Citrate , Analysis standard , 77-92-9

Synonym(s):
2-Hydroxy-propane-1,2,3-tricarboxylic acid;2-Hydroxypropane-1,2,3-tricarboxylic acid, Hydroxytricarballylic acid;Citric acid

CAS NO.：77-92-9

Empirical Formula: C6H8O7

Molecular Weight: 192.12

MDL number: MFCD00011669

EINECS: 201-069-1

PRODUCT Properties

• Melting point: 153-159 °C (lit.)
• Boiling point: 248.08°C (rough estimate)
• Density: 1.67 g/cm3 at 20 °C
• vapor density: 7.26 (vs air)
• vapor pressure: <0.1 hPa (20 °C)
• refractive index: 1.493~1.509
• FEMA: 2306 | CITRIC ACID
• Flash point: 100 °C
• storage temp.: 2-8°C
• solubility: Citric acid also dissolves in absolute (anhydrous) ethanol (76 parts of citric acid per 100 parts of ethanol) at 15 °C.
• form: grit
• pka: 3.14(at 20℃)
• color: White
• Odor: Odorless
• PH: 3.24(1 mM solution);2.62(10 mM solution);2.08(100 mM solution)
• Odor Type: odorless
• explosive limit: 8%, 65°F
• Water Solubility: soluble in Water (1174g/L at 10°C, 1809g/L at 30°C, 3825g/L at 80°C).
• Sensitive: Hygroscopic
• λmax: λ: 260 nm Amax: 0.20; λ: 280 nm Amax: 0.10
• JECFA Number: 218
• Merck: 14,2326
• BRN: 782061
• Stability: Stable. Incompatible with bases, strong oxidizing agents, reducing agents, metal nitrates.
• InChIKey: KRKNYBCHXYNGOX-UHFFFAOYSA-N
• LogP: -1.64

Description and Uses

Citric acid is a white, crystalline, weak organic acid present in most plants and many animals as an intermediate in cellular respiration. Citric acid contains three carboxyl groups making it a carboxylic, more specifically a tricarboxylic, acid.the name citrus originates from the Greek kedromelon meaning apple of melon for the fruit citron. Greek works mention kitron, kitrion, or kitreos for citron fruit, which is an oblong fruit several inches long from the scrublike tree Citrus medica. Lemons and limes have high citric acid content, which may account for up to 8% of the fruit's dry weight.

Citric acid is a weak acid and loses hydrogen ions from its three carboxyl groups (COOH) in solution.the loss of a hydrogen ion from each group in the molecule results in the citrate ion,C3H5O(COO)₃3. A citric acid molecule also forms intermediate ions when one or two hydrogen atoms in the carboxyl groups ionize.the citrate ion combines with metals to form salts, the most common of which is calcium citrate. Citric acid forms esters to produce various citrates, for example trimethyl citrate and triethyl citrate.

Citric Acid is an acidulant and antioxidant produced by mold fermentation of sugar solutions and by extraction from lemon juice, lime juice, and pineapple canning residue. it is the predominant acid in oranges, lemons, and limes. it exists in anhydrous and monohydrate forms. the anhydrous form is crystallized in hot solutions and the monohydrate form is crystallized from cold (below 36.5°c) solutions. anhydrous citric acid has a solubility of 146 g and monohydrate citric acid has a solubility of 175 g/100 ml of distilled water at 20°c. a 1% solution has a ph of 2.3 at 25°c. it is a hygroscopic, strong acid of tart flavor. it is used as an acidulant in fruit drinks and carbonated beverages at 0.25-0.40%, in cheese at 3-4%, and in jellies. it is used as an antioxidant in instant potatoes, wheat chips, and potato sticks, where it prevents spoilage by trapping the metal ions. it is used in combination with antioxidants in the processing of fresh frozen fruits to prevent discoloration.

Safety

• Symbol(GHS): GHS07
• Signal word: Warning
• Hazard statements: H319-H335
• Precautionary statements: P261-P264-P271-P280-P304+P340+P312-P305+P351+P338
• Hazard Codes: Xi,C,T
• Risk Statements: 41-36/37/38-36/38-37/38-34-36-35-61-60
• Safety Statements: 26-39-37/39-24/25-36/37/39-45-36-53
• RIDADR: UN 1789 8/PG 3
• WGK Germany: 1
• RTECS: GE7350000
• F: 9
• TSCA: Yes
• HS Code: 2918 14 00
• Toxicity: LD50 in mice, rats (mmol/kg): 5.0, 4.6 i.p. (Gruber, Halbeisen)