Durability enhanced ionic liquid catalyst for Friedel–Crafts reaction between benzene and 1-dodecene: insight into catalyst deactivation

Abstract

Friedel-Craft alkylation of benzene with 1-dodecene, which is an important reaction of synthetic detergent, was studied using the catalyst of [bmim][TFSI]/AlCl3 (1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide/AlCl3). These ionic liquid catalysts show biphasic behaviors at specific condition. Active site species and Lewis acidity were determined by NMR and acetonitrile probe FT-IR. NMR spectroscopy investigations indicated that "Coordinated" and "uncoordinated"[TFSI]existed in the ionic liquid catalyst system sumultaneity, while tetrahedral 4-coordinate Al2Cl7was the main active specie for Friedel-Craft alkylation. The complexation [AlClx(TFSI)y]tend to decompose and release 4-coordinated Al2Cl7and [TFSI] -. The phase behaviors study of the ionic liquid [bmim][TFSI]/AlCl3 demonstrated that the upper phase could be used as an efficient heterogeneous catalyst when AlCl3/IL≥1.5. Due to the presence of anion [TFSI]around active sites, especially [TFSI]at "uncoordinated" state, ionic liquid formed a stable and hydrophobic chemical environment, which enhanced catalysts durability. The influence of various reaction conditions including catalyst reusability on the alkylation reaction was studied, and the potential reasons to catalyst deactivation were discussed. The highest 2-LAB selectivity was more than 50% when 1-dodecene conversion was nearly 100%. Comparing with liquid or solid acid catalyst, ionic liquid catalysts have many advantages in perspectives concerning energy and environmental.

Chloroaluminate Gel Electrolytes Prepared with Copolymers Based on Imidazolium Ionic Liquids and Deep Eutectic Solvent AlCl3:Urea

“…The presence of the TFSI anion could lead to the formation of different structures of coordination with AlCl 3 , which would affect the aluminum speciation and therefore the electrodeposition. The results agree with those of other authors, where it was seen by Raman spectroscopy that uncoordinated TFSI anions decreased with increasing AlCl 3 concentration in mixtures of ionic liquid with TFSI and AlCl 3 [ 26 , 27 ].…”

Group IIIA Halometallate Ionic Liquids: Speciation and Applications in Catalysis

“…Recently, [C 4 mim]­[NTf 2 ]-AlCl 3 ([NTf 2 ] − , bis­((trifluoromethyl)­sulfonyl)­imide) was reported to enhance stability and durability in the alkylation of benzene. Uncoordinated [NTf 2 ] − provided durability and water resistance by forming a stable and hydrophobic environment . In order to combine the advantages of ILs and heterogeneous systems, the catalytic IL system [C 4 mim]­[NTf 2 ]-AlCl 3 supported on mesoporous material Santa-Barbara Amorphous 15 (SBA-15) has been investigated .…”

“…Uncoordinated [NTf 2 ] − provided durability and water resistance by forming a stable and hydrophobic environment. 115 In order to combine the advantages of ILs and heterogeneous systems, the catalytic IL system [C 4 mim]-[NTf 2 ]-AlCl 3 supported on mesoporous material Santa-Barbara Amorphous 15 (SBA-15) has been investigated. 116 Due to its ordered structure and high specific surface area, the immobilized catalyst presents advantages such as enhanced selectivity, Lewis acidity, and reusability.…”

Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

“…Successive research for the Friedel-Crafts acylation lead to the development of various reaction protocols using different metal salts [25][26][27][28][29][30] and ionic liquids [31][32][33][34][35] to acylate [36][37][38][39][40][41], alkylate [42][43][44], benzylate [45][46][47] and alkenylate [48,49] different benzene derivatives. But surprisingly, a robust protocol using commercially available and cost-efficient metal salts in a water and air stable ionic liquid is still hard to find [50,51].…”