Hydroxy‐Functionalized Basic Ionic Liquids—An Unexpected “Hydroxy” Effect on the Transesterification of Glycerides with Methanol

Abstract

New task-specific ionic liquids, hydroxy-functionalized 1methyl-3-alkylimidazolium hydroxides, were used as catalysts in the transesterification of rapeseed oil with methanol. In comparison to the well-described 1-methyl-3-butylimidazolium hydroxide [bmim]OH, the new ionic liquids show unexpectedly high catalytic activity.I nc ase of the ionicl iquid [glymim]OH, which is structurally similart og lycerol, the conversiono fr apeseed oil was nearly 100 %.Applications of ionic liquids( ILs), due to their unique properties, are the subject of al arge number of studies. In comparison to acidic and neutral ionic liquids, which have been widely described in the literature, reports describing the synthesis and use of basic ionic liquids are relatively limited. [1][2][3] Popular imidazolium ionic liquidsc ontaining BF 4 or PF 6 anions are characterized by low stabilityi na lkaline reaction media. The first stable basic IL 2,3-dimethylimidazolium hydroxide[ dmim]OH was described by Seddon et al. [4] In 2005 Ranu et al. described the synthesis of the now well-known basic ionic liquid 1methyl-3-butylimidazolium hydroxide [bmim]OH. [5] Both of these ionic liquids have strong basic character and are active in base-catalyzed reactions, in particulari nM ichael and Knoevenagel condensations. [6][7][8][9] Recently an immobilized form of [bmim]OH was also described. [10] As supports, CoFe 2 O 4 and SiO 2 /CoFe 2 O 4 magnetic nanoparticles were used.The properties of ionic liquidsc an be modified by the introductiono fv ariousf unctional groups. Such ionic liquidsa re known as task-specific ionic liquids (TSIL) or third-generation ionic liquids. ILs called "functionalized ionic liquids" combines the classic features of ionic liquidsa nd the specific activity. TSILs also include hydroxy-functionalized ionic liquids containing free OH groups. "Hydroxy" imidazolium ionic liquids[ HOpmim]BF 4 and [HOpmim]PF 6 were first described Branco et al. [11] The populari onic liquids [Rmim]X have been supplemented with strong polar and solvation properties. This meanst hat in some applications the "hydroxy" ionic liquidsc an replace conventional alcohols.H olbrey et al. described the synthesis of 1methyl-3-hydroxypropylimidazolium ionic liquids through the reactiono fp ropylene oxide with N-methylimidazole. [12] Un- [a] Dr.

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

“…A recent example has reported that a methylimidazolium salt with an alkyl chain mimicking the glycerol structure, promotes the almost quantitative conversion of rapeseed oils into FAMEs products [45]. …”

Linking Diffusion–Viscosity Decoupling and Jump Dynamics in a Hydroxyl‐Functionalized Ionic Liquid: Realization of Microheterogeneous Nature of the Medium

“…[1] Functionalized and task-specific ILs are interesting as they are capable of performingaparticulara pplication. [2][3][4][5][6][7] Moreover,t he hydroxyl groups in the IL also make them useful for solubilizing inorganic salts, [2,8] synthesizingo rganic [9][10][11] and inorganic materials, [12] enzyme activity, [13,14] and so forth. [2][3][4][5][6][7] Moreover,t he hydroxyl groups in the IL also make them useful for solubilizing inorganic salts, [2,8] synthesizingo rganic [9][10][11] and inorganic materials, [12] enzyme activity, [13,14] and so forth.…”

“…[2][3][4][5][6][7] Moreover,t he hydroxyl groups in the IL also make them useful for solubilizing inorganic salts, [2,8] synthesizingo rganic [9][10][11] and inorganic materials, [12] enzyme activity, [13,14] and so forth. [9][10][11][12][13][14] Fewer studies are aimed at understanding the physical chemistry of these media. [14,15] Many of the above-mentioned studies are directed towards the use of hydroxyl ILs as media for the synthesis of organic and inorganic materials.…”

“…[14,15] Many of the above-mentioned studies are directed towards the use of hydroxyl ILs as media for the synthesis of organic and inorganic materials. [9][10][11][12][13][14] Fewer studies are aimed at understanding the physical chemistry of these media. Recently,D eng and co-workersi nvestigated the polarity of as eries of hydroxyl-functionalized ILs.…”

Synthesis of 2, 2, 4‐trimethyl‐1, 3‐pentaerediol monoisobutyrate catalyzed by homogeneous catalysis‐liquid/liquid separation catalytic system based on Bibasic sites Ionic Liquids

“…[11][12][13][14] Bibasic sites were confirmed by two endothermic peaks on the TG-DCS curve of [Aemim]IMC. [15][16][17] 2 | EXPERIMENTAL…”