• Ionic Liquids
• Microcapsules
• Natural Ionic Liquids
• Pollen
• Sporopollenin
• Supported Ionic Liquids

ILs are a class of compounds with very interesting properties. In particular, their unique solvation properties allow them to act as liquid supports for inorganic, organic and organometallic catalysts, as well as to find application in several industrially relevant fields such as gas absorption, metals recovery, extraction of natural compounds, and solubilisation of biopolymers. However, due to the rather high cost of ILs, their recycling is fundamental for their use as solvents in industrial processes to be viable. The anchoring of ILs to a solid support may be an efficient solution to this issue. In fact, SILs retain some of the features of the parent unsupported solvent, while gaining some advantageous properties, such as easy recovery and purification.
Although a great variety of solid supports have been functionalised using ionic moieties, ILs-modified sporopollenins have been completely unexplored to date. In this work, we report for the first time the covalent binding of some ILs to the SECs extracted from the pollen of Populus deltoides. The extraction was carried out using a recently developed method involving the treatment of the pollen with an acidic IL. The ionic moieties attached to the sporopollenin were obtained from inexpensive natural products, i.e. terpenoid alcohols and amino acids. The novel IL-modified SECs were characterised by ATR-FTIR, TGA, elemental analysis, and solid-state NMR in order to elucidate their composition and confirm the effectiveness of the immobilisation procedure. Due to the complexity and limited understanding of the chemical structure of sporopollenin, several preliminary experiments were conducted using silica as a model solid support. One chosen IL were supported onto silica surface following different synthetic paths in order to assess advantages and disadvantages for each method, and select the best one to use in the functionalisation of sporopollenin.