Abstract:

The ether preparation experiment is important in organic chemistry experiments. "The preparation of methyl tert-butyl ether" and "The preparation of n-butyl ether" are the corresponding experiments in the textbook. Studying these ether preparation experiments is important for a comprehensive understanding of the chemical properties of alcohols and the S_N1 and S_N2 mechanisms of nucleophilic substitution reactions. However, there are still many issues in "The preparation of methyl tert-butyl ether" based on the S_N1 mechanism in the textbook, such as the requirement of a stoichiometric amount of the sulfuric acid catalyst, difficult reaction monitoring, challenging purification of the product, and low yields. Herein, a non-flammable solid, diphenylmethanol, and ethanol were used as starting materials, and anhydrous ferric chloride was used as the catalyst to prepare the desired benzhydryl ethyl ether. After simple washing extractions, the desired benzhydryl ethyl ether product could be purified and obtained in 88%–90% yields and 95%–97% purities. Notably, the reaction mechanism of this experiment is the same as that of methyl tert-butyl ether preparation; however, the catalyst amount is significantly reduced, product separation and purification steps are greatly simplified, and product yield is significantly improved. This experiment is helpful for students to comprehensively understand basic theories, including the properties of carbocation intermediates, organic Lewis acid-base theories and their applications, and the S_N1 mechanism. Further, it can cultivate students' appreciation of green chemistry principles.

Key words: Ether, Dehydration of alcohols, Ferric chloride, Benzhydryl ethyl ether