Alkylations of benzene in room temperature ionic liquids modified with HCl

Synthesis of pyranobenzopyrans from D-glucal using ionic liquids

Imidazolium room temperature ionic liquids (RTILs) were used as solvents in the Lewis acid-catalyzed cycloaddition reactions of D-glucal with substituted salicylaldehydes. These reactions selectively led to various, novel, cis-pyrano [4,3-b]benzopyrans in modest yields, different products than those isolated from analogous solution studies. Furan diol was isolated as the major byproduct from all the reactions. The use of RTILs facilitated the use of unprotected sugars in these reactions.

Direct Syntheses of Diphenylmethanol Derivatives from Substituted Benzenes and CHCl3 through Friedel-Crafts Alkylation and Post-Synthetic Hydrolysis or Alcoholysis Catalyzed by Alumina

The present study reports an innovative finding that alumina containing water or primary alcohol catalyzes the hydrolysis or alcoholysis, respectively, of the product formed through AlCl3 -mediated Friedel-Crafts alkylation of methyl-substituted benzenes and CHCl3 . The former and later reactions mainly provided hydroxy- and alkoxy-substituted diarylmethanes, respectively, while the reference reactions without alumina provided bisarylchloromethane. This method enables the selective syntheses of diphenylmethanol derivatives with very simple procedures, without expensive reagents and apparatuses. Furthermore, the alumina used in the reaction could be recycled by washing with water and subsequent drying. From the viewpoint of material recycling, this function is very important for the development of sustainable chemical reactions.

Silica-immobilized ionic liquid Brønsted acids as highly effective heterogeneous catalysts for the isomerization of n-heptane and n-octane

Metal-free imidazolium-based ionic liquid (IL) Brønsted acids 1-methyl imidazolium hydrogen sulphate [HMIM]HSO₄ and 1-methyl benzimidazolium hydrogen sulphate [HMBIM]HSO₄ were synthesized. Their physicochemical properties were investigated using spectroscopic and thermal techniques, including UV-Vis, FT-IR, ¹H NMR, ¹³C-NMR, mass spectrometry, and TGA. The ILs were immobilized on mesoporous silica gel and characterized by FT-IR spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller analysis, ammonia temperature-programmed desorption, and thermogravimetric analysis. [HMIM]HSO₄@silica and [HMBIM]HSO₄@silica have been successfully applied as promising replacements for conventional catalysts for alkane isomerization reactions at room temperature. Isomerization of n-heptane and n-octane was achieved with both catalysts. In addition to promoting the isomerization of n-heptane and n-octane (a quintessential reaction for petroleum refineries), these immobilized catalysts are non-hazardous and save energy.

Metal-free imidazolium-based ionic liquid (IL) Brønsted acids 1-methyl imidazolium hydrogen sulphate [HMIM]HSO₄ and 1-methyl benzimidazolium hydrogen sulphate [HMBIM]HSO₄ were synthesized.

Oxidative Carbonylation of Methanol to Dimethyl Carbonate in Ionic Liquid 1-Butyl-3-Methylimidazolium Hexafluorophosphate

The synthesis of dimethyl carbonate (DMC) by oxidative carbonylation of methanol with PdCl2 as a catalyst was investigated in the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]). The products were recovered in situ using supercritical carbon dioxide. Enhanced selectivity of DMC over this catalyst was observed in the synthesis in [bmim][PF6] compared with the situation without the ionic liquid (IL). The mixture of catalyst and [bmim][PF6] could be recycled.

Green synthesis of 1-phenyl-1-ortho-xylene ethane in IL and reaction mechanism

In this study, 1-phenyl-1-ortho-xylene ethane (PXE) is synthesized in IL and the catalysts used were AlCl₃ in 1-butyl-3-methylimidazolium bromide ([BMIM][Br]) or 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]).

Catalytic activity comparison of Zr–SBA-15 immobilized by a Brønsted–Lewis acidic ionic liquid in different esterifications

Zirconium-incorporated SBA-15 mesoporous molecular sieves (Zr–SBA-15) with different Si/Zr molar ratios were one-pot synthesized and characterized by XRD, TEM and N₂ physical adsorption.

Durability enhanced ionic liquid catalyst for Friedel–Crafts reaction between benzene and 1-dodecene: insight into catalyst deactivation

Friedel–Crafts alkylation of benzene with 1-dodecene, which is an important reaction of synthetic detergent, was studied using the durability enhanced catalyst [bmim][TFSI]/AlCl₃ (1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide/AlCl₃).

Recent development in functionalized ionic liquids as reaction media and promoters

The recent development in the use of functionalized ionic liquids as both reaction media and promoters is reviewed. Ionic liquids designed with special functionality can enhance the reaction rate, selectivity, and productivity in various chemical reactions. In this context, some important chemical reactions involving C–C, C–O, C–N, and C–S bond formation in functionalized ionic liquids are discussed. These functionalized ionic liquids were found to provide distinct advantages over conventional organic solvents in these catalytic reactions.