Influencing the Product Distribution in Citral Hydrogenation Using Ionic Liquid Modified Cu Catalysts. Issue 19 (1st September 2022)

• Record Type: Journal Article
• Authors: Naicker, Letisha; Schörner, Markus; Kremitzl, Daniel; Friedrich, Holger B.; Haumann, Marco; Wasserscheid, Peter
• Is Part Of: ChemCatChem. Volume 14:Issue 19(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-01
• Subjects: Copper -- Selective Hydrogenation -- Citral -- SCILL -- Ionic liquid; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.202200388
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: This work shows the effect of selected ionic liquids on the catalytic performance of a Cu/Al2 O3 catalyst towards citral hydrogenation. The Cu/Al2 O3 was prepared using a combination of wet impregnation and strong electrostatic interaction technique. The catalyst was coated with three ionic liquids, namely: [C4 C1 Pyrr][OTf], [C2 C1 C1 Im][NTf2 ], and [C2 C1 Im][NTf2 ] resulting in Cu‐based SCILL catalysts (solid catalyst with an ionic liquid layer). The fresh and used SCILL catalysts were characterized using FT‐IR spectroscopy and thermal gravimetric analysis. All Cu‐SCILL catalysts were stable throughout the liquid‐phase reactions with no leaching of ionic liquid being detectable by means of TGA. All ionic liquids investigated prevented the formation of undesired isopulegol compared to the 30 % isopulegol selectivity obtained over the bare Cu/Al2 O3 catalyst. The Cu‐SCILL (coated with 15 wt% [C2 C1 Im][NTf2 ]) increased the selectivity towards geraniol and nerol by 340 %. Abstract : Cu‐alumina catalysts were coated with thin films of ionic liquid. In the hydrogenation of citral these Cu‐SCILL catalysts were able to suppress formation of undesired isopulegol. Selectivity of fragrance compounds nerol and geraniol increased by 340 % compared to the bare Cu system.