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.