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.