New Graphite-Based Catalyst in Biodiesel Production

<div>Climate change and the depletion of fossil fuels have increased the need for renewable energy sources such as biodiesel. Biodiesel is an environmentally friendly fuel derived from various vegetable oils through a process known as transesterification. In this study, a new graphite-based heterogeneous catalyst was developed by modifying it Na<sub>2</sub>CO<sub>3</sub>, K<sub>2</sub>CO<sub>3</sub>, Al<sub>2</sub>O<sub>3</sub> and was used for biodiesel production from linseed, cottonseed, sunflower, olive oils. Catalyst activity gradually decreased from 90.0 to 76.7% for cottonseed oil, from 93.0 to 76.0% for olive oil, from 95.0 to 77.0% for sunflower oil, and from 89.0 to 69.0% for linseed oil after the fourth operation. The fuel properties of the obtained biodiesel samples were investigated and the most favorable characteristics of cottonseed oil–based biodiesel were found to be <span> <math> <msubsup> <mi>d</mi> <mn>4</mn> <mn>20</mn> </msubsup> </math> </span> = 0.8448, <i>ν</i> <sup>40</sup> = 3.3820, flash point of 93°C. Based on the X-ray broad peaks at 22.8° and 26.4°, we can note that after the four-time reaction cycle, the structure of the catalyst was destroyed to expanded and pure graphite with the loss of catalytic activity. Additionally, the influence of the amount of oleic, linoleic, linolenic, and saturated acyl groups in oil samples on exploitation properties was investigated by NMR spectroscopy.</div>