2,2-Bis:(aminophenyl)-propane prodn. - by nitration of 2,2-di:phenyl-propane and redn. of resulting 2,2-bis:(nitrophenyl)-propane

摘要

Process for the prodn. of 2,2-bis-(aminophenyl)-propane (I) with a proportion of the 4,4'-isomer of at least 70 %, comprises nitrating 2,2-diphenylpropane (II) to 2,2-bis-(nitrophenyl)-propane (III) and reducing the (III) in a subsequent step to form (I). - Pref. nitration is carried out using 50-100 % HNO3, HNO3/H2SO4 mixts. or mixts. of H2SO4 with alkali (ne earth) nitrates. In the HNO3/H2SO4 mixts. the HNO3 may contain up to 60 wt. % H2O and the H2SO4 may contain up to 20 wt. % H2O or up to 20 wt. % SO3. Pref. the nitration reaction is carried out in a solvent chosen from aliphatic hydrocarbons, aliphatic halohydrocarbons and aromatic nitro cpds., at a temp. of 0 - 150 deg. C and using a mol. ratio of (II) to the nitro gp. contg. nitrating reagent of 1:2-15, esp. 1:2-5. Redn. of the nitro cpd. (III) is carried out eg with mixts. of non-noble metals and acids, mixts. of hydrazine and hydrogenation catalysts, mixts. of sulphides or H2S and dithionites or by catalytic hydrogenation at 0-200, esp. 20-150 deg.C and a H2 pressure of 1-100 bar, esp. 2-50 bar, and pref. using an excess of H2 of 1-10 mol H2 per mol (III) above the amt. of H2 required for complete hydrogenation of the nitro gps.