A new “multiple-interaction model” for low-density lipoprotein (LDL) adsorption to a specific surface containing saccharide and alkanesulfonate ligands is proposed. The model suggests that there are interactions of the saccharide component beyond electrostatic interactions of the alkanesulfonate component that both influence the LDL adsorption process. This concept of multiple interactions between saccharide and LDL was inspired by the similarity in structures of LDL receptors (LDLR), heparin, and heparans used in LDL-apheresis. The model was confirmed by SPR analysis by the adsorption maxima on SAM surfaces with different compositions of saccharide and alkanesulfonate and additionally by CD detection of the conformation of LDL when in contact with saccharide.
Carbon nanostructures (carbon nanotubes, nano carbon spheres, layered carbon nanostructures) were prepared from a sodium dodecyl sulfonate @ sodium chloride system. Sodium dodecyl sulfonate was used as a carbon source. A sodium chloride crystal in the carbonization procedure was used to separate ordered aggregates of sodium dodecyl sulfonate. The results show that different carbon nanostructures were prepared at low concentrations (1CMC~5CMC) by controlling the concentration of sodium dodecyl sulfonate, such as nano carbon spheres and carbon nanotubes, and that layered carbon nanostructures were formed at high concentrations (10CMC). The prepared carbon nanostructures were characterized by transmission electron microscopy, fluorescence spectrometry and Raman spectrometry. The results of this experiment show that the surfactant @ salt system is a potential method for the preparation of carbon nanostructures.
Catalytic reaction of methylal (DMM) with trioxane (TOX) for preparation of polyoxymethylene dimethyl ethers (PODMEn, CH3O(CH2O)nCH3, where n > 1) was investigated in a series of Brønsted acid ionic liquids with alkanesulfonic acid groups. The structures, acidities, and properties of ionic liquids were experimentally characterized and theoretically analyzed. The Brønsted acidity–activity correlation for the ionic liquids was studied. Among all these ionic liquids, 1-(4-sulfonic acid) butylpyridinium hydrogen sulfate ([PY-BS][HSO4–]) exhibited the best catalytic performance, which was ascribed to its strong Brønsted acidity. The influences of ionic liquid dosage, molar ratio of DMM to TOX, and reaction temperature on the catalytic reaction were explored using [PY-BS][HSO4–] as the catalyst. Under the optimal conditions of n(methylal):n(trioxane):n(ILs) = 180:60:1, 170 °C, and 10h, the conversion of trioxane and the selectivity of PODME3–8 were as high as 91.18% and 70.90%, respectively. The ionic liquid [PY-BS][HSO4–] could be reused.
The interlamellar spacing of layered double hydroxides (LDHs) was enlarged by dodecyl sulfonate ions firstly, and then, (3-aminopropyl)triethoxysilane (APS) was chemically grafted (APS/LDHs). The structural characteristics and thermal stability of these prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), reflectance Fourier transform infrared spectrometer (FTIR), thermogravimetric analysis (TG), and elemental analysis (EA) respectively. The CO 2 adsorption performance was investigated adopting TG and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results presented that the CO 2 adsorption capacity on APS/LDHs was as high as 90 mg/g and showed no obvious reduction during a five cyclic adsorption-desorption test, indicating its superior performance stability. The DRIFTS results showed that both carbamates and weakly bounded CO 2 species were generated on APS/LDHs. The weakly adsorbed species was due to the different local chemical environment for CO 2 capture provided by the surface moieties of LDHs like free silanol and hydrogen bonds.
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