Formation of Aniline from Chlorobenzene

Question

My textbook says:

When chlorobenzene is treated with aqueous ammonia at 473K under a pressure of 60 atmospheres in presence of cuprous oxide or cuprous chloride, aniline is formed.

Notice the reaction given. It shows Cuprous chloride ($\ce{Cu2Cl2}$) as a by-product. The question is, if cuprous chloride is used for treating chlorobenzene initially, the whole equilibrium should shift backwards, that is, the formation of aniline shouldn't be favourable, because $\ce{Cu2Cl2}$ is formed in the process.

Is my textbook wrong here in giving the statement? Or am I missing something?

Answer 1

Your textbook's text is correct but the reaction image is incomplete. Reaction of chlorobenzene with ammonia in presence of both the cuprous chloride and cuprous oxide forms aniline but via two different reactions. Your textbook only mentions one of the reactions in the image.

In the reaction involving the oxide, cuprous oxide is a reactant and is consumed during the reaction whereas in the case of the second reaction, cuprous chloride acts as a catalyst and isn't used up during the reaction. The mention of the second reaction can be found in Industrial Organic Chemistry, Klaus Weissermel and Hans-Jurgen Arpe^[1], where the following reaction is mentioned,

$$\ce{Ph-Cl + 2NH3 + CuCl -> Ph-NH2 + NH4Cl}$$

The same reaction can also be found on The chemical thesaurus reaction chemistry database^[2].

---

References:

^{(1) Rose, J. Industrial Organic Chemistry Klaus Weissermel and Hans-Jurgen Arpe 3rd Edn. VCH, Weinheim, 1997 Xvii + 464 Pages. £70 ISBN 3-527-28838-4. Appl. Organomet. Chem. 1999, 13 (11), 857–858.}

^{(2) Leach, M. R. The chemical thesaurus reaction chemistry database
http://www.chemthes.com/rxn_dp.php?id=3489 (accessed Jun 25, 2021).}