W. Herrmann, C. Kohlpaintner, R. Manetsberger
Apr 1, 1995
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Journal
Journal of Molecular Catalysis A-chemical
Abstract
The monophosphine 3,4-dimethyl-2,5,6-triphenyl-1-phosphanorborna-2,5-diene (1, DMTPPNOR) and the diphosphine 2,2′-bis (diphenylphosphinomethyl)-1,1′-binaphthalene (7) were sulfonated by means of oleum. The sulfonation products 8 (BINAS) and 2 (NORBOS) were purified by extraction-reextraction and by gel permeation chromatography. While the sodium salt 9 (BINAS-Na) of BINAS (8) was accessible as a mixture of different degrees of sulfonation, the sodium salt of NORBOS (2) was available as an analytically clean, completely characterized, triply sulfonated compound, NORBOS-Na (3). For the synthesis of 2,2′-bis (diphenylphosphinomethyl)-1,1′-binaphthalene (7), a new method has been used: Commercially available 1-bromo-2-methylnaphthalene (4) was first dimerized by means of magnesium, and then the resulting 2,2′-dimethyl-1,1′-binaphthalene (5) was treated with n-BuLiTMEDA and chlorodiphenylphosphine. In the ‘heterogeneous’ (bi-phasic) hydroformylation of propene, the sulfonated ligands 3 and 9 exhibited very high activities and productivities at low phosphine/rhodium ratios. Furthermore, phosphine 9 was advantageous in n/iso ratios of the resulting butyric aldehyde (rhodium catalysis). The new catalyst system RhI/BINAS-Na has an apparent activation energy of 10.8 kcal/mol explaining the outstanding performance of this system in continuous hydroformylation, with the activity data being: 16 (TPPTS), 90 (BISBIS-Na), 118 (NORBOS-Na), and 178 (BINAS-Na).