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Glucose palladium

The reaction is used for the chain extension of aldoses in the synthesis of new or unusual sugars In this case the starting material l arabinose is an abundant natural product and possesses the correct configurations at its three chirality centers for elaboration to the relatively rare l enantiomers of glucose and mannose After cyanohydrin formation the cyano groups are converted to aldehyde functions by hydrogenation m aqueous solution Under these conditions —C=N is reduced to —CH=NH and hydrolyzes rapidly to —CH=0 Use of a poisoned palladium on barium sulfate catalyst prevents further reduction to the alditols... [Pg.1056]

Fischer s original method for conversion of the nitrile into an aldehyde involved hydrolysis to a carboxylic acid, ring closure to a cyclic ester (lactone), and subsequent reduction. A modern improvement is to reduce the nitrile over a palladium catalyst, yielding an imine intermediate that is hydrolyzed to an aldehyde. Note that the cyanohydrin is formed as a mixture of stereoisomers at the new chirality center, so two new aldoses, differing only in their stereochemistry at C2, Tesult from Kiliani-Fischer synthesis. Chain extension of D-arabinose, for example, yields a mixture of D-glucose and o-mannose. [Pg.994]

Wenkin, M., Touillaux, R., Ruiz, P., Delmon, B., and Devillers, M. (1996) Influence of metallic precursors on the properties of carbon-supported bismuth-promoted palladium catalysts for the selective oxidation of glucose to gluconic acid. Appl. Catal., A, 148, 181-199. [Pg.187]

Li et al. reported first on the decoration of hydrothermal carbon spheres obtained from glucose with noble metal nanoparticles [19]. They used the reactivity of as-prepared carbon microspheres to load silver and palladium nanoparticles onto then-surfaces, both via surface binding and room-temperature surface reduction. Furthermore, it was also demonstrated that these carbon spheres can encapsulate nanoparticles in their cores with retention of the surface functional groups. Nanoparticles of gold and silver could be encapsulated deep in the carbon by in situ hydrothermal reduction of noble-metal ions with glucose (the Tollens reaction), or by using silver nanoparticles as nuclei for subsequent formation of carbon spheres. Some TEM images of such hybrid materials are shown in Fig. 7.4. [Pg.206]

The second way is semisynthetic, consisting of fermentation of D-glucose in the presence of 3-acetoxybenzaldehyde, which forms (-)-l-hydroxy-l-(3-hydroxyphenyl)-acetone (11.3.12), the carbonyl group of which is reduced by hydrogen over a palladium catalyst in the presence of ammonia, giving metaraminol (11.3.11) [62-65]. [Pg.157]

Besson M, Gallezot P, Lahmer E, Eleche G, Euertes P (1993) Oxidation of glucose on palladium catalysts particle size and support effects. In Kosak JR, Johnson TA (eds) Catalysis of organic reactions. Marcel Dekker, New York... [Pg.92]

Aldosen werden leicht zu Aldonsauren oxydiert. So wird D-Glucose in Gegenwart der theoretischen Menge Alkali in guten Ausbeuten zu D-Gluconsaure oxydiert, wobei als Katalysator Palladium/Calciumcar-... [Pg.161]

The kinetics of the potassium hexacyanoferrate(III)-catalysed oxidation of glucose with ammonium peroxodisulfate have been studied.82 The kinetics and mechanism of oxidation of some cycloalkanols by alkaline Fe(CN) have been reported.83 The same group has also studied the oxidation of cycloalkanones under comparable conditions and determined the order of reactivity as cyclohexanone > cyclopentanone > cyclo-octanone > cycloheptanone.84 Palladium(II) has been found to catalyse the oxidation of formaldehyde, thiourea, and thioacetamide by alkaline Fe(CN)g, whereas no effect is observed in the oxidation of acetaldehyde.85 The orders of reaction have been determined and a mechanism was proposed. [Pg.186]

Ivekovic et al. [42] Fruit juice, yoghurt drink Glucose oxidase (GOx)/ into palladium hexacyanoferrate (PdHCF) hydrogel Nickel hexacyanoferrate (NiHCF) electrodeposited onto graphite electrode/-0.075V vs. SCE Nickel hexacyanoferrate... [Pg.262]

M. Besson, F. Lahmer, P. Gallezot, P. Fuertes, and G. Fleche, Catalytic oxidation of glucose on bismuth-promoted palladium catalyst, J. Catal., 152 (1995) 116-121. [Pg.281]

As with platinum, the palladium-catalyzed oxidation of anomeric hydroxyl groups in aldoses is a rather selective process.84 The influence of pH in the Pd-catalyzed oxidation of glucose has been studied. It was observed that the gluconic acid formed, in its free form, reversibly inhibits the oxidation process in acidic media.85 The oxidation of D-glucose has been performed with palladium-on-alumina and with bismuth-containing palladium-on-charcoal in water.85 The selectivity in the air oxidation of... [Pg.333]


See other pages where Glucose palladium is mentioned: [Pg.49]    [Pg.161]    [Pg.53]    [Pg.27]    [Pg.181]    [Pg.540]    [Pg.88]    [Pg.319]    [Pg.48]    [Pg.11]    [Pg.159]    [Pg.214]    [Pg.108]    [Pg.83]    [Pg.83]    [Pg.169]    [Pg.34]    [Pg.55]    [Pg.80]    [Pg.113]    [Pg.165]    [Pg.35]    [Pg.49]    [Pg.10]    [Pg.65]    [Pg.254]    [Pg.145]    [Pg.73]    [Pg.156]    [Pg.237]    [Pg.242]    [Pg.2328]    [Pg.82]    [Pg.94]   
See also in sourсe #XX -- [ Pg.509 ]




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Palladium glucose oxidation

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