3,4-Dihydroxybenzoic Acid: Real-World Safety Considerations

Identification

Name: 3,4-Dihydroxybenzoic Acid
Other Names: Protocatechuic acid
CAS Number: 99-50-3
Molecular Formula: C7H6O4
Molecular Weight: 154.12 g/mol
Appearance: White to off-white crystalline powder with a faint aromatic scent
Uses: Intermediary in chemical synthesis, food preservation, pharmaceuticals, analytical chemistry, plant-derived antioxidant research
Odor: Slight, sometimes compared to musty or earthy plant materials
Solubility: Soluble in water and alcohol; sparingly soluble in some organic solvents

Hazard Identification

Hazard Classification: Not classified as hazardous under major global chemical regulations
Acute Health Effects: May irritate skin, eye, and respiratory tract if exposed to dust or concentrated material
Chronic Health Effects: Prolonged or repeated exposure could lead to respiratory discomfort or dermatitis, especially for sensitive individuals
Inhalation Risk: Fine powder could cause coughing, throat irritation, or mild headache with heavy airborne concentrations
Eye Contact Risk: Dust in eyes stings upon contact and produces noticeable discomfort, short-lived redness
Skin Contact Risk: Minor redness or drying with repeat contact, no long-term effects documented in typical lab use
Ingestion Risk: Low toxicity by oral route, but unintentional ingestion should be avoided

Composition / Information on Ingredients

Chemical Content: Pure 3,4-Dihydroxybenzoic Acid
Purity Range: Usually exceeds 98% in commercial and research-grade samples
Impurities: Trace phenolic compounds possible, depending on manufacturing process

First Aid Measures

Inhalation: Move to fresh air; seek medical attention if persistent coughing or breathing trouble continues
Skin Contact: Wash thoroughly with water and soap, remove contaminated clothing, apply lotion for dryness
Eye Contact: Rinse cautiously with water for several minutes, blink often, remove contacts if present, see physician if irritation holds
Ingestion: Rinse mouth, drink water, do not induce vomiting, consult a healthcare provider if feeling unwell or large amount swallowed

Fire-Fighting Measures

Suitable Extinguishers: Water spray, dry chemical, foam, carbon dioxide
Combustion Products: Carbon dioxide, carbon monoxide, possibly phenolic fumes under uncontrolled burning
Fire Hazards: Organic powder can augment fire risk if stored or handled in cloud form, dust can burn
Protective Equipment: Full protective gear, self-contained breathing apparatus in case of heavy fire
Other: Keep containers cool by spraying with water, isolate hazardous area, ensure adequate ventilation

Accidental Release Measures

Personal Precautions: Gloves, goggles, dust mask for sizable spills, avoid spreading dust
Spill Cleanup: Sweep up gently, avoid dry sweeping, use damp paper or HEPA vacuum, ventilate area well
Environmental Precautions: Do not allow powder to enter drains or water systems; contain and collect for disposal
Disposal: Place in compatible, sealable container, label for proper hazardous waste disposal

Handling and Storage

Handling: Wear protection when weighing or mixing, keep containers sealed when not in use, minimize dust
Storage Conditions: Store in a cool, dry site away from strong oxidizers and direct sunlight
Incompatible Materials: Oxidizing agents, bases, strong acids
Engineering Controls: Utilize chemical fume hood for transferring powders, especially in research labs

Exposure Controls and Personal Protection

Exposure Limits: No established occupational limits in most countries
Personal Protective Equipment: Gloves (nitrile or latex), splash-resistant goggles, lab coat, dust mask or respirator if airborne powder persists
Ventilation: Strong general and local exhaust recommended, particularly during powder handling
Hygiene Measures: Wash hands after use, do not eat or drink while handling, keep work surface clean

Physical and Chemical Properties

Appearance: White to yellowish crystalline solid
Odor: Mild, plant-like
Melting Point: Reported near 200°C
Boiling Point: Decomposes before boiling
pH: Acidic in solution
Vapor Pressure: Negligible at room temperature
Density: Close to 1.49 g/cm³
Solubility: Water-soluble, higher in hot water; moderate in ethanol
Stability: Stable under standard conditions, may brown in air after extended time
Auto-Ignition: No reliable reports of spontaneous ignition under normal conditions
Decomposition: Forms smoke and irritating vapors if heated significantly

Stability and Reactivity

Thermal Stability: Robust at ambient temperature, breaks down upon prolonged heating
Reactive Hazards: Contact with oxidizers can generate heat, acid fumes
Hazardous Polymerization: Not expected
Incompatible Substances: Sodium hypochlorite, strong acids, alkalis, peroxides
Hazardous Decomposition: Releases carbon oxides and potentially phenolic byproducts during fire

Toxicological Information

Acute Toxicity: Generally low toxicity, no widespread reports of severe effects in humans
Skin Sensitization: Irritation possible on repeated or prolonged contact
Inhalation Effects: Dust exposure produces coughing, throat scratchiness, headache uncommon
Eye Effects: Stings, redness, tears for several minutes after dust exposure
Chronic Effects: No evidence for cancer, mutagenicity, or reproductive toxicity in available studies
LD50 (oral, rat): Reported above 1,000 mg/kg, much higher than accidental exposure scenarios

Ecological Information

Aquatic Toxicity: Low toxicity in short-term studies on fish and invertebrates
Persistence and Degradability: Biodegradable, typical for small aromatic acids
Bioaccumulation: No significant build-up observed in animal studies
Environmental Pathways: Likely broken down by soil microbes if released in small quantities
Other Concerns: Large scale spills may still disrupt mild aquatic systems for a short time

Disposal Considerations

Preferred Methods: Incinerate in approved facility, chemical landfill for lab-scale residue
Packing Waste: Use labeled, sealed containers suitable for organic waste
Wastewater Caution: If dissolved in water, send to licensed treatment depending on local rules
Special Instructions: Avoid mixing with incompatible substances before disposal

Transport Information

International Transport Classification: Non-hazardous for air, land, and sea under most chemical transport codes
Precautionary Packaging: Use double-sealed bags and secure, break-resistant containers to minimize leak risk
Transport Limitations: Avoid excessive heat, moisture, physical abuse during transit

Regulatory Information

Global Inventory Status: Listed on major chemical inventories like TSCA, EINECS
Hazard Label: Most jurisdictions require no hazard symbol
Workplace Regulations: General dust safety standards apply, lab chemical handling protocols enforced
Use Restrictions: Special registration not widely demanded, but local policy determines storage volume
Environmental Law: Small-scale use considered low environmental risk, subject to general chemical disposal acts