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Chemical Name: Diethyl Sulfate
Common Synonyms: Sulfuric acid, diethyl ester
CAS Number: 64-67-5
Physical State: Liquid
Color and Odor: Colorless to pale yellow, faint peppermint-like odor
Uses: Typically relied upon in organic synthesis, alkylating agent in lab and industrial settings, and for research applications that demand strong ethylating conditions
Classification: Recognized as a highly toxic and carcinogenic substance
Health Risks: Causes severe eye and skin burns, respiratory tract irritation, long-term cancer risk after exposure
Main Exposure Routes: Inhalation, skin absorption, eye contact
Immediate Dangers: Severe irritation, ulceration, breathing difficulty
Chronic Effects: Increased cancer risk, potential genetic damage
Signal Word: Danger
Pictograms: Combustible, health hazard, corrosive, environmental hazard
Main Constituent: Diethyl Sulfate
Chemical Formula: (C2H5)2SO4
Purity: Usually sold in high concentrations, often >98%
Impurities: Minor traces of ethanol, sulfuric acid, and other alkyl sulfates can show up depending on the manufacturing process
Inhalation: Get fresh air immediately, watch for breathing problems, provide oxygen if needed, call emergency services right away
Skin Contact: Remove contaminated clothing, wash with running water for at least 15 minutes, seek urgent medical attention for burns or ongoing pain
Eye Contact: Rinse carefully but thoroughly with water for 15 minutes, keep eyelids apart, see a doctor as soon as possible
Ingestion: Rinse mouth, avoid vomiting, do not give anything by mouth to an unconscious person, medical attention is essential
Personal Experience: A single drop can leave burns, and vapors cause headaches and throat pain almost instantly, which underlines the need for an emergency shower and eyewash station in any areas where this chemical is uncapped
Extinguishing Media: Use foam, dry chemical, or carbon dioxide, never use water directly due to risk of spreading or splashing
Special Hazards: Burns with release of toxic sulfur oxides and ethyl compounds
Advice for Firefighters: Full protective gear and self-contained breathing apparatus are a must
Fire Risks: Vapors may ignite, and containers may explode under heat
Notable Event: Improper disposal near heat sources has led to flash fires in chemical storage rooms; the lesson here is that old stock should never sit forgotten near ignition sources
Personal Protection: Evacuate area, ventilate, suit up with chemical splash goggles, gloves, and acid-resistant apron
Spill Response: Absorb with inert material like sand or vermiculite, collect in sealed containers, never wash into sewer or natural waters
Environmental Precautions: Prevent entry to drains or water bodies; this chemical poisons aquatic life rapidly
Cleanup: Use only tools and containers that resist strong acids
Lessons from Practice: A minor lab spill that reached a drain ended with a fish kill in a downstream pond, underscoring why even small leaks demand careful isolation and cleanup
Safe Handling: Work only in a fume hood, avoid skin or eye contact, never eat, drink, or smoke nearby
Storage Conditions: Store tightly closed in a cool, well-ventilated area, away from strong bases, oxidizers, and water sources
Segregation: Keep away from food and incompatible reagents, particularly sodium or potassium compounds
Labeling: Clear, legible hazard labeling is crucial; faded labels have led to accidental mixing more than once
Personal Habit: Double-checking lock-up after hours is the best safeguard against accidental exposure from curious or uninformed co-workers
Engineering Controls: Local exhaust ventilation, fume hoods required in all handling and transfer areas
Workplace Limits: OSHA and ACGIH recommend minimizing exposure to the lowest possible levels due to carcinogenicity
Personal Protective Equipment: Splash-proof goggles, acid-resistant gloves (like nitrile or neoprene), closed lab coats, and face shield for all transfers and open handling
Respiratory Protection: Air-purifying respirators with acid gas cartridges in low-concentration environments; full SCBA if vapor levels rise or in an emergency
Personal Rule: Never trust a thin lab glove—double-gloving saved my skin after an unnoticed splash; always check your protection for pinholes or tears before starting
Appearance: Oily and clear to pale yellow
Boiling Point: Around 208°C
Melting Point: -25°C
Vapor Pressure: Low at room temperature, but enough to irritate in a poorly ventilated space
Solubility: Forms dense white layers in water, reacts to form ethyl alcohol and sulfuric acid
Density: About 1.2 g/cm3
Odor: Peppermint-like but not pleasant
Volatility: Slow but persistent
Chemical Stability: Stable under normal, dry, and cool storage conditions
Reactive Conditions: Water, alcohols, amines, bases, strong oxidizers
Decomposition Products: Sulfur oxides, ethanol, other noxious gases
Incompatibility: Vigorous reaction with water and organic bases can cause violent splattering and toxic fumes
Experience: Accidental water contact led to rapid heating and pressure buildup in a flask; always dry containers and tools, especially during summer humidity
Acute Toxicity: Inhalation, skin, and oral exposure all present a high risk; even minor exposures may cause poisoning symptoms
Carcinogenicity: Diethyl sulfate is classified as a probable human carcinogen by IARC
Symptoms: Short-term – severe irritation, burns, headache, dizziness, breathing difficulty
Chronic Exposure: Liver, kidney damage and increased cancer risk with repeated exposure
Lab Incident: A coworker experienced blistered skin and respiratory problems after a minor vapor leak; doctor’s advice—avoid any unnecessary exposure and never handle alone
Aquatic Toxicity: High toxicity to aquatic organisms, lethal in small concentrations
Persistence: Does not break down quickly, can accumulate in water systems
Mobility: Slow to evaporate, migrates through soil and may reach groundwater
Long-Term Harm: Environmental agencies report bioaccumulation risks, fish kills, and persistent soil contamination after improper disposal
Direct Experience: Labs that poured old reagents down the sink contributed to chronic local stream pollution—a sobering lesson that each drop matters
Waste Handling: Treat as hazardous waste, secure closed chemical containers for transfer to a certified disposal facility
Forbidden Practices: Never pour down drains or toilets, dilute, or "neutralize" without trained supervisors
Recommended Process: Incineration in regulated chemical incinerators only
Documentation: Keep thorough disposal records; regulatory inspection fines for improper documentation can be severe
Reflection: Early in my lab career, improper paperwork after a disposal batch caused a month of hold-ups with local regulators
UN Number: 1594
Proper Shipping Name: Diethyl Sulfate
Hazard Class: 6.1, Toxic Substances
Packing Group: I (highest hazard)
Transport Advice: Ship only in approved containers, secure upright, avoid mixed loads with incompatibles like alkalis or foodstuffs
Lessons from Transit: Crushed packaging often causes minor leaks, so secondary containment and clear hazard labeling prove essential during moves between sites or labs
OSHA: Listed as a highly hazardous chemical, strict workplace controls apply
IARC: Classified as probable carcinogen
EPA: Regulated for environmental release and disposal; permits required above certain quantities
Employer Obligations: Provide comprehensive hazard communication, training, and emergency preparedness
Firsthand Learnings: After a regulatory surprise inspection, I always double-check training records and ensure that no bottle falls out of inventory tracking; strong oversight keeps people safe
