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Citric acid CAS#77-92-9

· Naturally occurring organic acid – Citric acid is widely found in plants and animals, making it a naturally derived and widely accepted ingredient.

· Multifunctional chemical properties – As a tricarboxylic acid with three carboxyl groups, it offers strong chelating and buffering capabilities.

· High reactivity and versatility – It can form citrate salts and esters, enabling diverse applications in food, pharmaceuticals, and industry.

· Effective acidulant – As a weak acid, it provides controlled acidity and pH regulation in various formulations.

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Product Details

Product Description of Citric Acid CAS#77-92-9

Citric acid is a white crystalline weak organic acid that occurs naturally in most plants and many animals, where it functions as an intermediate in cellular respiration. It contains three carboxyl groups, classifying it as a tricarboxylic acid. The term “citrus” is derived from the Greek word kedromelon, meaning “apple of melon,” referring to the citron fruit (Citrus medica), which has been historically described as an oblong fruit from a shrub-like tree. Lemons and limes are particularly rich in citric acid, with contents reaching up to 8% of their dry weight.

As a weak acid, citric acid releases hydrogen ions from its three carboxyl groups (COOH) in solution, forming the citrate ion (C₃H₅O(COO)₃³⁻). It can also form intermediate ions when one or two hydrogen atoms dissociate. The citrate ion readily combines with metals to form salts, the most common being calcium citrate. Additionally, citric acid can form esters, producing various citrate compounds such as trimethyl citrate and triethyl citrate.

Citric acid CAS#77-92-9

Citric acid Citric acid Chemical 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
Fp	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
PH	3.24(1 mM solution);2.62(10 mM solution);2.08(100 mM solution);
Odor	Odorless
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
Merck	14,2326
JECFA Number	218
BRN	782061
Stability:	Stable. Incompatible with bases, strong oxidizing agents, reducing agents, metal nitrates.
InChIKey	KRKNYBCHXYNGOX-UHFFFAOYSA-N
LogP	-1.64
CAS DataBase Reference	77-92-9(CAS DataBase Reference)
NIST Chemistry Reference	1,2,3-Propanetricarboxylic acid, 2-hydroxy-(77-92-9)
EPA Substance Registry System	Citric acid (77-92-9)

Chemical 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
Fp	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
PH	3.24(1 mM solution);2.62(10 mM solution);2.08(100 mM solution);
Odor	Odorless
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
Merck	14,2326
JECFA Number	218
BRN	782061
Stability:	Stable. Incompatible with bases, strong oxidizing agents, reducing agents, metal nitrates.
InChIKey	KRKNYBCHXYNGOX-UHFFFAOYSA-N
LogP	-1.64
CAS DataBase Reference	77-92-9(CAS DataBase Reference)
NIST Chemistry Reference	1,2,3-Propanetricarboxylic acid, 2-hydroxy-(77-92-9)
EPA Substance Registry System	Citric acid (77-92-9)

Safety Information

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
Hazardous Substances Data	77-92-9(Hazardous Substances Data)
Toxicity	LD50 in mice, rats (mmol/kg): 5.0, 4.6 i.p. (Gruber, Halbeisen)

Citric acid is an acidulant and antioxidant produced through mold fermentation of sugar solutions, as well as by extraction from lemon juice, lime juice, and residues from pineapple canning. It is the primary acid found in oranges, lemons, and limes. Citric acid is available in both anhydrous and monohydrate forms: the anhydrous form crystallizes from hot solutions, while the monohydrate form crystallizes from cold solutions (below 36.5°C).

At 20°C, anhydrous citric acid has a solubility of 146 g, while the monohydrate form has a solubility of 175 g per 100 ml of distilled water. A 1% solution has a pH of 2.3 at 25°C. It is hygroscopic and has a strong, tart taste.

Citric acid is commonly used as an acidulant in fruit drinks and carbonated beverages at levels of 0.25–0.40%, in cheese at 3–4%, and in jellies. It also functions as an antioxidant in products such as instant potatoes, wheat chips, and potato sticks by binding metal ions to prevent spoilage. Additionally, it is used in combination with other antioxidants in the processing of fresh frozen fruits to help prevent discoloration.

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