Preparation of ILe@Cu@MOF Catalyst and Its Application in Biodiesel Catalysis

Abstract

Heterogeneous catalysts play a dual role in transesterification due to their advantages of being separable and reusable. In recent years, heterogeneous catalysts derived from renewable resources have received more attention. In this paper, the production of biodiesel from Xanthoceras sorbifolia bunge oil via transesterification was studied under the action of an ILe@Cu@MOF catalyst. Fourier-Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, scanning electron microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Thermogravimetric (TG) and other characterization methods were used to characterize the microstructure and thermal stability of the catalyst and further study the ILe@Cu@MOF catalyst for the preparation of biodiesel from Xanthoceras sorbifolia bunge oil. The results show that the surface of the ILe@Cu@MOF catalyst is attached with a sheet-like structure of isoleucine (ILe), which mainly contains Cu, O, C and N elements. The specific surface area is 19.687 m2/g, and the average pore size is 31.74 nm, which belongs to mesoporous material. The pyrolysis temperature of ILe@Cu@MOF reached 360 °C, indicating that the grafting of ILe had a protective effect on Cu@MOF and increased the pyrolysis temperature of Cu@MOF. At the same time, the water contact angle increased from 86° to 121°, and the material was hydrophobic. The optimum conditions for the preparation of biodiesel were as follows: the amount of catalyst was 3 wt%, the molar ratio of methanol to oil was 35:1, the reaction temperature was 50 °C, and the reaction time was 4 h. At this time, the biodiesel yield was up to 82.85%. Moreover, after five cycles of ILe@Cu@MOF, the yield still reached 73.4%. GC–MS and MNR studies showed that the quality of biodiesel after catalysis was higher. The prepared catalyst can make biodiesel products more sustainable, environmentally friendly and economical, and can provide future prospects for the energy utilization of renewable resources.