Poly(4-vinylpyridine)-Supported Dual Acidic Ionic Liquid: A Novel Heterogeneous Catalyst for the Synthesis of β-Acetamido Ketones

Recent Advances in Applications of Supported Ionic Liquids

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The supported ionic liquids have shown immense potential for numerous applications in catalysis and separation science. In the present review, the remarkable contribution of supported ionic liquids has been highlighted. The main emphasis has been laid on describing the facile separation of gas from binary gas mixtures owing to the capability of selective transport of permeable gases across supported membranes and removal of environmentally hazard sulfur compounds from fuels. The catalytic action of supported ionic liquids has been discussed in other applications such as biodiesel (biofuel) synthesis by transesterification/esterification processes, waste CO2 fixation into advantageous cyclic carbonates, and various chemical transformations in organic green synthesis. This review enclosed a maximum of the published data of the last ten years and also recently accomplished work concerning applications in various research areas like separation sciences, chemical transformations in organic green synthesis, biofuel synthesis, waste CO2 fixation, and purification of fuels by desulfurization.

Synthesis of organophosphorus compounds using ionic liquids

Organophosphorus chemistry was developed in the last decade by promoting the synthesis reactions using ionic liquids either as solvent or catalyst. Ionic liquids (ILs), the so-called “green solvents”, have gained interest in the synthesis of organophosphorus compounds as alternatives to flammable and toxic organic solvents and catalysts. ILs have beneficial properties because they provide high solubility for many organic and inorganic compounds or metal complexes, have no vapor pressure, and are reusable. Also, in some cases, they can enhance the reactivity of chemical reagents. In this review, we aimed at showing the synthesis of different organophosphorus compounds under green and mild conditions using ILs as reaction media or catalysts, according to a trend developed in the last years. A novel trend is to perform these syntheses under microwave irradiation conditions together with ILs as solvents and catalysts.

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.