For the DESs-aiding systems, the density profiles of H2SO4 and MixC4 (isobutane + butene) are shown in Figure 8 and Figure S4, respectively. It is clearly seen that there is a good fitting for all the systems. The obtained
for different DESs as a function of concentrations as shown in Figure 8d. The of pure H2SO4 system is taken from our recent work as a benchmark15. The results indicate that the addition of DESs can significantly increase
in comparison to the pure H2SO4 systems. Furthermore, the interfacial thickness rises along with the concentration of DESs. From experimental point of view, the enlargement of the interfacial thickness provides the larger interfacial reaction zones, which is better for higher-quality alkylate. At the same conditions, the ChCl-TsOH (1:1) additive can contribute more to the interfacial thickness compared to ChCl-Pho (1:2) and ChCl-BOA (1:2) additives.