Citric acid

  • 2-Hydroxy-1,2,3-propanetricarboxylic acid
  • 3-Carboxy-3-hydroxypentane-1,5-dioic acid
  • Hydrocerol A
  • Citro
  • Chemfill
  • Aciletten
Formula
(HOOCCH2)2C(OH)COOH
Structure
Description
Colorless crystals, or white, granular to fine crystalline powder, deliquescent in moist air.
Uses
Acidulant in beverages, to adjust ph of foods and as a synergistic antioxidant, in processing cheese, used in beverages, jellies, jams, preserves and candy to provide tartness, in special inks, in electroplating, in the manufacture of alkylated resins, in esterified form as plasticizer, foam inhibitor, in the manufacture of citric acid salts, as mordant to brighten colors.

Registry Numbers and Inventories.
CAS
77-92-9
EC (EINECS/ELINCS)
201-069-1
EC Class
irritant
R 37/38 41
S 26 36/37/39
RTECS
GE7350000
RTECS class
Agricultural Chemical and Pesticide; Drug; Primary Irritant
UN (DOT)
1759
Merck
13,2350
Beilstein/Gmelin
782061
Beilstein Reference
4-03-00-01272
EPA OPP
21801
Swiss Giftliste 1
G-1438
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C6H8O7
Formula mass
192.13
Melting point, °C
149 - 151
Boiling point, °C
310
Vapor pressure, mmHg
6E-5 (25 C)
Evaporization number
Probably very low at normal temperatures.
Odor Threshold Odor threshold Odorless
Density
1.665 g/cm3
Solubility in water
590 g/L
Viscosity
6.5 cp 50% aq soln @ 25C
Refractive index
1.44
pKa/pKb
2.93 (pKa)
Partition coefficient, pKow
-1.72
Heat of vaporization
63.8 kJ/mol
Heat of combustion
-1983 kJ/mol

Hazards and Protection.
Storage
Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances. Store protected from moisture.
E
Handling
Wash thoroughly after handling. Use with adequate ventilation. Minimize dust generation and accumulation. Avoid contact with eyes, skin, and clothing. Keep container tightly closed. Avoid ingestion and inhalation. Do not allow contact with water. Keep from contact with moist air and steam.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators
Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks
Vacuum or sweep up material and place into a suitable disposal container. Very fine particles can cause a fire or explosion. Eliminate all ignition sources. Clean up spills immediately, using the appropriate protective equipment. Avoid generating dusty conditions. Remove all sources of ignition. Provide ventilation. Spill may be neutralized with lime. Do not get water inside containers.
Stability
Stable under normal temperatures and pressures.
Incompatibilities
Oxidizing agents, sulfides (inorganic, e.g. ferric sulfide, lead sulfide, sodium sulfide), metal nitrates, alkali carbonates, alkalis, potassium tartrate, acetates, bicarbonates.
Decomposition
Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide.

Fire.
Flash Point,°C
155
Autoignition, °C
345
Upper exp. limit, %
4.8
Lower exp. limit, %
1.8
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. This material in sufficient quantity and reduced particle size is capable of creating a dust explosion. To extinguish fire use water spray, dry chemical, carbon dioxide, or chemical foam. Use agent most appropriate to extinguish fire. Do NOT get water inside containers.
Fire potential
Slight - when heated.
Hazards
Melts and decomposes. The reaction is not hazardous.
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.
Health
2
 
Flammability
0
 
 
Reactivity
0
 

Health.
Poison_Class
5
Exposure effects
Repeated exposure may cause sensitization dermatitis.
   Ingestion
May cause gastrointestinal irritation with nausea, vomiting and diarrhea. Excessive intake of citric acid may cause erosion of the teeth.
   Inhalation
Causes respiratory tract irritation.
   Skin
Causes skin irritation. May cause skin sensitization, an allergic reaction, which becomes evident upon re-exposure to this material.
   Eyes
Causes severe eye irritation and possible injury.

First aid
 
   Ingestion
Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid.
   Inhalation
Remove from exposure to fresh air immediately. If breathing is difficult, give oxygen. Get medical aid. DO NOT use mouth-to-mouth respiration. If breathing has ceased apply artificial respiration using oxygen and a suitable mechanical device such as a bag and a mask.
   Skin
Flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Get medical aid if irritation develops or persists. Wash clothing before reuse.
   Eyes
Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid. Do NOT allow victim to rub or keep eyes closed.

Transport.
UN number
1759
Response guide
Hazard class
8
Packing Group
I; II; III
 
USCG CHRIS Code
CIT
 
HS Code
2918 14 00
 
IMO Pollution Category
D