Isocyanic acid
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| General | ||||||||||||||||
| Surname | Isocyanic acid | |||||||||||||||
| Molecular formula | HNCO | |||||||||||||||
| Brief description |
Liquid that is not very stable above 0 ° C and tends to polymerize |
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| properties | ||||||||||||||||
| Molar mass | 43.03 g · mol -1 | |||||||||||||||
| Physical state |
liquid |
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| Melting point |
- 86 ° C |
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| boiling point |
23.5 ° C |
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| pK s value |
3.92 |
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| safety instructions | ||||||||||||||||
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||||||||
The isocyanic acid is a reactive, little resistant Cyansauerstoffsäure which is liberated from their salts by careful acidification and at temperatures above 0 ° C polymerized . It can be kept for weeks in benzene or ether below 0 ° C. As a solution in ice water, the more dilute the solution, the longer it can be kept. Their esters are called isocyanates ; their salts are usually not referred to as isocyanates but as cyanates . The free acid polymerizes very easily to form a mixture of cyanuric acid and cyamelide . Analogous to other pseudohalogens , it can also form a dimer “ diisooxocyan ” OCN-NCO.
The cyanic acid than their tautomeric form is very unstable and is formed during the acidification of cyanates only in trace amounts (up to 3%).
Isocyanic acid is formally the imide of carbonic acid .
See also
Individual evidence
- ↑ a b Entry on isocyanic acid. In: Römpp Online . Georg Thieme Verlag, accessed on June 13, 2014.
- ^ A b c d A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 .
- ↑ There is not yet a harmonized classification for this substance . A labeling of isocyanic acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), which was retrieved on July 19, 2019, is reproduced from a self-classification by the distributor .
- ↑ Beyer-Walter, Textbook of Organic Chemistry, 23rd edition, S. Hirzel Verlag 1998.
- ^ Wissenschaft-Online-Lexika: Entry on Cyanate in the Lexikon der Chemie. , accessed February 24, 2009.