We have developed direct asymmetric cross-aldol reactions that can be performed in water without addition of organic solvents. A bifunctional catalyst with a long hydrophobic alkyl chain efficiently catalyzed the reactions and afforded the desired aldol products in excellent yield with high enantiomeric excess, even when only an equal molar ratio of the donor and acceptor was used. These result...

ABSTRACT In order to improve efficiency, processability, and stability, two groups of novel poly(p-phenylene vinylene) (PPV) derivatives (P1-P3 and P4-P6) with hyperbranched structure and containing a nitro substituent were synthesized via a Gilch reaction in different monomer ratios. The properties of the polymers were investigated by using UV-Vis absorption, fluorescence spectroscopy, cyclic ...

Monte Carlo computer simulations are used to study transient cavities and the solvation of hard-spheroid solutes in dipolar hard-sphere solvents. The probability distribution of spheroidal cavities in the solvent is shown to be well described by a Gaussian function, and the variations of fit parameters with cavity elongation and solvent properties are analyzed. The excess chemical potentials of...

A low temperature, simple, surfactant-free and one pot solution chemistry route was employed to synthesize diverse Zinc sulfide (ZnS) nanostructured assemblies at 70 °C by varying the solvent (water or ethylene glycol, or their mixture in the ratio of 1:1). In 1:1 water-EG solvent ratio, ZnS nanoflowers morphology was obtained. Morphology, structure, and composition of the obtained products wer...

objective(s) the aim of this study was to formulate and evaluate microencapsulated controlled release preparations of theophylline using ethylcellulose as the retardant material with high entrapment efficiency. materials and methods microspheres were prepared by water-in-oil-in-oil (w/o1/o2) emulsion-solvent diffusion (esd). a mixed solvent system consisting of acetonitrile and dichloromethane ...

A vapor generator for multicomponent organic solvents was developed and its performance was investigated experimentally. The vapors were generated from the surface of a sintered sphere of glass beads containing the organic solvents. The solvents were automatically supplied from the solvent reservoir to the sphere by suction pressure caused by the evaporation of the solvents and the generated va...

The use of mixed selective solvents provides an effective means to control self-assembly of the all-conjugated diblock copolymer poly(3-butylthiophene)-b-poly(3-hexylthiophene) (P3BHT) into nanostructured morphologies. The solvent and temperature effects on the self-assembly of P3BHT during cooling and subsequent crystallization were explored for the first time. Depending on the poor/good solve...

Crude topiramate was prepared from the reaction between diacetonefructopyranose, sulfuric diamide, and 2-picoline. During a controlled processing the presence of Triton-X-100, crude topiramate in a methanol-water solvent, was converted to pure micron size topiramate particles. The factors affecting the purification and micronization of topiramate, such as solvent and anti-solvent type and conce...

a series of ethylene-propylene-2-ethylidenebicyclo [2.2.1] hept.5-ene terpolymers (epdm) have been prepared using a vocl3/al2et3cl3 catalyst under various al/v ratios and diene concentrations via solution polymerization and characterized by ftir, mooney viscosity (ml1+4,125oc), and thermal gravimetery analyzing. the polymerization yield was seen to increase with augmentation of the al/v ratio a...

We investigated solvent induced transition of surface instability from wrinkles to creases in poly(2-hydroxyethyl methacrylate) (PHEMA) gels with depth-wise crosslinking gradients. The mode of surface instability and morphology of surface patterns was found to be dependent on the equilibrium linear expansion, which was a function of crosslinker concentration and the solvent–polymer interaction....