Nitrogen trichloride

Structural formula
General
Surname	Nitrogen trichloride
other names	Trichloramine
Molecular formula	NCl 3
Brief description	viscous, yellow, chlorine-like smelling, explosive liquid
External identifiers / databases
CAS number 10025-85-1 EC number 233-045-1 ECHA InfoCard 100.030.029 PubChem 61437 ChemSpider 55361 Wikidata Q409473
properties
Molar mass	120.36 g mol −1
Physical state	liquid
density	1.64 g cm −3
Melting point	−40 ° C
boiling point	71 ° C
safety instructions
GHS hazard labeling no classification available
MAK	Switzerland: 0.06 ml m −3 or 0.3 mg m −3
Toxicological data	112 ppm · 1 h ( LC 50 ,  rat ,  inh. )
Thermodynamic properties
ΔH f 0	+229  kJ mol −1
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Nitrogen trichloride (also known as trichloramine) is an explosive chemical compound that belongs to the group of nitrogen halides and chloramines .

history

In 1811 the French chemist Pierre Louis Dulong experimented with chlorine gas and a solution of ammonium chloride, whereby nitrogen trichloride was formed. During his experiments with the dangerous compound, an explosion occurred in which Dulong lost three fingers, prompting him to investigate the substance further. After the accident became known, the British chemist Humphry Davy also dealt with the substance in 1813 . Other manufacturing processes were later discovered by Balard and Böttger and Kolbe .

Occurrence

When disinfecting swimming pools with chlorine , the reaction with urea produces nitrogen trichloride as a by-product from human excretions. The nitrogen trichloride is responsible for the typical smell of chlorine in indoor swimming pools , which can occasionally occur if the pool water is too heavily polluted.

Extraction and presentation

Nitrogen trichloride is formed by chlorinating a saturated, acidic ammonium chloride solution, with chloramine and dichloramine being formed as intermediate products .

${\displaystyle \mathrm {4\ NH_{3}+3\ Cl_{2}\longrightarrow NCl_{3}+3\ NH_{4}Cl} }$

An approximately 1.4 molar solution of nitrogen trichloride in carbon tetrachloride is by passing chlorine gas into a with carbon tetrachloride subcoated ammonium accessible solution.

${\displaystyle \mathrm {2\ (NH_{4})_{2}CO_{3}+3\ Cl_{2}\longrightarrow NCl_{3}+3\ NH_{4}Cl+2\ CO_{2}+2\ H_{2}O} }$

Furthermore, calcium hypochlorite and ammonium chloride can be obtained in the presence of hydrochloric acid in methylene chloride and water, in which case it can then be isolated from the organic phase.

properties

Physical Properties

When exposed to UV radiation in the UVB range at 340 nm, nitrogen trichloride decomposes by reacting with free hydroxide ions :

${\displaystyle \mathrm {2\ NCl_{3}+6\ OH^{-}\ \rightleftharpoons \ N_{2}+3\ OCl^{-}+3\ Cl^{-}+3\ H_{2}O} }$

Like ammonia, nitrogen trichloride has a pyramidal molecular structure with a Cl-N-Cl angle of 107.78 ° and a leg length (N-Cl) of 175.3 pm.

Chemical properties

With water , nitrogen trichloride is hydrolyzed to ammonia and hypochlorous acid (HClO) (since nitrogen is somewhat more electronegative than chlorine due to the strongly polarized atomic bonds in this compound).

${\displaystyle \mathrm {NCl_{3}+3\ H_{2}O\rightarrow NH_{3}+3\ HClO} }$

use

Until around 1950, a large part of the flour was bleached with nitrogen trichloride ("agene process"). However, this leads to the formation of methionine sulfoximide , a toxic derivative of the amino acid methionine , which is why this process has been banned.

safety instructions

Nitrogen trichloride is irritating to the eyes, respiratory tract and mucous membranes. The metastable compound explodes when the temperature rises. Solutions with a concentration of up to 18 percent are considered harmless.

Studies from 1983 with rats showed an LC ₅₀ value of 112  ppm / 1 h after uptake via the airways. Symptoms that occurred in the animals were increased lacrimation, cramps and organic and functional disorders of the salivary glands .

At the end of 2010, the Federal Health Gazette raised the suspicion that nitrogen trichloride formed in chlorinated pool water could trigger asthma when babies swim . The Federal Environment Agency advises against baby swimming, especially for children under two years of age, in whose families there are frequent allergies , until further findings are available that speak in favor of harmlessness.

Individual evidence

1. ↑ ^{a b} Entry on nitrogen trichloride in the GESTIS substance database of the IFA , accessed on February 27, 2017(JavaScript required) .
2. ↑ ^{a b} webelements.com: nitrogen trichloride
3. ^ ^{A b c} A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 .
4. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
5. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 10025-85-1 or nitrogen trichloride ), accessed on November 2, 2015.
6. ↑ ^{a b} American Industrial Hygiene Association Journal. Vol. 44, 1983, pg. 145.
7. ↑ ^{a b} Entry on nitrogen trichloride in the ChemIDplus database of the United States National Library of Medicine (NLM) .
8. ↑ Lateral Science: Fulminating oils ( Memento of the original of September 21, 2008 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
9. ↑ Water, drinking water and water protection - swimming and bathing pool water - chemistry & analytics ( Memento from February 12, 2013 in the web archive archive.today ).
10. ↑ ^{a b} Georg Brauer (Ed.), With the collaboration of Marianne Baudler u a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 462.
11. ^ E-EROS Encyclopedia of Reagents for Organic Synthesis , 1999-2013, John Wiley and Sons, Inc., entry for Trichloramines, accessed July 26, 2017 .
12. ↑ Technical article: Energy and water saving concepts for swimming pools (PDF).
13. ↑ TM Klapötke , H.-J. Meyer, C. Janiak, E. Riedel: Modern inorganic chemistry ., 2003, Walter de Gruyter, ISBN 3-11-017838-9 , p. 75.
14. ↑ Ludwig Acker : Handbook of food chemistry . Carbohydrate-rich foods. Springer-Verlag, 1967, ISBN 978-3-662-34537-5 ( Google Books ).
15. ↑ CA Shaw, JS Bains: Did consumption of flour bleached by the agene process contribute to the incidence of neurological disease? In: Medical Hypotheses . tape 51 , no. 6 , December 1998, pp. 477 , doi : 10.1016 / s0306-9877 (98) 90067-6 (English, PDF ).
16. ↑ Baby swimming and disinfection by-products in swimming pools. (PDF; 132 kB) Bundesgesundheitsblatt 01/2011, 54: 142–144, December 29, 2010 (published online). doi: 10.1007 / s00103-010-1177-x .