Are ionic liquids and liquid coordination complexes really different? – Synthesis, characterization, and catalytic activity of AlCl₃/base catalysts

Abstract

Unique Lewis acid/base liquid coordination catalysts were compared to the known super acidic ionic liquid chloroaluminates and found to have higher catalytic activity in the alkylation of benzene.

Gradient Equivalent Feeding in the Acylation of 2,3-Dihydrobenzofuran Catalyzed by Chloroaluminate Ionic Liquids

“…The ILs [HN 222 ]­[Al 2 Cl 7 ] and [HN 222 ]­[AlCl 4 ] were prepared by following the reported procedures. , [HN 222 ]­[Al 2 Cl 7 ] and [HN 222 ]­[AlCl 4 ] were prepared by stirring solid [HN 222 ]Cl (30 mmol, 4.13 g) and solid anhydrous AlCl 3 (30 mmol (4.13 g) or 60 mmol (8.26 g) at a 1:1 or 1:2 ratio under an N 2 atmosphere. The preparation process is shown in Scheme .…”

Replacing HF or AlCl3 in the Acylation of Isobutylbenzene with Chloroaluminate Ionic Liquids

“…The ILs [HN 222 ]­[AlCl 4 ] and [HN 222 ]­[Al 2 Cl 7 ] and LCC AlCl 3 /O-NMPχ AlCl3 0.6 , were prepared by following the reported procedures. [HN 222 ]­[AlCl 4 ] and [HN 222 ]­[Al 2 Cl 7 ] were prepared by reacting solid [HN 222 ]Cl (20 mmol, 2.76 g) with solid anhydrous AlCl 3 (20 mmol (2.67 g) or 40 mmol (5.34 g)) at a 1:1 or 1:2 molar ratio under an Ar atmosphere, as reported previously .…”

“…Other alternative classes of catalysts which have received some attention in this regard are ionic liquids (ILs) − and liquid coordination compounds (LCCs). , ILs have attracted significant attention in the past few decades due to their favorable physicochemical properties, and they have been widely investigated in different research areas such as electrochemistry, organometallics, biological uses, analytical chemistry, polymers, and material synthesis, including as catalysts. ,,− Among the several types of ILs, chloroaluminate-based ILs exhibit unique chemistry due to their anionic speciation, resulting in distinctive properties (e.g., acidity, low melting point, viscosity) . Some chloroaluminate-based ILs show great potential as Lewis acids and have been evaluated as an industrial-scale replacement for HF in several catalytic processes such as alkylation of isobutane with butene and benzene with dodecene. ,, Recently, Chevron and Honeywell UOP announced the use of a proprietary Lewis acidic chloroaluminate IL catalyst in a new liquid phase alkylation technology known as ISOALKY …”

“…Usually, chloroaluminate-based ILs contain only anionic Al species (e.g., [AlCl 4 ] − , [Al 2 Cl 7 ] − ) with an inert cation (e.g., 1-butyl-3-methylimidazolium). , Recently, however, our group studied new chloroaluminate-based catalysts which contain both cationic as well as anionic Al species which formed in our investigation of LCCs . For example, when we studied the formation of LCCs formed by mixing AlCl 3 with N -methyl-2-pyrrolidone (O-NMP) in different stoichiometric amounts, we found at χ AlCl3 = 0.6, a mixture of anionic [Al 2 Cl 7 ] − and cationic [AlCl 2 (O-NMP) 2 ] + in equilibrium with neutral [AlCl 3 (O-NMP) n ] which was active in benzene alkylation.…”

Recyclable Magnetic Fe3O4 Nanoparticle-Supported Chloroaluminate Ionic Liquids for Heterogeneous Lewis Acid Catalysis

“…An advantage of the chloroaluminate ILs is that their Lewis acidity can be tuned simply by varying the mole ratio of the AlCl 3 . Due to the Al speciation and acidic properties, chloroaluminate ILs have emerged as an important Lewis acid catalyst that can be used to overcome shortcomings associated with use of conventional H 2 SO 4 /AlCl 3 /HF catalysts in many industrial important reactions. − Recently, Chevron and Honeywell UOP announced the commissioning and startup of the world’s first commercial-scale alkylation process to produce alkylate using proprietary chloroaluminate IL catalysts. , …”