Abstract:

Bisphenol AF was prepared from HFA•3H₂O and aniline under atmospheric pressure in 4 steps: condensation, diazotization, hydrolysis and Friedel-Crafts alkylation. Firstly, 2-(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropan-2-ol (Ⅰ) was obtained in a yield of 96.3% from HFA•3H₂O and aniline under optimal conditions with Nb₂O₅ as catalyst at an n (HFA•3H₂O) : n (aniline) : n (Nb₂O₅) ratio of 2 : 1 : 0.1 under reflux for 6 h. Then 2-(4-hydroxy phenyl)-1,1,1,3,3,3-hexafluoropropan-2-ol (Ⅱ) was synthesized from compound Ⅰ via diazotization﹑hydrolysis. The optimum reaction conditions were as follows: during diazotization, n (Ⅰ) : n (H₂SO₄) : n (NaNO₂) is 1 : 4.1 : 1.1, the content of H₂SO₄ is 14.7% and reaction temperature ﹣2 ～ 2 ℃; during hydrolysis, the content of H₂SO₄ is 50%, n (H₂SO₄) : n (Ⅰ) is 11 : 1. Under these conditions, the yield was 92.7%. Subsequently, in the presence of methanesulfonic acid, the Friedel-Crafts alkylation of compound Ⅱ with phenol yielded target compound bisphenol AF (Ⅲ) in a yield of 72.4%.  The total yield was 64.6% based on aniline.

Key words: bisphenol AF, hexafluoroacetone hydrate, aniline, Friedel-Crafts alkylation, diazotization, hydrolysis