Bromoethene

Structural formula
General
Surname	Bromoethene
other names	Vinyl bromide Vinyl bromur Monobromethylene R 1140B1 Bromoethylene
Molecular formula	C 2 H 3 Br
Brief description	extremely flammable, colorless gas with a pleasant odor
External identifiers / databases
CAS number 593-60-2 EC number 209-800-6 ECHA InfoCard 100.008.911 PubChem 11641 Wikidata Q421041
properties
Molar mass	106.95 g mol −1
Physical state	gaseous
density	1.53 kg m −3
Melting point	−138 ° C
boiling point	15.7 ° C
Vapor pressure	119 k Pa (20 ° C)
solubility	practically insoluble in water
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 220-350 P: 201-308 + 313-410 + 403
MAK	Switzerland: 5 ml m −3 or 22 mg m −3
Toxicological data	500 mg kg −1 ( LD 50 ,  rat ,  oral )
Thermodynamic properties
ΔH f 0	79.2 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Bromoethene is a chemical compound from the group of aliphatic unsaturated halogenated hydrocarbons and organic bromine compounds .

history

Bromethene was discovered in 1835 by Henri Victor Regnault and described for the first time.

Extraction and presentation

Bromoethene can be obtained by reacting ethyne with hydrobromic acid with the help of mercury (II) bromide , which also produces 1,1-dibromoethane .

${\displaystyle \mathrm {C_{2}H_{2}+HBr\ {\xrightarrow[{HgBr_{2}}]{200\;^{\circ }C}}\ C_{2}H_{3}Br+{(CH_{2}Br)}_{2}} }$

It can also be prepared by reacting 1,1-dibromoethane with 1,2-dibromoethane (both of which are formed during the reaction of ethene with bromine) and subsequent reduction with potassium hydroxide .

${\displaystyle \mathrm {{(CH_{2}Br)}_{2}+C_{2}H_{4}Br_{2}\ {\xrightarrow {KOH}}\ C_{2}H_{3}Br} }$

properties

Bromoethene is chemically unstable and can polymerize spontaneously (under the influence of light) , which is why it is sold in compressed gas cylinders in liquefied form, sometimes mixed with stabilizers. It is only slightly soluble in water, but soluble in ethanol, acetone, benzene, ether and chloroform. Under certain conditions it attaches various simple compounds, such as hydrohalic acids. With diazomethane it combines to pyrazole hydrobromide :

${\displaystyle \mathrm {CH_{2}N_{2}+C_{2}H_{3}Br\longrightarrow C_{3}H_{5}N_{2}Br} }$

use

Bromoethene is used as a flame-retardant monomer for copolymers in the polymerization to synthetic fibers (e.g. of polyvinyl bromide ) and as an alkylation reagent in organic syntheses.

safety instructions

Bromethene is classified as a category 2A carcinogen. The vapors of bromoethene can form an explosive mixture with air ( ignition temperature 500 ° C).

Web links

• organic-chemistry: Synthesis of vinyl bromides
• ETH: About the physical properties of vinyl bromide

Individual evidence

1. ↑ ^{a b c d e f g h} Entry on bromethene in the GESTIS substance database of the IFA , accessed on February 22, 2017(JavaScript required) .
2. ↑ Entry on Bromoethylene 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 .
3. ↑ Data sheet Bromethen from Sigma-Aldrich , accessed on March 14, 2011 ( PDF ).
4. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 593-60-2 or bromethene ), accessed on November 2, 2015.
5. ↑ 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. 5-21.
6. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 85th edition. (Internet version: 2005), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-68.