Selective palladium-catalyzed dehydrogenation of limonene to dimethylstyrene

• Verfasst von: Horrillo Martínez, Patricia [VerfasserIn]
• Verfasst von: Virolleaud, Marie‐Alice [VerfasserIn]
• Verfasst von: Jäkel, Christoph [VerfasserIn]
• Titel: Selective palladium-catalyzed dehydrogenation of limonene to dimethylstyrene
• Verf.angabe: Patricia Horrillo-Martínez, Marie-Alice Virolleaud, and Christoph Jaekel
• E-Jahr: 2010
• Jahr: [February 8, 2010]
• Umfang: 7 S.
• Illustrationen: Diagramme
• Fussnoten: First published: 01 February 2010 ; Gesehen am 17.04.2023
• Titel Quelle: Enthalten in: ChemCatChem
• Ort Quelle: Weinheim : Wiley-VCH, 2009
• Jahr Quelle: 2010
• Band/Heft Quelle: 2(2010), 2 vom: Feb., Seite 175-181
• ISSN Quelle: 1867-3899
• DOI: doi:10.1002/cctc.200900200
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: aromaticity
• Sach-SW: CH activation
• Sach-SW: heterogeneous catalysis
• Sach-SW: homogeneous catalysis
• Sach-SW: palladium
• K10plus-PPN: 1842965077

Abstract

Conditions for the selective dehydrogenation of (+)-limonene 1 to the polymer building block dimethylstyrene 2 are described. The reaction occurs smoothly in the presence of Pd(OTFA)2 as catalyst and CuCl2 as oxidant. High selectivity for retaining the exocyclic double bond during aromatization is achieved (>14:1). Initially, variable-temperature NMR experiments, under stoichiometric conditions, showed a stepwise formation of a π-allyl intermediate and subsequent reaction to give a mixture of products. However, kinetic experiments showed a sigmoidal curve, pointing to the heterogeneous nature of the catalytically active species. A number of experiments were undertaken to differentiate between homogeneous, molecularly defined catalysis and heterogeneous, nanocluster-based catalysis. Based on the results, it is proposed that the true catalytic system is heterogeneous in nature.