One-pot three-component reaction: Synthesis of substituted β-cyanocarbonyls in aqueous media

An environmentally friendly and simple method for the synthesis of alkyl nitriles or β-cyanocarbonyls via a one-pot three-component reaction of Meldrum's acid, aldehydes and sodium cyanide in water, without using any catalyst or activation at room temperature is reported.     

An efficient,expeditious, and diastereoselective one-pot pseudo-five-component reaction for the synthesis of new bis-Betti bases under catalyst-free conditions

A novel, diastereoselective, one-pot synthesis of new bis-Betti bases via condensation of dihydroxynaphthalene, two equivalents of aryl aldehydes, and two equivalents of 3-amino-5-methylisoxazole is reported. Conversion into the adducts was almost quantitative without the use of solvent or catalyst. The reaction conditions are very simple and enable easy isolation of the product.     

Analytical solution of three-dimensional Navier–Stokes equations for the flow near an infinite rotating disk

In this letter, we will consider variational iteration method (VIM) and Padé approximant, for finding analytical solutions of three-dimensional viscous flow near an infinite rotating disk. The solutions is compared with the numerical (fourth-order Runge–Kutta) solution. The results illustrate that VIM–Padé is an appropriate method in solving the systems of nonlinear equations. It is predicted that VIM–Padé can have wide application in engineering problems (especially for boundary-layer and natural convection problems).     

Highly Regioselective Ring Opening of Epoxides with Thiols Catalyzed by SbCl3 Under Solvent-Free Conditions

The ring-opening reaction of epoxides with thiols by SbCl ₃ supported on Kieselguhr under solvent-free conditions, afforded high yields of β-hydroxy sulfides. Nucleophilic attack of the thiols occurs regioselectively at the less hindered side of the epoxides.     

Novel toughened automotive clearcoats modified by a polyester‐amide hyperbranched polymer: structural and mechanical aspects

The present work attempts to study the mechanical properties and toughness behavior of a typical acrylic melamine clearcoat modified by a polyester‐amide hyperbranched polymer (HBP). Formulations were such that 0, 5, 10, 25 and 50% (molar percent) of total acrylic hydroxyl groups were stoichiometrically substituted by those of HBP. Bulk and surface of the clearcoats were studied by various mechanical techniques including hardness, tensile, dynamic mechanical thermal analysis (DMTA), nano‐indentation and scratch tests. In addition a scanning electron microscope (SEM) was utilized to observe the morphology of the fractured films. The bulk mechanical properties showed that a low loading (5 molar %) of HBP was sufficient to considerably increase the bulk hardness, cross‐linking density and toughness. DMTA and SEM results proved the occurrence of a single‐phase blend and that the shear deformation was the main toughening mechanism of HBP modified clearcoats. In general, it was revealed that the HBP not only could act as an excellent compatible toughening agent, but also maintained the clarity of the clearcoat and increased its scratch resistance. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis and Characterization of Organosoluble Poly(imide-ether)s with Bulky 2,3-Diaryl Imidazole Moiety: Study Physical,Thermal and Optical Properties

Two new symmetrical diamines were designed and synthesized having different functional groups such as a pair of phenyl ether linkages, 2,3-diaryl substituted imidazole rings and CF₃ groups as pendant, and characterized by FT-IR, ¹H and ¹³C-NMR spectroscopy and elemental analysis. A series of new fluorescent poly(imide-ether)s (PIEs) was prepared by polymerization of the diamines with commercial tetracarboxylic dianhydrides such as pyromellitic dianhydride and 3,3′,4,4′-benzophenone tetracarboxylic dianhydride. The resulting PIEs were amorphous and had intrinsic viscosity [η] in the range of 0.42–0.51 dL/g. The weight average molecular weights (Mw) of these polymers were measured by GPC and were in the range of 28658–35595 g/mol with molecular weight distribution (MWD) of 2.12–2.27. These polymers were readily soluble in a variety of organic solvents and formed low-colored and flexible thin films with cut-off wavelength (λ₀) in the range of 385–420 nm, and all PIEs films exhibited high optical transparency. They also possessed good thermal stability with 10% weight loss temperatures (T_10%) in the range 486–537°C in N₂. The glass transition temperatures (T_g) of PIEs are in the range 251–324°C. These polymers showed fluorescence emission in film and in solution at 459–476 nm with the quantum yields in the range 4–12%.