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Monoglyceride synthesis by glycerolysis of methyl oleate on MgO: Catalytic and DFT study of the active site

Paper ID Volume ID Publish Year Pages File Format Full-Text
41124 45877 2012 10 PDF Available
Title
Monoglyceride synthesis by glycerolysis of methyl oleate on MgO: Catalytic and DFT study of the active site
Abstract

The synthesis of monoglycerides by glycerolysis of methyl oleate, a fatty acid methyl ester (FAME), was efficiently promoted on strongly basic MgO. The chemical nature of the base sites responsible for the catalytic activity was investigated, both experimentally and by density functional theory (DFT). MgO catalysts stabilized at different temperatures were used to control the distribution of surface base sites. The nature, density and strength of the catalyst base sites were characterized by TPD and FTIR of CO2. Catalytic results suggested that the synthesis of monoglycerides was promoted mainly on strongly basic low coordination O2− surface sites.The molecular modeling of glycerol (Gly) and FAME adsorptions was carried out using terrace, edge and corner sites for representing the MgO surface. Results indicated that Gly was more strongly adsorbed than FAME. Dissociative chemisorption of Gly with O–H bond breaking was favored on low coordination O2− surface sites such as those on edges, in agreement with the experimental results. Thus, the proton abstraction from the OH groups of Gly, a necessary step in the reaction mechanism, would take place on unsaturated oxygen anions and the resulting glyceroxides would react with weakly adsorbed FAME molecules.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (190 K)Download as PowerPoint slideHighlights► MgO basicity can be tuned by changing the calcination temperature. ► MgO strong base site density decreases with increasing calcination temperature. ► Methyl oleate (FAME) glycerolysis is promoted on strong base sites. ► DFT calculations corroborate that glycerol O–H bond breaking occurs on strong base sites. ► DFT calculations show FAME adsorption on MgO is much weaker than that of glycerol.

Keywords
Glycerol; Monoglyceride; DFT; Base catalysis; Glycerolysis; Fatty acid methyl ester
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Monoglyceride synthesis by glycerolysis of methyl oleate on MgO: Catalytic and DFT study of the active site
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volumes 413–414, 31 January 2012, Pages 322–331
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us