Chlorinated cyanuric acid derivatives

Cyanuric chloride is prepared by chlorinating hydrocyanic acid at 20 - 40 °C in aqueous medium, and after drying, trimerizing to cyanuric acid.The most important cyanuric acid derivates are the aminotriazines, which are used as pesticides, especially as herbicides [335],... 

Sta.bilizers. Cyanuric acid is used to stabilize available chlorine derived from chlorine gas, hypochlorites or chloroisocyanurates against decomposition by sunlight. Cyanuric acid and its chlorinated derivatives form a complex ionic and hydrolytic equilibrium system consisting of ten isocyanurate species. The 12 isocyanurate equilibrium constants have been determined by potentiometric and spectrophotometric techniques (30). Other measurements of two of the equilibrium constants important in swimming-pool water report significantly different and/or less precise results than the above study (41—43). A critical review of these measurements is given in Reference 44. 

Toxicity of Chlorine Sanitizers. Chlorine-based swimming-pool and spa and hot-tub sanitizers irritate eyes, skin, and mucous membranes and must be handled with extreme care. The toxicities are as follows for chlorine gas, TLV = 1 ppm acute inhalation LC q = 137 ppm for 1 h (mouse) (75). The acute oral LD q (rats) for the Hquid and soHd chlorine sanitizers are NaOCl (100% basis) 8.9 g/kg (76), 65% Ca(OCl)2 850 mg/kg, sodium dichloroisocyanurate dihydrate 735 mg/kg, and trichloroisocyanuric acid 490 mg/kg. Cyanuric acid is essentially nontoxic based on an oral LD q > 20 g/kg in rabbits. Although, it is mildly irritating to the eye, it is not a skin irritant. A review of the toxicological studies on cyanuric acid and its chlorinated derivatives is given in ref. 77. 

Cyanuric acid is sold mainly in coarse granular form, >85% 2—0.15 mm (10 to 100 mesh). It is also available in powdered form. Typical analysis of commercial CA is CA >98.5% ammelide <1% water <0.6% pH of 1% slurry >2.8. Eor the chlorinated derivatives ... 

Direct bromination readily yields the 6-bromo derivative (111), just as with uracil. Analogous chlorination and iodination requires the presence of alkalies and even then proceeds in low yield. The 6-chloro derivative (113) was also obtained by partial hydrolysis of the postulated 3,5,6-trichloro-l,2,4-triazine (e.g.. Section II,B,6). The 6-bromo derivative (5-bromo-6-azauracil) served as the starting substance for several other derivatives. It was converted to the amino derivative (114) by ammonium acetate which, by means of sodium nitrite in hydrochloric acid, yielded a mixture of 6-chloro and 6-hydroxy derivatives. A modified Schiemann reaction was not suitable for preparing the 6-fluoro derivative. The 6-hydroxy derivative (115) (an isomer of cyanuric acid and the most acidic substance of this group, pKa — 2.95) was more conveniently prepared by alkaline hydrolysis of the 6-amino derivative. Further the bromo derivative was reacted with ethanolamine to prepare the 6-(2-hydroxyethyl) derivative however, this could not be converted to the corresponding 2-chloroethyl derivative. Similarly, the dimethylamino, morpholino, and hydrazino derivatives were prepared from the 6-bromo com-pound. ... 

A continuous or semi-continuous process for bleaching of jute fabric with chlorinated derivatives of cyanuric acid is developed [126]. The process comprises a preliminary treatment with boiling water, followed by impregnation of the materials with 0.4-0.6% aqueous alkaline solution, and then subjection of the material to steam treatment. Thereafter, the material is treated at 20-50 C with a mixture of trichlorocyanuric acid and cyanuric acid (with available chlorine content 7-15 g/1), containing sodium carbonate or bicarbonate. The pH of the solution is finally adjusted to 4-5 with acetic acid or phosphoric acid. The treated material is then bleached with H,0,. The time of treatment is usually 40-60 min, but can be extended to 2 h in the case of a heavy fabric with high lignin content. 

Triazines are one of the oldest known compound classes in organic chemistry. First reports date back to 1776 when cyanuric acid (l,3,5-triazine-2,4,6-triol 1,3,5-triazine-2,4,6(l//,3//,5f/)-trione) was obtained by the pyrolysis of uric acid.1 The same method was also utilized in 1820 2 however, triazine compounds were probably first prepared in 1704 upon trimerization of cyanide derivatives when the Berlinerblau -complex salt, the first known cyano compound, was discovered.468 Cyanuric chloride was synthesized in 1828 from hydrogen cyanide and chlorine.3 Another method, discovered in 1834, involves treatment of potassium thiocyanate with chlorine. When heated, cyanuric chloride is obtained.4 Melamine (1,3,5-triazine-2,4,6-triamine) was also prepared in 1834 by heating potassium thiocyanate with ammonium chloride.5 Although 2,4,6-substituted 1,3,5-triazine derivatives were identified very early, the unsubstituted parent compound was not synthesized before 1895.6 At that time, however, the isolated compound was assigned to a dimeric species and not to the trimeric hydrogen cyanide. This was finally proven much later."... 

Af-chloroisocyanuric acid derivatives are produced in a continuous process involving the reaction of chlorine with cyanuric acid and a solution of alkali at 0-15°C. The reaction conditions should be carefully controlled to avoid the formation of the explosive NCI3 [8,9]. 

Chloro-l,3,5-triazines and cyanuric chloride (2,4,6-trichloro-l,3,5-triazine) are the commonest starting materials for the synthesis of many 1,3,5-triazine derivatives.10,12,14,18,19,21 Cyanuric chloride behaves like an acid chloride the chlorine atoms can be replaced sequentially but with increasing difficulty as nucleophilic attack is progressively hindered by the presence of more electron-donating substituents. The reaction mechanism is dependent on the reaction... 

Cyanuric chloride on monosubstitution with nucleophiles such as methanol or 4-amino-azobenzene followed by displacement of a second chlorine with alanine amide gave compounds which are used for precolumn derivatization of amino acids. The diastereoisomers formed are resolved by reverse-phase HPLC <92MI 6l2-0i>. Enantiomeric amino acids are separated by HPLC on bis[carbamoyl(alkyl)methylamino]-6-chloro-l,3,5-triazine derived stationary phases <93JC277>. 

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