Cyanuric chloride is prepared in two steps from hydrogen cyanide via the intermediacy of cyanogen chloride, which is trimerized at elevated temperatures over a carbon catalyst:
HCN + Cl2 → ClCN + HCl
In 2005, approximately 200,000 tons were produced.[2]
Industrial uses
It is estimated that 70% of cyanuric chloride is used in the preparation of the triazine-class pesticides, especially atrazine. Such reactions rely on the easy displacement of the chloride with nucleophiles such as amines:
Cyanuric chloride is also used as a precursor to dyes and crosslinking agents. The largest class of these dyes are the sulfonated triazine-stilbene optical brighteners (OBA) or fluorescent whitening agents (FWA) commonly found in detergent formulas and white paper.[2] Many reactive dyes also incorporate a triazine ring. They are also manufactured by way of the chloride displacement reaction shown above.[3][4]
Reactivity
The chloride centers are easily replaced. Amines give melamine derivatives, for example in the synthesis of dendrimers:[5][6]
Cyanuric chloride is employed as a reagent in organic synthesis for the conversion of alcohols into alkyl chlorides,[8] and carboxylic acids into acyl chlorides:[9]
It is also used as a dehydrating agent, e.g. in the conversion of amides to nitriles,[10] and for the activation of carboxylic acids for reduction to alcohols. Heating with DMF gives "Gold's reagent" Me2NCH=NCH=NMe2+Cl−, which is a versatile source of aminoalkylations and a precursor to heterocycles.[11][12]
^ abKlaus Huthmacher, Dieter Most "Cyanuric Acid and Cyanuric Chloride" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a08_191.
^Abdellatif Chouai & Eric E. Simanek (2008). "Kilogram-Scale Synthesis of a Second-Generation Dendrimer Based on 1,3,5-Triazine Using Green and Industrially Compatible Methods with a Single Chromatographic Step". J. Org. Chem.73 (6): 2357–2366. doi:10.1021/jo702462t. PMID18307354. S2CID24304872.
^Henke, Kevin R.; Hutchison, Aaron R.; Krepps, Matthew K.; Parkin, Sean; Atwood, David A. (2001). "Chemistry of 2,4,6-Trimercapto-1,3,5-triazine (TMT): Acid Dissociation Constants and Group 2 Complexes". Inorganic Chemistry. 40 (17): 4443–4447. doi:10.1021/ic0103188. PMID11487353.
^Stanley R. Sandler (1970). "Cyanuric chloride. A novel laboratory hydrochlorinating reagent for alcohols". J. Org. Chem.35 (11): 3967–3968. doi:10.1021/jo00836a088.
^K. Venkataraman & D. R. Wagle (1979). "Cyanuric chloride : a useful reagent for converting carboxylic acids into chlorides, esters, amides and peptides". Tetrahedron Lett.20 (32): 3037–3040. doi:10.1016/S0040-4039(00)71006-9.
^George A. Olah; Subhash C. Narang; Alexander P. Fung & B. G. Balaram Gupta (1980). "Synthetic Methods and Reactions; 82. Cyanuric Chloride, a Mild Dehydrating Agent in the Preparation of Nitriles from Amides". Synthesis. 8: 657–658. doi:10.1055/s-1980-29160.
^Probst, D. A.; Hanson, P. R.; Barda, D. A. "Cyanuric Chloride" in Encyclopedia of Reagents for Organic Synthesis, 2004, John Wiley & Sons. doi:10.1002/047084289X.rn00320
^De Luca, L.; Giacomelli, G.; Procheddu, A (2001). "A Mild and Efficient Alternative to the Classical Swern Oxidation". J. Org. Chem. 66 (23): 7907–7909. doi:10.1021/jo015935s. PMID11701058.
