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Chemical Name: 1-Hydroxybenzotriazole Hydrate
Common Uses: Found in peptide coupling reactions, and in many chemical labs, this compound helps drive processes that create everyday pharmaceuticals and specialty chemicals. Chemists tend to favor its reactivity and selectivity, giving projects an important edge.
Appearance: White or off-white crystalline powder
Odor: Practically odorless, so accidental spills can go unnoticed without visual inspection.
CAS Number: 123333-53-9 (hydrate form)
Classification: Noted as an irritant. Some sources classify it as potentially harmful if swallowed, inhaled, or in contact with skin. Exposure can lead to discomfort or more severe symptoms, depending on the dose and route of exposure.
Hazard Symbols: Irritant (exclamation mark GHS pictogram).
Risk Phrases: Causes irritation to eyes, respiratory system, and skin. Inhalation may cause respiratory tract discomfort, coughing, or difficulty breathing. Ingestion can upset the stomach or worse, depending on the amount.
Precautionary Statements: Avoid breathing dust. Wear protective gloves and eye protection. Wash hands thoroughly after handling.
Chemical Formula: C6H5N3O·xH2O
Main Ingredient: 1-Hydroxybenzotriazole hydrate in its pure form. Labs rarely tolerate adulterants for this compound due to the high reactivity of its core structure.
Impurities: Usually negligible if kept sealed and purchased from established suppliers who follow rigorous QC standards.
Inhalation: Move person to fresh air right away. Seek medical attention if irritation or breathing difficulty develops. Do not hesitate if coughing continues or if lab workers start feeling dizzy.
Skin Contact: Wash thoroughly with soap and water. Remove contaminated clothing as soon as possible. Persistent redness or burns need attention from a healthcare provider.
Eye Contact: Rinse eyes gently with water for at least 15 minutes, keeping eyelids apart. If irritation remains afterwards, medical help should be sought.
Ingestion: Rinse mouth. Do not induce vomiting. If large amounts have been swallowed, seek immediate medical attention, because the irritation might turn into more systemic symptoms.
Suitable Extinguishing Media: Use water spray, carbon dioxide, dry powder, or foam. Fires involving chemicals demand readiness to switch tactics—the tried and true water spray method keeps dust clouds from forming, reducing risks.
Hazardous Combustion Products: Burns can release nitrogen oxides and other toxic fumes. Responders need full gear and chemical-resistant breathing apparatus.
Special Precautions: Avoid breathing fumes. Cut off runoff to prevent contaminated water from entering sewage systems.
Personal Precautions: Wear gloves, goggles, and a mask to minimize exposure. Fine powder spreads easily on air currents, covering benches and nearby surfaces—contain spills quickly.
Spill Cleanup Method: Sweep up without creating dust. Place material in a closed container for disposal. Ventilate the area well. Small spills can seem harmless but, over time, even minor exposure adds up and can sensitize workers.
Environmental Precautions: Keep out of drains and waterways. Collect as much material as possible to avoid soil or groundwater contamination.
Handling: Only open containers in well-ventilated areas. Chemicals like this have a way of escaping poorly sealed lids and clogging up fume hoods, so tight storage becomes a necessity. Prevent formation of airborne dust. Never eat, drink, or smoke while handling.
Storage: Keep tightly closed in a cool, dry, well-ventilated place. No exposure to direct sunlight or sources of heat. Store away from oxidizing agents or acids. Moisture control matters, since the hydrate can degrade if left open too long.
Engineering Controls: Use fume hoods and local exhaust where possible. Routine air monitoring for fine particulates pays off, especially in shared lab environments.
Personal Protective Equipment: Safety glasses or goggles; chemical-resistant gloves such as nitrile; lab coats or aprons. If airborne dust levels are high, a well-fitted respirator protects the lungs.
Hygiene Practices: Wash hands and face thoroughly after handling, even if everything looked clean.
Physical State: Crystalline powder
Color: White to off-white
Solubility: Soluble in water and many polar organic solvents.
Melting Point: Decomposes before melting
Odor: Odorless
Vapor Pressure: Negligible under ambient conditions.
pH: Slightly acidic when dissolved in water.
Chemical Stability: Stable under recommended storage conditions. Open containers left out in humid air break down faster, forming byproducts that no longer work in synthesis.
Conditions to Avoid: Avoid excess moisture, heat, and direct sunlight.
Incompatible Materials: Strong oxidizers and acids—these combinations set up unexpected reactions in even the cleanest flask.
Hazardous Decomposition Products: Nitrogen oxides and other toxic fumes may result during burning or thermal degradation.
Acute Effects: Dust can cause eye, skin, or respiratory irritation, especially after repeated or prolonged exposure. Some people report a scratchy throat and mild headaches after working all day with it, though these symptoms tend not to linger if proper protection is used.
Chronic Effects: Not fully studied, but there’s a good reason to take precaution: similar compounds have been found to sensitize skin.
Routes of Exposure: Eyes, skin, inhalation, ingestion
Symptoms: Irritation, redness, or coughing
Medical Conditions Aggravated: Individuals prone to allergies or with preexisting respiratory concerns may notice symptoms sooner.
Aquatic Toxicity: Insufficient data, but not considered especially hazardous in small quantities. Good lab practice calls for avoiding unnecessary release, since even “small” amounts can build up locally.
Persistence and Degradability: Some breakdown occurs naturally, especially if exposed to sunlight or moisture, but leftover residues in lab wastewater might resist full degradation.
Bioaccumulation: Evidence remains weak, but repeated discharge into surface waters raises long-term questions.
Waste Treatment: Treat as hazardous laboratory waste. Never flush down a sink. Collect in clearly labeled drums for pick-up by a certified chemical waste disposal contractor.
Contaminated Packaging: Empty containers that held chemical powder should be treated as hazardous waste and disposed of via the same channels.
Legislation: Local guidelines often govern disposal, so consult regional waste management agencies if unsure. Lab managers sometimes underestimate the costs and complexity of proper disposal, risking both fines and environmental harm.
UN Number: Not commonly regulated for transport in small laboratory quantities, though bulk shipments to industry might fall under different codes.
Proper Shipping Name: Chemical, N.O.S. Most courier services require proper containment, watertight packaging, upright boxes, and clear labeling.
Hazard Class: Not classed as dangerous for most land and air transport, but packaging instructions should always be double-checked to keep handlers safe.
Precautions During Transport: Keep containers sealed tight, upright, and cushioned against movement. Temperature swings can force containers to “sweat,” potentially damaging the hydrate.
Workplace Regulations: Occupational exposure limits have not been set for this compound in most countries, reflecting its niche use. Still, workplace safety bodies encourage engineering controls and robust PPE, modeled on best practices for chemical irritant powders.
Labeling Requirements: Containers should bear clear hazard pictograms and risk statements, in accordance with GHS standards. Labs using the compound should keep safety documentation accessible to all staff.
Labelling under REACH or TSCA: Not a widely restricted substance, but comes under general chemical safety regulations for laboratory use.
Community Right-to-Know: Research facilities often include 1-Hydroxybenzotriazole hydrate in annual chemical inventories to comply with local environmental health and safety legislation.
