Mereotopology: Difference between revisions
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{{chembox | |||
| verifiedrevid = 443544577 | |||
| ImageFile_Ref = {{chemboximage|correct|??}} | |||
| ImageFile = Cyanuric acid.png | |||
| ImageSize = 250px | |||
| ImageName = Structural formulae of both tautomers | |||
| ImageFileR2 = Cyanuric-acid-from-xtal-3D-balls.png | |||
| ImageSizeR2 = 120px | |||
| ImageNameR2 = Ball-and-stick model of the trione tautomer | |||
| ImageFileL2 = Cyanuric-acid-triol-3D-balls.png | |||
| ImageSizeL2 = 120px | |||
| ImageNameL2 = Ball-and-stick model of the triol tautomer | |||
| IUPACName = 1,3,5-Triazinane-2,4,6-trione | |||
| OtherNames = 1,3,5-Triazinetriol; ''s''-Triazinetriol; 1,3,5-Triazine-2,4,6(1''H'',3''H'',5''H'')-trione; ''s''-Triazinetrione; Tricarbimide; Isocyanuric acid; Seudocyanuric acid | |||
| Section1 = {{Chembox Identifiers | |||
| KEGG_Ref = {{keggcite|correct|kegg}} | |||
| KEGG = C06554 | |||
| InChI = 1/C3H3N3O3/c7-1-4-2(8)6-3(9)5-1/h(H3,4,5,6,7,8,9) | |||
| InChIKey = ZFSLODLOARCGLH-UHFFFAOYAR | |||
| ChEMBL_Ref = {{ebicite|correct|EBI}} | |||
| ChEMBL = 243087 | |||
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} | |||
| StdInChI = 1S/C3H3N3O3/c7-1-4-2(8)6-3(9)5-1/h(H3,4,5,6,7,8,9) | |||
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | |||
| StdInChIKey = ZFSLODLOARCGLH-UHFFFAOYSA-N | |||
| CASNo=108-80-5 | |||
| CASNo_Ref = {{cascite|correct|CAS}} | |||
| PubChem=7956 | |||
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | |||
| ChemSpiderID = 7668 | |||
| ChEBI_Ref = {{ebicite|correct|EBI}} | |||
| ChEBI = 17696 | |||
| SMILES = O=C1NC(=O)NC(=O)N1 | |||
| RTECS = XZ1800000 | |||
}} | |||
| Section2= {{Chembox Properties | |||
| Formula = C<sub>3</sub>H<sub>3</sub>N<sub>3</sub>O<sub>3</sub> | |||
| MolarMass = 129.07 g/mol | |||
| Appearance = white crystalline powder | |||
| Density = 2.5 g/cm<sup>3</sup> | |||
| MeltingPt = decomp. 320–360 ºC | |||
| BoilingPt = | |||
| Solubility = 0.27 g/100 ml (25 ºC) | |||
}} | |||
| Section7= {{Chembox Hazards | |||
| ExternalMSDS = [http://www.inchem.org/documents/icsc/icsc/eics1313.htm ICSC 1313] | |||
| MainHazards = | |||
| FlashPt = | |||
}} | |||
| Section8= {{Chembox Related | |||
| OtherFunctn = [[Cyanuric fluoride]]<br/>[[Cyanuric chloride]] | |||
| Function = [[triazine]]s | |||
| OtherCpds = | |||
}} | |||
}} | |||
'''Cyanuric acid''' or '''1,3,5-triazine-2,4,6-triol''' is a [[chemical compound]] with the [[chemical formula|formula]] (CNOH)<sub>3</sub>. Like many industrially useful chemicals, this [[triazine]] has many synonyms. This white, odorless solid finds use as a precursor or a component of [[bleach]]es, disinfectants, and herbicides. In 1997, worldwide production was 160 million kilograms.<ref name="Ullmann">Klaus Huthmacher, Dieter Most "Cyanuric Acid and Cyanuric Chloride" Ullmann's Encyclopedia of Industrial Chemistry" 2005, Wiley-VCH, Weinheim. ISBN 10.1002/14356007.a08 191</ref> | |||
== Properties and synthesis == | |||
=== Properties === | |||
Cyanuric acid is the cyclic [[trimer (chemistry)|trimer]] of the elusive species [[cyanic acid]], HOCN. The two [[chemical structure|structures]] shown in the infobox readily interconvert; that is, they are [[tautomer]]s. However, mixture with [[melamine]] forms [[melamine cyanurate]], which locks cyanuric acid in the tri-keto tautomer and makes melamine cyanurate insoluble in water. The triol tautomer, which may have [[aromatic]] character, predominates in solution. The [[hydroxyl]] (-OH) groups assume [[phenol|phenolic]] character. Deprotonation with base affords a series of cyanurate [[salt]]s: | |||
: [C(O)NH]<sub>3</sub> <math>\overrightarrow{\leftarrow}</math> [C(O)NH]<sub>2</sub>[C(O)N]<sup>−</sup> + H<sup>+</sup> (pK<sub>a</sub> = 6.88)<ref name="CRC85">"Dissociation constants of organic acids and bases" CRC Handbook of Chemistry and physics, Internet Version 2005 (85th ed.)</ref> | |||
: [C(O)NH]<sub>2</sub>[C(O)N]<sup>−</sup> <math>\overrightarrow{\leftarrow}</math> [C(O)NH][C(O)N]<sub>2</sub><sup>2−</sup> + H<sup>+</sup> (pK<sub>a</sub> = 11.40) | |||
: [C(O)NH][C(O)N]<sub>2</sub><sup>2−</sup> <math>\overrightarrow{\leftarrow}</math> [C(O)N]<sub>3</sub><sup>3−</sup> + H<sup>+</sup> (pK<sub>a</sub> = 13.5) | |||
=== Synthesis === | |||
Cyanuric acid (CYA) was first synthesized by [[Friedrich Wöhler]] in 1829 by the thermal decomposition of [[urea]] and [[uric acid]].<ref>Wöhler, F. On the decomposition of urea and uric acid at high temperature. Ann Phys Chemie 1829 15:619-30</ref> The current industrial route to CYA entails the [[pyrolysis|thermal decomposition]] of urea, with release of ammonia. The conversion commences at approximately 175 °C:<ref name="Ullmann" /> | |||
: 3 H<sub>2</sub>N-CO-NH<sub>2</sub> → [C(O)NH]<sub>3</sub> + 3 NH<sub>3</sub> | |||
CYA crystallizes from water as the dihydrate. | |||
Cyanuric acid can be produced by hydrolysis of crude or waste [[melamine]] followed by crystallization. Acid waste streams from plants producing these materials contain cyanuric acid and on occasion, dissolved amino-substituted triazines, namely, [[ammeline]], [[ammelide]], and [[melamine]]. In one method, an [[ammonium sulfate]] solution is heated to the "boil" and treated with a stoichiometric amount of melamine, by which means the cyanuric acid present precipitates as [[melamine-cyanuric acid complex]]. The various waste streams containing cyanuric acid and amino-substituted triazines may be combined for disposal and during upset conditions, undissolved cyanuric acid may be present in the waste streams. | |||
<ref name="CYApat">{{cite web | |||
| title=Process for preparing pure cyanuric acid | |||
| url=http://www.freepatentsonline.com/4278794.html | |||
| date=July 14, 1981 | |||
| accessdate=2007-12-10}}</ref><ref name="CYApat2">{{cite web | |||
| title=High pressure thermal hydrolysis process to decompose triazines in acid waste streams | |||
| url=http://www.freepatentsonline.com/4013757.html | |||
| date=March 22, 1977 | |||
| accessdate=2007-12-10}}</ref> | |||
=== Intermediates and impurities === | |||
Intermediates in the dehydration include both [[isocyanic acid]], [[biuret]], and triuret: | |||
: H<sub>2</sub>N-CO-NH<sub>2</sub> → HNCO + NH<sub>3</sub> | |||
: H<sub>2</sub>N-CO-NH<sub>2</sub> + HNCO → H<sub>2</sub>N-CO-NH-CO-NH<sub>2</sub> | |||
: H<sub>2</sub>N-CO-NH-CO-NH<sub>2</sub> + HNCO → H<sub>2</sub>N-CO-NH-CO-NH-CO-NH<sub>2</sub> | |||
One impurity in the production of CYA is [[ammelide]], especially if the reaction temperature exceeds 190 °C: | |||
3 H<sub>2</sub>N-CO-NH-CO-NH<sub>2</sub> → [C(O)]<sub>2</sub>(CNH<sub>2</sub>)(NH)<sub>2</sub>N + 2 NH<sub>3</sub> + H<sub>2</sub>O | |||
The first appearance of ammelamide occurs prior to 225 °C and is suspected also to occur from decomposition of biuret but is produced at a slower rate than that of CYA. | |||
[[Melamine]], [C(NH<sub>2</sub>)N]<sub>3</sub>, formation occurs between 325 and 350 °C and only in very small quantities.<ref> Shaber, Peter M. et al. "Study of the thermal decomposition of urea (pyrolysis) reaction and importance to cyanuric acid production," American Laboratory, August 1999: 13-21[http://www.iscpubs.com/articles/al/a9908sch.pdf]</ref> | |||
== Applications == | |||
=== Precursors to chlorinated cyanurates === | |||
Cyanuric acid is mainly used as a [[Precursor (chemistry)|precursor]] to ''N''-chlorinated cyanurates, which are used to disinfect water. The dichloro derivative is prepared by direct chlorination: | |||
: [C(O)NH]<sub>3</sub> + 2 Cl<sub>2</sub> + 2 NaOH → [C(O)NCl]<sub>2</sub>[C(O)NH] | |||
This species is typically converted to its sodium salt, [[sodium dichloro-s-triazinetrione]]. Further chlorination gives [[trichloroisocyanuric acid]], [C(O)NCl]<sub>3</sub>. These ''N''-chloro compounds serve as disinfectants and algicides for swimming pool water.<ref name="Ullmann" /> It stabilizes the chlorine in the pool and prevents the chlorine from being quickly consumed by sunlight. | |||
=== Precursors to crosslinking agents === | |||
Because of their trifunctionality, CYA is a precursor to crosslinking agents, especially for polyurethane resins. | |||
== Analysis == | |||
Testing for cyanuric acid concentration is commonly done with a turbidometric test, which uses a reagent, melamine, to precipitate the cyanuric acid. The relative turbidity of the reacted sample quantifies the CYA concentration. Referenced in 1957.<ref name="Mercktest">{{ cite web|url=http://www.merckserono.net/servlet/PB/menu/1169010/index.html | |||
| title=Merck Turbidity Test|date=June 6, 2003 | |||
| publisher=[[Merck KGaA|Merck]] | |||
| accessdate=2007-05-06}}</ref> | |||
This test works because melamine combines with the cyanuric acid in the water to form a fine, insoluble, white precipitate ([[melamine cyanurate]]) that causes the water to cloud in proportion to the amount of cyanuric acid in it. More recently, a sensitive method has been developed for analysis of cyanuric acid in urine. <ref>Panuwet P, Wade EL, Nguyen JV, Montesano MA, Needham LL, Barr DB. Quantification of cyanuric acid residue in human urine using high performance liquid chromatography-tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2010 878(28):2916-2922.</ref> | |||
== Animal feed == | |||
FDA permits a certain amount of cyanuric acid to be present in some [[non-protein nitrogen]] (NPN) additives used in animal feed and drinking water.<ref name="FDAcyan">{{ cite web | |||
| url=http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?fr=573.220 | |||
| title=21CFR573.220 Feed-grade biuret | |||
| date=April 1, 2006 | |||
| publisher=[[Food and Drug Administration (United States)|U.S. Food and Drug Administration]] | |||
| accessdate=2007-05-06}}</ref> Cyanuric acid has been used as NPN. For example, [[Archer Daniels Midland]] manufactures an NPN supplement for cattle, which contains [[biuret]], [[triuret]], cyanuric acid and [[urea]].<ref name="RoughageBusterPlus">{{ cite web | |||
| url=http://www.admani.com/alliancebeef/RoughageBusterPlus.htm | |||
| title=Roughage Buster Plus: ingredients | |||
| publisher=[[Archer Daniels Midland]] | |||
| accessdate=2007-05-06}}</ref> | |||
=== 2007 pet food recalls === | |||
{{main|2007 pet food recalls#Melamine and cyanuric acid in pet sickness}} | |||
Cyanuric acid is implicated in connection to the [[2007 pet food recalls]], the contamination and wide recall of many brands of cat and dog foods beginning in March 2007. Research has found evidence that cyanuric acid, a constituent of urine, together with [[melamine]] forms poorly soluble crystals which can cause renal failure (see Analysis section above). | |||
== Safety == | |||
Cyanuric acid is classified as "essentially nontoxic".<ref name="Ullmann" /> | |||
The 50% oral median lethal dose ([[median lethal dose|LD<sub>50</sub>]]) is 7700 mg/kg in rats.<ref>[[Food and Drug Administration (United States)|U.S. Food and Drug Administration]], [http://www.cfsan.fda.gov/~dms/melamra.html "Interim Melamine and Analogues Safety/Risk Assessment; Availability",] [[Federal Register]]: May 30, 2007 (Volume 72, Number 103). Accessed 2008-09-27.</ref> | |||
However, when cyanuric acid is administered together with [[melamine]] (which by itself is another low-toxicity substance), they may form extremely insoluble crystals,<ref>[http://www.avma.org/press/releases/070501_petfoodrecall.asp "Melamine and Cyanuric Acid Interaction May Play Part in Illness and Death from Recalled Pet Food"], American Veterinary Medical Association (AVMA), Press Release, May 1, 2007. Accessed 2008-09-27.</ref> leading to formation of [[kidney stones]] and potentially causing [[kidney failure]] and [[death]] -- as evidenced in dogs and cats during the [[2007 pet food recalls|2007 pet food contamination]] and in children during the [[2008 Chinese milk scandal]] cases. | |||
== See also == | |||
* [[Melamine cyanurate]] | |||
== References == | |||
{{Reflist}} | |||
== External links == | |||
* {{ICSC|1313|13}} | |||
* [http://www.oregonvma.org/news/recallnews.asp Oregon Veterinary Medical Association (OVMA) Pet Food Contamination Page] – News and developments updated regularly | |||
[[Category:Triazines]] | |||
Revision as of 20:36, 19 April 2013
Cyanuric acid or 1,3,5-triazine-2,4,6-triol is a chemical compound with the formula (CNOH)3. Like many industrially useful chemicals, this triazine has many synonyms. This white, odorless solid finds use as a precursor or a component of bleaches, disinfectants, and herbicides. In 1997, worldwide production was 160 million kilograms.[1]
Properties and synthesis
Properties
Cyanuric acid is the cyclic trimer of the elusive species cyanic acid, HOCN. The two structures shown in the infobox readily interconvert; that is, they are tautomers. However, mixture with melamine forms melamine cyanurate, which locks cyanuric acid in the tri-keto tautomer and makes melamine cyanurate insoluble in water. The triol tautomer, which may have aromatic character, predominates in solution. The hydroxyl (-OH) groups assume phenolic character. Deprotonation with base affords a series of cyanurate salts:
- [C(O)NH]3 [C(O)NH]2[C(O)N]− + H+ (pKa = 6.88)[2]
- [C(O)NH]2[C(O)N]− [C(O)NH][C(O)N]22− + H+ (pKa = 11.40)
- [C(O)NH][C(O)N]22− [C(O)N]33− + H+ (pKa = 13.5)
Synthesis
Cyanuric acid (CYA) was first synthesized by Friedrich Wöhler in 1829 by the thermal decomposition of urea and uric acid.[3] The current industrial route to CYA entails the thermal decomposition of urea, with release of ammonia. The conversion commences at approximately 175 °C:[1]
- 3 H2N-CO-NH2 → [C(O)NH]3 + 3 NH3
CYA crystallizes from water as the dihydrate.
Cyanuric acid can be produced by hydrolysis of crude or waste melamine followed by crystallization. Acid waste streams from plants producing these materials contain cyanuric acid and on occasion, dissolved amino-substituted triazines, namely, ammeline, ammelide, and melamine. In one method, an ammonium sulfate solution is heated to the "boil" and treated with a stoichiometric amount of melamine, by which means the cyanuric acid present precipitates as melamine-cyanuric acid complex. The various waste streams containing cyanuric acid and amino-substituted triazines may be combined for disposal and during upset conditions, undissolved cyanuric acid may be present in the waste streams. [4][5]
Intermediates and impurities
Intermediates in the dehydration include both isocyanic acid, biuret, and triuret:
- H2N-CO-NH2 → HNCO + NH3
- H2N-CO-NH2 + HNCO → H2N-CO-NH-CO-NH2
- H2N-CO-NH-CO-NH2 + HNCO → H2N-CO-NH-CO-NH-CO-NH2
One impurity in the production of CYA is ammelide, especially if the reaction temperature exceeds 190 °C: 3 H2N-CO-NH-CO-NH2 → [C(O)]2(CNH2)(NH)2N + 2 NH3 + H2O The first appearance of ammelamide occurs prior to 225 °C and is suspected also to occur from decomposition of biuret but is produced at a slower rate than that of CYA.
Melamine, [C(NH2)N]3, formation occurs between 325 and 350 °C and only in very small quantities.[6]
Applications
Precursors to chlorinated cyanurates
Cyanuric acid is mainly used as a precursor to N-chlorinated cyanurates, which are used to disinfect water. The dichloro derivative is prepared by direct chlorination:
- [C(O)NH]3 + 2 Cl2 + 2 NaOH → [C(O)NCl]2[C(O)NH]
This species is typically converted to its sodium salt, sodium dichloro-s-triazinetrione. Further chlorination gives trichloroisocyanuric acid, [C(O)NCl]3. These N-chloro compounds serve as disinfectants and algicides for swimming pool water.[1] It stabilizes the chlorine in the pool and prevents the chlorine from being quickly consumed by sunlight.
Precursors to crosslinking agents
Because of their trifunctionality, CYA is a precursor to crosslinking agents, especially for polyurethane resins.
Analysis
Testing for cyanuric acid concentration is commonly done with a turbidometric test, which uses a reagent, melamine, to precipitate the cyanuric acid. The relative turbidity of the reacted sample quantifies the CYA concentration. Referenced in 1957.[7] This test works because melamine combines with the cyanuric acid in the water to form a fine, insoluble, white precipitate (melamine cyanurate) that causes the water to cloud in proportion to the amount of cyanuric acid in it. More recently, a sensitive method has been developed for analysis of cyanuric acid in urine. [8]
Animal feed
FDA permits a certain amount of cyanuric acid to be present in some non-protein nitrogen (NPN) additives used in animal feed and drinking water.[9] Cyanuric acid has been used as NPN. For example, Archer Daniels Midland manufactures an NPN supplement for cattle, which contains biuret, triuret, cyanuric acid and urea.[10]
2007 pet food recalls
Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. Cyanuric acid is implicated in connection to the 2007 pet food recalls, the contamination and wide recall of many brands of cat and dog foods beginning in March 2007. Research has found evidence that cyanuric acid, a constituent of urine, together with melamine forms poorly soluble crystals which can cause renal failure (see Analysis section above).
Safety
Cyanuric acid is classified as "essentially nontoxic".[1] The 50% oral median lethal dose (LD50) is 7700 mg/kg in rats.[11]
However, when cyanuric acid is administered together with melamine (which by itself is another low-toxicity substance), they may form extremely insoluble crystals,[12] leading to formation of kidney stones and potentially causing kidney failure and death -- as evidenced in dogs and cats during the 2007 pet food contamination and in children during the 2008 Chinese milk scandal cases.
See also
References
43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.
External links
- Template:ICSC
- Oregon Veterinary Medical Association (OVMA) Pet Food Contamination Page – News and developments updated regularly
- ↑ 1.0 1.1 1.2 1.3 Klaus Huthmacher, Dieter Most "Cyanuric Acid and Cyanuric Chloride" Ullmann's Encyclopedia of Industrial Chemistry" 2005, Wiley-VCH, Weinheim. ISBN 10.1002/14356007.a08 191
- ↑ "Dissociation constants of organic acids and bases" CRC Handbook of Chemistry and physics, Internet Version 2005 (85th ed.)
- ↑ Wöhler, F. On the decomposition of urea and uric acid at high temperature. Ann Phys Chemie 1829 15:619-30
- ↑ Template:Cite web
- ↑ Template:Cite web
- ↑ Shaber, Peter M. et al. "Study of the thermal decomposition of urea (pyrolysis) reaction and importance to cyanuric acid production," American Laboratory, August 1999: 13-21[1]
- ↑ Template:Cite web
- ↑ Panuwet P, Wade EL, Nguyen JV, Montesano MA, Needham LL, Barr DB. Quantification of cyanuric acid residue in human urine using high performance liquid chromatography-tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2010 878(28):2916-2922.
- ↑ Template:Cite web
- ↑ Template:Cite web
- ↑ U.S. Food and Drug Administration, "Interim Melamine and Analogues Safety/Risk Assessment; Availability", Federal Register: May 30, 2007 (Volume 72, Number 103). Accessed 2008-09-27.
- ↑ "Melamine and Cyanuric Acid Interaction May Play Part in Illness and Death from Recalled Pet Food", American Veterinary Medical Association (AVMA), Press Release, May 1, 2007. Accessed 2008-09-27.