Biodiesel Production via Transesterification of Soybean Oil Catalyzed by Superhydrophobic Porous Poly(ionic liquid) Solid Base

In this work, the preparation and catalytic application of novel superhydrophobic porous poly(ionic liquid) (PIL) solid base catalyst have been reported. The PIL was synthesized by radical polymerization with subsequent anion exchange providing alkali catalysis. The as-prepared catalyst possesses favorable wetting properties in the reaction of biodiesel production. Various characterization techniques were utilized to characterize the as-prepared PIL catalyst, including nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), nitrogen adsorption–desorption isotherms, thermogravimetric analyses (TG), and static water contact angle measurement. In addition, the catalytic performance of the PIL catalyst was evaluated by the transesterification of soybean oil with methanol to produce biodiesel. The effects of various reaction parameters on the oil conversion ratio were systemically investigated by three-level and three-factorial central composite design of response surface methodology to obtain the optimum reaction conditions. The catalyst was reused for five cycles without a significant decrease in activity, and the activity could be recovered by anion exchange. Moreover, the properties of the prepared biodiesel were within the standards of EN14214 and ASTM D6751.