Im not really sure how to begin with this question..
1. The synthesis of toluene by the aluminum chloride-catalyzed Friedel-Crafts alkylation of benzene is badly complicated by the formation of di-, tri-, and polymethylated benzenes. A simple solution to the synthesis of toluene by this method would be to:
A) instead of aluminum chloride use an alternate Lewis acid that will be selective for monoalkylation
B) use a large excess of benzene
C) distill the toluene from the reaction flask as it is formed so it cannot react again
D) increase the amount of aluminum chloride to speed up the reaction
I believe the best answer choice is A. Using more Benzene wouldn't do anything to prevent the formation of undesirable side products. Distillation will remove H2O and wouldn't do anything as well; I do not believe that H2O will react with Toluene, but it will react with benzaldehyde and make benzoic acid. Increasing the amount of catalyst will do nothing but increase the rate at which toluene and the unwanted side products are produce, but nothing else.
Thank you for the feedback but after selecting this option it came up incorrect
The answer may be answer choice B. Answer choice A, in my opinion, is the best answer choice. However, adding more benzene would DECREASE the amount of undesirable side products, but would NOT prevent it. Adding more benzene would not solve the problem, but it would help.
To begin answering this question, it is important to understand the problem at hand. The synthesis of toluene by the aluminum chloride-catalyzed Friedel-Crafts alkylation of benzene is complicated by the formation of di-, tri-, and polymethylated benzenes. The objective is to find a simple solution to obtain toluene without the formation of these undesired by-products.
Let's analyze each option to determine the best solution:
A) Instead of aluminum chloride, use an alternate Lewis acid that will be selective for monoalkylation.
Using an alternative Lewis acid that is selective for monoalkylation may indeed be a solution. This would allow for the preferential formation of toluene and minimize the formation of unwanted by-products.
B) Use a large excess of benzene.
Using a large excess of benzene may encourage the formation of toluene as the major product. This strategy can help shift the equilibrium towards the desired monoalkylation product, reducing the formation of di-, tri-, and polymethylated benzenes.
C) Distill the toluene from the reaction flask as it is formed so it cannot react again.
Distillation of toluene as it is formed can prevent it from reacting further and forming undesired by-products. This selective removal would help increase the yield of toluene.
D) Increase the amount of aluminum chloride to speed up the reaction.
Increasing the amount of aluminum chloride may indeed speed up the reaction; however, it does not directly address the issue of selectivity. It might lead to an increase in all reaction products, including the unwanted di-, tri-, and polymethylated benzenes.
Based on the options provided, options A, B, and C could potentially be effective solutions. However, to determine the best solution, additional factors such as cost, ease of implementation, and potential side effects of using an alternative Lewis acid should be considered.
In conclusion, the simple solution to the synthesis of toluene by the aluminum chloride-catalyzed Friedel-Crafts alkylation of benzene would be to either use an alternate Lewis acid that is selective for monoalkylation (option A), use a large excess of benzene (option B), or distill the toluene from the reaction flask as it is formed to prevent further reactions (option C).