Contact Information

Author
  • James E. Hutchison
  • Professor
  • Chemistry
  • Materials Sci. Inst.
  • Univ. of Oregon
  • Eugene, OR 97403
Email
Phone
(541) 346 - 4228
Website

Bromination of an Alkene: Preparation of Stilbene Dibromide

Laboratory Procedures (PDF)

Author Contact: hutch@uoregon.edu

Summary

In this experiment, a safer, solid bromination reagent (pyridinium tribromide) and a more benign solvent (ethanol) are employed to green the reaction and provide an effective bromination of an alkene, stilbene. Although bromination of alkenes is an important reaction in organic chemistry, the standard procedures involve the use of liquid bromine and chlorinated solvents. The traditional reagent and solvent present serious safety concerns, health risks and environmental impact. The solid reagent and ethanol solvent significantly decrease the hazards associated with the exercise. On the other hand, the use of the pyridinium tribromide decreases the atom economy of the reaction. This compromise spurred the development of a (yet) greener bromination experiment involving hydrobromic acid and hydrogen peroxide. The link to the laboratory procedure includes post-lab questions.

Summary prepared July 2006 by James E. Hutchison, Department of Chemistry at the University of Oregon.

Source

Doxsee, K. M.; Hutchison, J. E. Green Organic Chemistry - Strategies, Tools, and Laboratory Experiments, Print 2004; pp 120-124.

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Category Descriptors

Chemistry Concepts
  • Addition Rxn
  • Alkenes
Laboratory Techniques
  • Assembly of Reaction Apparatus
  • Melting Points and Melting Ranges
  • Vacuum Filtration
Green Chemistry Principles
  • Design Less Hazardous Chemical Syntheses
  • Minimize the Potential for Accidents
  • Use Safer Solvents/Reaction Conditions
Chemistry Subdiscipline
  • Organic Chemistry
Target Audience
  • Colleges/Universities
Source
  • Books