No abstract

The performance of adsorption desulfurization and stability of MOF-5@AC were improved, when MOF-5 was covered on the surface of AC.

Porous liquids are porous materials that have exhibited unique properties in various fields. Herein, we developed a method to synthesize the type I porous liquids via liquefaction of cyclodextrins by chemical modification. The cyclodextrin porous liquids were characterized by Fourier-transform infrared (FTIR) spectroscopy, NMR, matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS), circular dichroism (CD), and UV−vis spectroscopy. The measured ionic conductivity of the γ-cyclodextrin porous liquid was 500 times as great as that of its reactants, which was found to be the first instance with such great conductivity for a type I porous liquid. What is more, the γ-cyclodextrin porous liquid had been demonstrated experimentally to have outstanding chiral recognition ability toward pyrimidine nucleosides in water, which was further confirmed by computational simulations. Additionally, enantiomeric excess of the extracted nucleoside was achieved up to 84.81% by convenient extraction from the mixture of racemic nucleosides and γcyclodextrin porous liquid. The great features of the novel cyclodextrin porous liquids could bring opportunities in many fields, including the preparation of chiral separation materials, development of new drug screening mechanisms, and construction of chiral response materials.

Asphaltenes have a tendency toward aggregation, leading to a series of problems (e.g., coking) in the field of refining or other oil utilization and making the development of a disaggregation method an urgent need. We employed functional group methylation experiments combined with molecular dynamics simulations and quantum chemical calculations to reveal the disaggregation mechanism of asphaltenes based on the chemical alteration method. Here, the experimental results show that the intersheet distances in the asphaltene aggregate increase after the methylation reaction, and the asphaltene molecules are not prone to reaggregation after methylation, which was demonstrated by an increase in the critical aggregation concentration in toluene. These disaggregation effects can be explained by the theoretical study results; that is, they can be attributed to the reduction of the electrostatic interaction, which is derived from the disappearance of the hydrogen bonds after methylation. However, a thorough disaggregation cannot be achieved only by methylation because the van der Waals force is always the dominant force in both raw and methylated asphaltenes, outweighing the electrostatic force. Asphaltene molecules with very short side chains containing more than one terminal polar group could obtain a better disaggregation effect by the methylation reaction, whereas those with long chains could not. Our results provide the underlying insights for the proposal of an effective method for asphaltene disaggregation to prevent coking.