Aluminum hydroxide-palladium catalyst

In this special field, earlier work had been done in other laboratories, such as by the Schering Company, Berlin (36), and by Ipatieff (37) in connection with his work on the hydrogenation of camphor and of other organic compounds. At both places, the favorable effect of alkali oxides and earth alkali oxides on nickel, cobalt and copper has been investigated. Similarly, Paal and his coworkers (38) have used a palladium-aluminum hydroxide catalyst in 1913 for the hydrogenation of double bonds. Bedford and Erdman (39) had reported that the catalytic action of nickel oxide is enhanced by the oxides of aluminum, zirconium, titanium, calcium, lanthanum, and magnesium. 

Unsupported palladium catalysts are often unstable in use at elevated temperatures and/or high hydrogen pressures. Yada et al. obtained a highly stable palladium black by precipitating palladium hydroxide from palladium chloride solution with an aqueous sodium aluminate instead of sodium hydroxide.177 The palladium catalyst obtained by reduction of the palladium hydroxide prepared with a 1M sodium aluminate solution at pH 10, in the same way as described above, kept a high surface area of 139 m2 g 1 even after the reduction at 200°C in a flow of hydrogen, compared to only 2.0 m2 g 1 with the catalyst prepared using a sodium hydroxide solution as precipitant. The thermally stable catalyst was found to contain 13 ppm of sodium and 1400 ppm (0.14%) of aluminum. 

Hydrogenation catalysts Dichlorotris(triphenylphosphine)ruthenium. Iridium. Iridium tetrachloride-Triethyl phosphite. Iridium-BaSO, or CaC04. Lithium aluminum hydride. Nickel catalyst, Raney. Palladium hydroxide. Platinum catalysts. Potassium hydride. Trihydridobis(triphenyIphosphine)iridium (III). 

Park and coworkers have developed a palladiinn nanocatalyst, applicable to the DKR of primary amines as well as amino acid amides [97]. This nanocatalyst, Pd/ AIO(OH), prepared as palladium nanoparticles entrapped in aluminum hydroxide required 70 °C for the racemization of benzylic amines and higher temperature (100 °C) in the case of aliphatic amines. For that reason, DKR processes were developed in combination with thermostable immobilized CALB. In fact, these authors have described the coupling of this catalyst with the activity of P. stutzeri lipase in the DKR of p-amino acid amides being necessary to perform the enzymatic resolution and the racemization at different temperatures and to add fresh lipase after the racemization due to the thermal enzyme deactivation [98]. 

Tetrahydrofurfuryl alcohol reacts with ammonia to give a variety of nitrogen containing compounds depending on the conditions employed. Over a barium hydroxide-promoted skeletal nickel—aluminum catalyst, 2-tetrahydrofurfurylamine [4795-29-3] is produced (113—115). With palladium on alumina catalyst in the vapor phase (250—300°C), pyridine [110-86-1] is the principal product (116—117) pyridine also is formed using Zn and Cr based catalysts (118,119). At low pressure and 200°C over a reduced nickel catalyst, piperidine is obtained in good yield (120,121). 

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