2,6-toluenediisocyanate

91-08-7

TDI (mixture) is a clear-to-yellow flammable, volatile liquid 
with a sweet, pungent odor.

USSR: human odour perception; non perception: 0.15 mg/m3;
                              perception:     0.020 mg/m3;
      human reflex response; no response: 0.050 mg/m3;
                             adverse response: 0.1 mg/m3;
      animal chronic exposure: no effect: 0.02 mg/m3;
                               adverse effect: 0.2 mg/m3
(Verschueren 1983).

174.17

The vapor pressure of commercial toluene diisocyanate (80% 2,4- 
and 20% 2,6-isomer) is 0.02 mmHg at 20 °C, suggesting that 
spilled TDI will not readly volatilize from soil and surfaces. 

TDI reacts with water; therefore volatilization from water is 
not expected to be important (HSDB 1999).

Photooxidation half-life in air:
3.21hr - 0.321hr, scientific judgement based upon estimated
rate constant for reaction with hydroxyl radical in air
(Howard 1991).

The half-life for toluene diisocyanate in the atmosphere is 3.3 
hours by reaction with photochemically producted hydroxyl 
radicals (HSDB 1999).

First-order hydrolysis half-life:
12hr, scientific judgement based upon observed disappearance of 
toluene diisocyanate in a model river (Howard 1991).

Aerobic half-life:
4w - 7d, scientific judgement (Howard 1991).

Anaerobic half-life:
16w - 28d, scientific judgement based upon estimated 
unacclimated aerobic aqueous biodegradation half-life 
(Howard 1991).

When low concentrations of TDI (2,4- and 2,6-isomers) are
released into model river or seaway systems, it is hydrolyzed
with in a day (HSDB 1999).

Toluene diisocyanates are expected to be hydrolyzed much more 
rapidly than they are attacked by microorganisms (HSDB 1999).

Mutation data:
microsomal assay;
Salmonella typhimurium, 0.010 mg/plate (Sweet 1987).

Grass shrimp (Palaemonetes pugio): no significant mortality
below 508 mg/l (Verschueren 1987).