Introduction of antimony triiodide (SbI3) as a new and efficient catalyst for synthesis of polyfunctionalized piperidines

Research on Chemical Intermediates - In the present work, an efficient and convenient one-pot multi-component reaction is reported for the synthesis of highly diversified piperidines by tandem...     

The Dark Side of Hydrogen Bonds in the Design of Optical Materials: A Charge‐Density Perspective

A combined investigation of the structural, electronic, and optical properties of three crystalline nonaaqualanthanoid(III) triflates, [Ln(H₂O)₉(CF₃SO₃)₃], has provided unambiguous experimental evidence for charge redistribution in the first coordination sphere of a lanthanide ion as a result of hydrogen bonds with outer‐sphere anions. As well as resulting in charge transfer from the noncoordinated anions to the coordinated water molecules, these hydrogen bonds give rise to a new excited state, an hydrogen‐bond‐induced charge‐transfer state, which is observed experimentally for the first time. This state was shown to be responsible for the previously unknown negative aspect of hydrogen bonds with a lanthanide‐bound water molecule: rather than increasing the luminescence efficiency of the complex, they can lead to additional quenching that is unfavorable for the task‐specific design of optical materials.     

Optimization technique in solving laminar boundary layer problems with temperature dependent viscosity

In this paper, a novel numerical method is proposed to solve specific third order ODE on semi-infinite interval. These kinds of problems often occur in laminar boundary layer with temperature dependent viscosity. Runge-Kutta method incorporating with optimization techniques is used to solve the problem. First, the semi-infinite interval is transformed into a finite interval. Second, by converting the boundary value problem, with some initial and distributed unknowns, into an optimization problem, solving the original problem is limited to solving a multiobjective optimization problem. Third, we use shooting-Newton’s method for solving this optimization problem. It is shown that the Falkner-Skan problem with constant surface temperature, that arise during the solution for the laminar forced convection heat transfer from wedges to flow, can be solved accurately and simultaneously by this strategy. Numerical results for different values of wedge angle and Prandtl number are presented, which are in good agreement with some of the successful provided solutions in the literature.     

Electro-catalyzed multicomponent transformation of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one to 1,4-dihydropyrano[2,3-c]pyrazole derivatives in green medium

An efficient and convenient synthesis of 1,4-dihydropyrano[2,3-c]pyrazole derivatives is described, using the electrogenerated anion of ethanol as the base in the presence of sodium bromide as an supporting electrolyte in a one-pot, three component condensation of malononitrile, aromatic aldehydes and 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one. The reaction is carried out in an undivided cell containing an iron electrode as the cathode and a graphite electrode as the anode, at a constant current at room temperature.     

Optimization of Oil-in-Water Emulsion Stability: Experimental Design,Multiple Light Scattering,and Acoustic Attenuation Spectroscopy

To find an optimal formulation of oil-in-water (O/W) emulsions (φ_o = 0.05), the effect of emulsifier nature and concentration, agitation speed, emulsifying time, storage temperature and their mutual interactions on the properties and behavior of these dispersions is evaluated by means of an experimental design (Nemrodw software). Long-term emulsion stability is monitored by multiple light scattering (Turbiscan ags) and acoustic attenuation spectroscopy (Ultrasizer). After matching surfactant HLB and oil required HLB, a model giving the Sauter diameter as a function of emulsifier concentration, agitation speed and emulsification time is proposed. The highest stability of C₁₂E₄-stabilized O/W emulsions is observed with 1% emulsifier.     

Water-Diesel Microemulsions Stabilized by an Anionic Extended Surfactant and a Cationic Hydrotrope

Alcohol-free microemulsions were formulated using mixtures of extended surfactant (C_12-14-PO₁₄-EO₂SO₄Na), sodium dodecyl benzene sulfonic acid and cationic hydrotropes with equal amounts of water and diesel. The cationic hydrotropes had short hydrocarbon or propylene oxide chain. The formulation included sodium carbonate to convert naphthenic acids in diesel to soaps. The phase behavior at ambient temperature of oil-free mixtures as a function of NaCl concentration was investigated. Visual inspection as well as cross polarizers were used to detect anisotropy. The microemulsion fish phase diagram and solubilization ratios for diesel and brine in the middle phases were determined. The minimum surfactant concentration needed to initiate middle phase formation was 0.10 wt%.

Salinity scans revealed that optimal salinity can be adjusted according to the hydrophilic/lipophilic nature of the hydrotrope used. Interfacial tension measurements using a spinning drop tensiometer showed a minimum value of 0.0015 mN/m between middle phase microemulsion and excess brine and a value of 0.032 mN/m between diesel and brine.     

Facile and Convenient Synthesis of 5-Arylalkylidenerhodanines by Electrocatalytic Crossed Aldol Condensation

Abstract

An electrochemically induced catalytic crossed Aldol condensation of one equivalent of rhodanine with various aromatic aldehydes and ketones in ethanol in an undivided cell in the presence of sodium bromide as an electrolyte results in the formation of the corresponding 5-arylalkylidenerhodanines in 80–96% yield with reactions in 40 min.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.