Chloroaluminate Ionic Liquids: from their Structural Properties to their Applications in Process Intensification

Abstract

Résumé -Les liquides ioniques Chloroaluminates : De leurs propriétés structurales à leurs applications pour l'intensification des procédés -Les propriétés structurales de nouveaux liquides ioniques organochloroaluminates, constitués à partir de mélanges de (Ethyl) n AlCl (3-n) (n = 1 à 3) avec du chlorure de 1-methyl-3-butyl-imidazolium (BMIC) ont été étudiées par spectrométrie Raman. À partir de cette technique, tous les anions mono et polynucléaires ont été identifiés et quantifiés. Les mélanges mixtes formés à partir d'AlCl 3 et EtAlCl 2 ou EtAlCl 2 et Et 2 AlCl, chaque couple étant à son tour mélangé avec du BMIC, ont aussi été considérés. Tous ces mélanges se comportent comme les chloroaluminates habituels : en particulier, leurs propriétés acide-base sont directement dépendantes de leurs compositions. Grâce à cette étude, il a été possible d'anticiper et d'optimiser la composition d'un liquide ionique basé sur de l'EtAlCl 2 , dans le but de l'utiliser pour l'oligomérisation industrielle des oléfines catalysées par les complexes du nickel, en milieux chloroaluminates. Les aspects fondamentaux de l'influence de la composition de ce solvant sur le mécanisme général de la réaction d'oligomérisation sont actuellement compris. Les liquides ioniques jouent un double rôle : ils sont à la fois solvants et activateurs du nickel (ou co-catalyseur). (3-n) ( (or co-catalyst). Abstract -Chloroaluminate Ionic Liquids: from their Structural Properties to their Applications in Process Intensification -The structural properties of new organochloroaluminate ionic liquids based on mixtures of (Ethyl) n AlCl

Aluminium Speciation in 1‐Butyl‐1‐Methylpyrrolidinium Bis(trifluoromethylsulfonyl)amide/AlCl3 Mixtures

“…According to the spectra of the C 4 mpyrCl/AlCl 3 chloroaluminate melts, the two bands at 347 and 179 cm −1 are indicative of AlCl 4 − whilst the two bands at 433 and 311 cm −1 are indicative of Al 2 Cl 7 − . These bands matched those previously recorded for these species 63–65. The bands for Al 2 Cl 7 − were absent in the spectra of the upper and lower phases of C 4 mpyrNTf 2 /AlCl 3 at x =0.50 confirming Al 2 Cl 7 − was not responsible for aluminium electrodeposition from the lower phase.…”

Homogeneous and Heterogeneous Nickel‐Catalyzed Olefin Oligomerization: Experimental Investigation for a Common Mechanistic Proposition and Catalyst Optimization

“…Since the electrophilic character and consequently the activity of this nickel system is increased with the Lewis acidity of the aluminium co‐catalyst, acidic dialkylimidazolium ionic liquids based on the mixtures of EtAlCl 2 and AlCl 3 were used as both co‐catalysts and solvents. An accurate adjustment of the EtAlCl 2 to AlCl 3 ratio allowed optimization of the efficiency of the catalytic system which could be correlated to the global Lewis acidity of the ionic liquid …”

Ethylene polymerization using vanadium catalyst supported on silica modified by pyridinium ionic liquid

“…Additionally, the efficiency of SIL system increases when the activator AlEtCl 2 is used. The type of alkylaluminium compound determines the type of alkylchloroaluminate anion, which in turn determines the Lewis acidity of the ionic liquid medium, suitable to form the active catalyst centres. Application of AlEt 2 Cl to create the anionic part of the ionic liquid, presented in this work, is much more suitable than AlEtCl 2 applied previously …”

“…It should also be noted that an increase of the amount of alkylaluminium activator is not advantageous and does not promote the activity of the SIL systems (Table , entries 10, 12, 14 and 17). Higher concentration of the alkylaluminium compound leads to the appearance of bridged bimetallic ethylchloroaluminates, which are less suitable as counter anions of the active species. Also, it probably promotes disproportionation reaction, in which inactive V(II) species are formed …”