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Dibromoethene
1,2-Dibromoethylene, also known as 1,2-dibromoethene and acetylene dibromide, is a dihalogenated unsaturated compound with one bromine on each of the two carbon atoms. There are two isomers of this compound, Cis–trans isomerism, ''cis'' and ''trans''. Both isomers are colorless liquids. Synthesis 1,2-Dibromoethylene can be synthesized by halogenation of acetylene (CH) with bromine (Br). In order to prevent the formation tetrahalogenated compounds, acetylene is used in excess, with Br as the limiting reagent. : Alternately, halogenation of this kind could also be achieved through the use of two equivalents of N-bromosuccinimide, ''N''-bromosuccinimide and lithium bromide (LiBr). ''N''-Bromosuccinimide provides Br as an electrophile, which is followed by Br from LiBr. : References {{DEFAULTSORT:Dibromoethylene, 1, 2- Bromoalkenes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromine
Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826), its name was derived from the Ancient Greek (bromos) meaning "stench", referring to its sharp and pungent smell. Elemental bromine is very reactive and thus does not occur as a native element in nature but it occurs in colourless soluble crystalline mineral halide salts, analogous to table salt. In fact, bromine and all the halogens are so reactive that they form bonds in pairs—never in single atoms. While it is rather rare in the Earth's crust, the high solubility of the bromide ion (Br) has caused its accumulation in the oceans. Commercial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
