Microstructures of the Sulfonic Acid-Functionalized Ionic Liquid/Sulfuric Acid and Their Interactions: A Perspective from the Isobutane Alkylation

Abstract

The all-atom force field for concentrated sulfuric acid (98.30 wt %) was developed in this work based on ab initio calculations. The structural and dynamical properties of sulfuric acid and the mixing behaviors of sulfuric acid with ionic liquids (ILs), i.e., SFIL (1-methyl-3-(propyl-3-sulfonate) imidazolium bisulfate ([PSMim][HSO])) and non-SFIL (1-methyl-3-propyl imidazolium bisulfate ([PMim][HSO])), were investigated using a molecular dynamics simulation. For sulfuric acid, most HO ions were found beside HSO ions, forming a contact ion pair with the HSO ions, and three-dimensional hydrogen-bonding networks existed in the sulfuric acid. Analyses indicate that both ILs could be miscible with sulfuric acid with a strong exothermic character. The new strong interaction site between the sulfonic acid group of SFIL and an HSO molecule through a strong hydrogen-bonding interaction was observed, which was beneficial to the catalytic activity and stability of the sulfuric acid. This observation is in good agreement with the experimental results that indicate SFILs could enhance the reusability of sulfuric acid for the isobutane alkylation about 4-fold compared to that of non-SFILs. Hopefully this work will provide insights into the screening and designing of new isobutane alkylation catalysts based on sulfuric acid and SFILs.

H2SO4‐catalyzed isobutane alkylation under low temperatures promoted by long‐alkyl‐chain surfactant additives

“…The long‐range electrostatic interactions were treated by the particle grid Ewald method. The all‐atom force field (OPLS‐AA) was used to treat the interaction between the surfactants (CTAB, DDAB, and SDBS), H 2 SO 4 and C4 hydrocarbons 22,23,30 . At the same time, the charges of the surfactants were refitted according to the ChelpG method at the Basis set of 6–311 + G(d,p) level using Gaussian 09 program 31…”

Ionic Liquid-Microwave-Based Extraction of Biflavonoids from Selaginella sinensis

“…Figure 2B illustrated that [C 6 mim]BF 4 had remarkable extraction efficiency towards the two targets among these five ILs. Considering the improvement of hydrophobic effect [21], the content of AME and HIN were obviously enhanced with increasing alkyl chain lengths. But when carbon chain lengths exceeded C-8, AME and HIN yields were clearly decreased in that the enhancement of stereo hindrance effect [22].…”

Synthesis of Functionalized Chiral Imidazole Derivatives Based on a Bornane Skeleton Bearing a Sterically Crowded Spirocyclic Substituent at the C-3 Position

“…In general, N -alkylimidazolium salts are prepared through the reaction of N -methylimidazole with an alkylating agent. 8,31,32 However, in our preliminary attempt, reaction of 4b with N -methylimidazole was sluggish to result in the formation of unpurifiable oily matter. Therefore, compounds 3a-b and 4a-b were subjected to the treatment with imidazole in place of N -methylimidazole to isolate 10-imidazolylbornane-2-thiones 6 as neutral form for the convenience of isolation and characterization of the further reaction products.…”