Ruthenium Hydroxides

Kotani, M., Koike, T., Yamaguchi, K. and Mizuno, N. (2006) Ruthenium hydroxide on magnetite as a magnetically separable heterogeneous catalyst for liquid-phase oxidation and reduction. Green Chemistry, 8 (8), 735-741. 

Ruthenium Hydroxide,187192 To an 1% aqueous solution of ruthenium chloride heated to 90-95°C is added an 5% lithium hydroxide solution dropwise under vigorous stirring until the pH of the supernatant liquid becomes 7.5-7.8. Addition of a few drops of the lithium hydroxide solution is usually necessary to prevent the pH of the liquid from becoming more acidic on continued stirring for a further 10-20 min. The black precipitate formed is collected on a filter paper, washed repeatedly with hot distilled water until the filtrate becomes almost neutral, and then dried in vacuo at room temperature. The dried hydroxide is pulverized into fine particles and can be used for hydrogenation at elevated temperatures and pressures without prereduction. 

Ruthenium Black from Ruthenium Hydroxide. The ruthenium hydroxide (1 g) prepared as described above is suspended in 100 ml of water in a hydrogenation bottle and reduced with atmospheric pressure of hydrogen at room temperature or 40-50°C until black precipitates of ruthenium are separated out. The supernatant liquid, which is not always clear but is often colored brown, is decanted and the precipitate is washed thoroughly with distilled water. To obtain a catalyst with lesser amounts of alkaline or acidic impurities, the reduction-washing process is repeated until the supernatant liquid becomes neutral. 

Ru(OH)3(10% Ru)-Pd(OH)2(0.1 % Pd)-C 7Aa RuC13-3H20 (52.4 g), PdCl2 (0.34 g), carbon (Darco G-60) (180 g), and water (2 liter) are mixed, rapidly stirred, and heated to 80°C. LiOH H20 (27 g) dissolved in water (100 ml) is added all at once and the heating stopped. The mixture is stirred overnight, filtered, and washed with a liter of 0.5 v/v% aqueous acetic acid. The product is dried in vacuo at 65°C. The yield is 202-211 g. The palladium hydroxide is incorporated in order to shorten the reduction time of the ruthenium hydroxide. 

Nishimura and Kasai studied the hydrogenation of acetophenone in f-butyl alcohol using carefully prepared ruthenium and rhodium blacks.176 The selectivities for the formation of cyclohexyl methyl ketone and 1-phenylethanol as simultaneous products have been determined by application of the equation in Scheme 11.7. The values of K and/as well as the composition of the final products obtained are summarized in Table 11.13. Three ruthenium blacks—Ru (A), Ru (N), and Ru (B)—were prepared from the ruthenium hydroxide precipitated at pH 5,7, and 7.8, respectively, by adding lithium hydroxide solution to an aqueous solution of ruthenium chloride. It is seen that the selectivity for the saturated ketone (see figures in parentheses) was considerably higher over Ru (B) (43%) than over Ru (A) (25%) and Ru (N) (20%). The selectivity over Ru (N) increased markedly to 65% at 100°C and 5.9-7.8 MPa H2. Over rhodium... 

Ruthenium hydroxide, is obtained in colloidal form by reducing an aqueous solution of potassium chlor-ruthenite, K2RuC15, by hydrazine sulphate in the presence of gum acacia, which serves as a protective colloid, preventing the coagulation of the hydroxide.6... 

The ruthenium catalyst (mean particle size 25 /im, Sbet = 75 m -g, mean pore size 60-70 nm) was prepared by reduction of ruthenium hydroxide, obtained by adding a sodium hydroxide solution to a ruthenium(lll)chloride solution [6,7]. 

Kim JW, Yamaguchi K, Mizuno N (2009) Heterogeneously catalyzed selective A-aUcylation of aromatic and heteroaromatic amines with alcohols by a supported ruthenium hydroxide. J Catal 263(l) 205-208... 

Yamaguchi K, He J, Mizuno N et al (2010) The borrowing hydrogen strategy by supported ruthenium hydroxide catalysts synthetic scope of syirunetrically and unsymmetrically substituted aitunes. Chem-Eur J 16(24) 7199-7207... 

Neutral or weakly acid solutions of alkali chlorates have but slight oxidizing action. On the other hand, they are strong oxidants in highly acid solutions. Alkali chlorate solutions are so activated by the addition of osmium tetroxide or ruthenium hydroxide that they give up their oxygen... 

Nikaidou, F., Ushiyama, H., Yamaguchi, K., et al. (2010). Theoretical and Experimental Studies on Reaction Mechanism for Aerobic Alcohol Oxidation by Supported Ruthenium Hydroxide Catalysts, J. Phys. Chem. C, 114, pp. 10873-10880. 

Related organic solvents-free protocols were described employing as catalysts ruthenium hydroxide supported on dopamine-functionahzed Pe304 nanoparticles... 

Yamaguchi K, Matsushita M, Mizuno N (2004) Efficient hydration of nitriles to amides in water, catalyzed by ruthenium hydroxide supported on alumina. Angew Chem Int Ed 43 1576... 

Polshettiwar V, Varma RS (2009) Nanoparticle-supported and magnetically recoverable ruthenium hydroxide catalyst Efficient hydration of nitriles to amides in aqueous medium. ChemEur J 15 1582... 

Baig RBN, Varma RS (2012) A facile one-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica Aqueous hydration of nitriles to amides. Chem Commun 48 6220... 

Oishi T, Yamaguchi K, Mizuno N (2010) An efficient one-pot synthesis of nitriles Ifom alcohols or aldehydes with NH3 catalyzed by a supported ruthenium hydroxide. Top Catal 53 479... 

He J, Yamaguchi K, Mizuno N (2011) Aerobic oxidative transformation of primary azides to nitriles by ruthenium hydroxide catalyst J Org Chem 76 4606... 

He J, Yamaguchi K, Mizuno N (2011) Aerobic oxidative transformation of primary azides to nitriles by ruthenium hydroxide catalyst. J Org Chem 76(11) 4606-4610 Zhou W, Xu J, Zhang L, Jiao N (2010) An efficient transformation from benzyl or allyl halides to aryl and alkenyl nitriles. Org Lett 12(12) 2888-2891... 

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