Comparison of Different Heterogeneous Catalysts for the Estolides Synthesis from Oleic Acid

Abstract:

Different catalysts, namely various loading of perchloric acid on various supports; HClO₄/silica (SiO₂), HClO₄/silica gel (SG) and HClO₄/alumina (Al₂O₃) were tested for the direct addition reaction of oleic acid (OA) to form estolide compounds. The reactions were carried out under vacuum (2 mBar) for 10 hours at 70 °C under solvent-less conditions. LC-MS ToF of reaction products results showed chromatographic peaks for the presence of two new estolide compounds, oleic-oleic monoestolide acid (m/z 563.51, as [M-H]^-), and oleic-oleic diestolide acid (m/z 845.77 [M-H]^-). The optimum loading of HClO₄ for every support are 15 wt.% HClO₄/SiO₂ (SiO₂15), 10 wt.% HClO₄/SG (SG10) and 35 wt.% HClO₄/Al₂O₃ (Al₂O₃35). The SG10 turned out to be the best catalyst, achieving a final conversion of 97.5 % with 79.8 % selectivity to oleic-oleic monoestolide acid and 17.7 % selectivity to oleic-oleic diestolide acid. The activity and selectivity of the SG10 have been investigated and compared with homogeneous HClO₄. The optimum catalysts for every support were characterized by XPS analysis, BET, TEM and TPD-NH₃.

• Periodical: Advanced Materials Research (Volume 364)
• Pages: 288-292
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.364.288
• Online since: October 2011
• Authors: Nor Asikin Mohamad Nordin, Nadia Farhana Adnan, Noraini Hamzah, Wan Nor Roslam Wan Isahak, Alifee Ayatillah, Jumat Salimon, Mohd Ambar Yarmo, Rose Aini Kamaruddin
• Keywords: Alumina, Estolide Synthesis, Oleic Acid, Silica, Silica Gel

References

[1] S.C. Cermak and T.A. Isbell: J. of the Amer. Oil Chem. Soc. Vol. 6 (2001), p.557.

[2] T.A. Isbell and R. Kleiman: J. of the Amer. Oil Chem. Soc. Vol. 9 (1996), p.109.

[3] T.A. Isbell and R. Kleiman: J. of the Amer. Oil Chem. Soc. Vol. 4 (1994), p.379.

[4] S.M. Erhan and T.A. Isbell: J. of the Amer. Oil Chem. Soc. Vol. 3 (1997), p.249.

[5] S.K. Bhorodwaj and D.K. Dutta: App. Cat. A: Gen. Vol. 2 (2010), p.221.

[6] S.P. Naik and J.B. Fernandes: Thermochim. Acta Vol. 1 (1999), p.21.

[7] Y. Miyamoto, N. Katada and M. Niwa: Micro. and Meso. Mat. Vol. 1-3 (2000), p.271.

[8] T. Hashiba, D. Hayashi, N. Katada and M. Niwa: Cat. Today Vol. 1 (2004), p.35.

[9] D. Jingfa, Z. Guirong, D. Shuzhong, P. Haishuiand W. Huaiming: App. Cat. (1988), p.13.