@ARTICLE{10.3389/fchem.2020.00305,
  
AUTHOR={Cabral, Natalia Mariano and Lorenti, Juliana P. and Plass, Winfried and Gallo, Jean Marcel R.},   
	 
TITLE={Solid Acid Resin Amberlyst 45 as a Catalyst for the Transesterification of Vegetable Oil},      
	
JOURNAL={Frontiers in Chemistry},      
	
VOLUME={8},      

PAGES={305},     
	
YEAR={2020},      
	  
URL={https://www.frontiersin.org/article/10.3389/fchem.2020.00305},       
	
DOI={10.3389/fchem.2020.00305},      
	
ISSN={2296-2646},   
   
ABSTRACT={Commercial transesterification of vegetable oil to biodiesel using alkaline hydroxides requires expensive refined vegetable oil and anhydrous alcohols to avoid saponification. These issues are not present in the acid-catalyzed process; however, the challenge still lies in developing stable and active solid acid catalysts. Herein, Amberlyst 45, a resin for high-temperature application, was efficiently used for biodiesel production by the methanolysis or ethanolysis of vegetable oil. Yields of up to 80 and 84% were obtained for the fatty acid methyl ester and the fatty acid ethyl ester, respectively. Two processes are proposed and showed to be efficient: (i) incremental addition of alcohol along with the reaction for both methanolysis and ethanolysis; or (ii) one-pot reaction for ethanolysis using oil/ethanol molar ratio of 1/18. The catalytic system used also showed to be compatible with used oil (2.48 ± 0.03 mg<sub>NaOH</sub><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:msub><mml:mrow><mml:mtext>g</mml:mtext></mml:mrow><mml:mrow><mml:mtext>oil</mml:mtext></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:math>) and to the presence of water (10–20 wt. % based on the alcohol), allowing the use of waste oil and hydrated alcohol.}
}