Preparation and Catalytic Property of Composite Ionic Liquid Immobilized on SBA-15

In this work, we report a more simple and efficient way to the synthesis of composite ionic liquid (IL) ([BMIM][Zn2Br5]) by directly coupling IL with molecular sieves. Two kinds of immobilized catalysts were successfully synthesized: SBA-15-[BMIM][Zn2Br5] and SBA-15-CPTES-[BMIM][Zn2Br5], respectively. The catalysts were used to catalyze the cycloaddition reaction of continuous transformation of CO2 and propylene oxide (PO) 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 better catalytic performance and significantly longer service life. The reason is that the catalysts are formed by high energy chemical bond of silane between IL catalysts and molecular sieves, which can effectively solve the problem of loss of IL active components in the catalytic process.

Sol–Gel Entrapped Lewis Acids as Catalysts for Biodiesel Production

Replacing fossil fuels with biodiesel enables the emission of greenhouse gases to be decreased and reduces dependence on fossil fuels in countries with poor natural resources. Biodiesel can be produced by an esterification reaction between free fatty acids (FFAs) and methanol or by transesterification of triglycerides from oils. Both reactions require homogeneous or heterogeneous catalysis. Production of biodiesel catalyzed by heterogeneous catalysts seems to be the preferred route, enabling easy product separation. As we have previously shown, the Lewis acids AlCl3 and BF3 can serve as highly efficient catalysts under ultrasonic activation. The present study focused on the development of oleic acid (OA) esterification with methanol by the same catalysts immobilized in silica matrices using the sol–gel synthesis route. During the course of immobilization, AlCl3 converts to AlCl3 × 6H2O (aluminite) and BF3 is hydrolyzed with the production of B2O3. The immobilized catalysts can be reused or involved in a continuous process. The possibility of biodiesel production using immobilized catalysts under ultrasonic activation is shown for the conversion of FFAs into biodiesel in batch and continuous mode.

Selective Reduction of Carbonyl Compounds via (Asymmetric) Transfer Hydrogenation on Heterogeneous Catalysts

Based on the ever-increasing demand for optically pure compounds, the development of efficient methods to produce such products is very important. Homogeneous asymmetric catalysis occupies a prominent position in the ranking of chemical transformations, with transition metals coordinated to chiral ligands being applied extensively for this purpose. However, heterogeneous catalysts have the ability to further extend the field of asymmetric transformations, because of their beneficial properties such as high stability, ease of separation and regeneration, and the possibility to apply them in continuous processes. The main challenge is to find potential synthetic routes that can provide a chemically and thermally stable heterogeneous catalyst having the necessary chiral information, whilst keeping the catalytic activity and enantioselectivity equally high (or even higher) than the corresponding homogeneous counterpart. Within this short review, the most relevant immobilization modes and preparative strategies depending on the support material used are summarized. From the reaction scope viewpoint, metal catalysts supported on the various solid materials studied in (asymmetric) transfer hydrogenation of carbonyl compounds are selected and represent the main focus of the second part of this overview.1 Introduction2 Synthesis of Chiral Heterogeneous Catalysts2.1 Immobilization of Homogeneous Asymmetric Catalysts2.1.1 Immobilization on Inorganic Supports2.1.2 Immobilization on Organic Polymers as Supports2.1.3 Immobilization on Dendrimer-Type Materials as Supports2.1.4 Self-Supported Chiral Catalysts: Coordination Polymers2.1.5 Immobilization Using Non-Conventional Media2.2 Chirally Modified Metal Surfaces for Heterogeneous Asymmetric Catalysis3 Examples of Transfer Hydrogenation on Heterogeneous Catalysts3.1 Silicon-Immobilized Catalysts3.2 Carbon-Material-Immobilized Catalysts3.3 Polymer-Immobilized Catalysts3.4 Magnetic-Nanoparticle-Immobilized Catalysts4 Conclusions

Liver-on-a-Chip‒Magnetic Nanoparticle Bound Synthetic Metalloporphyrin-Catalyzed Biomimetic Oxidation of a Drug in a Magnechip Reactor

Biomimetic oxidation of drugs catalyzed by metalloporphyrins can be a novel and promising way for the effective and sustainable synthesis of drug metabolites. The immobilization of 5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)iron(II) porphyrin (FeTPFP) and 5,10,15,20-tetrakis-(4-sulfonatophenyl)iron(II) porphyrin (FeTSPP) via stable covalent or rapid ionic binding on aminopropyl-functionalized magnetic nanoparticles (MNPs-NH2) were developed. These immobilized catalysts could be efficiently applied for the synthesis of new pharmaceutically active derivatives and liver related phase I oxidative major metabolite of an antiarrhythmic drug, amiodarone integrated in a continuous-flow magnetic chip reactor (Magnechip).

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.