Methanol → 1,1-Diphenylethylene

Participants

Reaction Steps

To this reaction mixture was added dropwise a liquid mixture of 182.2 g (1.1 mol) of benzophenone (8a; Ar=R=Ph) and 365 ml of dry THF at 35 to 40° C. over a period of 30 minutes. This mixture was stirred at that temperature for 2 hours and for further 13 hours to complete the reaction. The reaction mixture was poured into 1.4 kg of cooled 10% aqueous ammonium chloride solution with cooling with ice. This mixture was stirred for 30 minutes, allowed to stand, and then subjected to liquid separation, followed by washing with aqueous common salt solution, drying with magnesium sulfate, and concentration to obtain 200.2 g of a crude carbinol (theoretical yield based on the benzophenone, 98.6%). Into a 1-liter reaction flask were introduced 200.2 g of the crude carbinol, 400 ml of toluene, and 1 g of p-toluenesulfonic acid (PTSA). Azeotropic dehydration was conducted for 2 hours with toluene refluxing (94-116° C.). After cooling, this reaction mixture was washed with water, with 2% aqueous soda ash solution, and then with water, dried with magnesium sulfate, and concentrated to obtain 190.1 g of crude 1,1-diphenylethylene. This crude reaction product was distilled with a Claisen flask equipped with a vigreux to obtain 174.1 g of 1,1-diphenylethylene (9a; Ar=R=Ph). b.p., 103° C./1 mmHg.

Provenance & Evidence