The effect of zinc-bromine interactions on electrophilic bromination in concentrated ZnBr2 solutions

Daniel M. Epstein; Dan Meyerstein

doi:10.1016/S1387-7003(01)00313-6

The effect of zinc-bromine interactions on electrophilic bromination in concentrated ZnBr₂ solutions

Daniel M. Epstein, Dan Meyerstein

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

7 Scopus citations

Abstract

Facile bromination can be carried out in concentrated solutions of zinc bromide (60-80% w/w ZnBr₂ in water) [A. Ewenson, D. Itzhak, M. Freiberg-Bergstein, A. Shushan, B. Croitoru, D. Beneish, N. Faza, WO patent 99/19275, Bromine Compounds Ltd., Israel, 1999]. These brine solutions offer an alternative to expensive and harmful organic solvents. A correlation between the reactivity and the molecular ratio H₂O:Zn has been found and quantified using UV-Vis spectroscopy [J.A. Duffy, G.L. Wood, J. Chem. Soc., Dalton Trans. (1987) 1485; E. Eyal, A. Treinin, J. Am. Chem. Soc. 86 (1964) 4287-4290; D. Meyerstein, A. Treinin, Trans. Faraday Soc. 59 (1963) 1114-1120]. Based on spectrophotometric and NMR results, it is proposed that these concentrated aqueous solutions, which behave similarly to anhydrous media, enhance the reactivity of molecular bromine by polarizing the Br-Br bond. Furthermore they affect the electron density distribution in the organic substrates.

Original language	English
Pages (from-to)	705-707
Number of pages	3
Journal	Inorganic Chemistry Communications
Volume	4
Issue number	12
DOIs	https://doi.org/10.1016/S1387-7003(01)00313-6
State	Published - 24 Dec 2001

Keywords

Electrophilic aromatic substitution
Zinc bromide

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Inorganic Chemistry
Materials Chemistry

Access to Document

10.1016/S1387-7003(01)00313-6

Cite this

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title = "The effect of zinc-bromine interactions on electrophilic bromination in concentrated ZnBr2 solutions",

abstract = "Facile bromination can be carried out in concentrated solutions of zinc bromide (60-80% w/w ZnBr2 in water) [A. Ewenson, D. Itzhak, M. Freiberg-Bergstein, A. Shushan, B. Croitoru, D. Beneish, N. Faza, WO patent 99/19275, Bromine Compounds Ltd., Israel, 1999]. These brine solutions offer an alternative to expensive and harmful organic solvents. A correlation between the reactivity and the molecular ratio H2O:Zn has been found and quantified using UV-Vis spectroscopy [J.A. Duffy, G.L. Wood, J. Chem. Soc., Dalton Trans. (1987) 1485; E. Eyal, A. Treinin, J. Am. Chem. Soc. 86 (1964) 4287-4290; D. Meyerstein, A. Treinin, Trans. Faraday Soc. 59 (1963) 1114-1120]. Based on spectrophotometric and NMR results, it is proposed that these concentrated aqueous solutions, which behave similarly to anhydrous media, enhance the reactivity of molecular bromine by polarizing the Br-Br bond. Furthermore they affect the electron density distribution in the organic substrates.",

keywords = "Electrophilic aromatic substitution, Zinc bromide",

author = "Epstein, {Daniel M.} and Dan Meyerstein",

note = "Funding Information: This study was enabled by a grant from Bromine Compounds Ltd., Beer Sheva, Israel.",

year = "2001",

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N2 - Facile bromination can be carried out in concentrated solutions of zinc bromide (60-80% w/w ZnBr2 in water) [A. Ewenson, D. Itzhak, M. Freiberg-Bergstein, A. Shushan, B. Croitoru, D. Beneish, N. Faza, WO patent 99/19275, Bromine Compounds Ltd., Israel, 1999]. These brine solutions offer an alternative to expensive and harmful organic solvents. A correlation between the reactivity and the molecular ratio H2O:Zn has been found and quantified using UV-Vis spectroscopy [J.A. Duffy, G.L. Wood, J. Chem. Soc., Dalton Trans. (1987) 1485; E. Eyal, A. Treinin, J. Am. Chem. Soc. 86 (1964) 4287-4290; D. Meyerstein, A. Treinin, Trans. Faraday Soc. 59 (1963) 1114-1120]. Based on spectrophotometric and NMR results, it is proposed that these concentrated aqueous solutions, which behave similarly to anhydrous media, enhance the reactivity of molecular bromine by polarizing the Br-Br bond. Furthermore they affect the electron density distribution in the organic substrates.

AB - Facile bromination can be carried out in concentrated solutions of zinc bromide (60-80% w/w ZnBr2 in water) [A. Ewenson, D. Itzhak, M. Freiberg-Bergstein, A. Shushan, B. Croitoru, D. Beneish, N. Faza, WO patent 99/19275, Bromine Compounds Ltd., Israel, 1999]. These brine solutions offer an alternative to expensive and harmful organic solvents. A correlation between the reactivity and the molecular ratio H2O:Zn has been found and quantified using UV-Vis spectroscopy [J.A. Duffy, G.L. Wood, J. Chem. Soc., Dalton Trans. (1987) 1485; E. Eyal, A. Treinin, J. Am. Chem. Soc. 86 (1964) 4287-4290; D. Meyerstein, A. Treinin, Trans. Faraday Soc. 59 (1963) 1114-1120]. Based on spectrophotometric and NMR results, it is proposed that these concentrated aqueous solutions, which behave similarly to anhydrous media, enhance the reactivity of molecular bromine by polarizing the Br-Br bond. Furthermore they affect the electron density distribution in the organic substrates.

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