In this experiment, the methyl nitrobenzoate was prepared from methyl benzoate, concentrated HNO3, and concentrated H2SO4 via an electrophilic aromatic substitution reaction. The HNO3 and H2SO4 were combined to form a nitrating solution, which was mixed with a mixture of methyl benzoate and H2SO4. Percent yield for the final product was calculated followed by recrystallization and melting point was measured.
Nitration of Methyl Benzoate is one of the examples of Electrophilic aromatic substitutions. The use of a mixture of Sulfuric Acid and Nitric Acid is the classic way to make NO2+. The two main reaction types used for this are both substitutions: Electrophilic Aromatic Substitution and Nucleophile Aromatic Substitution. The benzene ring itself is electron-rich, which makes Nucleophile Aromatic Substitution difficult, unless there are a number of strongly electron-withdrawing substituents on the ring. EAS, on the other hand, is a very useful method for putting many different substituents on a benzene ring, even if there are other substituents already present.
In this experiment you will put a nitro (—NO2) group on a benzene ring, which already has an OCH3 group, attached to the methyl benzoate.
Procedure: reference to: Lab manual Exp 43 “Nitration of Methyl Benzoate” page 338-341
* Weight of methyl benzoate: 3.065g
* Weight of methyl m-nitrobenzoate: 3.3443g
Percentage yield of methyl m-nitrobenzoate: 112.3%
%yield= (weight of methyl m-nitrobenzoate)/ (weight of methyl benzoate) X 100%
= (3.443g) / (3.065g)X100%
* Melting point range of product: 1st time: 62oC- 72 oC
2nd time: 68oC- 72 oC
* Theoretically melting point of methyl m-nitrobenzoate: 78 oC Analysis:
From the results we could see, the weight of...