Catalysis of Organic..

182 Hydrogenation of Dehydrolinaloola Catalyst concentration.b Initial substrate concentrationCatalytic activity and selectivity of the catalysts developed are presented inTable 2.Table 2. Catalytic activity and selectivity of the catalysts developedCatalystPdcontent,wt.%W a ,m 3 (H 2 )/(molPd⋅molS⋅s)TOF b , l/s70 -5 0.44 i-PrOH +(7:3(vol.))Pd-PEO-960P2VP/A 2 O 3 (7:3(vol.))b-1.8⋅10waterPd-PS-b- 90 2.3⋅10 -5 0.44 toluene 480P4VPPd- 70 2.8⋅10 -4 0.44 i-PrOH 960PDADMACPd-HPS 90 2.9⋅10 -4 0.55 toluene 480Conversion,%Selectivity,%Pd-PEO-b- 0.060 9.3 3.4 100 98.4P2VPPd-PEO-b- 0.060 10.0 7.9 100 98.5P2VP/A 2 O 3Pd-PS-b- 0.036 31.8 18.5 100 99.8P4VPPd- 0.580 3.0 4.5 98.3 98.1PDADMACPd-HPS 0.050 4.4 2.1 100 99.0aRelative rate at 20% hydrogen uptakebTurnover frequency (TOF = mol DHL/ (mol Pd ⋅ s))It can be seen from Table 2 that the supported catalyst (Pd-PEO-b-P2VP/Al 2 O 3 )has almost twice the TOF compared to the unsupported one. It accounts for fact thatin the case of heterogeneous catalyst the micellar aggregates are distributed on thesupport surface, and the accessibility of catalytic sites increases. Besides, all theinvestigated catalysts have rather high selectivity compared to the traditionalcatalysts (e.g. the commercial Lindlar catalyst (palladium deposited on CaCO 3 andmodified with lead diacetate) provides the selectivity of 95% at 100% DHLconversion), which could be explained by the electronic structure of the catalysts. Asdiscussed in the preceding papers (1, 18), modification of the metal nanoparticlesurface, e.g. with aromatic rings or by the coordination of Pd atoms with nitrogen,