Composite Ionic Liquids Immobilized on MCM-22 as Efficient Catalysts for the Cycloaddition Reaction with CO2 and Propylene Oxide

Preparation of biacidic tin-based ionic liquid catalysts and their application in catalyzing coupling reaction between ethylene carbonate and dimethyl succinate to synthesize poly(ethylene succinate)

A new low-carbon and environmentally friendly process method for the catalytic synthesis of biodegradable polyester by utilizing ionic liquid catalysts.

Preparation and catalytic property of composite ionic liquid immobilized on SBA-15

In this work, we report a more simple and efficient way to synthesize a composite ionic liquid (IL) ([BMIM][Zn2Br5]) by directly coupling the IL with molecular sieves. Two kinds of immobilized catalysts were successfully synthesized: SBA-15-[BMIM][Zn2Br5] and SBA-15-CPTES-[BMIM][Zn2Br5]. The catalysts were used to catalyze the cycloaddition reaction of continuous transformation of CO2 and propylene oxide, and the catalytic performance of catalysts was further studied. Compared with the traditional IL catalysts, the catalysts not only have excellent catalytic performance, but also have a significantly longer service life. This is because the catalysts are formed by a high energy chemical bond of silane between IL catalysts and molecular sieves, which can effectively solve the problem of the loss of IL active components in the catalytic process.

Immobilizing Polyether Imidazole Ionic Liquids on ZSM-5 Zeolite for the Catalytic Synthesis of Propylene Carbonate from Carbon Dioxide

Traditional ionic liquids (ILs) catalysts suffer from the difficulty of product purification and can only be used in homogeneous catalytic systems. In this work, by reacting ILs with co-catalyst (ZnBr₂), we successfully converted three polyether imidazole ionic liquids (PIILs), i.e., HO-[Poly-epichlorohydrin-methimidazole]Cl (HO-[PECH-MIM]Cl), HOOC-[Poly-epichlorohydrin-methimidazole]Cl (HOOC-[PECH-MIM]Cl), and H₂N-[Poly-epichlorohydrin-methimidazole]Cl (H₂N-[PECH-MIM]Cl), to three composite PIIL materials, which were further immobilized on ZSM-5 zeolite by chemical bonding to result in three immobilized catalysts, namely ZSM-5-HO-[PECH-MIM]Cl/[ZnBr₂], ZSM-5-HOOC-[PECH-MIM]Cl/[ZnBr₂], and ZSM-5-H₂N-[PECH-MIM]Cl/[ZnBr₂]. Their structures, thermal stabilities, and morphologies were fully characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The amount of composite PIIL immobilized on ZSM-5 was determined by elemental analysis. Catalytic performance of the immobilized catalysts was evaluated through the catalytic synthesis of propylene carbonate (PC) from CO₂ and propylene oxide (PO). Influences of reaction temperature, time, and pressure on catalytic performance were investigated through the orthogonal test, and the effect of catalyst circulation was also studied. Under an optimal reaction condition (130 °C, 2.5 MPa, 0.75 h), the composite catalyst, ZSM-5-HOOC- [PECH-MIM]Cl/[ZnBr₂], exhibited the best catalytic activity with a conversion rate of 98.3% and selectivity of 97.4%. Significantly, the immobilized catalyst could still maintain high heterogeneous catalytic activity even after being reused for eight cycles.

Catalytic conversion of CO2 into propylene carbonate in a continuous fixed bed reactor by immobilized ionic liquids

In this study, functionalized composite catalysts, namely, ILs (ILX/(ZnBr₂)₂), with functional groups immobilized on a molecular sieve (MCM-22) support were synthesized with the help of a silane coupling agent, 3-chloropropyltriethoxysilane (CPTES).