CHEMICAL AND PHYSICAL PROPERTIES
| Physical Description | Benzidine appears as a grayish-yellow to grayish-red, crystalline solid. Toxic by ingestion, inhalation, and skin absorption. Combustion produces toxic oxides of nitrogen. Used to make other chemicals and in chemical and biological analysis. |
|---|---|
| Color/Form | White or slightly-reddish, crystalline powder |
| Boiling Point | 752 °F at 740 mmHg (NTP, 1992) |
| Melting Point | 262 °F (NTP, 1992) |
| Solubility | less than 1 mg/mL at 72 °F (NTP, 1992) |
| Density | 2.15 at 68 °F (USCG, 1999) - Denser than water; will sink |
| Vapor Density | 6.36 (NTP, 1992) - Heavier than air; will sink (Relative to Air) |
| Vapor Pressure | Low (NIOSH, 2023) |
| LogP | log Kow= 1.34 |
| Stability/Shelf Life | DARKENS ON EXPOSURE TO AIR & LIGHT |
| Decomposition | When heated to decomp it emits highly toxic fumes of /nitrogen oxides/. |
| Dissociation Constants | pKa1= 4.3 pKa2= 3.3 |
| Kovats Retention Index | 2042 2070 |
| Other Experimental Properties | CAN BE MADE TO SUBLIME |
| Chemical Classes | Nitrogen Compounds -> Benzidine and Derivatives |
SAFETY INFORMATION
| Signal word | Danger |
|---|---|
| Pictogram(s) |
 Exclamation Mark Irritant GHS07  Health Hazard GHS08  Environment GHS09 |
| GHS Hazard Statements |
H302:Acute toxicity,oral H350:Carcinogenicity H410:Hazardous to the aquatic environment, long-term hazard |
| Precautionary Statement Codes |
P201:Obtain special instructions before use. P202:Do not handle until all safety precautions have been read and understood. P264:Wash hands thoroughly after handling. P264:Wash skin thouroughly after handling. P273:Avoid release to the environment. P301+P312:IF SWALLOWED: call a POISON CENTER or doctor/physician IF you feel unwell. P308+P313:IF exposed or concerned: Get medical advice/attention. |
COMPUTED DESCRIPTORS
| Molecular Weight | 184.24 g/mol |
|---|---|
| XLogP3 | 1.3 |
| Hydrogen Bond Donor Count | 2 |
| Hydrogen Bond Acceptor Count | 2 |
| Rotatable Bond Count | 1 |
| Exact Mass | 184.100048391 g/mol |
| Monoisotopic Mass | 184.100048391 g/mol |
| Topological Polar Surface Area | 52 Ų |
| Heavy Atom Count | 14 |
| Formal Charge | 0 |
| Complexity | 145 |
| Isotope Atom Count | 0 |
| Defined Atom Stereocenter Count | 0 |
| Undefined Atom Stereocenter Count | 0 |
| Defined Bond Stereocenter Count | 0 |
| Undefined Bond Stereocenter Count | 0 |
| Covalently-Bonded Unit Count | 1 |
| Compound Is Canonicalized | Yes |
PRODUCT INTRODUCTION
description
Benzidine is a manufactured chemical that does not occur naturally. It is a crystalline solid that may be grayish-yellow, white, or reddish-gray. In the environment, benzidine is found in either its "free" state (as an organic base), or as a salt. Benzidine was used to produce dyes for cloth, paper, and leather. It is no longer produced or used commerically in the U.S.