Transesterification of hazelnut oil by ultrasonic irradiation

ABSTRACT

Ultrasonic irradiation is considered an effective way to increase mass transfer between immiscible liquid–liquid phases in a heterogeneous system leading to faster transesterification and higher yield and saving excess methanol and catalyst. In this study, the transesterification of hazelnut oil with methanol and ethanol was performed in the presence of potassium hydroxide or sodium methoxide as a catalyst using two types of ultrasonic irradiation with a probe (20 kHz, 200 W) and a bath (35 kHz, 400 W); a conventional production method was also used. The reaction time, alcohol:oil molar ratio, catalyst type (KOH or NaOCH₃), and catalyst amount (wt.% of oil) were studied as experimental parameters. The highest methyl ester conversion was obtained as 98.12% by using ultrasonic probe at a 5:1 methanol:oil molar ratio with KOH 1 wt.% of oil as catalyst in 20-min reaction time at autogenous temperature. The application of ultrasonic irradiation by using a probe decreased the level of energy consumption, showing that this method may be a promising alternative compared with the conventional production method.

KEYWORDS:

• Biodiesel
• cavitation
• fatty acid ester
• hazelnut oil
• ultrasonic irradiation

Additional information

Funding

The authors wish to express their sincere gratitude to the Yildiz Technical University Scientific Research Coordinator for supporting this research project (2011-07-04-YULAP02).