Benzene rings are energetically stable due to the delocalisation energy, addition reactions would involve breaking the ring but not re-forming it. So substitution can happen if the conditions for breaking the ring are met. You would think that electrophiles would be attracted strongly to all the electrons in the ring. But this is not the case Benzene rings don't polarise as much as Alkenes - each C-C bond has only 3 electrons rather than 4 in an alkene.
Weigh the vial containing about 3 grams of methyl benzoate and add it to the cooled sulfuric acid. Next pour about 2 ml of sulfuric acid to the nitric acid in the vial and allow for it to cool. Allow mixture to cool to room temperature and pour it over 25 g of ice and allow the ice to melt.
Next isolate the product by vacuum filtration and weigh the crude product. Recrystallize the product from equal weight of methanol.
Place mixture in water bath and heat it up so the solid dissolves. Next allow for solution to cool to room temperature and perform vacuum filtration again and then wash the solid with methanol.
Allow product to air dry for a week. The following week weigh the clean vial and cap and transfer the product to vial and weigh it. Finally, determine the melting point. Results and conclusions In this experiment 5. The amount of methyl benzoate obtained was 2.
The limiting reagent for this electrophilic aromatic substitution reaction is methyl benzoate. It yields the least amount of methyl nitrobenzoate in this reaction, and therefore is the limiting reagent.
The electrophilic aromatic substitution reaction between methyl benzoate and a nitrating solution of sulfuric and nitric acids was successful and yielded methyl m-nitrobenzoate. Therefore, my product is a meta-product.
The meta-product forms because the ortho- and para- products both have very unstable resonance forms with two positive charges next to each other. The two positive charges right next to one another causes the resonance forms to be unstable, so ortho- and para- substituted products do not form in this reaction.Electrophilic halogenation Reaction pathways involving attack by electrophilic halogens on Generalised pattern of reactions between electrophilic reagents and unsaturated compounds 53 Imidazole, pyrazole, thiazole and related com-pounds Electrophilic attack at carbon.
Electrophilic substitution in isoxazoles occurs most readily in the 4-position. The latter is part of the ring junction in the fused systems and . q One of their main uses in in electrophilic aromatic substitution reactions.
As very mild and selective electrophiles, they do not react with benzene or toluene or even anisole (methoxybenzene—normally considered a highly reactive aromatic). Nucleophilic Aromatic Substitution In our discussion so far, we focused on elctrophilic aromatic substitution.
Even though the electophilic substitution is by far the most common mode of substitution in aromatic systems, the nucleophilic substitution is indeed possible and is a useful tool in certain cases. There are more modern reagents and reaction conditions for many of these reactions that are vastly improved from the 's vintage and can control which side of the carbonyl is the site for substitution and eliminated problems of multiple reactions.
Examples Reactions of the Aromatic Heterocyclopentadienes Pyrroles, furans and thiophenes undergo electrophilic aromatic substitution. There are two possible sites of attack, C2 and C3, in the 1-hetero-2,4-cyclopentadienes undergoing electrophilic substitution.