Chloroethane

Structural formula
General
Surname	Chloroethane
other names	Ethyl chloride Monochloroethane R-160 Kelen Chloroethyl
Molecular formula	C 2 H 5 Cl
Brief description	colorless gas with an ethereal, pungent odor
External identifiers / databases
CAS number 75-00-3 EC number 200-830-5 ECHA InfoCard 100,000,755 PubChem 6337 ChemSpider 6097 DrugBank DB13259 Wikidata Q409133
properties
Molar mass	64.51 g mol −1
Physical state	gaseous
density	2.804 kg m −3 (15 ° C, 1 bar)
Melting point	−138.3 ° C
boiling point	13.1 ° C
Vapor pressure	1.343 bar (20 ° C) 1.9 bar (30 ° C) 3.4 bar (50 ° C)
solubility	sparingly soluble in water (5.74 g l −1 at 20 ° C) miscible with organic solvents
Dipole moment	2.05 D (6.8 × 10 -30  C  ·  m )
Refractive index	1.3798
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 220-280-351-412 P: 201-210-273-281-308 + 313-403 + 233
MAK	DFG : not specified as it is believed to be carcinogenic Switzerland: 9.0 ml m −3 or 25.0 mg m −3
Thermodynamic properties
ΔH f 0	−112.1 kJ / mol
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

Chlorethane is a chemical compound that can be used synthetically as an ethylating reagent. Other names are ethyl chloride, chloroethyl , monochloroethane, hydrogen chloride ether, light salt ether, Kelen and Chelen.

history

Ethyl chloride as a chemical compound was discovered and produced very early on. It is believed to be the first chlorinated hydrocarbon produced . As early as 1440 it was made by Basilius Valentinus by reacting ethanol with hydrochloric acid. Two centuries later - in 1648 - Johann Rudolph Glauber also got the connection by reacting ethanol with zinc chloride . In the context of industrialization and the increasingly growing automotive industry in the 1920s, chloroethane became an important mass product in the chemical industry . It was initially used in large quantities in the production of tetraethyl lead , an anti-knock agent for motor gasoline . Due to the stricter regulations with regard to leaded motor gasoline to increase the octane number (ban since 2000 in the EU, → see development of petrol ) and due to the development of alternative additives (e.g. methyl tert-butyl ether ) for petrol engines , the Demand for chloroethane has been falling sharply in recent years.

Extraction and presentation

As already mentioned, there are various ways of producing chloroethane, but only two of them are of industrial importance.

Thermal chlorination of ethane

An advantageous process for the large-scale production of chloroethane consists in the thermal chlorination of ethane with chlorine gas at temperatures of 400-450 ° C. and pressures of 5-10 bar.

The reaction is carried out without a catalyst in an adiabatically operated tubular reactor. A large excess of ethane is used in order to reduce the formation of more highly chlorinated hydrocarbons (e.g. 1,1-dichloroethane ). It is a radical substitution reaction that takes place without a catalyst due to the high temperature. Alternatively, the reaction can also be induced photochemically . The product mixture is purified by distillation and separated from other constituents.

Hydrochlorination of Ethene

Another process for the industrial production of chloroethane relates to the hydrochlorination of ethene with hydrogen chloride at temperatures of 30-50 ° C. and low pressures of 1-5 bar in the presence of aluminum chloride as a catalyst .

One works in the liquid phase in boiling bed reactors, in which the heat of reaction is dissipated by a cooling system. The conversion of ethene and hydrogen chloride is almost quantitative. The selectivity based on chloroethane is 98-99%. As by-products small amounts incurred to oligomeric ethene compounds (by Ziegler-Natta catalyst ) and higher chlorinated hydrocarbons .

properties

Physical Properties

Chlorethane vapors are heavier than air and accumulate on the ground ("heavy gas"). It has a critical temperature of 187.2 ° C, a critical pressure of 52.7 bar, a critical density of 0.331 kg / l and a triple point temperature of −138.3 ° C (melting temperature).

Chemical properties

Under normal conditions, chloroethane is gaseous, very reactive and sensitive to light. The thermal decomposition in the absence of oxygen produces hydrogen chloride and ethylene . In air and under the action of light, it slowly decomposes with the formation of hydrogen chloride and phosgene .

use

Because of its difficult handling, chloroethane is practically only used industrially, for example as an ethylating , solvent and extracting agent . In medicine it is used for local anesthesia ( freezing ). In industry, chloroethane was an important starting material for the production of the anti-knock additive tetraethyl lead for fuels . In dentistry it is used to test the sensitivity of the teeth ("vitality test").
Chlorethane was also used as a narcotic (stored in ampoules) in the past, but proved unsuitable for other substances because of its narrow therapeutic range .

safety instructions

Chlorethane is extremely flammable and harmful, possibly even carcinogenic. The gas has a strong anesthetic effect; 4% in the air you breathe cause anesthesia . Even narcotic concentrations can lead to ventricular fibrillation and cardiac arrest; higher concentrations (6%) can lead to respiratory paralysis after a short time.

Web links

Commons : Chlorethane  - Collection of pictures, videos and audio files

Individual evidence

1. ↑ ^{a b c d e f g h i j k l m n o} Entry on chloroethane in the GESTIS substance database of the IFA , accessed on March 13, 2020(JavaScript required) .
2. ↑ ^{a b} Entry on ethyl chloride. In: Römpp Online . Georg Thieme Verlag, accessed on March 14, 2020.
3. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Permittivity (Dielectric Constant) of Gases, pp. 6-188.
4. ↑ ^{a b c d e f} Eberhard ‐ Ludwig Dreher, Klaus K. Beutel, John D. Myers, Thomas Lübbe, Shannon Krieger, Lynn H. Pottenger: Chloroethanes and Chloroethylenees. In: Ullmann's Encyclopedia of Industrial Chemistry . Wiley ‐ VCH Verlag GmbH & Co. KGaA., November 19, 2014, doi : 10.1002 / 14356007.o06_o01.pub2 .
5. ↑ Entry on chloroethanes in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on March 13, 2020. Manufacturers or distributors can expand the harmonized classification and labeling .
6. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 75-00-3 or chloroethane ), accessed on March 13, 2020.
7. ↑ 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.
8. ↑ ^{a b c} Manfred Fedtke, Wilhelm Pritzkow, Gerhard Zimmermann: Technical organic chemistry - basic materials, intermediate products, final products, polymers . 1st edition. German publishing house for basic industry, Leipzig 1992, ISBN 3-342-00420-7
9. ↑ Johannes Petres, Rainer Rompel: Operative Dermatology: Textbook and Atlas. 2nd edition, Springer-Verlag, Heidelberg 2006, ISBN 978-3-540-34086-7 , p. 44.
10. ↑ Hans Killian : There is only God behind us. Sub umbra dei. A surgeon remembers. Kindler, Munich 1957; here: Licensed edition as Herder paperback (= Herder library. Volume 279). Herder, Freiburg / Basel / Vienna 1975, ISBN 3-451-01779-2 , p. 31.
11. ^ Harry Auterhoff, Textbook of Pharmaceutical Chemistry, Wissenschaftliche Verlagsgesellschaft Stuttgart, 1968