Al(III)-Cu(I) bimetallic composite ionic liquid is a novel high efficient catalyst in isobutane alkylation process, displaying good catalytic activity and high selectivity. Its bimetallic polynuclear anion, AlCuCl5-, crucially provides the multi active sites of precisely-controlled acidity and complexation. Therefore, interaction between bimetallic sites in this kind of bimetallic ionic liquid is worthy of being studied. In this research, the secondary metallic cation was extended to cuprous, silver, zirconium and neodymium ion. Bimetallic composite ionic liquid was synthesized stirring with imidazole chloroaluminate at 423.5 K and the ratio of AlCl3 to [BMIm]Cl ranged from 1.0 to 2.3. In addition, 27Al NMR was carried out to detect the chemical environment around aluminum ion. Results showed that acidity had a significant impact on maximum miscibility MCly (M=Cu, Ag, Zr, Nd) ratio, yet the tendency varied with different metallic cations. With increasing ratio of AlCl3 to [BMIm]Cl, maximum miscibility ratio of cuprous and silver ion gradually increased, but the growth rate decreased in high acid region. Zirconium ion showed maximum in medium acid region. Neodymium ion seldomly dissolved in low acidy region and soared in high acid region. Tendency was similar when Et3NHCl was used instead of [BMIm]Cl. In the 27Al NMR spectrum, new peak appeared in composite ionic liquid containing cuprous, silver and zirconium ion, suggesting a significant amount of bimetallic polynuclear anions.

Interaction between bimetallic sites in bimetallic composite ionic liquids

2019 Fall National Meeting

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