Benzophenone from benzoyl chloride and benzene

Freshly prepared, finely powdered aluminium chloride (35 g.), weighed in a dry corked test tube, is poured with frequent shaking during the course of ten minutes into a dry flask containing 50 c.c. of 

To a solution of 4 g. of benzophenone in 25 c.c. of alcohol, cooled solutions of 3 g. of hydroxylamine hydrochloride in 6 c.c. of water and 5 g. of potassium hydroxide in 5 c.c. of water are added and the whole is heated under reflux on the water bath for two hours. The product is then poured into 50 c.c. of water, any unchanged ketone is removed by filtration after shaking to cause aggregation, the filtrate is faintly acidified with dilute sulphuric acid, and the free oxime recrystallised from alcohol. Melting point 140°. 

A weighed quantity of the oxime is dissolved in some cold ether, free from water and alcohol, and to the solution 1 -5 parts of finely powdered phosphorus pentachloride are gradually added. The ether is then removed by distillation and water Is added to the residue with cooling the ensuing precipitate is recrystallised from alcohol. Melting point 163°. 

Under the influence of the catalyst (PC15, concentrated H2S04) a compound rich in energy is converted into its stable isomeride the change which occurs is similar to that which was discussed on pp. 186, 187 in connexion with the relationship between hydrazobenzene and benzidine. A comparison with the benzilic acid rearrangement also suggests itself. 

There is also some relationship to the degradation reactions of Hofmann and Curtius. 

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C. Friedel and J. M. Crafts described the reaction in 1877 [J. pr. Chem. 16, 233.] Two typical reactions given by them were (1) the formation of amylbenzene from amyf chloride and benzene and (2) the formation of benzophenone from benzoyl chloride and benzene, both in the presence of aluminium chloride and giving hydrogen chloride as byproduct. They suggested the following equations as an explanation of the first reaction ... 

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