Hydroformylation of olefins (OXO synthesis), one of the
oldest organometallic catalytic reactions, continues to be of
interest because of its commercial significance. Great
interest recently has been placed on the development of
immobilized homogeneous catalysts that combine the virtues of
conventional heterogeneous and homogeneous catalysts.
The objective of this dissertation is to investigate
novel phosphine modified water soluble cobalt and platinum
complexes as homogeneous and immobilized hydroformylation
catalysts. The ligands include (1) Monodentate phosphines:
P[ (CH2 ) n-C6H4-S03Na] 3 (n = 0-3) and P[C6H4-NMe3+BF4-]3; (2)
Bidentate asymmetric phosphines: CHlRAPHOS(NMe2)4 (CHlRAPHOS
= 2, 3-bis (diphenylphosphino) butane) , SKEWPHOS (NMe2) 4 (SKEWPHOS
= 2,4-bis(diphenylphospino)pentane), and DlOP(NMez)4 (DlOP =
2,2-dimethyl-4,5-bis(diphenyl(phosphinomethyl)-1,3-
dioxolane) ). These complexes were immobilized and/or recycled
by four different methods: (1) Two phase catalysis; (2)
Supported aqueous phase catalysis; (3) Catalyst supported on
ion exchange resins; (4) Extraction of the catalyst from an
organic phase into an aqueous phase.
Catalytic results for the hydroformylation of a-olefins
shows that nib (normal:branch of aldehyde product) ratio can
be increased if proper alkyl-phosphine ligands are chosen.
For example, as high as 18.5 of nib ratio was obtained in
Ptcl[P(C6Hs)3]2-snC13 system and 5.6 in CO2 (CO) 6 [TRlMAPP] 2
(TRlMAPP = trimethylamino-phenylphosphine) system.
Metal leaching, from the aqueous phase to the organic
phase during the catalytic reaction, was reduced by supporting
the water soluble cobalt and platinum complexes onto a high
surface area glass (CGP-350). For instance, 5.7% cobalt metal
was found in the organic phase when CO2(CO)6(TPPTS)2 was used
under reaction conditions (TPPTS = triphenylphosphine
trisulphonated salt). When the same cobalt complex was
immobilized on glass, no cobalt metal leaching was observed.
Asymmetric hyd
roformylation of styrene catalyzed by
PtCl [SKEWPHOS (NMe2) 4] -SnCl3 shows a very strong temperature
dependence on optical selectivity. Enantiomeric excess (ee's)
switches sign fromS toR form at 57°C. At 25°C, there is 60.6%
ee of S product, whereas 56.7% ee in favor of R product is
observed at 100°C.
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