TY - JOUR
T1 - Catalytic conversions in aqueous media
T2 - A novel and efficient hydrogenation of polybutadiene-1,4-block-poly(ethylene oxide) catalyzed by Rh/TPPTS complexes in mixed micellar nanoreactors
AU - Kotzabasakis, Vasilis
AU - Georgopoulou, Eleni
AU - Pitsikalis, Marinos
AU - Hadjichristidis, Nikolaos
AU - Papadogianakis, Georgios
PY - 2005/4/20
Y1 - 2005/4/20
N2 - Exceptionally high catalytic activities (TOF > 840 h-1) were achieved in the aqueous phase hydrogenation of polybutadiene-1,4-block- poly(ethylene oxide) (PB-b-PEO) catalyzed by water-soluble Rh/TPPTS complexes [TPPTS = P(C6H4-m-SO3Na)3] in mixed micellar nanoreactors formed by dodecyltrimethylammonium chloride along with PB-b-PEO especially when n-hexane was added to the reaction system. This is the first example of a catalytic hydrogenation of an unsaturated polymer using water-soluble transition metal TPPTS complexes in aqueous media. Using Rh/TPPTS catalysts high activities were observed in the hydrogenation of PB-b-PEO in mixed micelles whereas in single micelles the activities were lower. Dynamic light scattering experiments showed the presence of mixed nanomicelles with smaller hydrodynamic radii compared to the radii of single micelles. A model of a mixed micellar nanoreactor was proposed to rationalize the observed results. The hydrogenation reaction was shown to be homogeneously catalyzed by Rh/TPPTS complexes generated in situ from RhCl3·3H2O and TPPTS under the reaction conditions. A recycling experiment showed that the catalytic activity remained high in a consecutive run even at a rhodium concentration of only 1 ppm in water.
AB - Exceptionally high catalytic activities (TOF > 840 h-1) were achieved in the aqueous phase hydrogenation of polybutadiene-1,4-block- poly(ethylene oxide) (PB-b-PEO) catalyzed by water-soluble Rh/TPPTS complexes [TPPTS = P(C6H4-m-SO3Na)3] in mixed micellar nanoreactors formed by dodecyltrimethylammonium chloride along with PB-b-PEO especially when n-hexane was added to the reaction system. This is the first example of a catalytic hydrogenation of an unsaturated polymer using water-soluble transition metal TPPTS complexes in aqueous media. Using Rh/TPPTS catalysts high activities were observed in the hydrogenation of PB-b-PEO in mixed micelles whereas in single micelles the activities were lower. Dynamic light scattering experiments showed the presence of mixed nanomicelles with smaller hydrodynamic radii compared to the radii of single micelles. A model of a mixed micellar nanoreactor was proposed to rationalize the observed results. The hydrogenation reaction was shown to be homogeneously catalyzed by Rh/TPPTS complexes generated in situ from RhCl3·3H2O and TPPTS under the reaction conditions. A recycling experiment showed that the catalytic activity remained high in a consecutive run even at a rhodium concentration of only 1 ppm in water.
KW - Aqueous media
KW - Hydrogenation
KW - Mixed micelles
KW - Rhodium
KW - TPPTS
UR - http://www.scopus.com/inward/record.url?scp=14844316672&partnerID=8YFLogxK
U2 - 10.1016/j.molcata.2005.01.002
DO - 10.1016/j.molcata.2005.01.002
M3 - Article
AN - SCOPUS:14844316672
SN - 1381-1169
VL - 231
SP - 93
EP - 101
JO - Journal of Molecular Catalysis A: Chemical
JF - Journal of Molecular Catalysis A: Chemical
IS - 1-2
ER -