Fig. 2 FT-IR spectra : ( a ) 1-vinylimidazole, ( b ) 1,2-dibromoethane,
( c ) PILs-XSS, ( d ) N, N ’ -methylenebisacrylamide
3.1.2 BET-BJH analysis of PILs-XSS
BET-BJH analysis was performed on the structure of the sample, as shown
in Figure 3, showing the specific surface area and pore size test curve
of the material. First of all, the test chart of BET-specific surface
area consists of two curves of adsorption and analysis. It can be seen
from the figure that the adsorption hysteresis loop in the middle
represents the type IV isotherm [29], and the specific surface area
reaches 71.5m2/g, The average pore size of FILs-XSS is
greater than 14.8 nm, which is an important sign of mesoporous materials
[30]. The CO2 molecule can fully contact with
propylene oxide on the catalyst, which is very favorable for the first
step of the reaction between CO2 and propylene oxide,
and the average pore size of PILs-FL has reached the basic requirement
[31]. According to the situation analysis, PILs-FL has a
high-quality specific surface area (71.5m2/g) and pore
size (14.8nm), which can show good performance in the process of one-pot
production of DMC.