13C
NMR (101MHz, MeOD) δ: 12.66, 19.14, 31.87, 35.64, 47.14-48.42, 49.31,
122.4-122.44, 123.63-123.67, 136.57.
Scheme 2 . Synthesis and immobilization of IL2
2.2.4. Electrostatic immobilization of ionic liquids onto
SBA-15 - functionalized sulfonic acid
The concentration of H+ in the functionalized SBA-15
was determined as described in our previous work (Shalaby, 2018). The
method of alteration and immobilization was set out in Scheme 1
and 2. SBA-15 with surface sulfonic groups was dispersed in toluene and
equal mole of IL1 or IL2 in 1,4-dioxane
was added portion wise at ambient temperature. After that, the
temperature of the reaction mixture was ramped slowly up to
90oC and stirred for 2h and then, the mixed solvent
was removed under vacuum at 90oC (Zhang, 2009). The
obtained heterogenized catalyst was washed with ethanol, dried under
vacuum at 60oC and denoted as
IL1/SBA-15 or IL2/SBA-15.