New Adsorption Materials for Deep Desulfurization of Fuel Oil

In recent years, due to the rapid growth of mankind's demand for energy, harmful gases (SOx) produced by the combustion of sulfur-containing compounds in fuel oil have caused serious problems to the ecological environment and human health. Therefore, in order to solve this hidden danger from the source, countries around the world have created increasingly strict standards for the sulfur content in fuel. Adsorption desulfurization technology has attracted wide attention due to its advantages of energy saving and low operating cost. This paper reviewed the latest research progress on various porous adsorption materials. The future challenges and research directions of adsorption materials to meet the needs of clean fuels are proposed.

Structural and electronic properties of CuII, CoII, and NiII-containing chelate-based ionic liquids

Potential applications of chelate-based ionic liquids depend on the structural and electronic properties of this class of liquid materials. Due to the large size of chelated metal anions, the high number of potential interaction sites could lead to complex intermolecular interactions, but metal-based anions have many degrees of freedom, and they have great potential in the structural modification of the physical properties of ionic liquids. To explore the influence of varying the metal center of anions and the length of carbon chains of cationic species, four single crystal structures of chelate-based ionic liquids, ([C₁₀mim][M(F₆-acac)₃], M = Cu, Co, and Ni) and [C₆mim][Cu(F₆-acac)₃] were obtained. Taking these as the initial configurations, theoretical efforts were made to understand the structural and electronic properties. The hydrogen bonding energies of the primary hydrogen bonding interaction, in the range of 17.7-20.9 kJ mol^-1, follow the order of [C₁₀mim][Ni(F₆-acac)₃] < [C₁₀mim][Co(F₆-acac)₃] <[C₁₀mim][Cu(F₆-acac)₃], and [C_nmim][Cu(F₆-acac)₃] (n≠ 10) < [C₁₀mim][Cu(F₆-acac)₃], while the experimental viscosities exhibit an opposite trend. Furthermore, by NBO analysis, the more negative charge on the oxygen atoms of anions shows the stronger hydrogen bonding of imidazolium with C²H. The reliability of the theoretical method was supported by the comparison between the simulated and experimental infrared and UV/vis spectra. This work is useful in increasing the understanding of the structure-property relationship of chelate-based ionic liquids and furthering the rational design of novel ionic liquids.

A new and recyclable system based on tropin ionic liquids for resolution of several racemic amino acids

A new, recyclable solid-liquid resolution system was developed based on tropin ionic liquids [C_nDTr][L-Pro]₂ for the enantiomeric resolution of racemic phenylalanine and other α-substituted carboxylic acids including tryptophan, tyrosine, benzene glycine and mandelic acid. With racemic phenylalanine as resolution model, effect factors were investigated for better resolution conditions. On the conditions, some efficient resolution were achieved, for instance the e.e. (98%) and product yield (76%) in solid phase for phenylalanine, and the e.e. 99.71% in solid phase for tryptophan. Chiral product was verified with fourier transform infrared spectroscopy (FT-IR), Raman spectrum, thermal gravity analysis (TG), elemental analysis (EA) and chiral HPLC. Further, the resolution mechanism was studied with computer molecular dynamic simulations and UV-vis. The resolution was closely related to the formation of complexes (L-Phe-Cu(Ⅱ)-L-pro^-) and the spatial configuration of D/L-Phe. The system is characteristic of high resolution, no organic solvent, easy isolation of solid-liquid and recycle of all chemical materials as much as possible.

Structures and Electronic Properties of Lithium Chelate-Based Ionic Liquids

The conformations, electronic properties, and interaction energies of four chelate-based ionic liquids [Li(EA)][Tf2N], [Li(HDA)][Tf2N], [Li(DEA)][Tf2N], and [Li(DOBA)][Tf2N] have been theoretically explored. The reliability of the located conformers has been confirmed via the comparison between the simulated and experimental infrared spectra. Our results show that the N-Li and O-Li coordinate bonds in cation are elongated as the numbers of coordinate heteroatoms of alkanolamine ligands to Li(+) increased. Also the binding energies between Li(+) and ligands are increased and the interaction energies between cations and Tf2N anion are decreased. The cation-anion interaction energies follow the order of [Li(DOBA)][Tf2N] < [Li(HDA)][Tf2N] < [Li(DEA)][Tf2N] < [Li(EA)][Tf2N], which fall within the energetic ranges of conventional ionic liquids. Interestingly, the strongest stabilization orbital interactions in these ionic liquids and their cations revealed by the natural bond orbital analysis lie in the interaction between the lone pair (LP) of the coordinate heteroatoms in ligands or anion as donors and the vacant valence shell nonbonding orbital (LP*) of Li(+) as acceptors, which are very different from that of conventional ionic liquids. Moreover, the charges transferred from cations to anion are quite similar, and the charge of Li(+) is proposed for possibly predicting the order of the interaction energies of ionic liquids in series. The present study allows for the deeper understanding the differences between chelate-based ionic liquids and conventional ionic liquids.

Fabrication of dual-mesoporous silica by triblock copolymers and metal-based ionic liquid: efficient and durable catalyst for oxidative desulfurization in fuel

The D-MoO₃–SiO₂ material with two uniform sets of mesopores exhibited a very high efficiency and excellent stability in the oxidative desulfurization of model oil.

Hydrophobic mesoporous silica-supported heteropolyacid induced by ionic liquid as a high efficiency catalyst for the oxidative desulfurization of fuel

The hydrophobic HPMo-IL/SBA-15 material served not only as a high-efficiency catalyst but also as an adsorbent.