Synthesis of aromatic amine phosphonato ester derivatives from the stereoselective reaction between triphenyl phosphite and dimethyl acetylenedicarboxylate in the presence of derivatives of aromatic amines

Aromatic amine phosphonato esters 4a–d were obtained in excellent yields from the 1:1:1 addition reaction between triphenyl phosphite and dimethyl acetylenedicarboxylate in the presence of NH‐aromatic amines such as 2‐aminobenzophenone, 2‐aminoacetophenon, methyl‐2‐aminobenzoate, and 2‐aminobenzonitrile. In the recent works, the assignments of the configuration of 4a–d corresponding to the three‐bond carbon‐phosphorus coupling, ³Jpc, was determined on the basis of coupling constants by the Karplus equation as 2R *, 3R *or 2S *, 3S * while they were 2R *, 3S * or 2S *, 3R * in our previous works in the presence of same solvent. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:240–245, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20541     

Silver nanocluster catalytic microreactors for water purification

A new method for the elaboration of a novel type of catalytic microsystem with a high specific area catalyst is developed. A silver nanocluster catalytic microreactor was elaborated by doping a soda-lime glass with a silver salt. By applying a high power laser beam to the glass, silver nanoclusters are obtained at one of the surfaces which were characterized by BET measurements and AFM. A microfluidic chip was obtained by sealing the silver coated glass with a NOA 81 microchannel. The catalytic activity of the silver nanoclusters was then tested for the efficiency of water purification by using catalytic ozonation to oxidize an organic pollutant. The silver nanoclusters were found to be very stable in the microreactor and efficiently oxidized the pollutant, in spite of the very short residence times in the microchannel. This opens the way to study catalytic reactions in microchannels without the need of introducing the catalyst as a powder or manufacturing complex packed bed microreactors.     

Solvent effects on SN2 reaction between substituted benzyl chloride and chloride ion

The effects of solvent on S_N2 reaction between some substituted benzyl chlorides and chloride ion have been investigated by DFT and ab initio methods using the polarizabale continuum model. The activation energies are higher in the solution media relative to the gas phase and grow by the increase in the dielectric constant of solvent. The complexation energies in solution media are smaller than those in the gas phase and reduce with increasing the dielectric constant. The energy data are in good agreement with the geometrical parameters and substituent constants. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Effects of Brownian Motion and Thermophoresis on the Mixed Convection of Nanofluid in a Porous Channel Including Flow Reversal

This article is devoted to combined convection heat transfer of nanofluids through a vertical channel filled with a homogeneous and isotropic porous medium. The flow is assumed to be fully developed and the “Brinkman extended Darcy” model is used for the flow in the porous media and “clear compatible” viscous dissipation model is considered. Also the model utilized for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The governing momentum, energy, and nanopartices volume fraction equations are solved both analytically and numerically. The effects of the influential dimensionless parameters such as Brownian and thermophoresis parameters, mixed convection parameter (Gr/Re), Brinkman, Darcy and Lewis numbers on dimensionless velocity and temperature distributions and pressure drop are studied. Also, the results of the Nusselt number for the both left and right walls are presented and discussed.     

An efficient conversion of catechols into 6H‐benzofuro[3,2‐c][1]‐benzopyran‐6‐one derivatives

Coupling of in‐situ generated o‐benzoquinones with 4‐hydroxycoumarin as a nucleophile has been studied in the presence of potassium ferricyanide as an oxidizing agent in aqueous solution. The results indicate that the quinones derived from catechols, participate in Michael addition reactions with 4‐hydroxycoumarin to form the 6H‐benzofuro[3,2‐c][1]benzopyran‐6‐one derivatives.     

An efficient enzymatic method for the separation of stereoisomeric cis and trans-glycidic esters synthesised via Darzen's condensation reactions

Pig's liver esterase (PLE) was used efficiently in phosphate buffer for the separation of stereoisomeric mixtures of cis/trans-ethyl arylglycidates, produced via Darzen's condensation reactions.