Effects of the Molar Ratio of Acetic Acid to UFA and Stirring Velocity in the Tung Oil Epoxidation

Abstract

Epoxidation of the unsaturated fatty acids (UFA) in Tung oil provides a very interesting opportunity in the research and development of advanced materials. Tung oil is one of non-edible vegetable oils and epoxidized Tung oil (ETO) also provides benefits in terms of renewable and eco-friendly. This research evaluated the influences of acetic acid's molar ratio to UFA and stirring velocity in the epoxidation process of Tung oil. Epoxidation was carried out in a batch reactor using peroxyacetic acid produced in-situ with sulfuric acid as a catalyst. This reaction was run at a temperature of 60 °C and the catalyst concentration of 1.5% (w) for 4 hours, with a periodic 30-minutes sampling time interval. The samples' analyses were iodine value (IV), conversion to oxirane, selectivity, and FTIR spectrometry. The results showed that both the molar ratio of acetic acid to UFA and stirring velocity were directly proportional to the conversion to oxirane, and inversely proportional to the IV. In contrast, the two process variables did not show a definite result that can be interpreted to the selectivity (very fluctuated). The highest conversion (about 57.43%) and the lowest IV (8.3898 g I2/100 g) were obtained at a 1:1 ratio for the reaction times of 150 and 240 minutes, respectively.

Mass transfer and reaction rate parameters for the in-situ epoxidation of tamanu oil

“…These observations suggested that the formation of hydroxyl groups (-OH) is contingent upon the presence of an oxirane ring, and their concentration increases when there is an abundance of oxirane rings and heightened molecular kinetics in the reaction medium. This statement aligns with findings from previous research [2,3,19].…”

“…The samples are cooled and separated to obtain epoxidized tamanu oil, whose iodine and oxirane values will be analysed. The analysis was carried out using methods from previous research [1,3,18].…”

“…It's crucial to pay close attention to the exothermic nature of the epoxidation process when working with vegetable oils and peracetate. Avoiding potential risks requires the use of the in-situ epoxidation method [1][2][3], in which a heterogeneous system is employed, namely the aqueous and the organic phases, where the PAA formation reaction and the actual epoxidation process, respectively, take place. The step that governs the overall reaction rate is typically the slowest one; It often takes several hours of reaction time to get a high level of conversion [4].…”