Describe every aspect of the procedure clearly and explicitly. Include temperatures, appearance of the reaction (include pictures!). How is the reaction monitored? Is the order of addition important? 4,4'-DIBROMOBIPHENYL [Biphenyl, 4,4'-dibromo-] Submitted by Robert E. Buckles and Norris G. Wheeler1. Checked by R. S. Schreiber, Wm. Bradley Reid, Jr., and Robert W. Jackson. 1. Procedure In a 15-cm. evaporating dish is placed 15.4 g. (0.10 mole) of finely powdered biphenyl (Note 1). The dish is set on a porcelain rack in a 30-cm. desiccator with a 10-cm. evaporating dish under the rack containing 39 g. (12 ml., 0.24 mole) of bromine. The desiccator is closed, but a very small opening is provided for the escape of hydrogen bromide (Note 2). The biphenyl is left in contact with the bromine vapor for 8 hours (or overnight). The orange solid is then removed from the desiccator and allowed to stand in the air under a hood for at least 4 hours (Note 3). At this point, the product weighs about 30 g. and has a melting point in the neighborhood of 152°. The crude 4,4'-dibromobiphenyl is dissolved in 75 ml. of benzene, filtered, and cooled to 15°. The resulting crystals are filtered, giving a yield of 23.4– 24.0 g. (75–77%) of 4,4'-dibromobiphenyl, m.p. 162–163° (Note 4).
Describe every aspect of the procedure clearly and explicitly. Include temperatures, appearance of the reaction (include pictures!). How is the reaction monitored? Is the order of addition important?
4,4'-DIBROMOBIPHENYL [Biphenyl, 4,4'-dibromo-]
Submitted by Robert E. Buckles and Norris G. Wheeler1. Checked by R. S. Schreiber, Wm. Bradley Reid, Jr., and Robert W. Jackson.
1. Procedure In a 15-cm. evaporating dish is placed 15.4 g. (0.10 mole) of finely powdered biphenyl (Note 1). The dish is set on a porcelain rack in a 30-cm. desiccator with a 10-cm. evaporating dish under the rack containing 39 g. (12 ml., 0.24 mole) of bromine. The desiccator is closed, but a very small opening is provided for the escape of hydrogen bromide (Note 2). The biphenyl is left in contact with the bromine vapor for 8 hours (or overnight). The orange solid is then removed from the desiccator and allowed to stand in the air under a hood for at least 4 hours (Note 3). At this point, the product weighs about 30 g. and has a melting point in the neighborhood of 152°. The crude 4,4'-dibromobiphenyl is dissolved in 75 ml. of benzene, filtered, and cooled to 15°. The resulting crystals are filtered, giving a yield of 23.4– 24.0 g. (75–77%) of 4,4'-dibromobiphenyl, m.p. 162–163° (Note 4).
AI-generated content may present inaccurate or offensive content that does not represent bartleby’s views.
Unlock instant AI solutions
Tap the button
to generate a solution
