Facile synthesis of H3PW12O40-functionalized organosilicon nanotubes using singlemicelle templates: High catalytic activity for biodiesel methyl oleate

Biodiesel production by catalytic esterification over solid acid catalysts offers a promising approach for finding alternatives to fossil fuels. In this work, ethylene-bridged organosilicon nanotubes (Si(CH2-CH2)Si-NTs) loaded with phosphotungstic acid (HPW), named HPW@Si(CH2-CH2)Si-NTs, were synthesised for the first time by a one-pot method using P105 (EO37PO56EO37) as a singlemicelle template at 16 °C. The composites were characterized by SEM, TEM, N2 adsorption–desorption, FT-IR, wide-angle XRD, and solid-state NMR spectrum. All test results proved that HPW were uniformly dispersed in the unique hollow nanotubes. Finally, 60 mg of 0.7HPW@Si(CH2-CH2)Si-NTs(C) were applied to catalyze the esterification reaction of oleic acid with methanol at 120 °C for 10 h, and the conversion of oleic acid and yield of methyl oleate reached 94.7%. After five reused, the catalytic activity did not decrease significantly, indicating that the composites had high hydrothermal stability and recycling performance.