Carbon tetrachloride

Structural formula
General
Surname	Carbon tetrachloride
other names	Carbon tetrachloride; Carbon tetrachloride; Tetra; R-10; Hydrocarbon tetrachloride;
Molecular formula	CCl 4
Brief description	colorless, unpleasantly sweet-smelling liquid
External identifiers / databases
EC number	200-262-8
ECHA InfoCard	100,000,239
PubChem	5943
Wikidata	Q225045
properties
Molar mass	153.82 g mol −1
Physical state	liquid
density	1.594 g cm −3
Melting point	−23 ° C
boiling point	76.7 ° C
Vapor pressure	119.4 h Pa (20 ° C); 186.1 hPa (30 ° C); 411.9 hPa (50 ° C); 705 hPa (65 ° C);
solubility	very bad in water (0.8 g l −1 at 20 ° C)
Dipole moment	0
Refractive index	1.4630
safety instructions
H and P phrases	H: 301 + 311 + 331-317-351-372-412-420
	P: 261-273-280-301 + 310 + 330-403 + 233-502
MAK	DFG / Switzerland: 0.5 ml m −3 or 3.2 mg m −3
Toxicological data	2350 mg kg −1 ( LD 50 , rat , oral )
Global warming potential	2019 (based on 100 years)
Thermodynamic properties
ΔH f 0	−128.2 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

Tetrachloromethane (also carbon tetrachloride , tetra ) is a chemical compound from the series of chlorinated hydrocarbons . With him all hydrogen atoms of methane are substituted by chlorine atoms . Both names are according to the IUPAC - Nomenclature correctly, depending on whether the connection as organic ( carbon tetrachloride ) or inorganic ( carbon tetrachloride ) compound is considered.

Manufacturing

Tetrachloromethane is produced in the industrial production of chloroform . For this purpose, chlorine is heated to 400–500 ° C with methane or chloromethane . At this temperature, a gradual radical substitution up to carbon tetrachloride takes place:

{\ displaystyle {\ ce {CH4 + Cl2 -> CH3Cl + HCl}}}

{\ displaystyle {\ ce {CH3Cl + Cl2 -> CH2Cl2 + HCl}}}

{\ displaystyle {\ ce {CH2Cl2 + Cl2 -> CHCl3 + HCl}}}

{\ displaystyle {\ ce {CHCl3 + Cl2 -> CCl4 + HCl}}}

Methane reacts with chlorine to form hydrogen chloride first to form chloromethane, and then to dichloromethane , trichloromethane (chloroform) and finally carbon tetrachloride.

The result of the process is a mixture of the four chloromethanes, which can be separated by distillation .

properties

Physical Properties

Carbon tetrachloride is a colorless, strongly refractive, sweet-smelling, non-flammable, toxic liquid with a melting point of −23 ° C and a boiling point of 76.7 ° C. According to Antoine, the vapor pressure function results from log ₁₀ (P) = A− (B / (T + C)) (P in bar, T in K) with A = 4.02291, B = 1221.781 and C = −45.739 in the temperature range from 293 to 350 K. Tetrachloromethane can be mixed well with ethanol , ether or gasoline and it dissolves fats , oils and resins . The miscibility with water is limited. As the temperature rises, the solubility of carbon tetrachloride in water rises or the solubility of water in tetrachloromethane rises.

Solubilities between carbon tetrachloride and water
temperature	° C	0	10.0	20.5	31.0	41.3	52.5	64.0	75.0
Tetrachloromethane in water	in%	0.089	0.063	0.060	0.072	0.068	0.078	0.096	0.115
Water in carbon tetrachloride	in%	0.0086	0.0102	0.0124	0.0156	0.0194	0.0263	0.0284	0.0304

Chemical properties

Carbon tetrachloride is very inert and is not attacked by acids and alkalis. However, upon contact with alkali metals and aluminum , an explosive reaction occurs. Under light - and heat the poison gas is produced, especially in the presence of moisture phosgene . Tetrachloromethane is one of the carcinogenic substances and, like chloroform, is very damaging to the liver. It is also harmful to aquatic organisms and contributes to the breakdown of the ozone layer , as it splits under UV exposure: Chlorine radicals are formed which have a very harmful effect on ozone ( ozone hole in the Arctic and Antarctic ).

use

Carbon tetrachloride was used in the early generations of fire extinguishers and for dry cleaning textiles in the early to mid-20th century . However, today it is no longer used due to the substance's great toxicity .

Effect on humans

Depending on the inhaled concentration, vapors from carbon tetrachloride cause:

a headache
Nausea and dizziness
Damage to the central nervous system
Decrease in sensory performance (visual acuity, hearing sensitivity, etc.)

If it comes into contact with the skin, it can be washed off with plenty of water or polyethylene glycol .

Safety instructions / risk assessment

Long-term exposure causes severe damage to the liver and kidneys. In animal experiments, carbon tetrachloride is carcinogenic, while in humans there is a well- founded suspicion of carcinogenic potential . When taken together with ethanol or barbiturates , a potentiating effect occurs.

Tetrachloromethane was included by the EU in 2012 in accordance with Regulation (EC) No. 1907/2006 (REACH) as part of substance evaluation in the Community's ongoing action plan ( CoRAP ). The effects of the substance on human health and the environment are re-evaluated and, if necessary, follow-up measures are initiated. The causes of the uptake of carbon tetrachloride were concerns about its classification as a CMR substance, exposure of workers and high (aggregated) tonnage. The re-evaluation has been running since 2012 and is carried out by France . A final report was then published.

Due to its toxic and carcinogenic properties and also its effects on the ozone layer , carbon tetrachloride may no longer be used according to the Chemicals Ozone Layer Ordinance . Its use as a fire extinguishing agent and as a degreasing, cleaning, solvent and thinning agent is only allowed for research purposes due to its toxicity and its unfavorable environmental properties.

literature

M. Rossberg; W. Lendle; G. Pfleiderer, A. Tögel; TR Torkelson, KK bag: Chloromethanes , in: Ullmanns Enzyklopädie der Technischen Chemie , Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2012; doi : 10.1002 / 14356007.a06_233.pub3 .

Web links

Commons : Carbon Tetrachloride - Collection of Pictures, Videos and Audio Files

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Entry on carbon tetrachloride in the GESTIS substance database of the IFA , accessed on October 9, 2018(JavaScript required) .
↑ 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.
↑ CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .
↑ Entry on carbon tetrachloride 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 .
↑ Schweizerische Unfallversicherungsanstalt (Suva): Limit values - current MAK and BAT values (search for 56-23-5 or carbon tetrachloride ), accessed on November 2, 2015.
↑ Entry on carbon tetrachloride in the ChemIDplus database of the United States National Library of Medicine (NLM) .
↑ G. Myhre, D. Shindell et al .: Climate Change 2013: The Physical Science Basis . Working Group I contribution to the IPCC Fifth Assessment Report. Ed .: Intergovernmental Panel on Climate Change . 2013, Chapter 8: Anthropogenic and Natural Radiative Forcing, pp. 24-39; Table 8.SM.16 ( PDF ).
↑ 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. 5-19.
↑ Hildenbrand, DL; McDonald, RA: The Heat of Vaporization and Vapor Pressure of Carbon Tetrachloride; the Entropy from Calorimetric Data in J. Phys. Chem. 63 (1959) 1521-1523, doi : 10.1021 / j150579a053 .
^ ^A ^b R. M. Stephenson: Mutual Solubilities: Water-Ketones, Water-Ethers, and Water-Gasoline-Alcohols in J. Chem. Eng. Data 37 (1992) 80-95, doi : 10.1021 / je00005a024 .
↑ European Chemicals Agency (ECHA): Substance Evaluation Conclusion and Evaluation Report .
↑ Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): Carbon tetrachloride , accessed on May 1, 2020.

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Entry on carbon tetrachloride in the GESTIS substance database of the IFA , accessed on October 9, 2018(JavaScript required) .

[CRC90_6_188-2] 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.

[CRC-3] CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .

[CLP_100.000.239-4] Entry on carbon tetrachloride 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 .

[5] Schweizerische Unfallversicherungsanstalt (Suva): Limit values - current MAK and BAT values (search for 56-23-5 or carbon tetrachloride ), accessed on November 2, 2015.

[ChemIDplus-6] Entry on carbon tetrachloride in the ChemIDplus database of the United States National Library of Medicine (NLM) .

[7] G. Myhre, D. Shindell et al .: Climate Change 2013: The Physical Science Basis . Working Group I contribution to the IPCC Fifth Assessment Report. Ed .: Intergovernmental Panel on Climate Change . 2013, Chapter 8: Anthropogenic and Natural Radiative Forcing, pp. 24-39; Table 8.SM.16 ( PDF ).

[CRC90_5_19-8] 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. 5-19.

[Hildenbrand-9] Hildenbrand, DL; McDonald, RA: The Heat of Vaporization and Vapor Pressure of Carbon Tetrachloride; the Entropy from Calorimetric Data in J. Phys. Chem. 63 (1959) 1521-1523, doi : 10.1021 / j150579a053 .

[Stephenson-10] A ^b R. M. Stephenson: Mutual Solubilities: Water-Ketones, Water-Ethers, and Water-Gasoline-Alcohols in J. Chem. Eng. Data 37 (1992) 80-95, doi : 10.1021 / je00005a024 .

[11] European Chemicals Agency (ECHA): Substance Evaluation Conclusion and Evaluation Report .

[12] Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): Carbon tetrachloride , accessed on May 1, 2020.