Gluconic acid

 

Gluconic acid

Chemical formula	C6H12O7
OTP appearance	colorless crystals
Molar Mass(g/mol)	196.16
Melting Point(°C)	131
Solubility in water(g/L)	316
NFPA 704	1 1 0

Uses

Primary

• Precursor to WHO LEM entries calcium gluconate and sodium stibogluconate

Natural occurrence

• does not occur naturally

Production

Fermentation

• May, Orville E.; Herrick, Horace T.; Thom, Charles; Church, Margaret B. (1927) "The production of gluconic acid by the penicillium luteum-purpurogenum group. Part I."
  Journal of Biological Chemistry 75(22); pp417-422. 
  link courtesy ScienceDirect.
• May, Orville E.; Herrick, Horace T. (1928) "The production of gluconic acid by the penicillium luteum-purpurogenum group. Part II."
  Journal of Biological Chemistry 77(1); pp185-195. 
  link courtesy ScienceDirect.

Synthesis

via hydrogen peroxide

• Combine glucose and 12% hydrogen peroxide at 80°C for 70 minutes

C₆H₁₂O₆ + H₂O₂

{

→

80°C, 70min}

C₆H₁₂O₇ + H₂O

via bromine

Several systems for producing glucolic acids and gluconates rely on oxidation of glucose by bromine

50 g  of glucose dissolved in 400 ml of water are treated in a stoppered bottle with 100 g of bromine. The mixture is allowed to stand, with frequent shaking, for 3 days at ordinary temperatures, and then boiled in a porcelain dish in a fume cupboard with constant stirring, until all the bromine has disappeared. The solution is cooled, diluted with water to 500 ml, and neutralized with lead carbonate suspended in water. The precipitate is filtered at the pump, suspended in water and saturated with hydrogen sulphide, filtered and neutralized by boiling for 0.5 hour with precipitated chalk. The filtrate is evaporated to about 100 ml, and seeded in the cold with a crystal of calcium gluconate. After 24 hours the whole is filtered at the pump and the precipitate washed with cold water, redissolved in a small quantity of hot water, and boiled with addition of activated charcoal. The latter is filtered off and the solution treated with the exact quantity of oxalic acid in aqueous solution necessary to precipitate the calcium present. The precipitated calcium oxalate is filtered off and washed, and the washings and filtrate evaporated to a syrup on a warm water bath under reduced pressure. Yield 50%. Acid syrup; soluble in water; on standing or heating changes in part to a crystalline lactone; m.p. 130-135° C.