Cyanuric chloride

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Cyanuric chloride
Structural formula
Ball-and-stick model
CAS number 108-77-0 YesY
PubChem 7954
ChemSpider 7666 YesY
EC number 203-614-9
UN number 2670
ChEBI CHEBI:58964 YesY
RTECS number XZ1400000
Jmol-3D images Image 1
Molecular formula C3Cl3N3
Molar mass 184.41 g mol−1
Appearance White powder
Odor pungent
Density 1.32 g/cm3
Melting point 154 °C (309 °F; 427 K)
Boiling point 192 °C (378 °F; 465 K)
Solubility in water hydrolyzes
Solubility in organic solvents soluble
Crystal structure monoclinic
EU Index 613-009-00-5
EU classification Very toxic (T+)
Harmful (Xn)
Corrosive (C)
R-phrases R14, R22, R26, R34, R43
S-phrases (S1/2), S26, S28, S36/37/39, S45, S46, S63
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazard W: Reacts with water in an unusual or dangerous manner. E.g., cesium, sodiumNFPA 704 four-colored diamond
Flash point Non-flammable
LD50 485 mg/kg (rat, oral)
Related compounds
Related triazines Cyanuric acid
Cyanuric fluoride
Cyanuric bromide
Trichloroisocyanuric acid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Cyanuric chloride is an organic compound with the formula (NCCl)3. This white solid is the chlorinated derivative of 1,3,5-triazine. It is the trimer of cyanogen chloride.[1] Cyanuric chloride is the main precursor to the popular but controversial herbicide atrazine.


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
Cyanurchloride Synthesis V.1.svg

In 2005, approximately 200,000 tonnes were produced.[2]

Industrial Uses[edit]

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:

(ClCN)3 + 2 RNH2 → (RNHCN)(ClCN)2 + RNH3+Cl-

Other triazine herbicides, such as simazine, anilazine and cyromazine are made in an analogous way.[3]

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][2]

Organic synthesis[edit]

In one specialized application, cyanuric chloride is employed as a reagent in organic synthesis for the conversion of alcohols and carboxylic acids into alkyl and acyl chlorides, respectively:[4]

Synthesis of acyl chlorides with cyanuric chloride.png

It is also used as a dehydrating agent 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.[5][6]

The chloride centers are easily replaced by amines to give melamine derivatives, for example in the synthesis of dendrimers:[7][8]

Cyanuric chloride based dendrimer

It is also employed the synthesis of an experimental adenosine receptor ligand.:[9]

Example use cyanuric chloride in pharma WO 03101980 patent

Cyanuric Chloride can also be used as an alternative to oxalyl chloride in the Swern oxidation.[10]


  1. ^ Cyanuric chloride at
  2. ^ a b c Klaus 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.
  3. ^ a b Ashford's Dictionary of Industrial Chemicals, 3rd edition, 2011, pages 2495-8
  4. ^ K. Venkataraman, and D. R. Wagle (1979). "Cyanuric chloride : a useful reagent for converting carboxylic acids into chlorides, esters, amides and peptides". Tet. Lett. 20 (32): 3037–3040. doi:10.1016/S0040-4039(00)71006-9. 
  5. ^ 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
  6. ^ John T. Gupton; Steven A. Andrews (1990), "β-Dimethylaminomethylenation: N,N-Dimethyl-N'-p-tolylformamidine", Org. Synth. ; Coll. Vol. 7: 197 
  7. ^ Abdellatif Chouai and 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. PMID 18307354. 
  8. ^ Reagent: DIPEA, amine protective group: BOC
  9. ^ WO application 03101980, "1,3,5-TRIAZINE DERIVATIVES AS LIGANDS FOR HUMAN ADENOSINE-A3 RECEPTORS", published 2003-12-11  (Reagent number two: norephedrine, base DIPEA)
  10. ^ De Luca, L.; Giacomelli, G.; Procheddu, A. J. Org. Chem. 2001, 7907.