Oxalic acid, the simplest dicarboxylic acid, is a colorless crystal that contains two molecules of crystal water at room temperature. It becomes anhydrous when heated to 100.1°C. Toxic and hygroscopic, it dissolves easily in ethanol and water but is insoluble in benzene and chloroform. Oxalic acid forms complexes with metals and has a high acidity, over 10,000 times stronger than acetic acid. It is a strong reducing agent, easily oxidized to carbon dioxide and water. It can be oxidized by potassium permanganate, turning the solution colorless. Decomposing at 189.5°C or in concentrated sulfuric acid, it produces carbon dioxide, carbon monoxide, and water. Oxalic acid is also used in generating carbon monoxide gas in labs. It’s found in small amounts in human urine, with calcium oxalate being a major component of urinary stones.
Parameters
Melting point | 189.5 °C (dec.)(lit.) |
Boiling point | 365.1°C (estimate) |
density | 0.99 g/mL at 25 °C |
bulk density | 750kg/m3 |
vapor density | 4.4 (vs air) |
vapor pressure | <0.01 mm Hg ( 20 °C) |
refractive index | 1.4261 (estimate) |
Fp | 101-157°C |
storage temp. | Store below +30°C. |
solubility | water: soluble108g/L at 25°C |
form | Liquid |
pka | 1.23(at 25℃) |
color | White |
PH Range | 6 - 8 at 25 °C |
PH | 3(1 mM solution);2.09(10 mM solution);1.31(100 mM solution); |
Odor | odorless |
Water Solubility | 90 g/L (20 ºC) |
Sublimation | 101-157 ºC |
Merck | 14,6911 |
BRN | 385686 |
Henry's Law Constant | 1.43 at pH 4 (quoted, Gaffney et al., 1987) |
Exposure limits | NIOSH REL: TWA 1, STEL 2, IDLH 500; OSHA PEL: TWA 1; ACGIH TLV: TWA 1, STEL 2 (adopted). |
Stability: | Stable, but moisture sensitive. Incompatible with metals. |
InChIKey | MUBZPKHOEPUJKR-UHFFFAOYSA-N |
LogP | -1.7 at 23℃ |
CAS DataBase Reference | 144-62-7(CAS DataBase Reference) |
NIST Chemistry Reference | Oxalic acid(144-62-7) |
EPA Substance Registry System | Oxalic acid (144-62-7) |
Safety Information
Hazard Codes | Xn |
Risk Statements | 21/22-63-34-41 |
Safety Statements | 24/25-23-36/37/39-27-26-39-37-36-36/37 |
RIDADR | UN 3261 8/PG 3 |
OEB | C |
OEL | TWA: 1 mg/m3, STEL: 2 mg/m3 |
WGK Germany | 1 |
RTECS | RO2450000 |
TSCA | Yes |
HazardClass | 8 |
PackingGroup | III |
HS Code | 29171110 |
Hazardous Substances Data | 144-62-7(Hazardous Substances Data) |
Toxicity | LD50 orally in Rabbit: 375 mg/kg |
IDLA | 500 mg/m3 |
It is primarily employed as a reducing and bleaching agent, serves as a mordant in the printing and dyeing industry, and is also utilized in the refining of rare metals and the synthesis of various oxalates, oxalate salts, and oxalamides.
