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Chemical Name: 1-Chloro-2-butene
Chemical Formula: C4H7Cl
Common Synonyms: 1-Chloro-2-butene, 1-chlorobut-2-ene
CAS Number: 109-69-3
1-Chloro-2-butene stands out as a reactive, colorless liquid, distinct by its faint sweet odor. It sees use as an intermediate in organic synthesis, often for the creation of specialty chemicals. The nature of its reactive double bond and halogen atom lends itself to some sought-after transformations in chemical manufacturing—but these same traits demand real vigilance in handling.
Classification: Flammable Liquid, Acute Toxicity (inhalation and oral), Skin Irritant, Eye Irritant
Main Risks: Flammable vapors catch an ignition source easily, leading to fire. Short exposure burns eyes and skin; breathing in the vapors can trigger dizziness, headache, irritation in the throat, or, in extreme cases, central nervous system effects. Liquid contact often brings on burns and pain. Environmentally, spills run into water systems and harm aquatic organisms. The label’s signal word ‘Danger’ spells this out clearly.
Component: 1-Chloro-2-butene
Purity: Typically exceeds 95% by weight
Known for being supplied as a pure chemical for industrial situations, impurities usually consist of other butene isomers or trace chlorinated hydrocarbons from production. These low-level by-products rarely shift the risk profile much, but they can complicate environmental outcomes when a spill occurs.
Eye Contact: Prompt rinsing with running water for at least fifteen minutes, eyelids parted.
Skin Contact: Remove clothing touched by the liquid, wash thoroughly with soap and water.
Inhalation: Move to fresh air, support breathing as needed, seek medical attention for symptoms.
Ingestion: Rinse mouth, never induce vomiting, get medical attention.
Quick action becomes the dividing line between minor harm and something more serious. Rushed cleanup using just a rag rarely pays off. Medical evaluation is worth the time, since lingering effects can sneak up in hours rather than minutes.
Suitable Extinguishing Media: Dry chemical agents, carbon dioxide, alcohol-resistant foam.
Hazards: Vapors may form explosive mixtures with air, spreading across floors and flashing back. Combustion feeds off oxygen and releases hydrogen chloride and carbon monoxide.
Precautions for Firefighters: Full protective gear, SCBA, attention to wind direction, and distance from heated storage tanks.
Bad decisions in a chemical fire—a wrong extinguishing agent or no personal gear—bring real harm. Smoke and leftover gases go beyond the flames, causing respiratory danger.
Spill Response: Ventilate the space, eliminate sources of ignition. Absorb small spills with inert, non-combustible absorbents like vermiculite. Stop leak if without risk.
Personal Protection: Drop into gloves, splash goggles, respirators, and proper aprons.
Environmental Precautions: Block liquid from seeping into drains, water, or soil. Waste must be transferred into tightly sealed containers for later disposal.
Hastily mopping up without protective gear risks skin burns, while letting the chemical enter drains builds up community trouble—waterways don’t forgive these spills.
Safe Handling: Use only in well-ventilated areas, keep away from open flames, hot surfaces, and sparks. Never eat, drink, or smoke nearby.
Storage: Stow in tightly capped, corrosion-resistant containers, cool dry areas with clear hazard signage. Segregate from acids, bases, strong oxidizers.
Practical steps count more than policies here—shared chemical lockers and open-top containers lead to risk stacking. Labeling and separation from busy workspaces keep emergencies from moving into plain accidents.
Engineering Controls: Local exhaust ventilation, chemical fume hoods, explosion-proof electrical equipment.
Personal Protective Equipment: Splash goggles, chemical-resistant gloves, solvent-resistant apron, air-purifying respirators with organic vapor cartridges for short tasks.
Work Practice Controls: Wash hands after handling, change out of contaminated clothing before breaks.
Routine ventilator checks and real investment in gear bridge the gap between technical compliance and true workplace safety. Skipping on PPE for ‘just a minute’ often stretches into regret as exposure accumulates.
Appearance: Clear, colorless to pale-yellow liquid
Odor: Faint, sweet aroma
Boiling Point: Around 89°C
Melting Point: Near -130°C
Vapor Pressure: High (fumes off rapidly at room temperature)
Solubility: Negligible in water, fully soluble in organic solvents
Density: Around 0.92 g/cm³
Catching a whiff tells you all you need about volatility—it doesn’t hide quietly and tends to escape containment fast if not actively managed.
Chemical Stability: Typically stable at room temperature, but reacts under heat, light, or with incompatible substances.
Reactive Hazards: Combines energetically with strong oxidizers; decomposes at high temperature, producing hydrogen chloride and unsafe gases.
Long-term storage brings risk as even sealed containers can build up internal pressure or degrade from the inside—leading to ruptures or slow leaks.
Routes of Entry: Inhalation, skin and eye contact, ingestion
Acute Effects: Mucous membrane irritation, drowsiness, headaches, skin redness, burns, nausea
Chronic Exposure: Potential for liver and kidney effects in lab studies, though evidence in humans is limited
Short periods without real protection pile up health risks. Chemicals like this deserve the same seriousness as seen with more notorious industrial toxins, as subtle symptoms can mask cumulative harm until it becomes chronic.
Aquatic Toxicity: Harmful to aquatic organisms, risks of long-term impact on aquatic ecosystems
Persistence and Degradability: Not known for rapid breakdown, tends to persist in soil and sediment
Releasing even a small amount into rivers or lakes multiplies into harm that extends way past any single spill event—the toxic impact catches up to the ecosystem over time.
Waste Disposal: Incinerate at facilities equipped with scrubbers for chlorinated organics.
Avoidable Practices: Never pour into water systems or landfills.
Strict tracking and specialized destruction keep unused chemical stock from leaking through the cracks. Pretending small volumes “disappear” through drains only postpones—and amplifies—problems downstream.
Shipping Name: 1-Chloro-2-butene, Flammable Liquid
Hazard Class: 3
Packing Group: II
Shipping these containers means rigid labeling, sealed drums, and trained carriers. Rolling chemical drums in regular trucks has no place in responsible industry; correct marks and handling shape the difference between routine transit and disaster on the highway.
Global Regulations: Featured on many chemical control lists; national restrictions target flammability, workplace exposure, and environmental discharge.
Workplace Exposure Limits: Set by government agencies—limits for airborne concentrations, personal exposure time, and controls for routine handling.
Some jurisdictions consider even low-level environmental emissions as reportable, with fines for non-compliance. Policy gaps and weak enforcement often shift the consequences onto local communities and water supplies.
