Title: Benzidine
CAS Registry Number: 92-87-5
CAS Name: [1,1¢-Biphenyl]-4,4¢-diamine
Additional Names: p-diaminodiphenyl
Molecular Formula: C12H12N2
Molecular Weight: 184.24
Percent Composition: C 78.23%, H 6.56%, N 15.20%
Literature References: Discovered by Zinin in 1845. Produced by reduction of nitrobenzene with Zn and NaOH; the resultant hydrazobenzene is heated with acid. Lab proc: A. I. Vogel, Practical Organic Chemistry (Longmans, London, 3rd ed., 1959) p 633; Gattermann-Wieland, Praxis des Organischen Chemikers (de Gruyter, Berlin, 40th ed., 1961) p 165. Review of carcinogenic risk: IARC Monographs 1, 80-86 (1972); ibid. 29, 149-183 (1982); M. Boeniger, Carcinogenicity and Metabolism of Azo Dyes, Especially Those Derived from Benzidine (DHHS/NIOSH 80-119, 1980) 141 pp. Review of toxicology and human exposure: Toxicological Profile for Benzidine (PB2001-109102, 2001) 242 pp.
Properties: White or slightly-reddish, cryst powder; darkens on exposure to air and light. Poisonous! mp 115-120° when slowly heated; 128° when anhydr and rapidly heated. bp ~400°. Soly: one gram dissolves in 2500 ml cold, 107 ml boiling water, 5 ml boiling alcohol, 50 ml ether. Keep well closed and protected from light.
Melting point: mp 115-120° when slowly heated; 128° when anhydr and rapidly heated
Boiling point: bp ~400°
Derivative Type: Dihydrochloride
Molecular Formula: C12H12N2.2HCl
Molecular Weight: 257.16
Percent Composition: C 56.05%, H 5.49%, N 10.89%, Cl 27.57%
Properties: Crystals. Sol in water, alcohol.
CAUTION: Potential symptoms of overexposure are hematuria; secondary anemia from hemolysis; acute cystitis; acute liver disorders; dermatitis; painful and irregular urination. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 26. Benzidine and dyes metabolized to benzidine are listed as known human carcinogens: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-28, III-29.
Use: Manuf direct azo dyes; as a reagent for H2O2 in milk; for detection of blood. Dihydrochloride used for quantitative determn of sulfates, and as reagent for metals. |