cyanuric chloride

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

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In 2005, approximately 200,000 tons were produced.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}}.

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.Ashford's Dictionary of Industrial Chemicals, 3rd edition, 2011, pages 2495-8

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. Many reactive dyes also incorporate a triazine ring. They are also manufactured by way of the chloride displacement reaction shown above.{{cite book|last1=Tappe|first1=Horst|title=Ullmann's Encyclopedia of Industrial Chemistry|last2=Helmling|first2=Walter|last3=Mischke|first3=Peter|last4=Rebsamen|first4=Karl|last5=Reiher|first5=Uwe|last6=Russ|first6=Werner|last7=Schläfer|first7=Ludwig|last8=Vermehren|first8=Petra|year=2000|doi=10.1002/14356007.a22_651|isbn=978-3527306732}}

The chloride centers are easily replaced. Amines give melamine derivatives, for example in the synthesis of dendrimers:{{cite journal | title = 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 | author = Abdellatif Chouai | author2 = Eric E. Simanek | name-list-style = amp | journal = J. Org. Chem. | year = 2008 | volume = 73 | pages = 2357–2366 | doi = 10.1021/jo702462t | pmid = 18307354 | issue = 6| s2cid = 24304872 }}Reagent: DIPEA, amine protective group: BOC

:{{chem2|(ClCN)3 + R2NH -> (R2NCN)3 + 3 HCl }}

It reacts with hydrosulfide to give thiocyanuric acid ({{chem2|(S\dCNH)3}}).{{cite journal |doi=10.1021/ic0103188 |title=Chemistry of 2,4,6-Trimercapto-1,3,5-triazine (TMT): Acid Dissociation Constants and Group 2 Complexes |date=2001 |last1=Henke |first1=Kevin R. |last2=Hutchison |first2=Aaron R. |last3=Krepps |first3=Matthew K. |last4=Parkin |first4=Sean |last5=Atwood |first5=David A. |journal=Inorganic Chemistry |volume=40 |issue=17 |pages=4443–4447 |pmid=11487353 }}

Cyanuric chloride is employed as a reagent in organic synthesis for the conversion of alcohols into alkyl chlorides,{{cite journal | journal = J. Org. Chem. | volume = 35 | issue = 11 | pages = 3967-3968 | year = 1970 | doi = 10.1021/jo00836a088 | author = Stanley R. Sandler | title = Cyanuric chloride. A novel laboratory hydrochlorinating reagent for alcohols}} and carboxylic acids into acyl chlorides:{{cite journal | journal = Tetrahedron Lett. | volume = 20 | issue = 32 | pages = 3037–3040 | year = 1979 | doi = 10.1016/S0040-4039(00)71006-9 | author = K. Venkataraman | author2 = D. R. Wagle | name-list-style = amp | title = Cyanuric chloride : a useful reagent for converting carboxylic acids into chlorides, esters, amides and peptides}}

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It is also used as a dehydrating agent, e.g. in the conversion of amides to nitriles,{{cite journal | journal = Synthesis | volume = 8 | pages = 657-658 | year = 1980 | doi = 10.1055/s-1980-29160 | author = George A. Olah | author2 = Subhash C. Narang | author3 = Alexander P. Fung | author4 = B. G. Balaram Gupta | name-list-style = amp | title = Synthetic Methods and Reactions; 82. Cyanuric Chloride, a Mild Dehydrating Agent in the Preparation of Nitriles from Amides}} 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.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}}{{OrgSynth | collvol = 7 | collvolpages = 197 | prep = cv7p0197 | year = 1990 | author = John T. Gupton | author2 = Steven A. Andrews | title = β-Dimethylaminomethylenation: N,N-Dimethyl-N'-p-tolylformamidine}}

Cyanuric chloride can also be used as an alternative to oxalyl chloride in the Swern oxidation.{{cite journal | last1 = De Luca | first1 = L. | last2 = Giacomelli | first2 = G. | last3 = Procheddu | first3 = A | year = 2001 | title =A Mild and Efficient Alternative to the Classical Swern Oxidation| journal = J. Org. Chem. | volume = 66| issue = 23| pages = 7907–7909 | doi=10.1021/jo015935s| pmid = 11701058 }}

• Thiazyl chloride trimer – structural analogue with sulfur atoms in-place of carbon

{{Reflist}}

Category:Inorganic chlorine compounds

Category:Triazines

Category:Trimers (chemistry)

Category:Dehydrating agents