| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 64650 | Journal of Molecular Catalysis A: Chemical | 2016 | 6 Pages |
•Hydroformylation proceeds effectively with ruthenium–Biphephos systems, with very high selectivities for the linear aldehyde.•Readily available chloro–ruthenium precursors can be used, without detrimental effect on the stability of the active species.•Hydroformylation TOF that is ca. 1–2 orders of magnitude lower as compared to the analogous Rh-based system.
The hydroformylation of 10-undecenitrile (1), a route towards polyamide-12, has been studied using Ru-diphosphite catalysts. The reactions proceeded effectively by in situ combination of chloro precursors such as RuCl2(PPh3)3 and RuCl2(DMSO)4 with Biphephos. High productivities (TON up to 15,000 mol(aldehyde) mol(Ru)−1) were achieved by carrying the reactions at low catalyst loading ([1]0/[Ru] = 20,000), at 120 °C in toluene or acetonitrile under 20 bar CO/H2 (1:1), with 20 equiv of Biphephos vs. Ru. Up to 75% chemoselectivity for the aldehydes and very high regioselectivities for the linear aldehyde (l/b = 99:1) were reached under such optimized conditions. Lower loadings of Biphephos (down to 2.5 equiv. vs. Ru) did not affect the chemo- and regioselectivities but the activity. The Ru-Biphephos combinations showed a non-optimized hydroformylation TOFHF of ca. 2–7 min−1, that is ca. 1–2 order of magnitude lower than that of analogous Rh-based systems (TOFHF = ca. 80 min−1). These Ru-Biphephos systems are, however, incapable, under the conditions suitable for selective hydroformylation, to promote isomerization of internal olefins, and hence to achieve a tandem isomerization-hydroformylation process.
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