Solvent-free acid-catalyzed ring-opening of epoxidized oleochemicals using stearates/stearic acid, and its applications.
Toxic solvent and strong acid catalysts causing environmental issues have been mainly used for ring-opening of epoxidized oleochemicals. Here, we demonstrated that magnesium stearate (Mg-stearate) was a high efficient catalyst for solvent-free ring-opening of epoxidized methyl oleate, a model compound of midchain epoxide. Mg-stearate resulted in the highest yield (95%) and conversion rate (99%) toward midchain alkoxyesters under the same conditions (160 °C, 12 h) superior to other fatty acid derivatives such as a Lewis acid (lithium and sodium stearate) and Brønsted acid (stearic acid). Based on this chemical study, we synthesized biogrease and thermoplastic using epoxidized soybean oil (ESO) and Mg-stearate via one-pot, solvent-free, and purification-free process. Mg-stearate played a significant role as a reactant for epoxide ring-opening and as a thickener when excess loading rate was used; viscosity increased from 1800 to 4500 Pa·s at 25 °C when ESO:Mg-stearate increased from 1:1 equiv to 1:2, then behaved like thermoplastics (T(g) = -27 °C, T(m) = 90 °C) with 1:4.
Department of Grain Science and Industry, Kansas State University, Manhattan, Kansas 66506, United States.
Byung-Jun Kollbe
BJ
Ahn
Stefan
S
Kraft
Xiuzhi Susan
XS
Sun
D002384:Catalysis; D004852:Epoxy Compounds / Q000737:chemistry*; D054327:Lubricants / Q000138:chemical synthesis; D009829:Oleic Acids / Q000737:chemistry*; D010578:Petroleum; D013024:Soybean Oil / Q000737:chemistry; D013229:Stearic Acids / Q000737:chemistry*; D013816:Thermodynamics; D014783:Viscosity
D004852:Epoxy Compounds; D054327:Lubricants; D009829:Oleic Acids; D010578:Petroleum; D013229:Stearic Acids; C005576:methyl oleate; C031183:stearic acid; D013024:Soybean Oil