April 8, 2014
Lab Experiment: Nitration of Bromobenzene
Introduction: The chemical reaction of nitration consists of a nitro group being added to or substituted in a molecule. Nitration can basically be carried out by a mixture of concentrated nitric acid and sulfuric acid; this mixture is useful to obtain the active nitronium ion. Electrophilic aromatic substitution is a method used when a functional group is needed to be substituted on to an aromatic compound. In the nitration, nitronium ion acts as the electrophile that involves the attack of the electron-rich benzene ring.
Aromatic substitution is electrophilic, due to the high density in benzene ring. Benzene ring is one of the components in most important natural products and other useful products. The species reacting with the aromatic ring is usually a positive ion or the end of a dipole. Nitration is one of the most important examples of electrophilic substitution. The electrophile in nitration is the nitronium ion which is generated from nitric acid by protonation and loss of water, using sulfuric acid as the dehydrating agents. Data:
Beaker + Crystals
Weight of Crystals (Prior to Addition of Ethanol)
Figure 1: This table illustrates the weight of the crystals that were formed before the ethanol was added. 2.8 grams x 5= 14 mL
- This is the amount of ethanol that is needed to just dissolve the bromonitrobenzenes at 78.2oC.
Wet Sample of Crystals
Dry Sample of Crystals
Difference Between Wet and Dry Samples
Figure 2: This table illustrates the weight of the crystals that were formed as the final product. The wet sample and dry sample both have a different value.
Figure 3: This is the structure of bromobenzene; this was the liquid that was given for this laboratory experiment.
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