Ionic Liquid/Quaternary Ammonium Salt Integrated Heterogeneous Catalytic System for the Efficient Coupling of Carbon Dioxide with Epoxides

Abstract

A heterogeneous catalytic system featuring multifunctional sites has been constructed through the grafting of an amino-functionalized imidazolium ionic liquid (Si-IM-NH 2 ) and a quaternary ammonium salt (Si-TBAI) on mesoporous cagelike silica SBA-16 for the coupling of carbon dioxide (CO 2 ) with epoxides. The resultant composites SBA-16@IM-NH 2 and SBA-16@TBAI, even with much lower Brunauer−Emmett−Teller surface areas than SBA-16, exhibit highly increased CO 2 adsorption capacities (i.e., up to 3.13 mmol•g −1 at 80 °C, 3.5 times that of SBA-16). Under the synergistic effect of the good CO 2 enrichment ability, multiple active sites (I − , Cl − , −NH 2 group, and imidazolium ring), and open mesoporous channels, the catalytic system with a Si-TBAI/ Si-IM-NH 2 molar ratio of 3:1 can catalyze CO 2 into several kinds of cyclic carbonates with excellent yield and selectivity at low temperature and pressure (50 °C and 0.5 MPa) in the absence of any cocatalyst. This catalytic system can be easily recovered and recycled several times without loss of activity, making it a competitive catalyst for CO 2 conversion.

Study of Ground State Interactions of Enantiopure Chiral Quaternary Ammonium Salts and Amides, Nitroalkanes, Nitroalkenes, Esters, Heterocycles, Ketones and Fluoroamides

“…Quaternary ammonium salts (Quats) are species widely used in synthesis and catalysis, [1–4] medicinal chemistry, [5] drug discovery [6] and material science [7] . Quats have found major applications in recently developed organocatalyses where they have been used for the enantioselective formation of C−C, C−O, C−N and C−X bonds [3,4] .…”

“…Quaternary ammonium salts (Quats) are species widely used in synthesis and catalysis,[ 1 , 2 , 3 , 4 ] medicinal chemistry, [5] drug discovery [6] and material science. [7] Quats have found major applications in recently developed organocatalyses where they have been used for the enantioselective formation of C−C, C−O, C−N and C−X bonds. [ 3 , 4 ] Enantioselective Phase‐Transfer Catalysis[ 3 , 4 ] (PTC) emerged as a notable technology within the organocatalytic domain and it has been used for the large‐scale preparation of bioactive compounds[ 8 , 9 ] and unnatural aminoacids.…”

Influence of Site Pairing in Hydrophobic Silica-Supported Sulfonic Acid Bifunctional Catalysts

“…43 The organic loadings were determined by thermogravimetric analysis (TGA) through measurement of the mass loss in the 150−900 °C range (Figure S1). 44,45 While the pristine silica showed minor weight loss (ca. 2%) in this temperature range, a weight loss of ca.…”

Metal Organic Frameworks as Heterogeneous Catalysts in Olefin Epoxidation and Carbon Dioxide Cycloaddition

“…The CO 2 fixation reaction catalysed by homogeneous or heterogeneous catalysts has been extensively investigated, however some drawbacks remain. Differently from the homogeneous, heterogeneous catalysts (e.g., ionic liquid-supported solids [94][95][96], polymers [96,97], and porous organic frameworks [98]) have the advantages of easy separation and regeneration of the catalyst, but they often required rough conditions (high temperature, pressure, and time) due to a lack of accessible surface area for accelerating interactions of CO 2 and reagents with active sites. Therefore, the high surface area, tunability, and CO 2 sorption capacity of MOFs can be beneficial for improving the efficiency of the CO 2 cycloaddition reaction.…”