Reaction between enaminones and acetylenic esters in the presence of triphenylphosphine: a convenient synthesis of alkyl 2(1-benzyl-2,4-dioxo-2,3,4,5,6,7-hexahydro-1H-indol-3-yl)acetates

One-pot reaction between enaminocarbonyl compounds derived from six-membered 1,3-diketones and substituted benzylamines, and electron-deficient acetylenic esters in the presence of triphenylphosphine lead to alkyl 2-(1-benzyl-6,6-dimethyl-2,4-dioxo-2,3,4,5,6,7-hexahydro-1H-indol-3-yl)acetate derivatives in good yields.     

Synthesis of a novel magnetic nanocatalyst based on rhodium complex for transfer hydrogenation of ketone

A magnetic heterogeneous nanocatalyst based on novel rhodium complex is designed. The transfer hydrogenation of ketones with 2‐propanol as hydrogen donor and the rhodium complex as nanocatalyst was achieved. High yields of ketones under mild conditions were obtained from easily available precursors.     

Novel polyesters and polyester/Cloisite 30B nanocomposites based on a new rhodanine-based monomer

A novel bis-diol monomer, 3,3'-bis-(2-hydroxyethyl)-2,2'-dithioxo-[5,5']bithiazolidinylidene-4,4'-dione, was prepared in a one-pot three component reaction and used in a polyesterification reaction with various aromatic dicarboxylic acids using tosyl chloride/dimethylformamide/pyridine system as a condensing agent in order to generate a series of new polyesters. The prepared polyesters were characterized by FTIR spectroscopy and elemental analysis. In the next part, a series of polyester/clay nanocomposites were synthesized through a polyesterification reaction of the synthesized monomer with iso-phthalic acid. Cloisite 30B was used as the filler at different concentrations. Wide-angle X-ray diffraction and transmission electron microscopy studies showed that the organoclay layers are mainly exfoliated in the nanocomposites containing 1 wt % of Cloisite 30B.     

Preparation of an organic–inorganic hybrid based on synergy of Brønsted and Lewis acid centres as heterogeneous magnetic nanocatalyst for ultrafast synthesis of acetaminophen

A heterogeneous nanocatalyst based on a Cu(II) complex containing phosphotungstic acid and N/O‐donor ligands supported on cobalt ferrite nanoparticles was successfully prepared. The synthesized nanocatalyst was characterized using various techniques. The magnetic nanocatalyst was examined as an efficient and synergistic catalyst for ultrafast synthesis of acetaminophen at room temperature and under solventless conditions. The examined synergistic nanocatalyst, which has both Lewis and Brønsted acidic sites, could be easily separated from the reaction system and reused several times without significant loss of its activity. The synthesized acetaminophen was also fully characterized.     

Exact Analysis of Level-Crossing Statistics for (d+1)-Dimensional Fluctuating Surfaces

We carry out an exact analysis of the average frequency ν⁺ _αxi in the direction x _i of positiveslope crossing of a given level α such that, h(x, t) − = α, of growing surfaces in spatial dimension d. Here, h(x, t) is the surface height at time t, and is its mean value. We analyze the problem when the surface growth dynamics is governed by the Kardar-Parisi-Zhang (KPZ) equation without surface tension, in the time regime prior to appearance of cusp singularities (sharp valleys), as well as in the random deposition (RD) model. The total number N ⁺ of such level-crossings with positive slope in all the directions is then shown to scale with time as t ^d/2 for both the KPZ equation and the RD model. PACS number(s): 52.75.Rx, 68.35.Ct     

Comparison of the performance of different hybrid catalysts for direct synthesis of dimethyl ether from synthesis gas

Nine hybrid catalysts have been prepared, characterized and tested in a micro reactor for the direct synthesis of dimethyl ether. The physical mixtures of H-MFI-90 with ICI or KMT catalysts showed better performance.     

Synthesis of Highly Functionalized 1-Azadienes and Ketenimines

The 1:1 reactive intermediate generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylates was trapped by fairly strong NH-acids such as carbazole, indole, or pyrrole to yield highly functionalized 1-azadienes and ketenimines.     

Synthesis and dynamic NMR study of ketenimines derived from tert-butyl isocyanide,alkyl 2-arylamino-2-oxo-acetates,and dialkyl acetylenedicarboxylates

The adduct produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped by alkyl 2-arylamino-2-oxo-acetates. When the aryl group is 2-methyl-6-nitrophenyl or 2,6-di-isopropylphenyl, the product exists as two stable rotamers at room temperature as a result of restricted rotation around the Ar-N single bond. When the aryl group is 1-naphthyl or 8-quinolinyl, dynamic NMR effects are observed in the 1H NMR spectra. The calculated free-energy of activation for interconversion of the rotational isomers in 1-naphthyl and 8-quinolinyl derivatives amounts to about 99+/-2 and 68.5+/-2 kJ mol(-1), respectively.     

Zinc oxide nanorod‐loaded activated carbon for ultrasound‐assisted adsorption of safranin O: Central composite design and genetic algorithm optimization

This paper focuses on the development of an effective methodology to obtain the optimum ultrasonic‐assisted removal of a dye, safranin O (SO), under optimum conditions that maximize the removal percentage, using ZnO nanorod‐loaded activated carbon (ZnO‐NRs‐AC) in aqueous solution. Central composite design coupled with genetic algorithm was used for parameter optimization. The effects of variables such as pH, initial dye concentration, mass of ZnO‐NRs‐AC and sonication time were studied. The interactive and main effects of these variables were evaluated using analysis of variance. The structural and physicochemical properties of the ZnO‐NRs‐AC adsorbent were investigated using field emission scanning electron microscopy and X‐ray diffraction. Adsorption equilibrium data were fitted well with the Langmuir isotherm and the maximum monolayer capacity was found to be 32.06 mg g^?1. Studies of the adsorption kinetics of the SO dye showed a rapid sorption dynamic with a ^pseudo‐second‐order kinetic model, suggesting a chemisorption mechanism.