TY - JOUR
T1 - Evidence of colloidal rhodium formation during the biphasic hydroformylation of 1-octene with thermoregulated phase-transfer phosphine rhodium(I) catalyst
AU - Wen, Fei
AU - Bönnemann, Helmut
AU - Jiang, Jingyang
AU - Lu, Dongmei
AU - Wang, Yanhua
AU - Jin, Zilin
PY - 2005/1
Y1 - 2005/1
N2 - A thermoregulated phase-transfer (TRPT) Rh(I) complex catalyst A prepared from Rh(acac)(CO)2 and a thermoregulated ligand CH 3(OCH2CH2)mPPh2 (M w = 918) was applied to the biphasic hydroformylation of 1-octene, and a high activity with an aldehyde yield of 97.5% was demonstrated. After three recycling steps, the aldehyde yield gradually decreased. Transmission electron microscopy (TEM) revealed that after the first cycle Rh colloids were generated in situ in the aqueous phase, and in subsequent runs Ostwald ripening occurred. An independently prepared colloidal Rh(0) TRPT catalyst D also exhibited high hydroformylation activity under identical experimental conditions, and after two times of recycling an activity decrease was also observed. It is suggested that in situ from Rh(acac)(CO)2 colloidal Rh particles are generated, which demonstrate thermomorphic behaviour and a high hydroformylation activity. Subsequently, agglomeration processes result in an activity decay, as observed in the TRPT Rh(I) complex catalyst system.
AB - A thermoregulated phase-transfer (TRPT) Rh(I) complex catalyst A prepared from Rh(acac)(CO)2 and a thermoregulated ligand CH 3(OCH2CH2)mPPh2 (M w = 918) was applied to the biphasic hydroformylation of 1-octene, and a high activity with an aldehyde yield of 97.5% was demonstrated. After three recycling steps, the aldehyde yield gradually decreased. Transmission electron microscopy (TEM) revealed that after the first cycle Rh colloids were generated in situ in the aqueous phase, and in subsequent runs Ostwald ripening occurred. An independently prepared colloidal Rh(0) TRPT catalyst D also exhibited high hydroformylation activity under identical experimental conditions, and after two times of recycling an activity decrease was also observed. It is suggested that in situ from Rh(acac)(CO)2 colloidal Rh particles are generated, which demonstrate thermomorphic behaviour and a high hydroformylation activity. Subsequently, agglomeration processes result in an activity decay, as observed in the TRPT Rh(I) complex catalyst system.
KW - Biphasic hydroformylation
KW - Rhodium colloid catalyst
KW - Thermoregulated phase-transfer catalysis
UR - http://www.scopus.com/inward/record.url?scp=12844280504&partnerID=8YFLogxK
U2 - 10.1002/aoc.838
DO - 10.1002/aoc.838
M3 - Article
AN - SCOPUS:12844280504
SN - 0268-2605
VL - 19
SP - 81
EP - 89
JO - Applied Organometallic Chemistry
JF - Applied Organometallic Chemistry
IS - 1
ER -