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Evidence of colloidal rhodium formation during the biphasic hydroformylation of 1‐octene with thermoregulated phase‐transfer phosphine rhodium(I) catalyst
Author(s) -
Wen Fei,
Bönnemann Helmut,
Jiang Jingyang,
Lu Dongmei,
Wang Yanhua,
Jin Zilin
Publication year - 2005
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.838
Subject(s) - hydroformylation , rhodium , chemistry , catalysis , phosphine , ostwald ripening , colloid , aldehyde , yield (engineering) , organic chemistry , polymer chemistry , chemical engineering , metallurgy , materials science , engineering
A thermoregulated phase‐transfer (TRPT) Rh(I) complex catalyst A prepared from Rh(acac)(CO) 2 and a thermoregulated ligand CH 3 (OCH 2 CH 2 ) m PPh 2 ( 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. Copyright © 2005 John Wiley & Sons, Ltd.