A Study of the 1,3,5-Trialkylbenzenes with Aluminum Chloride-Hydrogen Chloride Systems

Abstract

The “red-oil” complex layers of systems of 1,3,5-trialkylbenzenes (Me3B, Et3B, i-Pr3B, and s-Bu3B) with AlCl3–HCl were prepared and studied by means of 1H NMR and 13C NMR spectroscopy. The results show that the 2,4,6-trialkylbenzenium ion is evidently formed in the complex layer of the AlCl3–HCl system, much as in other super acid systems, and that those ions from i-Pr3B and s-Bu3B are substantially stable, even at room temperature. The molar ratios of i-Pr3B and s-Bu3B to HAl2Cl7 are almost 1. On the other hand, the molar ratios of Me3B and Et3B to HAl2Cl7 are 4.5 and 1.9 respectively. These two complex layers are considered to be formed by both 1,3,5-trialkylbenzene and its protonated product, and to be in a certain equilibrium state as a result of proton exchange at room temperature.