3.3 Effect of temperature
C4 alkylation is an exothermic reaction. The low temperature is
beneficial to the formation of C8 key components with
higher RON40,41. Thus, the effect of reaction
temperature on C4 alkylation from 281.2 K to 269.2 K with ChCl-Pho (1:2)
additive was listed in Table 1. The difference of alkylate components
between DESs-aiding systems and pure
H2SO4 system as a function of
temperature are shown in Figure 4. For the system with 1.0 wt% ChCl-Pho
(1:2), it is clear that the targeted
C8 components and the RON increase obviously from
83.77% at 281.2 K to 86.07% at 274.2 K, 97.39 at 281.2 K to 98.27 at
274.2 K, respectively, which is mainly attributed to lower reaction
temperature. This tendency is in good agreement with our previous work,
in which, lower temperature leads to a great increase in
C8 contents and significant decrease in LEs, HEs and
DMHs components15. However, in ChCl-Pho (1:2)-aiding
system, when the temperature is below 274.2 K, the quality of alkylate
is not improved as expected. The C8 contents
dramatically decrease and HEs sharply increase at the 269.2 K. The
C8 key components and the RON decrease obviously, and
the content of C9+ components dramatically increase.
Table 1. Temperature-dependent alkylate components for
H2SO4 alkylation with
ChCl-Pho (1:2) as additive.