Iranian Journal of Catalysis
Volume:6 Issue: 3, Summer 2016

CdO nanoparticles efficiently catalyzes the condensation of aromatic aldehydes with 2-aminophenol at room temperature to afford 2-aryl benzoxazole derivatives by grinding method. The reactions proceed under heterogeneous and mild conditions to provide 2-aryl benzoxazoles in excellent yields (87-97 %) with high purity under solvent free condition. The reaction requires short time (5-23 minutes) under moderate conditions. The purification of products by non-chromatographic methods is additional feature of this method. A series of 2-aryl bezoxazole have been successfully synthesized by this method. Ease of recycled catalyst, cleaner process, solvent free and lower catalytic loading are the most advantages of the proposed method.

An efficient and eco-friendly method for the one-pot synthesis of 14-aryl-14H-dibenzo [a,i]xanthene-8,13-dione derivatives has been developed in the presence of Fe3O4@SiO2 core-shell nanoparticles. The multi-component reactions of 2-hydroxy-1,4-naphthoquinone, β-naphthol and aldehydes were efficiently catalyzed using novel nano-scale materials under reflux conditions. The present method offers several advantages such as environmentally benign, simple work-up, excellent yield of products, short reaction times, little catalyst loading and facile catalyst separation. The nanomagnetic catalyst could be readily recovered using a simple external magnet and reused several times without any significant loss in activity. The catalyst was fully characterized by FT-IR, SEM, XRD, EDX and VSM analysis.

A convenient synthetic method for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetra substituted imidazole derivatives, has been developed via one-pot condensation reaction in solvent-free condition when aldehyde, ammonium acetate/amine, and 1,2-diketone are reacted using 0.8 mol% of NP-LaMnO3 at 80 °C under solvent free conditions. Catalyst could be recovered and reused in five reaction cycles without any loss of its activities, giving a total turnover number (TON) = 594 and turn over frequency (TOF) = 71 h−1. High yield, little catalyst loading, elimination of solvent, simple workup, recovery and reusability of the catalyst are some of the impressive features of the present method.

A series of tungestophosphoric acid and vanadium oxide supported on Mesocellulous Silica Foams (MCFs) featuring a well-defined three-dimensional (3D) mesoporosity were studied with regard to their performance in the photocatalytic activity to degrade Oezine Y (OY). This nanosized mesoporous catalyst (PW12@V-MCF) was characterized by FTIR, XRD, BET and TEM. XRD shows that the structure of MCF remains intact after PW12 modification, while spectral techniques show the successful grafting of the PW12 on the MCF cavities. PW12-MCF was used as a catalyst in the photodecolorization process of Oezine Y (OY) dye in aqueous solution under UV radiation. It was found that the catalyst exhibited significantly high catalytic stability, and the activity loss is negligible after three OY degradation cycles.

Sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) with a pore size of 6 nm catalyzed three component coupling of aromatic aldehydes, urea and ethyl acetoacetate to afford the corresponding dihydropyrimidinones under solvent free condition. This new protocol for Biginelli reaction has important advantages such as green synthesis, short reaction time, easy isolation and high yields of products and reusability of the catalyst. SBA-Pr-SO3H was proved to be an efficient heterogeneous nanoporous solid acid catalyst which could be easily handled and removed from the reaction mixture by simple filtration and can be recovered and reused for several times without any loss of activity.

Red pine leafs were applied for the green method preparation of MgO nano-plates. The MgO nano-plates were used for the one-pot synthesis of dihydropyrano [3,2-c] chromene derivatives. This procedure is very simple and affords excellent yields.
MgO nanoplates were synthesized via a simple precipitation method with the using of an extract solution of red pine leaves. The XRD pattern shows a cubic phase ofMgO .
Field Emission Scanning Electronic Microscopy (FE-SEM) shows clearly that the surface of the as-prepared MgO nano-plates have a homogeneous microstructure made up of layers of various sizes and forms. The plates form irregular grains with a lateral size of 40-110 nm.

5-Substituted-1H-tetrazoles were synthesized by the [3 2] cycloaddition of sodium azide with various nitriles in the presence of nickel zirconium phosphate (NiZrP) as an effective heterogeneous catalyst in dimethylsulfoxide at 120 °C. This method has the advantages of good to high yields, simple methodology and easy work-up. The catalyst can be recovered by centrifuging and reused with good yields. There is no appreciable loss of catalytic activity up to five cycles. All aromatic nitriles with electron-donating group could be accomplished as well as that with electron-withdrawing groups. The structural characteristics of the catalyst are identified by scanning electron microscopy (SEM) and XRD instruments.

TiCl2/nano-γ-Al2O3 as a new heterogeneous Lewis acid catalyst was synthesized and characterized by FE-SEM, XRD, FT-IR, EDS, XRF, BET and TGA. N-substituted pyrroles have been synthesized via Paal–Knorr reaction in the presence of TiCl2/nano-γ-Al2O3 at room temperature under solvent-free conditions.

BiFeO3 (BFO), Bi0.86Sm0.07Eu0.07FeO3 (BSEFO), and Bi0.86Sm0.07Cd0.07FeO3 (BSCFO) nano powders were prepared by the sol-gel combustion method and the catalytic performances were evaluated in the acetylation reaction of benzyl alcohol. The physical chemical properties of the catalysts were characterized by using XRD, FT-IR, scanning electron microscope (SEM), EDX and BET surface. The efficient acetylation of benzyl alcohol was carried ­out over all the nano powders using acetyl chloride/ acetonitrile at room temperature. Among the nano powders, BSCFO showed the highest catalytic performance and the yield of benzyl acetate was 89, 45, and 69 percent over BSCFO, BFO, and BSEFO, respectively. Partial substitution of Sm-Eu and Sm-Cd in bismuth ferrite improved the catalytic performance and increased the specific surface area of the catalysts. A direct relationship resulted between the catalytic performance and the specific surface of catalysts, where BSCFO with the highest surface area (11.7m2/g) exhibited the superior catalytic performance. The quantitative yield for the acetate product also resulted for the acetylation of p-methyl benzyl alcohol, p-nitro benzyl alcohol and p-chloro benzyl alcohol on BSCFO. The catalysts showed good reusability in the process. The study confirmed that the catalysts could be promising for the acetylation of alcohols.

In this work, CuO nanoparticles (CuO NPs) was prepared by a simple and green method using Rosmarinus officinalis extract containing phenolic constituents as both the chelating and the stabilizing agents. CuO nanoparticles/polyorthoaminophenol composite (CuO NPs/POAP) as electro-active electrodes for electrocatalytic oxidation of methanol with good uniformity are prepared by electropolymerization. Composite of CuO NPs/POAP was synthesized by cyclic voltammetry (CV) methods and electrochemical properties of film were investigated by using electrochemical techniques. New composite modified electrode shows a significantly high response for methanol oxidation. This method of synthesis of the catalyst and composite has the advantages of high yields, elimination of chemical reagent and simple methodology. Catalytic efficiency remains unaltered even after several repeated cycles.

Nano hexagonal wurtzite ZnO has been prepared on zeoliteA by the sono-chemical method. The zeoliteA was mixed into Zinc gel, after stirring for two days, the mixture was irradiated 30 min by ultrasonic probe. The filtrated composite gel was calcinated at 500°C for 3h in furnace. The produced composite was characterized using X-ray diffraction, FT-IR spectroscopy and field emission scanning electron microscopy. The average crystal size of the nanoZnO and nanoZnO on zeoliteA was determined 53 and 38 nm, respectively. The range of particles size of the nanoZnO on zeoliteA is 30-50 nm. The particles of nanoZnO on the surface of zeoliteA has been dispersed over the zeoliteA framework and the results have shown a higher rate of photodegradation of Congo red (an azo-dye) as compared with bare nanoZnO.

Titania, single-doped and lanthanum-silver co-doped titania nanocomposite were coated on cellulosic and polyacrylonitrile fibers via sol–gel method. The prepared samples were evaluated using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and BET surface area measurement. The photo self-cleaning activity of the nanocomposites coated-fibers were determined by degradation of methylene blue and eosin yellowish under UV-Vis light. Diffuse reflectance spectroscopy was used to monitor photodegradation of dyes. The results of EDX and XPS revealed that La and Ag was doped into TiO2 structure. The results of EDX, TEM and BET analyses indicated that the TiO2 and TiO2 nanocomposite coatings were composed of nanoparticles or aggregates with a size of less than 20 nm. All samples demonstrated photocatalytic self-cleaning properties when exposed to UV-Vis irradiation. The results showed that the La3ﰈ co-doping is more beneficial than single doping of TiO2 coating and the synergistic effect of La3 and Ag is responsible for improving the photo-activity. This may be ascribed to the microstructure of TiO2 and the effect of the doping modes on the structural and electronic properties of the anatase phase.

ZnO nanoparticles have been prepared by a simple method in a short period of time. In this synthetic method, the sample was obtained using Zn(CH3COO)2·2H2O and a new template of hexamine salt. Their crystalline structure and morphology were studied by XRD and SEM. The optical properties of the sample were studied by UV–visible spectroscopy. The absorption spectrum of ZnO shows that the optical band gap is 3.02 eV. In this investigation, the photocatalytic degradation of Indigo carmine(IC) in water was studied. The degradation rate is reduced as a function of increase in the initial concentration of IC. The effects of some parameters such as pH and initial concentration of dye were examined.

This study reports a new methodology for the efficient synthesis of trisphenol compounds using the reaction of
2,6-bis(hydroxymethyl) phenols with phenols under heterogeneous conditions. A sulfonated reduced graphene oxide
(RGO-SO3H) nanocatalyst was used to promote the reaction under solvent-free conditions. A range of trisphenol compounds were produced in the presence of this catalyst system in good to excellent yields. In the presence of this catalyst system, a less amount of phenol is required, which improves the environment through its capability in synthesis of trisphenols. The
RGO-SO3H catalyst was reusable at least for 8 times in this process without a significant decrease in its catalytic activity.

In this paper, undoped TiO2 and Ag-Nd-codoped TiO2 nanocomposites with different molar ratios of dopants were synthesized by the sol-gel method using starch as a natural additive. Structures were investigated by FT-IR and UV–Vis spectroscopy, SEM, and XRD methods. Moreover, the direct band gap was calculated by Tauc's approach. Furthermore, photocatalytic activity of all samples were investigated under UV irradiation in an aqueous medium. Compared with undoped TiO2, the band gap of the Ag-Nd -TiO2 samples decreases and depends on the content of dopants. In addition, photocatalytic activity improves in the presence of appropriate amount (1.5 mol%) of Ag and Nd as dopants.