1-Ethyl-3-methylimidazolium halogenoaluminate melts as reaction media for the Friedel–Crafts acylation of ferrocene

Abstract

Ionic liquid mediated Friedel-Crafts acylation of the organometallic complex ferrocene can be performed in l-ethyl-3-methylimidazolium halogenoaluminate melts, Et-MeimI-A1C13, as well as in the liquid clathrate formed upon addition of an excess of toluene to EtMeimI-A1Cl3 affording solely the monoacylated product acetylcyclopentadienyl (cyclo-pentadienyl)iron(II) in good to excellent yields under the appropriate conditions.Use of low-melting ionic liquids composed of an organic chloride and aluminium chloride as solvent and catalyst for Friedel-Crafts reactions at ambient temperatures was first reported in 1976.1 Other electrophilic substitution reactions have been performed in chloroaluminate salts such as AlC13-NaCl and A1C13-NH4C1, but these reactions were generally performed at substantially elevated temperatures (i.e.

Ionic Liquids in Catalysis

“…Among the key applications of liquid-ionic liquid biphasic catalysis with acidic chloroaluminate ILs are Friedel-Crafts alkylation [26][27][28][29], Friedel-Crafts acylation [30][31][32] and carbonylation reactions [33][34][35]. Other important acid catalyzed reactions that have been successfully carried out in form of liquid-ionic liquid biphasic catalysis include oligomerization [36], cracking [37,38] and refinery alkylation reactions [39][40][41].…”

Polarity study of some 1-alkyl-3-methylimidazolium ambient-temperature ionic liquids with the solvatochromic dye, Nile Red

“…[9][10][11][12] These solvents, which have been the subject of a number of reviews, [13][14][15][16][17][18][19][20] have also received much popular attention. [21][22][23][24][25][26][27] To give a sense of the scope for these solvents, it is worth mentioning that recent studies have shown that ambient-temperature ionic liquids can be used as media for a wide range of chemical reactions, including hydrodimerization, 28 hydrogenation, [29][30][31][32][33][34] dimerization, 35 polymerization, 36 alkylation, 37 FriedelCrafts reactions, [38][39][40][41] Heck coupling, 42,43 the DielsAlder reaction [44][45][46] and enzymatic catalysis of biotransformations. 47 As part of a programme aimed at understanding more about the nature of these ambient-temperature ionic liquids, and how they compare with conventional solvents, we have undertaken a study of their polarity using the solvatochromic dye Nile Red (Fig.…”

Supramolecular Structures in the Presence of Ionic Liquids

“…However, when both dipole and quadrupole moments are present in an aromatic compound, they have an antagonistic effect, reducing the solubility in the IL (Shimizu et al, 2009). Up to now, such liquid clathrates or IL-biphases have been used in the fields of organic syntheses (Boxwell et al, 2002;Clavier et al, 2008;DeCastro et al, 2000;Surette et al, 1996), polymerization (Csihony et al, 2002), separations of aromatics from hydrocarbons (Arce et al, 2007;Selvan et al, 2000) and so on. Holbrey et al obtained crystalline [C 1 mim][PF 6 ]·0.5C 6 H 6 by cooling the lower phase of the [C 1 mim][PF 6 ]−C 6 H 6 system to room temperature.…”