Dibromoacetylene

Last updated
Dibromoacetylene
Dibromoacetylene.png
Names
Preferred IUPAC name
1,2-Dibromoethyne [1]
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
  • InChI=1S/C2Br2/c3-1-2-4
    Key: JNFBOWNNNAHVNZ-UHFFFAOYSA-N
  • C(#CBr)Br
Properties
C2Br2
Molar mass 183.830 g·mol−1
AppearanceColorless liquid
Melting point −16.5 °C (2.3 °F; 256.6 K)
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Dibromoacetylene is an organic compound with the chemical formula C 2 Br 2. It is a molecular chemical compound containing acetylene, with its hydrogen substituted by bromine. Its molecule is linear, with the structure Br−C≡C−Br.

Contents

Production

Dibromoacetylene can be made by reacting 1,1,2-tribromoethylene with potassium hydroxide. This method has a danger of causing explosions. [2]

Another way is to react acetylene with phenyl lithium (at −50 °C) to make lithium acetylide, which then reacts with bromine to yield the product. [3]

Yet another way is to react acetylene with sodium hypobromite NaOBr. [4]

Properties

Dibromoacetylene is explosive and sensitive to air. [4] Its appearance is a clear water like liquid. It has a sweetish smell, but makes a white fume in air that then smells like ozone, possibly because it forms ozone.[ how? ] [2] Dibromoacetylene is lachrymatory. [2]

Dibromoacetylene can be polymerised to polydibromoacetylene using catalysts like titanium tetrachloride and triethylaluminium. Polydibromoacetylene is black, electrically conducting, and stable in air to over 200 °C. [4]

The infrared spectrum has absorption at 2185 cm−1 due to symmetrical stretching on the C≡C bond, 832 cm−1 asymmetrical stretch on C-Br bond, 311 cm−1 bending on Z shape BrCC, 267 symmetrical stretch on all bonds, and 167 cm−1 for C-shaped bending. [2]

Reactions

In air dibromoacetylene spontaneously inflames producing black sooty smoke and a red flame. When heated, it explodes, yielding carbon and other substances. A slower reaction with oxygen and water, yields oxalic acid and hydrobromic acid and other bromine containing substances. A reaction with hydrogen iodide yields dibromoiodoethylene. Dibromoacetylene reacts with bromine to yield tetrabromoethene. [5]

Dibromoacetylene reacts with Apiezon L, which is used as a vacuum grease in distillation, so its use is unsuitable with this chemical. [2]

References

  1. ↑ "Dibromoacetylene". PubChem. National Library of Medicine. Retrieved 24 March 2022.
  2. 1 2 3 4 5 Kloster-Jenson, Else (1971). "Preparation and physical characterization of pure hetero and homo dihaloacetylenes". Tetrahedron. 27 (1): 33–49. doi:10.1016/S0040-4020(01)92395-6.
  3. ↑ Meijere, Armin de (2014). Science of Synthesis: Houben-Weyl Methods of Molecular Transformations Vol. 24: Three Carbon-Heteroatom Bonds: Ketene Acetals and Yne-X Compounds. Georg Thieme Verlag. pp. 1191–1192. ISBN   978-3-13-178171-0.
  4. 1 2 3 Leben, S.; Janevski, A.; Šebenik, A.; Osredkar, U. (May 1992). "The synthesis and characterization of polydibromoacetylene" (PDF). Polymer Bulletin. 28 (3): 287–292. doi:10.1007/BF00294824. S2CID   94005740.
  5. ↑ Sartori, Mario (1939). The War Gases Chemistry and Analysis. Translated by L. W. MARRISON. New York: D. Van Nostrand Co., Inc. p. 51.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.