Nitrobenzene is an organic compound represented by the chemical formula C6H5NO2. It has significant roles both commercially, and within the laboratory as a solvent. The upload is a lab report of how the experiment goes on within the lab, through a process of electrophilic aromatic substitution.
2. LABORATORY REPORT 2
Preparation of Nitrobenzene
Nitrobenzene is an important organic compound it is generally represented by the
chemical formula C6H5NO2. It has significant roles both commercially, and within the
laboratory as a solvent. Below is a review of how the experiment goes on within the lab,
through a process of electrophilic aromatic substitution.
Procedure
Begin with about 80 millilitres of concentrated sulphuric acid. However, it should be set to
settle for some time to ensure that it gets cold. Then in a graduated cylinder put about 70
millilitres of concentrated nitric acid. From there, place the concentrated sulphuric acid, after
settling and getting cold in a cold ice bath, and add the nitric acid slowly in the beaker with
the concentrated sulphuric acid (Myst32YT, 2010). The nitric acid, being the stronger acid,
deprotonates the sulphuric acid removing the nitronium ion which acts as the electrophile
within the reaction.
After mixing the acids, and having cooled, the benzene can be added which is about 60
millilitres and add it through a SEP funnel in order to drip into the mixture of the acids. A
thermometer should also be added to keep track of the temperature, at an all-time the
temperature should not reach 50 degrees Celsius in the heed of avoiding a side-reaction
(Myst32YT, 2010). Thus, the SEP funnel can be set such that the temperature maintains
within the temperature range of 40 degrees Celsius, which should take the full reaction about
an hour.
Having added all the benzene to the mixture, remove the beaker with the mixture of
benzene and the acids from the ice bath, and stir them for about 30 minutes. This is done to
ensure that the mixture attains room temperature. Stopped stirring to ensure that the mixture
3. LABORATORY REPORT 3
sit, a factor that sees two layers are formed, the top should be that of nitro benzene and the
bottom should that be of the mixture of the acids. Pour the contents of the beaker to a
separating funnel till two layers are formed and remove the bottom layer and discard
(Myst32YT, 2010). Then to the separating funnel add about 40 millilitres of cold water while
shaking. Two layers are expected to form of Nitrobezene which will have turned to a yellow
color, and now on the bottom layer. Finally, remove the aqueous layer, and discard.
To the removed nitrobenzene, place to a SEP funnel, and repeat the washing process for
about three times. This ensures the removal of the acid. Then, distillation of the nitrobenzene,
now in a beaker, should be distilled in the heed of having a pure product, by removing
contaminants such as side products, and water. Pour the now distilled nitrobenzene to a
boiling flask, and put it up for simple distillation by heating up the product to about
temperatures of about 207 to 211 degrees Celsius citing that is the temperature range of pure
nitrobenzene (Myst32YT, 2010). The final product of nitrobenzene should be clear to pale
yellow. Any cloudiness should be due to water contamination, and can be removed by adding
about three to five grams of calcium chloride which removes turbidity giving a clear yellow
color of nitrobenzene, and finally decant solution to a bottle for storage.
Results
Below is an image of how the reaction goes on in the formation of nitrobenzene, from
nitric acid, sulphuric acid, and benzene.
4. LABORATORY REPORT 4
Discussion
The nitration process, in preparation of nitrobenzene is highly exothermic, and to some
point explosive. As such, the reactants are added slowly with the view of foreseeing that the
temperature levels are not exceeded. Agitation of the mixtures is further ensured citing that
benzene, and the nitrating mixture are almost immiscible in a view of breaking down two
phases which may be formed into small drops in maximizing surface area of their contact
(Huang, 2014). Heating the mixture should equally take a long time in the strive of increasing
the yield of the product formed, nitrobenzene.
Cold ice bath is further added to ensure that low temperatures are maintained. Calcium
chloride as explained is added in the view of removing turbidity, as it works as a drying agent
(Huang, 2014). The nitration process generally leads to the formation of a nitronium ion, by
first deprotonating the sulphuric acid, a process that can be inferred to as electrophilic
aromatic substitution.
Conclusion
The objectives of the experiment were achieved, despite the fact that some challenges may
be encountered due to side reactions, formation of side products, and contamination of water.
5. LABORATORY REPORT 5
References
Huang, J. (2014, February 20). The Nitration of Benzene: A Love Story and Song |
Nitrobenzene [YouTube]. Retrieved from
https://www.youtube.com/watch?v=DbTxFdeDoQ8
Myst32YT. (2010, October 19). Make Nitrobenzene [YouTube]. Retrieved from
https://www.youtube.com/watch?v=8czz7FdFUNk
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About the author
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processes in the past. Preparation of Nitrobenzene being one of his many documented
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