Propylsulfonic acid anchored on mesoporous SBA-15 as heterogeneous catalyst for esterification of fatty acids

ln the esterification process for biodiesel production it's possible used a not refined raw material as vegetable oil with high amount of free fatty acids or fatty acids from refined vegetable oil [1, 2]. Propylsulfonic acid functionalized mesostructured silica (Pr-S03H-SBA-15) have been reported in the literature as acid catalyst for esterification of fatty acids [3]. The present work aimed to evaluate the catalytic activity of Pr-S03H-SBA- 15 in the esterification of fatty acids with methanol present in vegetable oil (babaçu and pequi) and in the fatty acids residue of the soybean oil and babaçu refining industry. This catalyst was produced by the cocondensation method and characterized by textura! properties, FTIR, CP/MAS NMR and thermal analysis. The vegetable oils babaçu and pequi were characterized in terms of acid value and were found about 2.36 and 2.32 mg KOH. g oW1, respectively. Some reaction variables such as: oil:methanol ratio, temperature, time and the amount of catalyst were evaluated. By using babaçu oil and pequi oil in an oil:methanol ratio of 1 :8, 110ºC, 5,0% of catalyst for 120 minutes of reaction was achieved conversion of 94% and 86% into esters, respectively. ln the esterification reaction of fatty acids residue of the soybean and babaçu oil were used oil:methanol ratio of 1:10, 120ºC, 15,0% of catalyst and 90 minutes of reaction and was achieved conversion up to 96%.This catalyst is effective for fatty acids esterification and can be reused without significant loss of the activity.