o-TOLUIDINE CAS N°: 95-53-4 - UNEP Chemicals

OECD SIDS o-TOLUIDINE
1.3 Physico-Chemical properties
Table 1 Summary of physico-chemical properties of o-toluidine
Property Value Reference IUCLID
Substance type Organic, aromatic, amino
compound
Physical state Light yellow liquid
becoming reddish brown
on exposure to air and
light
Melting point -24.4 °C (α-form)
-16.3 °C (β-form)
Boiling point
at 1013 hPa
Density
at 20 °C
Vapour pressure
at 25 °C
Octanol/water partition
coefficient (log Kow)
at 24.5 °C
Water solubility
Flash point
(Closed cup)
Auto flammability
(ignition temperature)
Dissociation constant
(pKa)
1.1.1
Merck Index, 2001 1.1.1
Roempp, 1999 2.1
200.2 °C Bowers, 2002 2.2
0.9984 g/cm 3 Lide, 1995;
Bowers, 2002
UNEP PUBLICATIONS 9
2.3
34.5 Pa Yaws, 1994 2.4
1.40
(Directive 79/831/EEC)
15.0 g/l at 25 °C
16.22 g/l at 20 °C
85 °C
482 °C
4.44 - 4.45*
Conversion factor 1 ppm = 5.87 mg/m 3
BASF AG, 1987 2.5
Beilstein, 2003
Chiou and Schmedding,
1982; Kim and Lee,
2002
2.6.1
Bowers, 2002 2.7
Bowers, 2002 2.8
Essington, 1994 2.12
IARC, 2000 2.14
* The pKa of the substance (4.45) indicates that, except in very low pH environments (e.g. pH < 5), the substance
will exist almost entirely in the unprotonated form.
2 GENERAL INFORMATION ON EXPOSURE
2.1 Production Volumes and Use Pattern
Commercial toluidine manufacturing starts with the mononitration of toluene by mixed-acid (nitric
acid/sulfuric acid) which yields the three isomers of nitrotoluene, mostly o- and p-nitrotoluene, and
to a smaller extend m-nitrotoluene. In general, the nitrotoluene isomers are separated by distillation
before the nitro group is reduced (Bowers, 2002).
Most important method for the manufacture of o-toluidine is the catalytic vapor-phase reduction of
o-nitrotoluene with hydrogen according to