DATA REGARDING ASCORBIC ACID
Ascorbic acid is vitamin C. It is a well-known antioxidant in the food industry. In the past, its deficiency used to be linked to cases of scurvy.
CAS Registry Number: 50-81-7
Molecular Mass: 176.12 g.mol-1
Crystals (usually flat, sometimes needle-like). mp 190-192°C. density 1.65. [α]D25 = +20.5 to +21.5° (c = 1 in water); redox potential: E0= +0.166 V (pH 4).
One gram dissolves in around 3 mL of water, 30 mL of alcohol, 50 mL of absolute alcohol, 100 mL of glycerol, 20 mL of propylene glycol. Solubility in water 80.0% at 100°C, 40.0% at 45°C. Insoluble in ether, chloroform, benzene, petroleum ether, oil, fats and fatty solvents. Strong reducing agent. Stable in air when it is dry.
In an aqueous solution, it is quickly oxidized by air:
pKa : pK1 = 4.17; pK2 = 11.57
Maximum absorption: UV max at pH 2: l max = 245 nm (E1%(1cm) = 695); at pH 6.4: l max: 265 nm (E1%(1cm) = 940)
Optical rotation: [α]D25 = +20.5 to +21.5° (c = 1 in water); [α]D23 =+48° (c = 1 in MeOH)