Product Name: Tetraethyl Orthosilicate
Synonyms: Tetraethoxysilane, TEOS
Chemical Formula: Si(OC2H5)4
CAS Number: 78-10-4
Use: Precursor to silicon dioxide, binder in paints, sealants, catalyst support
Manufacturer Information: Supplier contact details on shipping label, emergency phone line usually available 24/7 for hazardous chemicals like Tetraethyl Orthosilicate, specific distributor and location details depend on sourcing but should always be checked
Recommended Use Restrictions: Should not be used in medical or food applications unless specifically approved, only trained professionals in well-ventilated industrial settings should handle
Hazard Classification: Flammable liquid, eye irritation, skin irritation, potential to cause serious damage to organs through prolonged or repeated exposure, vapor may be harmful if inhaled
Signal Word: Danger
Hazard Statements: Highly flammable liquid and vapor; causes skin and serious eye irritation; suspected of causing cancer with long term exposure; causes damage to respiratory tract through inhalation
Precautionary Statements: Keep away from heat, sparks, and open flames; ground and bond all containers when transferring; avoid breathing vapor or mist; wear protective gloves, eyewear, and a face shield where splashing is possible; wash all exposed skin areas after use; use explosion-proof electrical equipment; take precautionary measures against static discharge; obtain special instructions before use; if exposed or concerned, seek medical attention without delay
Chemical Name: Tetraethyl Orthosilicate
Concentration: 98% or greater
CAS Number: 78-10-4
Other Ingredients: May contain trace amounts of ethanol and other related silicon-ethoxide compounds especially in technical or industrial grades, these traces result from manufacturing or handling processes, none exceed thresholds that alter hazard or response measures
Inhalation: Move person to fresh air; support breathing with oxygen if available and respiratory distress occurs; do not attempt mouth-to-mouth; seek immediate medical advice if symptoms such as coughing, difficulty in breathing, dizziness, or drowsiness persist
Skin Contact: Take off contaminated clothing immediately; wash skin thoroughly with soap and water for at least 15 minutes; do not reuse clothing until thoroughly cleaned; consult medical services if irritation or burn develops or persists
Eye Contact: Flush eyes slowly and gently with water for at least 15 minutes while holding eyelids apart; remove contact lenses if present and easy to do, continue rinsing; call for urgent medical attention
Ingestion: Rinse mouth, give one cup of water to drink if person is fully conscious; do not induce vomiting unless directed by poison center or medical personnel; never give anything by mouth to an unconscious person; seek emergency medical help right away
Additional Notes: Medical personnel should understand risk of delayed onset symptoms after exposure; monitor for severe respiratory issues or chemical burns
Suitable Extinguishing Media: Use alcohol-resistant foam, dry chemical, or carbon dioxide to put out fire; avoid direct water stream, risk of spreading fire
Special Hazards: Highly flammable by ignition source, forms explosive mixtures with air, combustion yields toxic fumes of silicon oxides and carbon oxides
Special Protective Equipment: Firefighters require positive pressure self-contained breathing apparatus, full chemical-protective clothing
Specific Firefighting Procedures: Approach incident from upwind, remove containers from fire if it can be done safely, stay away from storage tanks that might rupture
Explosion Risk: Vapors heavier than air can travel significant distance and cause flashback ignition, closed containers may rupture from buildup of pressure and heat
Advice for Fire Response: Evacuate area, cool fire-exposed containers with water mist as long as safe to do so, avoid inhaling hazardous decomposition products
Personal Precautions: Evacuate unnecessary personnel from area, wear full personal protective equipment including goggles, gloves, chemical-resistant clothing, use approved respirator for organic vapors
Environmental Precautions: Prevent liquid from entering drains, soil, or waterways—contains persistent compounds harmful to aquatic life, may bioaccumulate
Containment and Cleanup: Stop leak if safe, use inert absorbent such as sand or non-combustible absorbent to contain spill, sweep up and place in sealed drums or double-bagged containers for proper disposal, ventilate area to disperse vapors
Decontamination: Wash residue into waste containers with copious water, avoid direct contact or splash
Emergency Procedures: Notify site safety and environmental authority, follow up with decontamination and monitoring to confirm thorough cleanup
Precautions for Safe Handling: Use in well-ventilated chemical fume hoods, ground and bond containers when moving or dispensing liquid, keep away from heat or open flames, avoid skin and eye contact, always check for spills or leaks before use, do not eat, drink, or smoke while handling, train all operators in safe chemical work practices
Storage Requirements: Store in tightly closed containers made of compatible material (prefer glass or steel, HDPE for larger lots), keep in cool, dry, well-ventilated areas far from direct sunlight or ignition sources, use only with appropriate secondary containment, label all containers clearly
Incompatibilities: Strong acids, strong bases, oxidizing agents, water (hydrolyzes forming silanols and ethanol), avoid moisture introduction in storage area
Storage Life: Shelf stable under recommended conditions but check regularly for formation of gel or crystals indicating hydrolysis exposure
Exposure Limits: Occupational exposure limit for tetraethyl orthosilicate may not be defined in all jurisdictions but general 8-hour TWA for vapor is typically 0.5 ppm; check regional authority guidance
Engineering Controls: Use local exhaust ventilation, chemical fume hoods, explosion-proof equipment; monitor vapor concentration using appropriate detection methods, keep eyewash stations and safety showers nearby
Personal Protective Equipment (PPE): Nitrile or neoprene gloves, splash-proof goggles or face shield, flame-resistant lab coat, long pants, closed-toe chemical-resistant shoes, full respiratory protection in poorly ventilated spaces or high-concentration exposures
Hygiene Measures: Wash hands and exposed skin thoroughly after handling; do not allow contaminated clothing to be worn outside work area
Appearance: Clear, colorless, volatile liquid
Odor: Ethereal or alcohol-like odor
Boiling Point: 168°C (334°F)
Melting Point: -77°C (-107°F)
Flash Point: 46°C (115°F, closed cup)
Vapor Pressure: 1.3 mmHg at 20°C
Vapor Density: 8.2 (air=1)
Solubility: Hydrolyzes slowly in water, soluble in most organic solvents including ethanol, acetone, chloroform
Density: 0.934 g/cm³
pH: Not applicable (not miscible in water, hydrolyzes)
Evaporation Rate: Moderate (relative to solvents like ethanol)
Viscosity: 0.95 mPa.s at 20°C
Chemical Stability: Stable under recommended storage conditions with exclusion of moisture and air
Conditions to Avoid: Heat, sparks, open flames, exposure to humid air, prolonged sunlight
Reactivity: Hydrolyzes with water, forming silicon dioxide and ethanol, potentially generating heat and pressure in closed containers
Hazardous Decomposition Products: Silica (SiO2), ethanol vapors, carbon monoxide, carbon dioxide, traces of ethyl silicates and ethers
Incompatible Materials: Strong acids and bases, oxidizers, strong reducing agents
Polymerization: Does not polymerize but may gradually gel due to moisture
Acute Toxicity: Oral LD50 in rats around 6270 mg/kg but vapor inhalation may cause respiratory tract irritation, eye and skin irritation observed at lower concentrations
Symptoms of Overexposure: Coughing, shortness of breath, headache, dizziness, weakness, skin or eye burns, possible delayed onset pulmonary edema
Chronic Toxicity: Repeated exposure can lead to cumulative organ damage, especially to liver and lungs, risk of carcinogenicity debated but not confirmed, may aggravate existing respiratory conditions
Routes of Exposure: Inhalation, skin absorption, eye contact, ingestion (accidental or intentional rare in industrial setting)
Skin/Sensitization: May cause long term dermatitis or sensitization in some occupational cases
Carcinogenicity/Mutagenicity: Not classed as confirmed human carcinogen by IARC, NTP, or OSHA, but prudent to treat as potential risk due to volatility
Reproductive Effects: No conclusive evidence, limited animal studies, avoid exposure during pregnancy for precaution
Aquatic Toxicity: Harmful to aquatic organisms, possible long-term adverse effects in aquatic environment due to silica and ethanol by-products
Persistence and Degradability: Undergoes slow hydrolysis in sediments and soils, generating non-volatile silica which persists, ethanol released degrades more quickly by microbial action
Bioaccumulation: Minimal data for tetraethyl orthosilicate itself, end-product silica does not bioaccumulate, limited risk from organic intermediates
Mobility in Soil: Volatile, evaporates into air or is degraded, non-mobile after conversion to silica
Effects on Wastewater Treatment: High concentrations can disrupt normal microbial treatment due to toxicity
Other Harmful Effects: Consider local regulations and sensitive environments, avoid release to waterways
Waste Treatment Methods: Dispose through incineration in a chemical incinerator equipped with afterburner and scrubber, follow local, regional, and national regulations for hazardous organic compounds
Container Disposal: Triple rinse and puncture empty containers before disposal as hazardous waste, never reuse containers for water or food storage
Special Precautions: Prevent vapor exposure during disposal steps, do not wash into drains or soil, coordinate with certified hazardous waste handler
Waste Classification: May be regulated as hazardous waste under federal and state laws, check classification codes
Regulatory Guidance: Consult environmental and safety compliance officer for plant or facility, maintain record-keeping for all quantities used and disposed
UN Number: UN1292
Proper Shipping Name: Tetraethyl Silicate
Transport Hazard Class: 3 (Flammable liquid)
Packing Group: III
Label: Flammable Liquid
Marine Pollutant: Not classified as such, but spills affect waterways
Special Precautions: Secure drums and containers upright, avoid mixing with incompatible shipments (acids, oxidizers), placard vehicles as required
Emergency Response Guide Number: 127
Transport in Bulk: Comply with IBC regulatory requirements, use containers built to handle hazardous chemical cargo
OSHA Status: Hazardous by definition of Hazard Communication Standard
TSCA Status: Listed on United States TSCA inventory
DSL/NDSL (Canada): Listed/Compliant
REACH (Europe): Registered substance, subject to safety provisions and exposure limits
SARA Title III: Not regulated for Section 313, but listed for Section 302/304/311/312 due to acute and chronic health hazards
Hazard Symbols: Flammable, Irritant
WHMIS (Canada): B2 (Flammable Liquid), D2B (Toxic Material causing other chronic effects)
Other Regulations: Subject to restriction or special reporting under country, state, and local rules—always review current agency documentation before shipping, using, or disposing
Labeling Requirements: Requires pictogram, signal word, major risk statements per GHS labeling system
