3,3',5,5'-Tetra-tert-butyl-4,4'-dibenzoquinone → 4,4'-Dihydroxybiphenyl

Participants

Reaction Steps

10 g (24.5 mmole) of 3,3',5,5',-terta-tert-butyl-diphenoquinone in 40 ml of ethylbenzene was hydrogenated as in Example 9. The filtered reaction mixture containing 4,4'-bis(2,6-di-tert-butylphenol) was transferred to a heavy walled bottle containing a magnetic stirring bar and as strong solid acid 9 g of Nafion® 117, which was obtained from the Du Pont Company as a film, which was cut into small pieces, treated with conc. HCl at 70° C. for one hour, washed with water and acetone and dried in an oven at 70° C. over night. The reactor was placed in an oil bath at 170° C. with stirring. The dealkylation was completed within 30 minutes. 3.8 g (20.4 mmol) of 4,4'-biphenol was obtained in the same way as described in Example 9 (83.3% yield). The filtrate containing 14.3 g p- and m-tert-butyl-ethylbenzene was placed in a popbottle containing 0.2 g 5% Pd/C, 10 g 3,3',5,5'-tetra-tert-butyl-diphenoquinone, and magnetic stirring bar. The hydrogenation was completed after 3 hours at 130° C. under 25 psi H2 pressure. The removal and washing of the catalyst was done as described above. The filtrate was transferred to a popbottle containing a magnetic stirring bar and the catalyst from the previous dealkylation, which had been treated with conc. HNO3, washed with acetone and water and dried at 70° C. overnight. The reaction mixture was kept at 170° C. for 45 minutes, cooled and worked up in the same way as above. 3.9 g (20.9 mmole) of 4,4'-biphenol was obtained (85.5% yield). The filtrate contained 22.2 g of p- and m-tert-butyl-ethylbenzene (69.9% yield).

Provenance & Evidence