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) was 1:4.1:1.1,the mass fraction of H₂SO₄ was 14.7% and reaction temperature-2～2 ℃;during hydrolysis,the mass fraction of H₂SO₄ was 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.