| Summary: | 碩士 === 明志科技大學 === 化學工程系碩士班 === 105 === Phytosterol ester can effectively reduce the levels of total cholesterols and decrease the risk of cardiovascular diseases. Although the enzyme-catalyzed esterification process is one of the most common methods for the synthesis of phytosterol esters, it remains many drawbacks, including high costs of enzymes, low product characteristic, and long reaction time.
Microwave irradiation may become an alternative method for phytosterol ester synthesis since it generates a high esterification reaction rate. In this study, the effects of non-catalytic esterification of Phytosterol with oleic acids using microwave heating were investgated to find a optimal kinetic. The esterification conversion was examined at different temperatures reaction (120-170 °C), molar ratios of oleic acid to Phytosterol (2:1-5:1), and microwave irradiation powers (150-250 W) at a constant pressure. An increase in reaction temperature, oleic acid/Phytosterol molar ratio, and microwave irradiation power was observer to significantly enhance the esterification conversion. The esterification reaction was reached the highest conversion rate of 89.55% under the reaction condition: oleic acid/phytosterols molar ratio of 5:1, a reaction temperature of 170 °C, microwave irradiation power of 200 W, and a reaction time of 50 min.
To determine the effects of microwave heating on this reaction, the activation was calculated by using the Arrhenius equation in a temperature range of 120 to 220°C, the reaction activation energy was 36.493kJ/mol, smaller than the activation energy (46.220kJ/mol) using Conventional heating.
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