Haixiang Gao

Microemulsions with ionic liquid polar domains

In this work 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4], an ionic liquid)/Triton X-100 (TX-100)/cyclohexane microemulsions have been prepared and characterized by phase behavior, conductivity measurement, dynamic light scattering, freeze-fracturing electron microscopy, and UV-vis techniques, and our attention is concentrated on the microemulsions with the ionic liquid as the nano-sized polar domains.

Mannich reaction using acidic ionic liquids as catalysts and solvents

Several Bronsted acidic ionic liquids were synthesized and successfully used as solvents and catalysts of three-component Mannich reactions of aldehdyes, amines, and ketones at 25 °C. The used Bronsted acidic ionic liquids include l-butyl-3-methylimidazolium hydrogen sulfate ([Bmim]+[HSO4]−), l-butyl-3-methylimidazolium dihydrogen phosphate ([Bmim]+[H2PO4]−), 1-methylimidazolium p-toluenesulfonic acid ([Hmim]+Tsa−) and 1-methylimidazolium trifluoroacetic acid ([Hmim]+Tfa−). Higher yields were obtained in the presence of [Hmim]+Tfa− in comparison with other Bronsted acidic ionic liquids. The [Hmim]+Tfa− was reused four times without considerable loss of activity.

Hydrogenation of olefins using ligand-stabilized palladium nanoparticles in an ionic liquid

Phenanthroline (Phen) ligand-protected palladium nanoparticles in ionic liquid (IL) 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) are very active and selective for the hydrogenation of olefins, and the nanoparticles/IL system can be reused many times without reducing the activity.

A study of tri-phasic behavior of ionic liquid–methanol–CO2 systems at elevated pressures

The phase behavior of CO2–methanol–1-n-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6]) system under different conditions has been studied by a static method. The results demonstrate that at 40.0u2006°C there can exist three phases (IL-rich phase, the methanol-rich phase, CO2-rich phase) in the pressure range from 6.95 to 8.21 MPa when the concentration of the IL is low. In the high IL concentration region, however, there is only one liquid phase in the entire pressure range. In the three-phase region, the difference of the concentrations of the IL in the two liquid phases becomes larger and larger with increasing pressure. The results also show that the three-phase region exists only in the temperature range from 35 to 44.5u2006°C at 7.6 MPa. In the three-phase region IL concentration in the IL-rich phase decreases with increasing temperature, while that in the methanol-rich phase increases as temperature rises, and the difference of IL concentration in the two liquid phases is sensitive to temperature. On the basis of phase equilibrium data the distribution coefficients of [bmim][PF6] in the two liquid phases are calculated and discussed.

Synthesis and characterization of polyether structure carbon nitride

Carbon nitride powder with an atomic N/C ratio of 1 has been prepared by reaction of cyanuric chloride with sodium metal. X-ray diffraction, Fourier transform infrared spectra, and x-ray photoelectron spectroscopic data provide substantial evidence for a graphite-like sp 2 -bonded structure composed of building blocks of s-triazine rings bridged by carbon-carbon atoms in the bulk carbon nitride. The electron-microscopy results reveal that the material is spherical particles with an average diameter of 50 nm. The optical properties and thermal stability are also characterized. Based on the experimental results, it is deduced that the structure of as-prepared material carbon nitride has polyether structure.

A simple route to micropatterned polymer surfaces

Polymer surfaces with uniform microscale concave arrays were fabricated by spreading polymer solution on the nonsolvent surface, and the concave-patterned surface could further be used as a template to structure convex-patterned polymer surfaces.