Hydroxyl-Exchanged Nanoporous Ionic Copolymer toward Low-Temperature Cycloaddition of Atmospheric Carbon Dioxide into Carbonates

Abstract

An ionic copolymer catalyst with nanopores, large surface area, high ionic density, and superior basicity was prepared via the radical copolymerization of amino-functionalized ionic liquid bromide and divinylbenzene, followed with a hydroxyl exchange for removing bromonium. Evaluated in chemical fixation of CO2 with epoxides into cyclic carbonates in the absence of any solvent and basic additive, the nanoporous copolymer catalyst showed high and stable activity, superior to various control catalysts including the halogen-containing analogue. Further, high yields were obtained over a wide scope of substrates including aliphatic long carbon-chain alkyl epoxides and internal epoxide, even under atmospheric pressure and less than 100 °C for the majority of the substrates. On the basis of in situ Fourier transform infrared (FT-IR) investigation and density functional theory (DFT) calculation for the reaction intermediates, we proposed a possible reaction mechanism accounting for the superior catalytic activity of the ionic copolymer. The specifically prepared ionic copolymer material of this work features highly stable, noncorrosive, and sustainable catalysis and, thus, may be a new possibility for efficient chemical fixation of CO2 since it is an environmentally friendly, metal-free solid catalyst.

Metallosalen‐Based Ionic Porous Polymers as Bifunctional Catalysts for the Conversion of CO2 into Valuable Chemicals

“…First, comparative studies of IR spectra between DVB@ISA, poly(DVB), 1-butyl-3-methylimidazolium bromide ([BMIm]Br), and ISZ were conducted to understand the structure of the ionic POPs as shown in Figure 1A.T he two characteristic bands at 1632 and 660 cm À1 might be assigned to the imidazolium IL units in the framework of POPs owing to the deficiency of adsorption peaks in poly(DVB), [3] and the peaks at 1227 and 1147 cm À1 reveal the presence of CÀNa nd CÀO bonds within the salen ligand of both DVB@ISAa nd DVB@ISZ, respectively,b ecause similar vibration bands wereo bserved in the simple ISZ catalyst. [18] Thus,t he results suggest that the synthesized POPs featured the coexistence of metal center and imidazolium moietiesw ithin their skeleton.…”

“…On the other hand, the solid-state 13 CNMR spectrum of DVB@ISA exhibited an ew weak signal at around 162 ppm assignedt ot he C2 atom of the imidazolium ring with the nearbyb romide anion compared to that of poly(DVB). [3] Thermogravimetric analysis (TGA) of DVB@ISA in air flow revealed its excellent thermals tability up to 260 8C( Figure 1C), which was crucial for the catalytic application in CO 2 -involved organic reactions, especially under harsh conditions. These ionic metallosalen copolymer frameworks might also possess plenty of imidazolium-basedI Lm oieties ( Figure 1B).…”

“…[1] Although homogeneous catalytic systems often exhibit high activity under mild conditions in CO 2 -involvedr eactions, an umber of heterogeneous catalysts such as metal oxides, [2] traditional immobilized materials, [3] metal-organic frameworks (MOFs), [4] covalent organic frameworks (COFs), [5] and porous organic polymers (POPs) [6] have been employedt oa chieve the catalytic cycles owing to the facile separation of the solid catalyst.A mong these, POPs have revealed promising applicabilityb ecause of their much improvedc hemical/mechanical stabilityc ompared to MOFs. [1] Although homogeneous catalytic systems often exhibit high activity under mild conditions in CO 2 -involvedr eactions, an umber of heterogeneous catalysts such as metal oxides, [2] traditional immobilized materials, [3] metal-organic frameworks (MOFs), [4] covalent organic frameworks (COFs), [5] and porous organic polymers (POPs) [6] have been employedt oa chieve the catalytic cycles owing to the facile separation of the solid catalyst.A mong these, POPs have revealed promising applicabilityb ecause of their much improvedc hemical/mechanical stabilityc ompared to MOFs.…”

Porous Polyelectrolytes: The Interplay of Charge and Pores for New Functionalities

“…prepared porous PIL complexes in which the porous network was first loaded with as high as 13 wt % copper ions and next used as a composite catalyst for the highly efficient aerobic oxidation of hydrocarbons under mild conditions 68a. Zhou and co‐workers synthesized a high surface area porous PIL network with high ion density and basicity for the cycloaddition of CO 2 and epoxides 104. The groups of Wang,69c Xiao,69e and Bordiga69b copolymerized several IL monomers with divinylbenzene to prepare mesoporous PILs that function as a solid–liquid heterophase catalyst.…”

Sustainable Cyclic Carbonate Production, Utilizing Carbon Dioxide and Azolate Ionic Liquids

“…[36][37][38][39][40][41][42] Some key processes, to date, using homogenous ionic liquid systems are summarised in Table 1. It is noteworthy, that there have also been a number of solid-supported ionic liquid systems [41][42][43][44][45][46] employed for producing cyclic carbonates. Though they produce high yields of products, these systems also contain undesirable halides and/or metals.…”