BENZIDINE 107
4. CHEMICAL AND PHYSICAL INFORMATION
4.1 CHEMICAL IDENTITY
Table 4-1 lists common synonyms, trade names and other pertinent identification information for
benzidine.
4.2 PHYSICAL AND CHEMICAL PROPERTIES
Table 4-2 lists important physical and chemical properties of benzidine.
BENZIDINE 108
4. CHEMICAL AND PHYSICAL INFORMATION
Table 4-1. Chemical Identity of Benzidine
Characteristic Information Reference
Chemical name
Synonym(s)
Registered trade name(s)
Chemical formula
Chemical structure
Identification numbers:
CAS Registry
NIOSH RTECS
EPA Hazardous Waste
OHM/TADS
DOT/UN/NA/IMCO
shipping
HSDB
NCI
Benzidine
4,4'-Bianiline;
4,4'-Diphenyldiamine;
4,4'-Diaminobiphenyl;
4,4'-Diphenylenediamine;
(1,1'-Biphenyl)-4,4'-diamine;
C.I. Azoic Diazo Component 112
Fast Corinth Base B
C
12
H
12
N
2
NH
2
H
2
N
92-87-5
DC 9625000
U021
8100001
UN 1885
IMO Class 6.1
948
C03361
HSDB 1999
IARC 1982a;
HSDB 1999
IARC 1982a
Lide 1998
Lide 1998
NIOSH 1984c
HSDB 1999
HSDB 1999
HSDB 1999
HSDB 1999
HSDB 1999
NLM 1988
CAS = Chemical Abstracts Services; DOT/UN/NA/IMCO = Department of Transportation/United
Nations/North America/International Maritime Dangerous Goods Code; EPA = Environmental Protection
Agency; HSDB = Hazardous Substances Data Bank; NCI = National Cancer Institute; NIOSH = National
Institute for Occupational Safety and Health; OHM/TADS = Oil and Hazardous Materials/Technical
Assistance Data System; RTECS = Registry of Toxic Effects of Chemical Substances
BENZIDINE 109
4. CHEMICAL AND PHYSICAL INFORMATION
Table 4-2. Physical and Chemical Properties of Benzidine
Property Information Reference
Molecular weight 184.24 Lide 1998
Color Grayish-yellow, white or reddish- Lewis 1993
gray
Physical state Crystalline powder Budavari et al. 1996
Melting point 120
EC Lide 1998
Boiling point 401
EC Lide 1998
Specific gravity (20/4
EC) 1.250 Verschueren 1983
Odor No data
Odor threshold:
Air No data
Water No data
pK
a
4.3 (monoprotonated) Zierath et al. 1980
3.3 (diprotonated)
Solubility:
Water at 12
EC 400 mg/L Verschueren 1983
at 20
EC 276 mg/L EPA 1987b
at 25
EC 520 mg/L EPA 1987b
at 100
EC 9,346 mg/L Budavari et al. 1996
Organic solvent(s) 200 g/L (boiling alcohol) Budavari et al. 1996
20 g/L ether Budavari et al. 1996
Partition coefficients:
Log K
ow
1.34 Hansch et al. 1995
Log K
oc
1.02–4.9 EPA 1981b, 1987b; Johnson
and Means 1986
Vapor pressure:
25
EC 7.0x10
-7
mmHg Neely and Blau 1985
20
EC 7.5x10
-9
mmHg Schmidt-Blelk et al. 1982
Henry's law constant
at 25
EC 5.2x10
-11
atm-m
3
/mol Meylan and Howard 1991
Autoignition temperature No data
Flashpoint No data
Flammability limits Does not burn or burns with HSDB 1999
difficulty
Conversion factors at 25
EC 1 ppm = 0.133 mg/m
3
IARC 1982a
1 mg/m
3
= 7.52 ppm
Explosive limits No data
pK
a
= The dissociation constant of the conjugate acid
