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Chemical Name: Trimethyl Phosphite
Synonyms: Phosphorous acid, trimethyl ester; TMP; Methyl phosphite
CAS Number: 121-45-9
Recommended Uses: Used in organic synthesis, as a reagent in chemical manufacturing, and in processes involving pesticides
Supplier Information: Manufacturer’s address, contact phone number, and emergency contact number provided with shipments
UN Number: UN2323
EC Number: 204-471-3
Molecular Formula: C3H9O3P
Molecular Weight: 124.08 g/mol
Emergency Overview: Flammable liquid and vapor, colorless, faint odor
Hazard Classification: Flammable liquids (Category 3); Acute toxicity, oral (Category 4); Skin irritation (Category 2); Eye irritation (Category 2A); Sensitization, skin (Category 1)
Signal Word: Warning
Hazard Statements: H226: Flammable liquid and vapor; H302: Harmful if swallowed; H315: Causes skin irritation; H319: Causes serious eye irritation; H317: May cause an allergic skin reaction
Pictograms: Flame, exclamation mark
Precautionary Statements: Keep away from heat, sparks, and open flame; Wear protective gloves, eye protection, face protection; Do not breathe vapors, mist, or spray; Wash skin thoroughly after handling; Avoid release to the environment; Contaminated clothing should not leave the workplace
Routes of Exposure: Inhalation, ingestion, skin, eyes
Medical Conditions Aggravated: Individuals with preexisting skin or respiratory conditions may experience increased risk
Chemical Identity: Trimethyl Phosphite
Chemical Formula: C3H9O3P
Concentration: ≥ 99% by weight
Impurities: Trace quantities of related phosphorous esters possible
Other Ingredients: No known significant non-hazardous components noted
Inhalation: Move person to fresh air; if breathing drops or becomes difficult, seek medical attention; provide oxygen support as necessary
Skin Contact: Wash with soap and plenty of water for at least 15 minutes; remove contaminated clothing and shoes; consult a physician in case of persistent irritation or burns
Eye Contact: Rinse immediately with plenty of water, lifting upper and lower eyelids; continue for at least 15 minutes and seek immediate medical assistance
Ingestion: Rinse mouth with water; never administer anything by mouth to an unconscious individual; obtain medical attention; do not induce vomiting unless directed by medical personnel
Most Important Symptoms: Eye redness, skin irritation, dizziness, coughing, headache, nausea possible after significant exposure
Notes for Medical Providers: Treat symptomatically and provide supportive care; monitor respiratory and cardiovascular functions closely
Suitable Extinguishing Media: Carbon dioxide, dry chemical powder, alcohol-resistant foam, water spray for cooling containers
Unsuitable Extinguishing Media: Direct streams of water may be ineffective and spread fire
Hazardous Combustion Products: Phosphorous oxides, carbon monoxide, carbon dioxide, irritating fumes
Fire Hazards: Vapors may form explosive mixtures with air, may travel considerable distances to ignition sources
Protective Equipment for Firefighters: Self-contained breathing apparatus and full protective gear; wear flame-resistant suit and gloves
Fire Fighting Instructions: Cool fire-exposed containers with water spray, avoid inhaling combustion gases; evacuate personnel to a safe area; contain run-off to prevent contamination
Personal Precautions: Wear chemical-resistant gloves, goggles, protective clothing, adequate respiratory protection
Environmental Precautions: Prevent entry into sewers, drainage systems, surface water, and soil
Cleanup Methods: Eliminate ignition sources nearby; ventilate area; use non-sparking tools to soak up with inert absorbent (sand, vermiculite); place in sealed, labelled containers for disposal; wash contaminated areas with water and detergent
Decontamination: Thoroughly wash any surfaces and clothing that came into contact; handle with appropriate chemical hygiene
Spill Size Considerations: Isolate small spills with absorbent material; for large spills, evacuate area and follow emergency protocol
Handling: Avoid inhaling vapors, absorbing through skin, or contact with eyes; use only in well-ventilated areas; keep away from open flames, hot surfaces, static discharge, and oxidizing agents; handle with grounded, explosion-proof equipment
Storage: Store in tightly closed, properly labelled containers; keep in cool, dry, and well-ventilated place; segregate from acids, alkalis, oxidizers; keep away from ignition sources and incompatible chemicals
Incompatible Materials: Strong acids, bases, oxidizing agents, reducing agents
Special Requirements: Use secondary containment storage to avoid accidental releases; ensure containers are corrosion resistant
Temperature Sensitivity: Protect from heat and sunlight; recommended storage temperature below 25°C (77°F)
Exposure Limits: No OSHA PEL or ACGIH TLV specific for trimethyl phosphite; minimize exposure as much as possible
Engineering Controls: Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels low
Personal Protective Equipment: Chemical-resistant gloves (nitrile, neoprene recommended); splash goggles or face shield; flame-resistant long-sleeve lab coat; appropriate chemical-resistant footwear
Respiratory Protection: Use NIOSH/MSHA approved respirators if airborne levels exceed safe exposure guidelines or ventilation is insufficient
Hygiene Measures: Wash hands, face, and exposed skin thoroughly after handling; avoid eating, drinking, or smoking in work area; emergency eyewash and safety shower accessible in work area
Workplace Monitoring: Regular air monitoring for phosphite vapors recommended in handling zones
Appearance: Clear, colorless liquid
Odor: Mild, faintly fruity odor
Odor Threshold: Not established
pH: Not applicable (non-aqueous)
Melting Point/Freezing Point: -80°C (-112°F)
Boiling Point/Range: 112°C (234°F) at 1 atm
Flash Point: 27°C (80.6°F) (closed cup)
Evaporation Rate: Not determined
Flammability: Flammable liquid
Upper/Lower Flammability Limits: Not available
Vapor Pressure: 12 mmHg @ 20°C (68°F)
Vapor Density: 4.3 (air = 1)
Density: 1.06 g/cm³ @ 20°C
Solubility in Water: Slightly soluble; hydrolyses slowly in water
Partition Coefficient (log Kow): Not available
Auto-Ignition Temperature: 395°C (743°F)
Decomposition Temperature: Not established
Viscosity: Not determined
Chemical Stability: Stable under recommended storage and handling conditions
Reactivity: Reacts with strong oxidizing agents; reacts slowly with moisture, producing methanol and phosphorous-containing acids
Hazardous Reactions: Exothermic reactions possible with acids, bases, and oxidants
Hazardous Decomposition Products: Methanol, phosphorous oxides, carbon monoxide, carbon dioxide, irritating fumes
Incompatible Materials: Acids, oxidizers, strong bases, moisture
Conditions to Avoid: Heat, sparks, flames, static discharge, exposure to moisture
Acute Toxicity: Oral LD50 (rat): 1600 mg/kg; Inhalation LC50 (rat): no data; Dermal LD50 (rabbit): not available
Skin Corrosion/Irritation: Causes moderate irritation; may cause burns on prolonged contact
Eye Damage/Irritation: Causes irritation; may lead to redness, pain, or impaired vision if contact is severe
Respiratory Sensitization: May cause coughing, sore throat, difficulty breathing at high concentrations
Skin Sensitization: May cause allergic reactions in some individuals
Genotoxicity: No data indicating mutagenic effect
Carcinogenicity: Not classified as carcinogenic by IARC, NTP, or OSHA
Reproductive Toxicity: Not established
Target Organ Effects: Eyes, skin, respiratory system
Chronic Effects: Prolonged or repeated exposure may cause dermatitis, respiratory tract irritation
Ecotoxicity: Harmful to aquatic life with short-term effects; LC50 or EC50 values not fully established for aquatic species
Persistence and Degradability: Readily undergoes hydrolysis in water, producing environmentally persistent fragments
Bioaccumulation Potential: Low; breaks down into methanol and phosphorous acid derivatives
Mobility in Soil: Moderately mobile; hydrolysis products can leach in moist environments
Other Adverse Effects: Can contribute to chemical oxygen demand in water systems; should not enter drains or watercourses
Precautionary Measures: Prevent accidental release into environment; use containment measures to collect spillage
Waste Disposal: Dispose of in accordance with all local, regional, and national regulations; collected waste should be sent for incineration by qualified operators according to hazardous material standards
Contaminated Packaging: Empty containers retain product residue and vapors; treat as hazardous waste; triple rinse and puncture before disposal; recycle or dispose through authorized waste management facility
Sewage Disposal: Do not dispose of into municipal sewers, storm drains, or waterways
Handling Instructions: Use non-leaking, sealed containers clearly marked for hazardous waste transport
Other Considerations: Keep waste separate from incompatible materials; avoid mixing with non-hazardous waste streams
UN Number: UN2323
Proper Shipping Name: Trimethyl phosphite
Hazard Class: 3 (Flammable liquid)
Packing Group: III
Labels: Flammable liquid
Marine Pollutant: Not designated as marine pollutant
Environmental Hazards: See Ecological Information section for spill response guidance
Special Precautions: Use only approved containers and proper securing methods during transit; segregate from incompatible materials during shipment
Transport by Land/Road: Follow US DOT, ADR/RID regulations
Transport by Air (IATA): Regulated; same UN and hazard classification
Transport by Sea (IMDG): Regulated as hazardous
US Regulation: SARA 313: Not subject to reporting; TSCA Inventory: Listed; OSHA: Hazardous chemical under Hazard Communication Standard
EU Regulation: REACH: Registered; Classification, Labelling and Packaging (CLP) regulation applies; Safety data sheet required for supply
Canada Regulation: Domestic Substances List (DSL): Listed; WHMIS classification: Class B2 (flammable liquid), Class D2B (toxic material causing other effects)
Australia: AICS: Listed
Other Regulations: Follow specific state, provincial, and national requirements for handling, use, transportation, and disposal
Workplace Labelling: Ensure clear, legible container labels on all packaging and secondary containment
Consumer Use Restrictions: Restricted to professional and industrial users with suitable safety training
