Gluconic acid, calcium salt

Oxidation with Bromine Gluconic Acid Calcium Salt, 

After the reaction is over the excess of bromine is boiled off, stirring to prevent local overheating, and the golden yellow solution is cooled and the volume measured. Bromine ion is then determined in an aliquot portion, after which the calculated amount of lead carbonate, ground to a thin paste with water, is added in small portions, with stirring. An appreciable excess of lead carbonate is to be avoided, as lead gluconate is 

The free glucomc acid is a syrup and passes over 

The sugar may be freed from traces of ash by re-crystallization from one-half its weight of water, with the aid of bone-black. It should then form rhombic prisms which melt at 158.5-9.50 when anhydrous and 

The essential requirement m the preparation of diethylmalonic ester and veronal is that all reagents must be absolutely anhydrous, otherwise the yields will be vanishingly small. All reagents and solutions must therefore be protected from the moisture of the air after drying. 

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D. Oxidation with Bromine Gluconic Acid Calcium Salt,... 

Calglucon Glucal Gluconic acid calcium salt D-Gluconic acid calcium salt d-Gluconic acid, calcium salt (2 1)... 

Gluconic acid calcium salt In calcium therapy In animal nutrition Heaney et al. (1977) and Perkins (1978)... 

Synonyms Calcium diborogluconate D-Gluconic acid cyclic 4,5-ester with boric acid calcium salt... 

The reduced catalyst deactivation compared to the analogous oxidations of glycerol and tartronic acid was attributed to the use of the calcium salt rather than the free acid. A recent publication describes a similar observation for the oxidation of sodium gluconate [15]. Sodium ions were assumed to counter catalyst deactivation by neutralizing the acid species responsible. 

A reaction of practical importance is the oxidation of a carbohydrate aldehyde group to a carboxyl group. This is the basis for a process converting glucose to calcium gluconate, a substance of pharmaceutical interest. The oxidation reaction occurs at graphite electrodes in the presence of the Brj/Br" redox system. Calcium salt is added to the solution to prevent further oxidation of free gluconic acid. 

Calcium D-galactonate, I, 70 Calcium D-gluconate, III, 141, 142, 149, 152, 155, 156, 161 IV, 331 Calcium hypochlorite, III, 165 Calcium 2-keto-D-gIuconate, III, 148, 155 Calcium 5-keto-D-gluconate, III, 156 Calcium lactobionate, calcium bromide double salt, III, 155 Calcium Ievulinate, IV, 311 Calcium maltobionate, III, 161 Calcium D-mannonate, III, 152 Calcium pectate, I, 334 Calcium D-rhamnonate, III, 144 Calcium salts, in preparation of aldonic acids with NaCN, I, 23 Calcium vicianobionate, III, 154 Calcium D-xylonate, III, 155 Camphor, optically active, formed from inactive (racemic) camphor carboxylic acid in the presence of quinine, quinidine or nicotine, V, 53 Camphor carboxylic acid. See Camphor. Camphor, 3-hydroxy-, IV, 89 Camphorquinone, phytochemical reduction of, IV, 89... 

In most cases, after the hydrogen bromide had been removed, the resulting solutions were treated with various carbonates or with ammonium hydroxide to form the desired salts. The salts could be recrystallized directly from water or precipitated into ethanol. The choice of salt depended on circumstances thus, calcium D-gluconate crystallized well, but in the case of n-galactonic acid, the cadmium salt was preferable. The lead or cadmium salt was preferred when the free acid was desired since treatment of the aqueous solution or suspension with hydrogen sulfide easily removed the cation. The barium salts could be treated with the calculated amount of sulfuric acid and the calcium salts with oxalic acid for the same purpose. 

Another method of preparing keto aldonic acids, those of the 2-keto type, is by oxidation of the corresponding osone. Neuberg and Kitasato obtained 18 g. of calcium 2-keto-D-gluconate from 20 g. of the osone by the action of bromine at 20 . Similarly, 2-keto-n-galactonic and 2-keto-maltobionic acids were prepared by Kitasato. The substances were characterized generally as the brucine salts because of the amorphous nature of the calcium salts. 

In 1931, Isbell and Frush reported the electrolytic oxidation of aldoses in the presence of calcium carbonate and a small amount of bromide, which served as a catalyst. The main solutes in the reaction mixture are the aldose and the calcium salt of the aldonic acid. The latter is easily crystallized from solution. The salts of D-gluconic, D-xylonic, lactobionic and maltobionic acids were prepared. A description of the process was published in 1932 and a patent was issued in 1934. German and French patents were issued in 1931 to the Rohm and Haas Co. ... 

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