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Keplerate Polyoxotungstate Nanowheel Functionalized Magnetic Nanoparticles for Sustainable Biodiesel Production by Esterification of Free Fatty Acids with Ethanol in an Ultrasound-Assisted

[ Vol. 5 , Issue. 2 ]

Author(s):

Reza Haddad   Pages 116 - 128 ( 13 )

Abstract:


Background: Biodiesel is briefly defined as the monoalkyl esters of vegetable oils or animal fats. Biodiesel is the best candidate for diesel fuels in diesel engines as a &quot;green chemistry&quot; that has several advantages over conventional diesel. Giant polyoxometalates are nanoscale architectures with highest Euclidean symmetry, which gained significant interest as cation carriers or nanosponges and for various other material science applications in the solid state. However, their catalytic properties in the esterification of FFAs really lag behind. In this work herein, we are reporting esterification of FFAs for biodiesel production in the presence of WPCu@ASMNP for the first time, in the presence of ethanol as a green solvent. </p> <p> Methods: Various free fatty acids, oleic, stearic and palmitic acid, were used for esterification. The catalyst (WPCu@ASMNP) is well characterized by various physicochemical techniques such as XRD, FT-IR, TGA¬, ICP-AES, TEM and SEM. Analyses of the reaction products were conducted using a gas chromatograph (GC). Ultrasonic irradiation enhanced the catalytic activity of this catalyst in esterification and this led to shorter reaction times and higher product yields. </p> <p> Results: The use of synthesized catalyst was explored for biodiesel production by esterification of free fatty acids (FFAs) with ethanol using ultrasound-assisted process was investigated. It was observed that the WPCu@ASMNP shows the highest catalytic activity on esterification of FFAs with ethanol. Influence of various reaction parameters (such as catalyst loading, acid/alcohol molar ratio, effect of ultrasonic irradiation power, reaction time and temperature) on the conversion were studied. The catalyst shows high activity in terms of conversion of oleic acid. The catalyst was recycled up to four times after simple work up without notable loss in the activity. </p> <p> Conclusion: Polyoxotungstate nanowheel, anchored to magnetic nanoparticles WPCu@ASMNP exhibits significant activity toward biodiesel production via esterification of free fatty acids under relatively mild condition. The catalyst was recycled up to four times after simple work up without notable loss in the activity. The FT-IR, XRD and leaching experiments after four successive cycles showed that the catalyst was most strongly anchored to the magnetite nanoparticles.It was no observed leaching in this system.

Keywords:

Biodiesel, Esterification, Nanocatalyst, Polyoxotungstate.

Affiliation:

Technology Management Department, Police Sciences and Social Studies Institute, Tehran, 19395-6516, Iran.

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