Hydrogenation using nanoparticle

Fig. 14 Summary of the best results obtained in the Ir-catalyzed hydrogenation using nanoparticles stabilized with furanoside diphosphite ligands 14 and 15...

Moreover, lr(0) nanoparticles recovered after benzene hydrogenation using solventless conditions can be reused for at least seven runs without any significant... 

Methoxyphenyl ethers can be cleaved by mild oxidants (Entry 10, Table 7.8). Because many acid-labile linkers are also readily oxidized, care must be taken when applying this deprotection strategy. Benzyl ethers have been removed from Tentagel-or PEGA-bound carbohydrates by catalytic hydrogenation using palladium nanoparticles [112],... 

Allylic alcohols were hydrogenated using f to 3 nm diameter bimetallic Pd-Au dendrimer-encapsulated catalysts (DECs) [fi8]. Both alloy and core/shell Pd-Au nanoparticles were prepared. The catalytic hydrogenation of allyl alcohol was significantly enhanced in the presence of the alloy and core/shell Pd-Au nanoparticles as compared to mixtures of single-metal nanoparticles [fi8]. 

Figure 13. Schematic of the photoelectrolytic cell designed for the generation of hydrogen using a light source (UV or visible). The anode is carbon-doped titania nanotubular arrays prepared by the sonoelectrochemical anodization technique and the cathode is platinum nanoparticles S3mthesized on undoped titania nanotubular arrays. (Redrawn from Misra et al. [220] with permission from publisher, American Chemical Society. License Number 2627061508363).

Hydrogenation with Nanoparticles Using Supported Ionic Liquids... 

Hydrogenation. There are many ways to hydrogenate quinoline to either the fliUy reduced product (DHQ) or to either of the two partially hydrogenated products ( THQ 1,2,3,4-tetrahydroquinoline and THQ 5,6,7,8-tetrahydroquinoline). While most conditions produce a statistical distribution of the three compounds, new methods employing transition metal nanoparticles have been found to selectively afford one product in excellent yield. Hydrogenation using rhodium nanoparticles affords DHQ (eq 15), while palladium nanoparticles produces THQ in nearly quantitative yield (eq 16). ... 

The hydrogenation of latex polymer was accomplished using nanoparticle polymers in aqueous solution, without added solvent, and using Wilkinson s catalyst. The use of extremely small latex particles allows high reaction rates with lower catalyst concentrations, two green chemistry benefits. At 120 C, 1 wt % catalyst, and 35.3 nm particles, the data in Table 6.6 is reported. 

Kinetics of linoleic acid hydrogenation using Pd containing nanoparticles was studied recendy the overall reaction can be written as follows... 

F1 NMR of chemisorbed hydrogen can also be used for the study of alloys. For example, in mixed Pt-Pd nanoparticles in NaY zeolite comparaison of the results of hydrogen chemisorption and F1 NMR with the formation energy of the alloy indicates that the alloy with platinum concentration of 40% has the most stable metal-metal bonds. The highest stability of the particles and a lowest reactivity of the metal surface are due to a strong alloying effect. 

Moreover, stable liquid systems made up of nanoparticles coated with a surfactant monolayer and dispersed in an apolar medium could be employed to catalyze reactions involving both apolar substrates (solubilized in the bulk solvent) and polar and amphiphilic substrates (preferentially encapsulated within the reversed micelles or located at the surfactant palisade layer) or could be used as antiwear additives for lubricants. For example, monodisperse nickel boride catalysts were prepared in water/CTAB/hexanol microemulsions and used directly as the catalysts of styrene hydrogenation [215]. 

In summary, super-lattices may be obtained using the estabUshed techniques of self-organization but also a technique derived from molecular chemistry, the creation of hydrogen bond networks, hi addition, the crystallization of nanoparticles inside 3D super-crystals may be achieved using ionic stabilizers. 

In the past five years, the use of nanoparticles in this active research area has received increased attention since some homogeneous catalysts have been shown to be nanoheterogeneous [24-26]. Today, soluble noble metal nanoparticles are considered as reference in monocyclic arene catalytic hydrogenation under mild conditions and several stabilized systems have been reported [27,28]. 

The isolated Ru(0) nanoparticles were used as solids (heterogeneous catalyst) or re-dispersed in BMI PP6 (biphasic liquid-liquid system) for benzene hydrogenation studies at 75 °C and under 4 bar H2. As previously described for rhodium or iridium nanoparticles, these nanoparticles (heterogeneous catalysts) are efficient for the complete hydrogenation of benzene (TOP = 125 h ) under solventless conditions. Moreover, steric substituent effects of the arene influenced the reaction time and the decrease in the catalytic TOP 45, 39 and 18h for the toluene, iPr-benzene, tBu-benzene hydrogenation, respectively, finally. The hydrogenation was not total in BMI PPg, a poor TOE of 20 h at 73% of conversion is obtained in the benzene hydrogenation. 

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