3. Results and discussions
3.1 Effect of DESs on reaction time
The effects of ChCl-Pho (1:2), ChCl-TsOH (1:1), ChCl-BOA (1:2) and ChCl-NH2OH•HCl (1:2) additives on the alkylate components as a function of time were initially investigated, as shown in Figure 2. At the initial time, the C9+ components are relatively high with the low conversion of C8 key components. With the extended reaction time, the RON and C8 key components increase gradually, and the LEs (C5-C7) and C9+ components present a decreasing trend. The RON and C8 approach a plateau basically after 15 min, as same as the reaction time of H2SO4system without any additive (see Figure S1). Among the reaction, the trimethylpentanes (TMPs) with higher RON (>100.0) grow in pace with the C8 components, leading to the higher RON of alkylate. Hence, the addition of DESs have no effect of the reaction time of H2SO4 alkylation in contrast to the pure H2SO4 system. The reaction time of 15 min was taken for the following experiments.