Facile one-pot synthesis of 5-amino-7-aryl-6-cyano-4H-pyrano[3,2-b]pyrroles using supported hydrogen sulfate ionic liquid

Silica-Based Supported Ionic Liquid-like Phases as Heterogeneous Catalysts

Supported ionic liquid phases offer several advantages related with catalysis. Immobilization of ionic liquid on the solid support provides catalytic activity or efficient matrix for active phases, as enzymes or metal compounds. Ionic liquid can be physically adsorbed on the carrier (supported ionic liquid phase) or chemically grafted to the material surface (supported ionic liquid-like phase). The use of supported ionic liquid phases improves mass transport, reduces ionic amount in the process and, most importantly, enables effortless catalyst separation and recycling. Moreover, chemical modification of the surface material with ionic liquid prevents its leaching, enhancing length of catalyst life. Silica-based materials have become an effective and powerful matrix for supported ionic liquid-like phase due to its cost-efficiency, presence of hydroxyl groups on the surface enabling its functionalization, and specific material properties, such as the size and shapes of the pores. For these reasons, supported ionic liquid-like phase silica-based materials are successfully used in the organic catalysis.

Preparation of imidazolium-type ionic liquids containing silsesquioxane frameworks and their thermal and ion-conductive properties

Imidazolium-type ionic liquids containing a random-structured (Im-Random-SQ-IL) and a cage-like (Im-Cage-SQ-IL) oligosilsesquioxanes were successfully prepared by hydrolytic condensation of MTICl in TFSI solutions in water and water/methanol solution, respectively.

The use of supported acidic ionic liquids in organic synthesis

Catalysts obtained by the immobilisation of acidic ionic liquids (ILs) on solid supports offer several advantages compared to the use of catalytically active ILs themselves. Immobilisation may result in an increase in the number of accessible active sites of the catalyst and a reduction of the amount of the IL required. The ionic liquid films on the carrier surfaces provide a homogeneous environment for catalytic reactions but the catalyst appears macroscopically as a dry solid, so it can simply be separated from the reaction mixture. As another advantage, it can easily be applied in a continuous fixed bed reactor. In the present review the main synthetic strategies towards the preparation of supported Lewis acidic and Brønsted acidic ILs are summarised. The most important characterisation methods and structural features of the supported ionic liquids are presented. Their efficiency in catalytic reactions is discussed with special emphasis on their recyclability.

Synthesis of a 3D-network polymer supported Bronsted acid ionic liquid based on calix[4]resorcinarene via two post-functionalization steps: a highly efficient and recyclable acid catalyst for the preparation of symmetrical bisamides

We report a straightforward route for the synthesis of a novel functional polymer bearing ionic liquid as an efficient and green acidic catalyst for the preparation of bisamides.