Issue 45, 2012

Aqueous-phase hydroformylation of 1-octene using hydrophilic sulfonate salicylaldimine dendrimers

Abstract

Water-soluble dendritic ligands based on tris-2-(5-sulfonato salicylaldimine ethyl)amine (5) and DAB-(5-sulfonato salicylaldimine) (6) (DAB = diaminobutane) were synthesized by means of Schiff base condensation and sulfonation reactions. These dendritic ligands were fully characterized by 1H NMR, 13C NMR and FT-IR spectroscopy, elemental analysis and mass spectrometry. Dendritic ligands (5 and 6) in combination with [RhCl(COD)]2 (COD = 1,5-cyclooctadiene) were evaluated in aqueous biphasic hydroformylation of 1-octene. New water-soluble mononuclear 5-sulfonato propylsalicylaldimine Rh(I) complexes (7 and 8) were synthesized and characterized using 1H NMR, 13C NMR and FT-IR spectroscopy, elemental analysis as well as mass spectrometry. These complexes were applied as catalyst precursors in aqueous biphasic hydroformylation reactions. All the catalyst precursors were active in the hydroformylation of 1-octene under the investigated conditions. Optimal conditions were realized at 75 °C (40 bars), where the best selectivity for aldehydes was noticed. Catalyst recycling was achieved up to 5 times with minimal loss in conversion and consistent chemoselectivities and regioselectivities. Less Rh leaching was observed in the dendritic systems (5 and 6)/[RhCl(COD)]2 as compared to mononuclear catalyst precursors (7 and 8) as determined by inductively coupled plasma-mass spectrometry (ICP-MS).

Graphical abstract: Aqueous-phase hydroformylation of 1-octene using hydrophilic sulfonate salicylaldimine dendrimers

Supplementary files

Article information

Article type
Paper
Submitted
05 Jul 2012
Accepted
05 Sep 2012
First published
01 Oct 2012

Dalton Trans., 2012,41, 13927-13935

Aqueous-phase hydroformylation of 1-octene using hydrophilic sulfonate salicylaldimine dendrimers

E. B. Hager, B. C. E. Makhubela and G. S. Smith, Dalton Trans., 2012, 41, 13927 DOI: 10.1039/C2DT31471A

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