Glucose reaction with aqueous ammonia

When sugars are treated with aqueous ammonia for a short time at low temperature in the absence of a catalyst, the reaction is arrested before heterocyclic compounds can be formed in appreciable proportion, and the products are mainly epimerization products of the sugars, probably formed by way of their 2,3-enediols. These epimerization products are summarized in Table I which shows the reactions of D-glucose, D-fructose, lactose, maltose, and melibiose with aqueous ammonia for a short time at low temperature. A dark-colored, high polymer is also formed in some instances (the browning reaction). In the ammoniacal solution, the monosaccharides are epimerized the disaccharides are epimerized and, in addition, may be hydrolyzed to monosaccharides that can also be epimerized hence, the variety of products obtained may be considerable. 

Cheap sources of acyloins are the reducing carbohydrates, and a number of new imidazoles have been isolated from the reaction of ammonia with these compounds. From the interaction of D-glucose and aqueous ammonia, Komoto has obtained 2-hydroxymethyl-4-methylimidazole,45 4-(2 -hydroxyethyl)imidazole,38 4-(2, 3 -dihydro-... 

Platinum catalysts were prepared by an ion-exchange method [16,17]. Oxidised sites on the surface of an activated carbon support (CECA SOS) were created by pre-treatment with sodium hypochlorite (3%) the associated protons were subsequently exchanged with Pt(NH3)4 " ions, in an aqueous ammonia solution, and reduction was carried out on the dry catalyst under a flow of hydrogen at 300°C. A surface redox reaction was subsequently employed to deposit the bismuth whereby the catalyst was suspended in a glucose solution, under an inert nitrogen atmosphere, and the required volume of a solution of BiONOs, dissolved in hydrochloric acid (IM), was added [18]. 

Consider next the fermentation of some nonnitrogenous, but otherwise unspecified, substrate (for example, a sugar such as glucose) in aqueous solution with dissolved ammonia as the nitrogen source to produce average biomass, carbon dioxide, and water. On a carbon mole basis, this reaction is... 

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