Emmett–Teller surface area analysis. The present method offers significant advantages over the reported methods like easy separation of catalyst, simple work-up procedure, and excellent yield of desired products. Furthermore, catalyst could be reused without significant loss in activity.