1,2-dibromethane

2-Dibromoethane 1
2-Dibromoethane 1
Are common
Systematic ; name	1,2-dibromethane
Traditional names	ethylene bromide; ethylene dibromide
Chem. formula	(CH 2 Br) 2
Rat formula	C 2 H 4 Br 2
Physical properties
condition	colorless liquid
Molar mass	187.86 g / mol
Density	2.18 g / cm³
Ionization energy
Thermal properties
T. melt.	9.79 ° C
T. bale.	131.36 ° C
Enthalpy of Education	-38.3 kJ / mol
Steam pressure
Chemical properties
Solubility in water	0.43 g / 100 ml
Optical properties
Refractive index	1,539
Classification
Reg. CAS number	106-93-4
PubChem
Reg. EINECS number
Smiles
Inchi
Reg. EC number	203-444-5
RTECS
Chebi
UN number
ChemSpider
Security
LD 50	rabbits (oral) 55.0 mg / kg
Toxicity	0 3 0

1,2-Dibromethan ( ethylene bromide, ethylene dibromide, ethylene bromide) is an organic compound , a halogenated hydrocarbon with the chemical formula C ₂ H ₄ Br ₂ . Present in small quantities in the water of the oceans.

Content

Properties

A colorless liquid with a sweet smell reminiscent of chloroform . The melting point of 1,2-dibromoethane is 9.79 ° C, the boiling point is 131.36 ° C. Soluble in benzene , acetone , ethanol . The solubility in 100 g of water is 0.43 g (at 20 ° C).

Getting

1,2-Dibromoethane can be obtained by the reaction of ethylene with bromine :

{\mathsf {C_{2}H_{4}+Br_{2}\rightarrow CH_{2}Br{\text{-}}CH_{2}Br}}

{\ displaystyle {\ mathsf {C_ {2} H_ {4} + Br_ {2} \ rightarrow CH_ {2} Br {\ text {-}} CH_ {2} Br}}}

Bromine is poured into a laboratory test tube with a drain tube and a gas supply tube, pieces of glass are placed in advance on the bottom of the tube (to increase the surface on which gas interacts with liquid bromine). A layer of water is poured onto the bromine surface (to reduce the loss of bromine due to evaporation). Ethylene is fed into a test tube in the bromine layer.

The tube is cooled with cold water, since the reaction is accompanied by heat. The tube must be shaken with care so as not to spill bromine into the bypass tube. Bromination ends when the amount of bromine taken completely reacts with ethylene - bromine will decolorize.

The obtained dibromoethane for cleaning is washed in a separatory funnel with water, then with a solution of caustic soda and several times with water. After drying with fused calcium chloride, the product is distilled from a small Würz flask , collecting a fraction with a boiling point of 130–132 ° С.

Application

1,2-Dibromoethane is used as an anti-knock additive together with tetraethyl lead in motor fuels to prevent deposition of solid lead oxides on engine parts due to the formation of volatile lead bromide .

It is used as a fumigant for processing wood from damage by termites and woodworms ^[2] .

It is also used for the synthesis of vinyl bromide , a precursor for various flame retardants , as well as for the synthesis of 1,2-dithiocyanethane , 1,4-benzodioxane , N-bromoethylphthalimide . In organic synthesis, it is used as a source of bromine in the reaction with carbcations , and for the activation of magnesium in the synthesis of Grignard reagents .

Security

Strong carcinogen . Irritating to the respiratory tract. It affects the liver and kidneys. Direct contact with the skin may cause ulcers .

Literature

Properties of Organic Compounds: A Handbook. - ed. Potekhina A.A. - L .: Chemistry, 1984 p. 434-435.
Handbook of a chemist. - T. 2. - L. — M .: Chemistry, 1964, pp. 1142–1143.
Seidell A. Solubilities of organic compounds. - 3d ed., Vol. 2 - New York: D. Van Nostrand Company, 1941, p. 97.
Yalkowsky SH, Yan H., Jain P. Handbook of aqueous solubility data. - 2ed. - CRC Press, 2010, p. 28.

Notes

↑ ¹ ² http://www.cdc.gov/niosh/npg/npgd0270.html
↑ Dagani MJ, Barda HJ, Benya, TJ, Sanders, DC Bromine Compounds. doi 10.1002 / 14356007.a04_405.