The catalyst RuCl2(PPh3)3 is transformed into a catalytically inactive complex RuCl2(CO)(PPh3)2(DMF) during disproportionation of D-glucose in dimethylformamide (DMF). In dimethylacetamide (DMA), the catalyst is converted to RuCl2(CO)(PPh3)2(DMA) and cis-RuCl2(CO)2(PPh3)2. The aldehydo-glucose is shown to be the main source of carbon monoxide. © 1983.

S. Vancheesan

Jayaraman Rajaram

Joseph C. Kuriacose

carbon monoxide

Organic compounds

glucose

CATALYSTS

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IIT Madras

Deactivation of RuCl2(PPh3)3 during disproportionation of D-glucose in amide solvents

Journal of Molecular Catalysis

Glucose is transfer hydrogenated by propan-2-ol, butan-2-ol, cyclohexanol, benzyl alcohol, 1-phenylethanol, benzhydrol, 2-methoxyethanol and tetrahydrofurfuryl alcohol in the presence of RuCl2(PPh3)3 at 100 °C and atmospheric pressure. Mixed solvent systems such as dimethylacetamide-water and dioxane-water are utilized for this reaction. The major product from glucose is sorbitol, although glucono-1,5-lactone is invariably formed as a side product from a disproportionation reaction. When 2-methoxyethanol and tetrahydrofurfuryl alcohol are used as hydrogen donors, the catalyst undergoes permanent change to a hydridocarbonyl complex, which catalyzes only disproportionation of glucose. Glucose also acts as a good hydrogen donor when hydrogen acceptors such as cyclohexanone are introduced into the reaction system. © 1992.

RuCl2(PPh3)3-catalyzed transfer hydrogenation of d-glucose

A mechanism for the transfer hydrogenation of ketones to secondary alcohols catalysed by HFe3(CO)11-1 (1) in the presence of Phase Transfer Catalysts (PTC) has been proposed using labelled hydrogen, NMR and IR techniques. © 1989.

Mechanism for transfer hydrogenation of ketones to alcohols catalysed by hydridotri-ironundecacarbonylate anion under phase transfer conditions

Transfer hydrogenation of ketones to alcohols using iron carbonyls as catalysts in liquid-liquid phase occurs in the presence of phase transfer catalysts (PTC). Based on the percentage yield of the products, the efficiencies of the phase transfer agent, iron carbonyls and the donors are compared. Benzyltriethylammonium chloride and 18-crown-6 are equally effective and better than tricaprylmethylammonium chloride (Aliquat® 336). Among the three iron carbonyls the order of efficiency is Fe3(CO)12 &gt; Fe2(CO)9 &gt; Fe(CO)5. 1-Phenylethanol is a better donor than isopropanol. The relative ease of reducibility of various ketones increases with increasing reduction potential. The stereochemistry of reduction of 4-t-butylcyclohexanone is discussed. © 1985.

Phase transfer-catalysed transfer hydrogenation of ketones using iron carbonyls as catalysts

d-Fructose is hydrogenated to d-glucitol and d-mannitol using RuCl2 (PPh3)3 as catalyst at 100°C and atmospheric pressure. Besides hydrogenation, fructose undergoes transfer hydrogenation when propan-2-ol and butan-2-ol are used as solvents. Under an inert atmosphere (nitrogen), only transfer hydrogenation of fructose is observed in these alcohols. The rate of hydrogenation is comparable with transfer hydrogenation under similar reaction conditions. Cyclohexanol, benzyl alcohol, 1-phenylethanol and benzhydrol are also found to be good hydrogen donors for fructose reduction. Both hydrogenation and transfer hydrogenation yield glucitol and mannitol whose ratio is always 1:1. The catalyst is deactivated when hydrogen donors such as 2-methoxyethanol and tetrahydrofurfuryl alcohol are employed. The deactivation is attributed to the formation of an inactive ruthenium carbonyl complex, viz., RuHCl (CO) (PPh3)3. The hydrogen donating ability of these alcohols and their oxidation potentials are compared and the relative degrees of correlation are rationalized. © 1993.

Journal	Journal of Molecular Catalysis
ISSN	03045102
Open Access	No