3065. 1,3-Dichloro-5,5-dimethylhydantoin

Nomenclature

CAS number: 118-52-5
1,3-Dichloro-5,5-dimethyl-2,4-imidazolidinedione; Dactin; Halane.
C5H6Cl2N2O2; mol wt 197.02.
C 30.48%, H 3.07%, Cl 35.99%, N 14.22%, O 16.24%.

Description and references

Prepd by passing chlorine through an aq soln of 5,5-dimethylhydantoin: Biltz, Slotta, J. Prakt. Chem. 113, 248 (1926); Orazi, Orio, An. Asoc. Quim. Argent. 41, 153 (1953), C.A. 48, 13634 (1954). Structure: Bogaert-Verhoogen, Martin, Bull. Soc. Chim. Belg. 58, 567 (1949). Purification by dissolving in concd H2SO4 and diluting with ice-water: Lorenz, US 2828308 (1958 to Purex).

Chemical structure

Properties

Four-sided, pointed prisms from chloroform, d2020 1.5. mp 132°. Sublimes at 100°. Turns brown and conflagrates at 212° (after melting at 132°). The dry crystals [combined available chlorine 77.6% (theory)] may be stored without much loss of available chlorine. After 14 weeks at 60° the loss was 1.5% Cl compared with a loss of 37.5% suffered by 70% calcium hypochlorite. On contact with water and esp hot water hypochlorous acid is liberated. At pH 9 nitrogen chloride is formed. Soly in water at 25° 0.21%; at 60° 0.60%. pH of aq soln about 4.4. Freely sol in chlorinated and highly polar solvents at 25°: Chloroform 14%, methylene chloride 30.0%, carbon tetrachloride 12.5%, ethylene dichloride 32.0%, sym-tetrachlorethane 17.0%, benzene 9.2%.

Caution

Potential symptoms of overexposure are irritation of eyes, mucous membranes and respiratory system. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 98.

Use

Chlorinating agent, disinfectant, industrial deodorant. In water treatment. Active ingredient of powder laundry bleaches such as Sage's Dry Bleach, Colgate's Pruf. Intermediate for amino acids, drugs, insecticides. Stabilizer for vinyl chloride polymers. Polymerization catalyst.