19. Reactions of Aromatics: EAS and Beyond

For each of the following compounds, indicate the ring carbon(s) that is/are nitrated when the compound is treated with HNO₃/H₂SO₄:

e.

f.

For each horizontal row of substituted benzenes, indicate

c. the one that yields the highest percentage of meta product in an electrophilic aromatic substitution reaction.

1.

2.

For each of the statements in Column I, choose a substituent from Column II that fits the description for the compound on the right:

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Are the following substituents ortho–para directors or meta directors?

a. CH=CHC≡N 

b. NO₂ 

c. CH₂OH

Predict the major products of bromination of the following compounds, using Br₂ and FeBr₃ in the dark.

(a)

A mixture of 0.10 mol benzene and 0.10 mol p-xylene was allowed to react with 0.10 mol nitronium ion until all the nitronium ion was gone. Two products were obtained: 0.002 mol of one and 0.098 mol of the other.

b. Why was more of one product obtained than of the other?

Propose a mechanism for the sulfonation of pyridine, and point out why sulfonation occurs at the 3-position.

Predict the major product of the following electrophilic aromatic substitution reactions.

(b) 

Give the products, if any, of each of the following reactions:

c. benzoic acid + CH₃CH₂Cl + AlCl₃

d. benzene + 2 CH₃Cl + AlCl₃

Would you expect chlorination to occur ortho, para, or meta to the pyridinium ion in the following molecule? Explain your answer.

Indigo is a dye that was originally isolated from coal tar. In 1905, Johann Friedrich Wilhelm Adolf von Baeyer won a Nobel Prize for a method that allowed indigo to be isolated from plants [a green chemist ahead of his time.] If you nitrated indigo using the reaction learned in this chapter, at which carbon would you expect the nitro group to attach?

For each horizontal row of substituted benzenes, indicate

a. the one that is the most reactive in an electrophilic aromatic substitution reaction.

Predict the mononitration products of the following compounds.

f. o-hydroxyacetophenone