SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 584849
CASRN 584-84-9
SynonymsToluene-2,4-diisocyanate
2,4-Tolylene diisocyanate
Benzene, 2,4-diisocyanato-1-methyl-
Molecular FormulaC9H6N2O2

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use CHEMICAL INTERMEDIATE POLYURETHANE COATINGS IN FLOOR & WOOD FINISHES & SEALERS, PAINTS, CONCRETE SEALERS, FOR AIRCRAFT & TANK TRUCKS; POLYURETHANE ELASTOMERS IN COATED FABRICS & CLAY-PIPE SEALS; IN ADHESIVES. CROSS-LINKING AGENT FOR NYLON 6 Use in the manufacture of polyurethane foam
Consumption Patterns 56% FOR FLEXIBLE AND SEMIFLEXIBLE POLYURETHANE FOAMS; 29% EXPORTED; 7% FOR RIGID POLYURETHANE FOAMS; 4% FOR URETHANE SURFACE COATINGS; 3% FOR POLYURETHANE ELASTOMERS; 1% FOR MISC APPLCNS INCLUDING SPANDEX FIBERS, ADHESIVES, SEALANTS (1970)
Apparent Color A WATER-WHITE LIQ WHICH TURNS STRAW-COLORED ON STANDING ; Clear to light yellow liq or crystals ; Colorless to pale yellow, solid or liquid
Odor SHARP, PUNGENT
Boiling Point 251 DEG C @ 760 MM HG
Melting Point 19.5-21.5 DEG C
Molecular Weight 174.15
Density 1.2244 @ 20 DEG C/4 DEG C
Odor Threshold Concentration The odor threshold is 0.4 ppm in about half of the subjects. 0.4-2.14 ppm Purity not specified Air: 0.17 ul/l; odor safety class E; E= Less than 10% of attentive persons can detect the TLV. Odor recognition in air: 2.10 ppm (purity) Odor low= 3.2 mg/cu m; High= 17.12 mg/cu m
Sensitivity Data AS A VAPOR TOLUENE DIISOCYANATE IS A POWERFUL IRRITANT TO EYES, SKIN, RESPIRATORY TRACT. TOLUENE DIISOCYANATE
Environmental Impact Commercial toluene diisocyanate (TDI) typically contains 80% of 2,4-toluene diisocyanate. It may be released to the environment as fugitive emissions and from stack exhaust during the production, transport, and use of TDI in the manufacture of polyurethane foam products and coatings as well as from spills. Much of the enviromental fate and monitoring data does not distinguish between the isomers of toluene diisocyanate, however, since the types of reactions are similar, some of the data presented below is for the commercial TDI mixture. The reactivity of the 2,4-toluene diisocyanate with compounds containing active hydrogen, such as water, alcohols or acids is greater than with the 2,6- isomer; therefore, the percentage of 2,4-toluene diisocyanate in monitored TDI is generally much less than 80% in the commercial mixture. If spilled on wet land, TDI is rapidly degraded. If released into water, a crust forms around the liquid TDI and < 0.5% of the original material remains after 35 days. Low concentrations of TDI hydrolyze in the aqueous environment in approximately a day. In the atmosphere, TDI reacts with photochemically produced hydroxyl radicals (half-life 3.3 hr) and is also removed by dry deposition. Human exposure is primarily occupational via inhalation and dermal contact.
Environmental Fate TERRESTRIAL FATE: Ten days after a spill of 13 tons of toluene diisocyanate (TDI) onto swampy, wet forest soil, TDI and toluenediamines were found in the soil(1,2). The TDI solidified and the area was covered with sand. The soil concn of TDI and toluenediamine combined declined from the parts per thousand to parts per million range between 10 days and 12 wk after the spill . No TDI was detected in a connecting brook 10 days after the spill . After 6 years, only TDI-derived polyureas were found at the site . In a simulated spill, 5 kg of TDI in a container was covered with 50 kg of sand and 5 kg of water at ambient temperatures and samples taken from the top and bottom of the sand pile. After 24 hr, 5.5% of the TDI remained unreacted and after 8 days 3.5% remained . The reaction product was largely polyureas . AQUATIC FATE: When low concns of TDI are released into model river or seaway systems, it is hydrolyzed within a day . In order to simulate a spill of TDI in stagnant water, 0.5 l of TDI was poured into 20 liters of water at pH 5, 7, or 9 at 20 deg C. A hard compact crust formed at the water TDI interface . This crust thickened over a period of 30 days until no liquid TDI remained. The solid crust contained < 0.5% of the original TDI after 35 days . Another experiment was performed to simulate a spill into running water by pouring 0.5 l of TDI into 20 l of slowly overflowing water. Barely detectable amounts of toluenediamine were present in the overflow samples. As in the stagnant water simulation, a crust formed that contained < 0.5% of the original TDI after 35 days . ATMOSPHERIC FATE: Removal of TDI from the atmosphere is due to reaction with photochemically produced hydroxyl radicals (half-life 3.3 hr) as well as through dry deposition. Earlier ideas that reaction with water vapor was of major importance have not been substantiated in recent experiments. EFFL: Toluene diisocyanate (TDI), no isomer specified, has been reported in waste water from furniture manufacturing in the concn range of 0.1- 4.1ppm . Stack exhaust from a polyurethane foam production plant were reported to contain 100-17,700 ug/cu m of TDI (no isomer specified) .

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