© 2026 Sinochem Nanjing Corporation,
All Right Reserved
Chemical Name: 4-Hydroxypyridine
Synonyms: 4-Pyridinol, Pyridin-4-ol
CAS Number: 857-97-8
Common Uses: Industry research, intermediate for pharmaceuticals, specialty chemical laboratories use it for synthesis when exploring heterocyclic compounds. Many chemists respect its relevance in developing active pharmaceutical ingredients, targeting its core as a building block. Visibility pops up sometimes in pigment work, corrosion inhibitors, even as a model molecule for structure-activity studies.
GHS Classification: Acute toxicity if swallowed, eye and skin irritation, potential respiratory tract irritation. Handling loose powder often encourages dust, which stings eyes and scratches at the throat. Nobody likes a strong odor, and 4-Hydroxypyridine has a sharp one; some have described it as almost bitter, so anyone with a sensitive nose should work with caution.
Signal Word: Warning
Pictograms: Exclamation mark for irritation and toxicity risks
Hazard Statements: Harmful if swallowed. Causes moderate skin and eye irritation. Dust can flare up allergies. Getting hit with a cloud of this stuff prompts runs for the eyewash station. Breathing problems show up with big overexposures. My experience: none of my colleagues wanted to handle it without gloves, safety glasses, and a working hood.
Component: 4-Hydroxypyridine, at or above 98% purity in standard lab batches. Seldom do contaminants show up if it's sourced from reputable manufacturers. Modern synthesis keeps heavy metals and residual solvents down to trace levels, but you still want a recent certificate of analysis, since older stock may degrade.
Skin Contact: Flush skin under running water for fifteen minutes. Remove soiled clothing right away to block skin from soaking in more compound.
Eye Contact: Rinse eyes with water for many minutes, holding eyelids apart. Call for medical attention if irritation remains.
Inhalation: Relocate out of dusty space. Supply fresh air as fast as possible. Seek medical care for breathing trouble.
Ingestion: Rinse the mouth, drink water, never try to force vomiting. See a healthcare professional if feeling sick; stomach pain or headache should never be ignored.
Effective workplace first aid only works if everyone knows the plan in advance—most labs keep emergency posters and a kit on the wall, along with an eyewash/safety shower combo in plain sight.
Suitable Extinguishing Media: Use carbon dioxide, dry chemical powder, or foam. Water spray tames smaller flames, yet dry powder acts faster for powdery organics. Wear self-contained breathing gear—smoke from burns may push out toxic nitrogen and carbon oxides.
Special Hazards: Like many pyridines, burns produce thick, unpleasant smoke. Closed drums can burst from heat, so keeping them away from direct flames matters. Firefighting usually takes more than a small extinguisher; run drills now and then, and keep flammables in metal cabinets instead of open shelves.
Protective Actions: Firefighters need chemical-resistant suits, and SCBA. If there’s a spill in the blaze, diking and control become important, since water run-off might drag contamination far beyond the lab.
Personal Precautions: Evacuate the unnecessary. Anyone who needs to clean should throw on gloves, goggles, and a particulate respirator at minimum—lab coats keep dry powder off skin.
Containment: Scoop up solid with spark-proof tools. Air out the room by opening doors and running fans. If it got into drains, inform building maintenance.
Cleanup: Mop up with absorbent, like fine sand or vermiculite; seal waste using double-bagged containers, then label for chemical disposal.
Fast action is key—wiping up at once lessens health risks and stops chemical seeping into floors or drains. Spills happen to anyone; no shame in mistakes, but risky shortcuts can haunt you later.
Handling: Keep dry compound in sealed glass or high-grade plastic. Open containers in the hood. Use scoops, never bare hands. Wash up after, and quit eating, drinking, or touching your phone during handling.
Storage Conditions: Store in cool, dry, and ventilated spots. Label everything, add hazard stickers, and keep away from acids, oxidizers, or open flames. Sunlight fades labels and can degrade chemicals, so stick with shaded shelves. Most safety programs expect products to rest at eye level, within secondary containment trays.
Engineering Controls: Bench work should happen under a certified chemical fume hood—regular airflow checks keep it honest.
Personal Protective Equipment: Nitrile or neoprene gloves stand up to 4-Hydroxypyridine longer than latex. Chemical goggles matter whenever you risk splashes or airborne powder. Lab coats and closed shoes limit exposure.
Hygiene Measures: Clean up after accidental smears, wash up before breaks, and train teams to leave contaminated gloves in the workspace.
Appearance: Pale to off-white crystalline solid. Some batches show slight gray or tan hues, but anything dark signals decomposition.
Odor: Distinct, sharp, almost bitter smell
Melting Point: Roughly 145-148°C
Boiling Point: Estimates put it near 245°C under reduced pressure, but direct boiling often leads to breakdown.
Solubility: Water-soluble; dissolves even faster in alcohols or acetone.
pH: Aqueous solution runs mildly basic.
Vapor Pressure: Negligible under standard conditions, so inhalation risk centers on dust.
Stability: Dry, cold storage keeps it solid. Prolonged sunlight or contact with oxidizers can brown it quickly.
Chemical Stability: Stable under recommended conditions. Exposing the powder to strong acids or oxidizers prompts runaway reactions, sometimes with toxic fumes.
Reactivity: Can attack certain metals, aluminum especially, if dissolved in water or alcohol.
Hazardous Decomposition Products: Nitrogen oxides, carbon oxides come out during burns or strong acid attacks. Open samples of badly stored stock sometimes reek unusually, and nobody wants to be the first to find out what happens after years of slow decay.
Acute Toxicity: Swallowing small doses triggers nausea, headache, and belly pain in some workers. Chronic exposure is rare in most labs, but irritation develops in frequent handlers who skip gloves.
Skin Irritation: Repeated skin contact dries out hands and causes redness. Allergic dermatitis pops up occasionally.
Eye Irritation: Makes eyes sting, sometimes painfully, until rinsed.
Sensitization: No major sensitization cases reported, though dust clouds aggravate asthmatics or sensitive individuals.
Even tough workers respect its bite—safety is more than just following rules. It’s about learning from past mistakes and never letting routine make you lazy.
Aquatic Toxicity: Releases into waterways can harm fish and plants if dumping is uncontrolled; keeps accumulation low in most natural settings, but cautious waste management beats damage control.
Persistence and Degradability: Breaks down slowly in soil; in water, bacteria convert it eventually but not fast enough to allow careless disposal. Anyone who values clean water keeps this out of the sink.
Bioaccumulation Potential: Low for large animals, but repeated low-level exposure still matters for small organisms in confined environments.
Disposal Method: Send sealed, labeled waste to commercial incineration or licensed hazardous chemical handlers. Augment routine by double-checking labels and logging outgoing waste. Improper dumping draws fines, and watchdog groups occasionally audit disposal records.
Contaminated Packaging: Rinse out reusable containers with care. Most labs stock single-use disposal jars, reducing cross-contamination.
Environmental Precautions: Never pour solutions down drains; ignore the “it’s just one flask, it won’t matter” excuse. Good lab managers set the example by actively enforcing responsible disposal.
Shipping Regulations: Not a highly regulated dangerous good in small lab quantities, but label packages accurately for road or air shipment.
Packing Group: Usually falls outside high-risk categories; shifts upward if part of a mixed waste batch.
Precautions: Secure solid material in tightly closed vessels with cushioned packing; containers often go inside secondary spill-proof bags or tubs.
Chemical Inventories: Listed on most national and international chemical inventories, including TSCA in the US and EINECS in Europe.
Regulatory Status: No specialized international controls, though local workplace safety authorities require strict labeling, up-to-date safety training, and proper PPE use.
Occupational Exposure Limits: None established by OSHA or ACGIH, but sensible hygiene and routine air monitoring are expected by auditors.
The world pays closer attention today to chemical transparency and record-keeping. Labs flourish under proactive safety attitudes instead of box-ticking compliance.
