Synthesis of biodiesel from Carthamus tinctorius L. oil using TiO2 nanoparticles as a catalyst

The present study aimed to synthesize Titanium dioxide (TiO2) nanoparticles and assess its catalytic role in the synthesis of biodiesel from Carthamus tinctorius L. (a non-edible plant source). The precipitation approach was used to synthesize TiO2 nanoparticles, and the process was verified using X-ray diffraction (XRD) and scanning electron microscope (SEM). The synthesized biodiesel was analyzed qualitatively through NMR, GC-MS, and FT-IR spectroscopy. XRD result showed that the crystal structure of TiO2 nanoparticles was a biphasic mixture of rutile and anatase phases. SEM analysis revealed that the synthesized TiO2 nanoparticles had size from 42 nm to 58 nm and a surface area of 21–27 m2/g. The oil content in the feedstock was 43.9 % with free fatty acids contents of 0.37 mg KOH/g. The suitable condition for optimum yield (95 %) of biodiesel was 1:10 of oil to methanol using 25 g of catalyst at a temperature of 65 °C for 80–120 min of reaction time. Results obtained through 1H NMR for methoxy proton at 3.661 ppm, an alpha-methylene proton in triplet from 2.015 to 2.788 ppm, terminal methyl protons at 0.885 to 0.910 ppm, and beta-carbonyl methylene protons from 1.253 to 1.641 ppm confirmed the synthesis of biodiesel. Similarly, the peaks obtained through FT-IR spectroscopy for methoxycarbonyl at 1740.6 cm−1 and ether at 1012.6 cm−1 are the evidence for the validation of transesterification reaction. Furthermore, GC-MS analysis showed peaks for 17 different types of fatty acid methyl esters. The chemical and physical properties of C. tinctorius showed that the oil of C. tinctorius could be a potential non-edible feedstock for the biodiesel industries.