Palladium-alumina Hydrazine

Ruthenium catalysts, supported on a commercial alumina (surface area 155 m have been prepared using two different precursors RUCI3 and Ru(acac)3 [172,173]. Ultrasound is used during the reduction step performed with hydrazine or formaldehyde at 70 °C. The ultrasonic power (30 W cm ) was chosen to minimise the destructive effects on the support (loss of morphological structure, change of phase). Palladium catalysts have been supported both on alumina and on active carbon [174,175]. Tab. 3.6 lists the dispersion data provided by hydrogen chemisorption measurements of a series of Pd catalysts supported on alumina. is the ratio between the surface atoms accessible to the chemisorbed probe gas (Hj) and the total number of catalytic atoms on the support. An increase in the dispersion value is observed in all the sonicated samples but the effect is more pronounced for low metal loading. 

Platinum/palladium nanoparticulate catalysts were synthesized [421] from microemulsions in the system PEGDE/hexadecane/water. The conversion of the platinum precursor to metal nanoparticles (10-100 nm, formed by aggregation of 2-5 nm particles) was achieved through hydrazine at ambient temperature. The nanoparticles could be deposited on alumina substrates. 

Hydrogenation is the most well studied area among immobilized palladium catalysis. While a great majority of the applications focused on the use of support such as alumina and activated carbon, a great diversity of novel support systems have been reported in recent years, aimed at finding a catalyst with a well-characterized coordination sphere and tailor-made activity. Pd(0) catalysts dispersed on crosslinked styrene-divinylbenzene copolymers have been prepared by impregnation of lipophilic complexes followed by reduction with hydrazine. It was found that the functional groups in the polymer as well as polymer particle sizes had a major effect on catalyst activity.t [i53]-[i95]... 

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