Cocatalyst‐Free Hybrid Ionic Liquid (IL)‐Based Porous Materials for Efficient Synthesis of Cyclic Carbonates through a Cooperative Activation Pathway

Abstract

Cocatalyst-free ionic liquid (IL)-based porous polymers (P -V -OH R) functionalized with an intermolecular hydroxyl group were prepared by means of radical copolymerization of 1-butyl-3-vinylimidazolium bromide, (4-vinylphenyl)methanol (VBzOH), and divinylbenzene (DVB) under solvothermal conditions. As the ratio of 4-vinylphenylmethanol in the initial mixture increased, the content of the hydroxyl groups in the polymer increased from 3.35 to 5.35 mmol g and the Brunauer-Emmett-Teller (BET) surface area of the polymer decreased sharply from 365 to 2.5 m g . In the carbonation of CO and epoxides, the turnover frequency (TOF) of P -V -OH R increased gradually from 25 to 67 h as the OH ratio increased irrespective of the sharp decrease in BET surface area, which suggests the existence of a cooperative activation effect between OH and ILs. To obtain a high OH content while still maintaining a high BET surface area, hybrid porous materials (SBA-[V OH ]R-n) were prepared by means of copolymerization of 1-ethyl-3-vinylimidazolium bromide and 4-vinylphenylmethanol in the mesopores of SBA-15. SBA-[V OH ]R-n was more active than its polymer counterpart (TOF: 188 versus 71 h ) in the cycloaddition of CO with propyl oxide owing to the combined effect of the high BET surface area and the high OH content. The hybridization of mesoporous materials with polymers represents an efficient strategy for the preparation of high-performance solid catalysts for chemical transformations.

Carbon Dioxide Conversion Upgraded by Host‐guest Cooperation between Nitrogen‐Rich Covalent Organic Framework and Imidazolium‐Based Ionic Polymer

“…As expected, 2‐phenyloxirane bearing large steric hindrance gave rise to the target product in low conversion of 66 % (entry 7a), while complete cycloaddition to cyclic carbonate was realized when reaction time was enhanced to 48 h (entry 7b). However, the use of the internal cyclohexene oxide gave 31 % GC yield in 48 h (entry 8a), its lower activity than those of terminal epoxides is consistent with previous reports [10a,20] . It is noteworthy that the reaction of diepoxide with CO 2 generated the target product in a 94 % GC yield after 48 h (entry 9a).…”

Cationic Zn-Porphyrin Immobilized in Mesoporous Silicas as Bifunctional Catalyst for CO2 Cycloaddition Reaction under Cocatalyst Free Conditions

“…The XRD pattern of all SBA-Zn-TPy + PBr – samples clearly shows a (100) diffraction peak, implying that all samples have an ordered mesostructure similar to SBA-15 (Figure S2). The fading of (110) and (200) diffraction peaks may be due to the occupation of the organic component in the mesopore, which decreases the contrast between the pore and the wall . The TEM image of representative SBA-Zn-TPy + PBr – DMF clearly shows the ordered arrangement of 2-D hexagonal mesopores, further confirming that SBA-Zn-TPy + PBr – has an ordered mesoporous structure.…”

Recent developments in organocatalysed transformations of epoxides and carbon dioxide into cyclic carbonates

“…In 2017, Yang et al developed ionic liquid-based hydroxyl-functionalised porous polymers 51 via the copolymerisation of three monomers (Scheme 27). 165 In polymers 51, the 1-alkyl-3-vinylimidazolium bromide provided the ionic liquid component, 4-vinylbenzyl alcohol provided hydroxyl groups and 1,4-divinylbenzene shaped the porous structure. By comparing different catalysts, it shown that the catalyst with the highest hydroxyl group content and largest BET surface area was the most active.…”