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Efficient isomerization of safrole by amino-grafted MCM-41 materials as basic catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
55625 47059 2012 5 PDF Available
Title
Efficient isomerization of safrole by amino-grafted MCM-41 materials as basic catalysts
Abstract

Design of base catalyst featuring large mesoporous surfaces allows performing base-catalysed reactions in the fields of production of perfumes. Post-synthesis grafting of organotrialkoxysilanes has effectively been applied to incorporate active organic functional groups onto the mesoporous silica surfaces. The novelty of our study is the use of mesoporous materials with different chemical compositions: silicate (MCM-41), aluminosilicate (AlMCM-41; Si/Al = 64) and niobosilicate (NbMCM-41; Si/Nb = 64) and consequently, different acidity, as supports for three aminopropylalkoxysilanes (APMS), [3-(2-aminoethylamino) propyl]trimethoxysilane (2APMS) and 3-[2-(2-aminoethylamino) ethylamino]propyltrimethoxysilane (3APMS). Isomerization of safrole to the corresponding thermodynamically stable isosafrole has been carried out on these amino-grafted MCM-41 materials. Maximum conversion of around 85% with a cis/trans ratio of 1/9 at 433 K in DMF as solvent was obtained. Isomerization is strongly dependent on the nature of the support and changed in the following order: APMS/AlMCM-41 > APMS/NbMCM-41 ≫ APMS/MCM-41. The nature of the amine chain is also responsible of the activity. The order of activity is APMS/AlMCM-41 > 2APMS/AlMCM-41 > 3APMS/AlMCM-41.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (19 K)Download as PowerPoint slideHighlights► We show isomerization of safrole to isosafrole over recyclable amino-grafted MCM-41 materials, being the maximum conversion of around 85% with a cis/trans ratio of 1/9 at 433 K in DMF. ► Isomerization is strongly dependent on the nature of the support and changed in the following order: APMS/AlMCM-41 > APMS/NbMCM-41 ≫ APMS/MCM-41. ► The nature of the amine chain is also responsible of the activity. The order of activity is APMS/AlMCM-41 > 2APMS/AlMCM-41 > 3APMS/AlMCM-41.

Keywords
Basicity; Mesoporous materials; MCM-41; AlMCM-41; NbMCM-41; Aminopropyl trimethoxysilanes; Isomerization; Safrole; Isosafrole
First Page Preview
Efficient isomerization of safrole by amino-grafted MCM-41 materials as basic catalysts
Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 179, Issue 1, 5 January 2012, Pages 159–163
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis