Acetonitrile
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| General | ||||||||||||||||
| Surname | Acetonitrile | |||||||||||||||
| other names |
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| Molecular formula | C 2 H 3 N | |||||||||||||||
| Brief description |
colorless, highly flammable liquid with an aromatic odor |
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| properties | ||||||||||||||||
| Molar mass | 41.05 g mol −1 | |||||||||||||||
| Physical state |
liquid |
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| density |
0.78 g cm −3 |
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| Melting point |
−45 ° C |
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| boiling point |
82 ° C |
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| Vapor pressure |
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| solubility |
Fully miscible with water |
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| Dipole moment |
3.91 D. |
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| Refractive index |
1.3442 (30 ° C) |
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| safety instructions | ||||||||||||||||
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| MAK |
DFG / Switzerland: 20 ml m −3 or 34 mg m −3 |
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| Thermodynamic properties | ||||||||||||||||
| ΔH f 0 |
40.6 kJ / mol |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C | ||||||||||||||||
Acetonitrile is an organic solvent and the simplest organic nitrile .
Occurrence
The emission lines of acetonitrile could be detected on December 1st 1973 by radio telescope in the core of comet C / 1973 E1 (Kohoutek) . In April 2015, ESO astronomers used the ALMA telescope to detect large amounts of acetonitrile around the young star MWC 480 for the first time.
Manufacturing
Ways to produce are nucleophilic substitution reactions of z. B. Bromomethane with Sodium Cyanide (NaCN).
Acetonitrile is produced industrially in relatively small quantities as a by-product in the production of acrylonitrile . Price and availability are therefore linked to the production of the polyacrylonitrile .
properties
Acetonitrile releases poisonous gases such as hydrogen cyanide and nitrogen oxides if heated to a great extent and in the event of a fire . Explosive mixtures are formed with air .
Acetonitrile attacks rubber and dissolves many polymers . Explosive polymerisation can occur on contact with sulfuric acid with the supply of heat .
With water it forms an azeotropic mixture of 83.7% by weight of acetonitrile to 16.3% by weight of water and a boiling point of 76.5 ° C., 5.5 K below the boiling point of pure acetonitrile.
Safety-related parameters
Acetonitrile forms highly flammable vapor-air mixtures. The compound has a flash point at 2 ° C. The explosion range is between 3.0% by volume (50 g / m 3 ) as the lower explosion limit (LEL) and 17% by volume as the upper explosion limit (UEL). The limit oxygen concentration at 25 ° C is 12.7% by volume. The limit gap width was determined to be 1.5 mm. This results in an assignment to explosion group IIA. The ignition temperature is 525 ° C. The substance therefore falls into temperature class T1. The electrical conductivity is rather low at 6 · 10 −8 S · m −1 .
use
Acetonitrile is a common solvent in the laboratory , in chemical analysis ( e.g. HPLC ) and in technical chemistry , mainly for the extraction of 1,3-butadiene . Acetonitrile is used as a solvent for conductive salts in double-layer capacitors .
Acetonitrile-d 3
Completely deuterated acetonitrile (acetonitrile-d 3 ) - in which all three hydrogen atoms have been replaced by deuterium - is used as a solvent in NMR spectroscopy .
safety instructions
Acetonitrile is irritating. It is harmful if inhaled, swallowed and in contact with the skin. Acetonitrile is absorbed through the skin ( percutaneously ) and acts as a blood poison in the body .
Acetonitrile has only a low toxicity at low doses. It is metabolized to hydrogen cyanide , which is the cause of the symptoms observed. Symptoms are usually delayed (between 2 and 12 hours) as it takes some time for the body to metabolize acetonitrile to cyanide.
Cases of symptoms of poisoning through inhalation, oral ingestion or absorption through the skin in humans are rare but not unknown. Symptoms that appear a few hours after exposure include difficulty breathing, low heart rate, nausea, and nausea. In severe cases, convulsions and coma can occur, followed by death from respiratory failure. The countermeasures are the same as for cyanide poisoning .
Individual evidence
- ↑ a b c d e f g h i j k l m n o p q Entry on acetonitrile in the GESTIS substance database of the IFA , accessed on December 6, 2016(JavaScript required) .
- ↑ P. Alston Steiner, W. Gordy: Precision measurement of dipole moments and other spectral constants of normal and deuterated methyl fluoride and methyl cyanide . In: Journal of Molecular Spectroscopy . tape 21 , no. 1-4 , January 1966, pp. 291-301 , doi : 10.1016 / 0022-2852 (66) 90152-4 .
- ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-6.
- ↑ Entry on acetonitrile in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
- ↑ Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 75-05-8 or acetonitrile ), accessed on November 2, 2015.
- ↑ a b Acetonitrile data sheet (PDF) from Merck , accessed on February 22, 2010.
- ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-22.
- ↑ BL Ulrich, EK Conklin: Detection of Methyl Cyanide in Comet Kohoutek (1973f). In: Bulletin of the American Astronomical Society. Vol. 6, 1974, p. 389 ( bibcode : 1974BAAS .... 6..389S ).
- ↑ Martin Holland: Building blocks of life: Complex organic molecules around a foreign star. In: heise online. April 9, 2015, accessed January 13, 2016 .
- ↑ Jack Ponton: Azeotropic Databank. (Queriable database) The Edinburgh Collection of Open Software for Simulation and Education, Edinburgh University, September 2001, accessed February 20, 2008 .
- ↑ Osterberg PM, JK Niemeier, CJ Welch, JM Hawkins, JR Martinelli, TE Johnson, TW Root, SS Stahl: Experimental Limiting Oxygen Concentrations for Nine Organic Solvents at Temperatures and Pressures Relevant to Aerobic Oxidations in the Pharmaceutical Industry. In: Org. Process Res. Dev. 19, 2015, pp. 1537–1542, doi: 10.1021 / op500328f
- ↑ E. Brandes, W. Möller: Safety-related parameters. Volume 1: Flammable Liquids and Gases. Wirtschaftsverlag NW - Verlag für neue Wissenschaft, Bremerhaven 2003.
- ↑ Technical rule for hazardous substances TRGS 727, BG RCI leaflet T033 Avoidance of ignition hazards due to electrostatic charges , status August 2016, Jedermann-Verlag Heidelberg, ISBN 978-3-86825-103-6 .
- ↑ Henning Wallentowitz, Konrad Reif (ed.): Handbook of automotive electronics: Basics - components - systems - applications. 2nd Edition. Vieweg + Teubner, 2010, ISBN 978-3-8348-0700-7 , p. 270.
- ^ Institut National de Recherche et de Sécurité (INRS), Fiche toxicologique nº 104: Acétonitrile , Paris, 2004.
- ^ A b Philip Wexler: Encyclopedia of Toxicology. 2005, Vol. 1, Elsevier, pp. 28-30.
- ^ Spanish Ministry of Health: Acetonitrile. Risk Assessment Report (PDF; 3.1 MB), European Chemicals Bureau.
- ↑ a b c Environmental Health Criteria (EHC) for acetonitrile , accessed November 29, 2014.
- ^ M. Greenberg: Toxicological Review of Acetonitrile (PDF; 336 kB), United States Environmental Protection Agency, Washington, DC, 1999.