Preparation of catalytic deep eutectic solvent-based silica microreactors using a non-aqueous sol-gel routeElectronic supplementary information (ESI) available: SEM images, FIB images, EDS, Mastersizer, BET, FTIR, TGA, 13C and 29Si CP-MAS NMR of the microencapsulated compounds. SEM images of systems prepared in different solvents, acids, and percentages of ABIL EM 90. TGA curves of CHCl:TA, CHCl:TSA, CHCl:U, CHCl:LA. The results of the recycling of the CHCl:TA@SiO2 in the condensation of p-anisi

• Main Authors: Batarseh, Charlie, Levi-Zada, Anat, Abu-Reziq, Raed
• Format: Journal Article
• Published: 29.01.2019
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c8ta09021a

This study describes the microencapsulation of deep eutectic solvents (DESs) via a non-aqueous sol-gel technique. The microencapsulation was performed using oil in oil emulsions as templates for the interfacial polycondensation of silane monomers such as tetraethoxyorthosilicate and polydimethoxysiloxane. The non-aqueous polycondensation of the silane monomers was achieved using formic acid, which acted as both a catalyst and a reagent. The process also required the presence of cetyl polyethyleneglycol/polypropyleneglycol-10/1 dimethicone as an emulsifier to stabilize the emulsion droplets. The silica-enclosed compounds were separated by centrifugation and dried to provide powders that were much easier to handle compared to the original, highly viscous DES bulks. These microcapsules were then used as hosts for palladium nanoparticles and applied in the hydrogenation of different unsaturated compounds. In addition, microcapsules containing choline chloride: l -tartaric acid (1 : 0.5) were used as heterogeneous Brønsted acidic catalysts for the preparation of N -substituted pyrroles. In both cases, the capsules were recycled several times without significant decrease in conversion. This work demonstrates: (1) the efficiency of combining O/O emulsions and formic acid-mediated non-aqueous sol-gel as a technique for microencapsulation, and (2) the benefits of using microencapsulated DESs as heterogeneous catalysts. We report the non-aqueous preparation of silica-based deep eutectic solvent microreactors. The palladium containing materials were applied in hydrogenation reactions.