Green syntheses of levulinate esters using ionic liquid 1-Methyl imidazolium hydrogen sulphate [MIM][HSO4] in solvent free system

Production of levulinic acid and alkyl levulinates: a process insight

“…[69][70][71] Mineral acids, such as H2SO4, H3PO4, HCl, and p-toluene sulphonic acid (PTSA), 72 were strongly employed in the esterification for their high yields (>95 %) 73 , fast reaction rates, and low cost, but their downstream drawbacks made it mandatory their replacement, even though there were some efforts to develop acid more sustainable as the bio-glycerol derived carbon sulfonic-acid. 74 Up to now, various heterogeneous catalysts, such as zeolites, 75-77 heteropolyacids, 78,79 acid ion exchange resins, 71,80,81 nanostructured solid acid, 82 sulfonic acid-functionalized organic polymer, 83 silica based, [84][85][86] metal oxide, zirconia based, 87 nano-material catalysts [88][89][90][91] , ionic liquids 92 and biocatalysts [93][94][95] have been efficiently used to produce alkyl levulinates from LA (Table 3). Zeolites are widely used as solid acid catalysts and ionexchangers in several processes thanks to the possibility of finetuning their properties.…”

“…One of the most active in the production of levulinates is the 1-Methylimidazolium hydrogen sulfate ([MIM][HSO4]) with yields in propyl levulinate and butyl levulinate of 91 % and 92 %, respectively. 92 Ionic liquids have a bifunctional role: solvent and catalyst, thanks to their thermal stability, non-volatility, non-flammability and high ionic conductivity. Principal drawbacks are related to their viscosity, separation, recyclability, corrosiveness and high cost.…”

“…Principal drawbacks are related to their viscosity, separation, recyclability, corrosiveness and high cost. 92,103 Besides the catalyst choice, the selection of the solvent has a significant role in favouring an easy dissolution, mass transfer diffusion, and final products recovery, respecting the "Safer Solvent and Auxiliaries" principle. Alcohols are generally used as reactants and solvents.…”

Magnetic Solid-Phase Extraction of Pyrethroid Pesticides from Environmental Water Samples Using Deep Eutectic Solvent-type Surfactant Modified Magnetic Zeolitic Imidazolate Framework-8

“…The adsorption bands at 432, 1418 and 811–1360 cm −1 can be attributed to the Zn–N stretching vibration, and the band at 891 cm −1 can be corresponded to the stretching vibration of C–N from imidazole ring. Compared to M-ZIF-8, the peak at 1145 cm −1 was ascribed to C–N stretch of DES, and the peak at 1456 cm −1 was ascribed to the asymmetric –CH3 stretch of DES [33,34]. The above-mentioned results indicated that the Fe 3 O 4 , ZIF-8 and DES were successfully retained in M-ZIF-8@DES composites.…”

N,N,N′,N′-Tetramethylethylene-diaminium-N,N′-disulfonic acid trifluoroacetate and pyridinium-N-sulfonic acid hydrogen sulfate as highly effective dual-functional catalysts for the preparation of N,N′-alkylidene bisamides

“…Ionic liquids (ILs) have attracted great attention for their use as attractive reaction media, reagents and catalysts in organic synthesis. The inimitable properties of ILs, which caused their wide applications in this field, include thermal and chemical stability, non-volatility, non-flammability, broad temperature range of the liquid state, aptitude to solve a wide range of compound classes, appropriate electrochemical window, catalyzation of various organic transformations and their capability to be functionalized for different purposes [1][2][3][4][5][6][7][8][9][10]. Among the ILs, Brønsted acids have been particularly found to be effective catalysts in several organic syntheses [4][5][6][7][8][9][10].…”