Browsing by Author "Riisager, Anders"
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Item Correction to: The influence of triphenylphosphine trisulfonate (TPPTS) ligands on the catalytic activity of the supported ionic liquid-phase catalysts for the hydroformylation of ethylene (Research on Chemical Intermediates, (2023), 49, 6, (2383-2398), 10.1007/s11164-023-05007-5)(2023-07) Nguyen, Van Chuc; Do, Van Hung; Truong, Duc Duc; Pham, Thi Tien; Dinh, Phuc Kien; Vu, Tung Lam; Garcia-Suarez, Eduardo J.; Riisager, Anders; Fehrmann, Rasmus; Le, Minh Thang; Tecnalia Research & InnovationThe author “Eduardo J. Garcia-Suarez” is additionally affiliated with “Center for Cooperative Research on Alternative Energies (CIC energiGUNE), Basque Research and Technology Alliance (BRTA), Alava Technology Park, Albert Einstein 48, 01510 Vitoria-Gasteiz, Spain” and “IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009, Bilbao, Spain”.Item Highly Efficient Rh-catalysts Immobilised by π-π Stacking for the Asymmetric Hydroformylation of Norbornene under Continuous Flow Conditions(2019-04-18) Cunillera, Anton; Blanco, Carolina; Gual, Aitor; Marinkovic, Jakob Maximilian; Garcia-Suarez, Eduardo J.; Riisager, Anders; Claver, Carmen; Ruiz, Aurora; Godard, Cyril; Tecnalia Research & InnovationThe application of C1-symmetrical diphosphite ligands containing furanose backbone in the Rh-catalysed asymmetric hydroformylation of norbornene is described. The catalysts were highly active and produced exclusively exo-norbornanecarboxaldehyde with enantioselectivities (ee) up to 71 %. Considering these promising results, the ligands were modified with a pyrene moiety to accomplish their immobilisation onto carbon materials. The corresponding Rh complexes bearing the novel pyrene-tagged ligands were synthesised and immobilised onto multiwalled carbon nanotubes (MWCNT), reduced graphene oxide (rGO) and carbon beads (CBs). The novel catalytic systems were tested in the asymmetric hydroformylation of norbornene providing similar performance in terms of both activity and selectivity compared to the non-immobilised systems. The recyclability of the new heterogenised catalysts was studied in the target reaction in batch mode. Nevertheless, the recycling was unsuccessful due to catalyst leaching. When used under continuous flow mode, these catalysts revealed robust and provided even higher ee than the corresponding homogeneous systems.Item Pd-catalysed formation of ester products from cascade reaction of 5-hydroxymethylfurfural with 1-hexene(2019-01-05) Garcia-Suarez, Eduardo J.; Paolicchi, Dario; Li, Hu; He, Jian; Yang, Song; Riisager, Anders; Saravanamurugan, Shunmugavel; Tecnalia Research & InnovationA cascade reaction involving decarbonylation of 5-hydroxymethylfurfural (HMF) followed by methoxycarbonylation of 1-hexene produces methyl heptanoate (MH) using a catalytic system composed of a Pd-phosphine complex and methanesulfonic acid (MSA) co-catalyst at moderate reaction temperature. Concomitant hydration of HMF followed by hydrogenation of methyl levulinate (ML) to γ-valerolactone (GVL) occurs with the catalytic system under the same reaction conditions using HMF and methanol as the source of CO and H2, respectively. Under optimized reaction conditions, about 50% of MH along with 12% ML and 35% GVL is obtained from HMF using Pd-(1,2-bis(di-tert-butylphosphinomethyl)benzene) (DTBPMB), MSA and 1-hexene in methanol at 120 °C. Interestingly, sugars, such as glucose, fructose and xylose, are able to be converted to MH, ML and GVL as well. Isotopic labeling studies with 13C1-fructose in methanol-d4 and 13C-methanol-d4 confirm that H2 originates from methanol, while CO generates predominantly from the formyl group of the HMF formed by fructose dehydration.Item Selective Oxidative Carbonylation of Aniline to Diphenylurea with Ionic Liquids(2018-06-07) Zahrtmann, Nanette; Claver, Carmen; Godard, Cyril; Riisager, Anders; Garcia-Suarez, Eduardo J.; Tecnalia Research & InnovationA catalytic system for the selective oxidative carbonylation of aniline to diphenylurea based on Pd complexes in combination with imidazolium ionic liquids is presented. Both oxidants, Pd complexes, and ionic liquids affect the activity of the reaction, and the choice of oxidant determines the selectivity of the reaction. Together they allow the reaction to proceed under comparatively mild conditions without a loss of activity. Examination of the reaction by use of in situ NMR spectroscopy allowed us to observe an intermediate suggested only previously, which supported the proposed mechanism.