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|OTP appearance||white solid|
|Index of refraction||1.49-1.51|
|Solubility in water(g/L)||1477|
|Solubility in ethanol(g/L)||489|
Citric acid is the tangy component of citrus fruit juice. It is an important acid medicinally because most of its conjugate bases can be digested. The pKa of the first three hydrogens are 3.13, 4.76, and 6.4
- Pharm: Feedstock for caffeine citrate on the WHO LEM.
- Prevents coagulation of stored blood.
- Occurs naturally in virtually all life on earth
- High concentrations in citrus fruit such as lemons
- Can be produced by aspergillus niger as well
- Combine calcium citrate with Sulfuric acid
- Ca3(C6H5O7)2 + 3 H2SO4 → 2 C6H8O7 + 3 CaSO4
- Would phosphoric acid work as well?
- 3 Ca3(C6H5O7)2 + 9 H3PO4 → 6 C6H6O7 + 5 CaHPO4 + 4 CaH4PO4
- Would carbon dioxide work as well?
- 4 Ca3(C6H5O7)2 + 18 CO2 + 7 H2O → 12 CaCO3 + 9 C6H6O7
from citrus juice
- Prepare filtered citrus juice
- Add sodium hydroxide until pH is 9, producing sodium citrate along with some sodium ascorbate
- Filter and discard residue
- Add an appropriate amount of saturated calcium chloride solution to the filtrate
- Heat the solution. This starts the reaction and gives sodium chloride and a precipitate
- Filter and discard filtrate.
- Wash residue with hot water. The washed residue is of calcium citrate. along with some calcium ascorbate
- Get the mass the residue to estimate moles
- Add dilute sulfuric acid to the solution precipitating calcium sulfate and leaving a solution of citric acid and ascorbic acid
- Separate the acids by fractional crystallization.
from Ascorbic Acid