Oxalic Acid
High purity organic acid for industrial and commercial applications
Overview
Oxalic Acid (CAS No: 144-62-7), also known as ethanedioic acid, is a colorless crystalline organic acid. It occurs naturally in many plants in the form of oxalate and is widely used in various industries.
Oxalic acid is a strong acid and reducing agent. It is soluble in water, alcohol, and ether. In industry, it is commonly used in dihydrate form (C₂H₂O₄·2H₂O). It is effective in metal cleaning, rust removal, and bleaching processes.
Applications
Oxalic Acid has diverse industrial and commercial applications:
Metal Cleaning
Used for removing rust and stains from metals, particularly iron and stainless steel.
Wood Bleaching
Effective for bleaching wood surfaces and lightening their color.
Textile Industry
Used for bleaching fabrics and wool, and as a mordant in dyeing processes.
Leather Processing
Used in leather tanning processes and for cleaning leather products.
Cleaning Products
Active component in lime and rust remover cleaning products.
Chemical Synthesis
Used as an intermediate in organic synthesis and pharmaceutical production.
Technical Specifications
| Property | Value | Unit | Test Method |
|---|---|---|---|
| Chemical Formula | C₂H₂O₄ | - | - |
| CAS Number | 144-62-7 | - | - |
| EC Number | 205-634-3 | - | - |
| Molecular Weight | 90.03 | g/mol | - |
| Appearance | Colorless crystalline powder | - | Visual |
| Odor | Odorless | - | - |
| Density (25°C) | 1.90 | g/cm³ | ASTM D4052 |
| Melting Point | 189.5 | °C | ASTM D1015 |
| Boiling Point | 365.1 | °C | ASTM D1078 |
| Flash Point | Non-flammable | - | - |
| Vapor Pressure (25°C) | <0.01 | mmHg | ASTM D2879 |
| Water Solubility (20°C) | 90 | g/L | ASTM E1148 |
| pH Value (0.1M sol.) | 1.3 | - | ASTM E70 |
| Purity | ≥99.6% | % | ASTM E611 |
| Ash Content | ≤0.02 | % | ASTM D482 |
| Heavy Metal Content (Pb) | ≤5 | ppm | ASTM E1613 |
Safety Information
Hazard Symbols and Statements
Corrosive Toxic Health Hazard
Personal Protective Equipment (PPE)
- Acid-resistant gloves (neoprene or nitrile)
- Dust mask or respiratory protection
- Chemical goggles or face shield
- Acid-resistant apron
- Closed shoes
Storage Conditions
- Store in cool, dry, well-ventilated areas
- Keep in original packaging, tightly closed
- Storage temperature: 15-25°C
- Keep away from bases, oxidizers, and metals
- Protect from moisture
Fire Fighting
- Suitable extinguishers: Water spray, dry chemical, CO₂
- Use appropriate respiratory protection during firefighting
- Combustion products may be toxic (carbon monoxide, carbon dioxide)
- Use dry chemical powder or CO₂ for small fires
Handling and Storage
Handling
- Ensure containers are tightly closed during transport
- Transport separately from oxidizers and bases
- Protect from moisture during transport
- Keep neutralizing materials available for spills
- Provide adequate ventilation in transport vehicles
Storage
- Store in polyethylene, glass, or stainless steel containers
- Display appropriate signs in storage area
- Keep acid neutralizing materials in storage areas
- Provide secondary containment for large quantities
- Storage shelves should be made of corrosion-resistant material
Spill Response Measures
- Evacuate exposed personnel from the area
- Use appropriate personal protective equipment
- Clean dust without raising it into the air
- Contain spill with sand, sodium bicarbonate or other neutralizing materials
- Wash spilled area with plenty of water
Regulatory Information
GHS Classification
- Acute Toxicity (Oral) Category 3
- Acute Toxicity (Dermal) Category 3
- Skin Irritation/Corrosion Category 2
- Eye Damage/Corrosion Category 1
- Respiratory Tract Irritation Category 3
Key Regulations
- REACH: Registered
- CLP: Compliant
- OSHA: Subject to hazard communication standard
- NFPA 704: Health 3, Flammability 1, Reactivity 1
International Legislation
- European Union: Subject to Directive 2008/58/EC
- USA: Available on EPA TSCA list
- China: Available on IECSC list
- Japan: Available on ISHL list
Environmental Information
Environmental Impact
Oxalic Acid shows moderate toxicity in aquatic environments. It can be harmful to aquatic life at high concentrations. It has high mobility in soil and may leach into groundwater. It is biodegradable.
Biodegradation
- Air: Degrades through photochemical reactions
- Water: Degrades through microbial activity
- Soil: Rapidly degrades through microbial activity
Waste Management
- Classified as hazardous waste
- Should be disposed of by neutralization at licensed hazardous waste disposal facilities
- Should not be discharged into sewers or surface waters
- Dispose of in accordance with local regulations
Frequently Asked Questions
Where is oxalic acid found naturally?
Oxalic acid and oxalate salts occur naturally in many plants. They are found in high amounts particularly in spinach, rhubarb, cocoa, tea leaves, and beans. They are also present in some mushroom species and lichens.
How is oxalic acid used for metal cleaning?
Oxalic acid has the ability to dissolve rust and metal oxides. A 5-10% aqueous solution is used for cleaning metals. Gloves and goggles should be used during application, and the surface should be rinsed thoroughly with water.
What are the health effects of oxalic acid?
It shows toxic effects at high doses. It may cause formation of calcium oxalate crystals in kidneys. Contact with skin and eyes may cause irritation and burns. Inhalation may irritate respiratory tract.
What are the differences between oxalic acid concentrations?
Industry generally uses anhydrous form with 99.6% purity or dihydrate form (C₂H₂O₄·2H₂O). Dihydrate form dissolves more easily in water. Dilute solutions (1-10%) are used for cleaning and bleaching purposes.
What should I do if oxalic acid contacts skin?
Remove contaminated clothing immediately and wash skin with plenty of water and soap for at least 15 minutes. If burn or irritation continues, seek medical attention. For eye contact, wash eyes with plenty of water for at least 15 minutes and seek immediate medical attention.