91. Acetylene Dibromide

Nomenclature

CAS number: 540-49-8
1,2-Dibromoethene; 1,2-dibromoethylene; sym-dibromoethylene.
C2H2Br2; mol wt 185.85.
C 12.93%, H 1.08%, Br 85.99%.
BrCH=CHBr.

Description and references

Prepd by reaction of tetrabromoethylene with Zn and alc followed by sepn of cis- and trans-forms by fractional distillation: Noyes et al., J. Am. Chem. Soc. 72, 33 (1950).

Properties

Liquid, gradually decomposed by air, moisture, or light. d417 2.21. nD20 1.5428. Practically insol in water. Sol in many organic solvents.

Derivative

cis-Form.

Properties

nD25 1.5370.

Derivative

trans-Form.

Properties

nD25 1.5440.

Caution

Narcotic in high concns.