Cyanuric Acid

Title: Cyanuric Acid
CAS Registry Number: 108-80-5
CAS Name: 1,3,5-Triazine-2,4,6(1H,3H,5H)-trione
Additional Names: sym-triazinetriol; 2,4,6-trihydroxy-1,3,5-triazine; tricyanic acid; trihydroxycyanidine
Molecular Formula: C3H3N3O3
Molecular Weight: 129.07
Percent Composition: C 27.92%, H 2.34%, N 32.56%, O 37.19%
Literature References: Prepn: Schmidt, J. Prakt. Chem. [2] 5, 41-52 (1872); Venable, Moore, J. Am. Chem. Soc. 39, 1752 (1917). HPLC determn: P. Beilstein et al., J. Agric. Food Chem. 29, 1132 (1981); in urine and pool water: T. V. Briggle et al., J. Assoc. Off. Anal. Chem. 64, 1222 (1981). Review of prepn, properties and uses: E. M. Smolin, L. Rapoport, "s-Triazines and Derivatives" in The Chemistry of Heterocyclic Compounds vol. 13, A. Weissberger, Ed.(Interscience, New York, 1959) pp 17-48; of chemistry, toxicity and antibacterial activity as applied to swimming pools: E. Canelli, Am. J. Public Health 64, 155-162 (1974); F. W. Linda, R. C. Hollenbach, J. Environ. Health 40, 324-329 (1978); of toxicology: B. G. Hammond et al., Environ. Health Perspect. 69, 287-292 (1986). Review: J. A. Wojtowicz in Kirk-Othmer Encyclopedia of Chemical Technology vol. 7 (John Wiley & Sons, 4th ed., 1993) pp 834-851.
Properties: White crystalline solid; does not melt up to 330°, sublimes and dissociates to isocyanic acid at higher temps. pKa1 6.88; pKa2 11.40; pKa3 13.5. uv max (0.1M HCl): 214 nm (log e 3.38). uv max (0.1M phosphate buffer pH 7): 214 nm (log e 4.00). uv max (0.1M NaOH) 213 nm (log e 4.64). Slightly sol in common organic solvents such as acetone, benzene, diethyl ether, ethanol, hexane. Soly (%): DMF 7.2; DMSO 17.4. Soly in water (%): 0.2 at 25°; 2.6 at 90°; 10.0 at 150°. Soly in 96% H2SO4 (25°): 14.1%. Sol in hot alcohols, pyridine, concd HCl without decompn; in aq solns of NaOH and KOH. Insol in cold methanol, ether, acetone, benzene, chloroform. Forms dihydrate in aq soln; crystallizes as colorless monoclinic prisms that effloresce in dry air. d25 1.75 (anhydr); d25 1.66 (dihydrate). Predominant tautomeric form in solid state and soln is keto form, isocyanuric acid; in basic soln the enol form is more stable. LD50 orally in rats: >5.00 g/kg (Canelli).
pKa: pKa1 6.88; pKa2 11.40; pKa3 13.5
Absorption maximum: uv max (0.1M HCl): 214 nm (log e 3.38); uv max (0.1M phosphate buffer pH 7): 214 nm (log e 4.00); uv max (0.1M NaOH) 213 nm (log e 4.64)
Density: d25 1.75 (anhydr); d25 1.66 (dihydrate)
Toxicity data: LD50 orally in rats: >5.00 g/kg (Canelli)
Use: Convenient lab source of cyanic acid gas. In prepn of melamine, sponge rubber, herbicides, dyes, resin, antimicrobial agents. As stabilizer and disinfectant in swimming pool water.
Cyanuric Chloride Cyazofamid Cycasin Cyclacillin Cyclamic Acid