2.3. Catalytic Performance
The catalytic activity of IL1/SBA-15 and IL2/SBA-15 catalysts was investigated via esterification of OA and TMP. The effect of temperature (100C – 140C) and molar ratio of OA to TMP (3:1- 5:1) on the ester percentage yield were studied at fixed catalyst dosage of 3 wt. % (weight percent based on palmitic acid) and reaction time of 20h. The esterification was performed as follows: the catalyst, IL1/SBA-15 or IL2/SBA-15, OA and TMP (in molar ratio under study) were charged into a 150 mL three neck round bottom flask containing toluene (as a water removing agent) with a reflux condenser and a magnetic stirrer. Then the reaction was allowed to proceed under nitrogen atmosphere and the chosen temperature for 20 h. At the end of each run, the exploited catalyst separated from the reaction mixture by centrifugation, washed with methanol and n-hexane and dried under vacuum at 80 °C to obtain the recovered catalyst.
From practical and economic point of view, the periodicity of the catalysts was studied. The recovered catalysts were directly applied in esterification of OA with TMP, in six consecutive runs, at the optimized conditions as will be discussed in section 3.