Hydrophobically modified poly (acrylic acid) using calix[4]arene derivative. Ionophoric properties and extraction abilities toward alkali metal cations

p‐t‐Butyl calix[4]arene diol (distal cone) (1) was grafted with poly (acrylic acid) (PAA) to obtain hydrophobically modified PAA (PAA‐C) bearing calixarene moieties. The grafting method includes the direct esterification reaction of PAA with calixarene diol 1 which was carried out in a system of tosyl chloride (TsCl), pyridine (Py), and N,N‐dimethylformamide (DMF). The grafting yield was studied using different molar ratios of PAA to calix[4]arene diol 1, temperature, and reaction time. The chemical composition of the PAA‐C was studied by IR and ¹H NMR spectroscopy. Also, the morphology of PAA‐C was evaluated by scanning electron microscopy. The PAA‐C had different solubility and thermal properties. The extraction ability measurements of modified PAA toward alkali metal cations (Na⁺, K⁺, Cs⁺) and Ag⁺ showed a remarkable efficiency and selectivity of PAA‐C toward Na⁺. The main goal of this work was to design hydrophobically modified PAA with binding ability that is suitable for ion selective membranes and chemical sensor devices such as ion‐specific electrodes, semipermeable membranes, and quartz microbalances. Copyright © 2009 John Wiley & Sons, Ltd.     

Basic ionic liquids. A short review

Basic ionic liquids as environmental-friendly solvents and catalysts with high activity and selectivity and easily recovered materials were used to replace traditional bases such as KOH, NaOH, K₂CO₃, NaHCO₃, NaOAc, triethylamine, or tetrabutylammonium acetate. Using the traditional bases generally suffered from disadvantages such as waste production, corrosion and environmental problems. Basic ionic liquids offering a new possibility for developing environmentally friendly basic catalysts due to the combination of the advantages of inorganic bases and ionic liquids. They are flexible, nonvolatile,noncorrosive, and immiscible with many organic solvents. Basic ionic liquids (BILs) have been used in base-catalyzed processes such as Michael addition, Markovnikov addition, Knoevenagel condensation, Henry reaction, Mannich reaction, oximation, Feist-Benary reaction and etc. In this short review, we wish to present an overview of the types, properties, synthesis and applications of basic ionic liquids.     

Quasi-radial wall jets as a new concept in boundary layer flow control

This work aims to introduce a novel concept of wall jets wherein the flow is radially injected into a medium through a sector of a cylinder, called quasi-radial (QR) wall jets. The results revealed that fluid dynamics of the QR wall jet flow differs from that of conventional wall jets. Indeed, lateral and normal propagations of a conventional three-dimensional wall jet are via shear stresses. While, lateral propagation of a QR wall jet is due to mean lateral component of the velocity field. Moreover, discharged Arrays of conventional three-dimensional wall jets in quiescent air lead to formation of a combined wall jet at large distant from the nozzles, while QR wall jet immediately spread in lateral direction, meet each other and merge together very quickly in a short distance downstream of the jet nozzles. Furthermore, in discharging the conventional jets into an external flow, there is no strong interaction between them as they are moving parallel. While, in QR wall jets the lateral components of the velocity field strongly interact with boundary layer of the external flow and create strong helical vortices acting as vortex generators.     

Microwave-enhanced synthesis of aryl nitriles using dimeric orthopalladated complex of tribenzylamine and K4[Fe(CN)6]

The activity of palladacycle [Pd{C₆H₄(CH₂N(CH₂Ph)₂)} (μ-Br)]₂ complex was investigated in the synthesis of benzonitriles under both conventional and microwave irradiation conditions and their results were compared together. This complex is an efficient, stable, and non-sensitive to air and moisture catalyst for the cyanation reaction. The substituted benzonitriles were produced of various aryl halides in excellent yields and short reaction times using a catalytic amount of [Pd{C₆H₄(CH₂N(CH₂Ph)₂)} (μ-Br)]₂ complex and K₄[Fe(CN)₆] in DMF at 130 °C. In comparison to conventional heating conditions, the reactions under microwave irradiation gave higher yields in shorter reaction times.     

Nitric acid in the presence of P2O5 supported on silica gel—a useful reagent for nitration of aromatic compounds under solvent-free conditions

A variety of aromatic compounds are nitrated to parent nitro aromatic compounds under solvent-free conditions using 65% nitric acid in the presence of P₂O₅ supported on silica gel is described. This methodology is useful for nitration of activated and deactivated aromatic rings.     

Palladium–quaternary phosphonium phase transfer catalyst brush assembly as reusable and environmentally benign catalyst for coupling of aryl halides and sodium tetraphenylborate in neat water

A first example of simultaneous covalent anchoring of a palladate anion–phosphonium cation matrix on the surface of silica nanoparticles and application in the Suzuki coupling reaction of a variety of different haloarenes and sodium tetraphenylborate in neat aqueous media without the addition of any organic co‐solvent are described. Copyright © 2015 John Wiley & Sons, Ltd.     

Selective and Efficient Oxidation of Sulfides to Sulfoxides Using Ceric Ammonium Nitrate (CAN)/Brönsted Acidic Ionic Liquid

A selective and efficient procedure for the oxidation of sulfides to the corresponding sulfoxides is reported using ceric ammonium nitrate in the presence of methylimidazolium hydrogensulfate as Brönsted acidic ionic liquid ([Hmim]HSO ₄ ) as the solvent under mild conditions. The use of nontoxic and inexpensive materials, straightforward procedure, short reaction times, and good yields of the products are the major advantages of this method.     

A comparative homocoupling reaction of aryl halides using monomeric orthopalladated complex of 4‐methoxybenzoylmethylenetri‐ phenylphosphorane under conventional and microwave irradiation conditions

The activity of [Pd(C₆H₄CH₂NH₂‐κ²‐C‐N)PPh₃MOBPPY]OTf complex, A (MOBPPY = 4‐methoxybenzoylmethylenetriphenylphosphoraneylide) was investigated in the homocoupling reaction of a vast range of aryl halides under both conventional and microwave irradiation conditions and their results were compared. The complex was active and showed high efficiency in the formation of new C‐C bonds. The yields were excellent using a catalytic amount of [Pd(C₆H₄CH₂NH₂‐κ²‐C‐N)PPh₃MOBPPY]OTf complex in N, N‐dimethylformamide at 120 °C. In comparison to conventional heating conditions, the reactions under microwave irradiation gave higher yields in shorter reaction times. Copyright © 2011 John Wiley & Sons, Ltd.     

Accelerated Heck reaction using ortho‐palladated complex in a nonaqueous ionic liquid with controlled microwave heating

The activity of {Pd[C₆H₂(CH₂CH₂NH₂)‐(OMe)₂,3,4] (µ‐Br)}₂ complex was investigated in the Heck–Mizoroki C C cross‐coupling reaction under conventional heating and microwave irradiation conditions in molten salt tetrabutylammonium bromide as the solvent and promoter at 130 °C. This complex in these conditions is an active and efficient catalyst for the Heck reaction of aryl iodides, bromides and even chlorides, and also arenesulfonyl chlorides. Copyright © 2011 John Wiley & Sons, Ltd.     

P2O5/Al2O3 as an efficient heterogeneous catalyst for chemoselective synthesis of 1,1-diacetates under solvent-free conditions

An efficient and chemoselective method for the preparation of acylals from different aldehydes using P₂O₅/Al₂O₃ and acetic anhydride under solvent-free conditions.