Product Name: Tetramethoxysilane
Synonyms: Tetramethyl orthosilicate, TMOS, Silicic acid, tetramethyl ester
CAS Number: 681-84-5
Recommended Use: Used in synthesis of silica materials, coatings production, adhesives, and sealants
Manufacturer: Major chemical suppliers and specialty material companies
Emergency Contact Number: Listed on supplier's product label
Address: Referenced according to supplier-specific information
Chemical Formula: Si(OCH₃)₄
UN Number: 1992 (flammable liquid)
Classification (GHS): Flammable liquids (Category 3), Acute toxicity, inhalation (Category 3), Serious eye damage (Category 1), Specific target organ toxicity—single exposure (Respiratory system, Category 3), Skin irritation (Category 2)
Signal Word: Danger
Hazard Statements: Causes severe eye damage, causes skin irritation, may damage respiratory organs, toxic if inhaled, flammable liquid and vapor
Pictograms: Flame, exclamation mark, health hazard, corrosive
Precautionary Statements: Avoid breathing vapors, use only outdoors or with adequate ventilation, keep container tightly closed, store in well-ventilated location, wear protective gloves and eye protection, keep away from sources of ignition and static discharge
Routes of Exposure: Skin contact, eye contact, inhalation of vapors, accidental ingestion
Chemical Name: Tetramethoxysilane
Concentration: 98-100%
CAS Number: 681-84-5
Impurities: Methanol (possible trace formation upon decomposition or hydrolysis), usually less than 0.1%
Additives: Not typically present in pure chemical
Inhalation: Move to fresh air, keep at rest, monitor breathing, provide oxygen if available, seek medical attention immediately in case of respiratory symptoms
Skin Contact: Remove contaminated clothing, flush affected area with soap and water for at least 15 minutes, do not rub skin, seek medical attention if irritation persists
Eye Contact: Rinse cautiously with water for several minutes, remove contact lenses if present, continue rinsing, seek immediate medical attention
Ingestion: Rinse mouth, never give anything by mouth to an unconscious person, do not induce vomiting, seek medical attention right away
Note to Physicians: Symptoms may include respiratory tract irritation, methanol poisoning in severe cases, monitor for delayed effects from hydrolysis products
Suitable Extinguishing Media: Carbon dioxide, dry chemical powder, alcohol-resistant foam
Unsuitable Extinguishing Media: Direct water jets (may spread flames)
Specific Hazards: Produces toxic fumes of silicon oxides and formaldehyde, methanol vapor formation, container rupture if exposed to intense heat
Special Equipment for Firefighters: Self-contained breathing apparatus (SCBA), full protective gear
Firefighting Procedures: Evacuate personnel from area, fight fire from upwind, use water spray to cool containers, avoid inhalation of hazardous combustion products
Personal Precautions: Evacuate unprotected personnel, avoid inhalation and contact with skin or eyes, ventilate area, remove ignition sources
Protective Equipment: Chemical-resistant gloves, protective clothing, eye protection, respirator recommended in poorly ventilated spaces
Environmental Precautions: Prevent material from entering drains, surface water, or soil
Containment: Stop leakage at source, dike and absorb with inert material (sand, earth, vermiculite)
Cleanup Methods: Collect in suitable labeled containers for disposal, provide adequate ventilation during cleanup, dispose of contaminated materials according to regulations
Handling: Use only in well-ventilated areas, avoid breathing vapors, avoid contact with skin and eyes, ground and bond containers during transfer, handle away from sources of ignition
Hygiene Measures: Wash hands thoroughly after handling, remove contaminated clothing and wash before reuse, avoid eating or drinking in work area
Storage: Store in tightly closed, properly labeled containers, keep away from sources of heat, sparks, and open flames, maintain in cool, dry, well-ventilated area
Storage Incompatibilities: Protect from moisture, acid, alkalis, oxidizing agents, and strong reducing agents
Engineering Controls: Use localized exhaust ventilation, maintain adequate general ventilation
Exposure Limits: Occupational Exposure Limit (OEL) for methanol (byproduct): ACGIH TLV 200 ppm TWA
Personal Protective Equipment (PPE): Chemical-resistant gloves (nitrile or neoprene), safety goggles, face shield, flame-retardant lab coat, chemical-resistant apron as needed
Respiratory Protection: Use NIOSH-approved respirator if ventilation is inadequate, especially for higher vapor concentrations
Environmental Controls: Prevent release to environment, use spill containment procedures in place
Appearance: Clear, colorless liquid
Odor: Alcoholic, similar to methanol
Melting Point: -2°C (28°F)
Boiling Point: 122°C (252°F)
Flash Point: 43°C (109°F)
Vapor Pressure: 7.3 mmHg at 25°C
Vapor Density: 4.1 (air = 1)
Solubility: Reacts with water, decomposes slowly
Specific Gravity: 1.03 (at 20°C)
Auto-ignition Temperature: 245°C (473°F)
Partition Coefficient (n-octanol/water): Not established
Evaporation Rate: Not determined
Decomposition Products: Methanol, silicon dioxide, formaldehyde under certain conditions
Chemical Stability: Stable under recommended storage conditions
Reactivity: Reacts with water, acids, and bases to form methanol and silicon dioxide
Hazardous Reactions: Rapid hydrolysis produces heat and methanol vapors, exothermic reactions possible
Conditions to Avoid: Heat, flames, sparks, moisture, exposure to air for long periods
Incompatible Materials: Water, strong acids, strong bases, oxidizing and reducing agents
Hazardous Decomposition Products: Methanol, silicon oxides, formaldehyde under fire conditions
Acute Toxicity: Inhalation may cause respiratory tract irritation, headaches, dizziness, central nervous system effects, possible methanol poisoning
Skin Contact: Irritates and can cause dermatitis upon prolonged exposure
Eye Contact: Causes severe irritation or burns, visual impairment possible from intense exposure
Ingestion: Harmful or fatal, methanol released in body can cause systemic toxicity
Chronic Effects: Prolonged exposure may impact liver, kidneys, or central nervous system due to methanol formation
Sensitization: Not reported
Carcinogenicity: Not classified as carcinogenic by IARC, NTP, or OSHA
Mutagenicity and Reproductive Toxicity: Data on reproductive toxicity limited, concern due to methanol formation
Ecotoxicity: Toxic to aquatic organisms, risk of long-term adverse effects in aquatic environment through formation of methanol and other byproducts
Persistence/Degradability: Undergoes rapid hydrolysis with water, eventually forms silica and methanol
Bioaccumulative Potential: Low, but methanol has potential for bioaccumulation in aquatic species
Mobility in Soil: Likely to leach to groundwater when spilled; product and hydrolysis byproducts mobile in soil
Other Adverse Effects: Methanol release to water or ground can have significant environmental consequences, adequate spill precautions necessary to limit contamination
Waste Treatment Methods: Dispose as hazardous waste by incineration in accordance with local, regional, and national regulations
Contaminated Containers: Triple rinse and send to recognized hazardous waste facility
Disposal Precautions: Prevent material and solutions from entering soil, drains, or natural water sources; avoid uncontrolled release or burning
Additional Notes: Regulations and recommended procedures may vary by jurisdiction, always consult regional waste guidelines
UN Number: 1992
Proper Shipping Name: Flammable liquid, toxic, n.o.s. (Tetramethoxysilane)
Transport Hazard Class: 3 (Flammable Liquid), 6.1 (Toxic Substance)
Packing Group: II
Label Requirements: Flammable Liquid, Toxic
Special Precautions: Secure containers to prevent tipping, ventilate transport vehicles, isolate from food and animal feed
Environmental Hazards: Substance presents marine pollutant risk due to methanol byproduct
TSCA: Listed in the United States Toxic Substances Control Act Inventory
REACH: Registered substance in the European Union
OSHA: Regulated as hazardous chemical
SARA Title III: Subject to reporting requirements for acute health hazards under Section 311/312
WHMIS (Canada): Class B2 (Flammable Liquid), Class D1B (Toxic matériel), Class D2B (Irritant)
State Specific Regulations: Listed in state hazardous substance inventories where applicable
Other International Regulations: Included on chemical inventories in Australia, New Zealand, Japan, Korea, China, Philippines
Product Labeling: Labels must include hazard pictograms, signal words, hazard and precautionary statements as required by GHS/OSHA
