Prepn. of 2,4-di:aminophenol or its di:hydrochloride - by redn. of 2,4-di:nitrophenol with palladium-rhodium membrane catalyst

摘要

Prepn. of 2,4-diaminophenol (I) or its 2HCl salt comprises hydrogenation of 2,4-dinitrophenol (II) on a membrane catalyst made of a 90-98% Pd/2-10% Rh or Ru alloy, by means of H2 diffusing through the catalyst. The (II) is used in aq. soln. or in 4-37% aq. HCl, the (II) being at 2-50% concn. Reaction is at 5-150 deg.C and at 1-60 atmospheres. Cpd. (I) is used in the prepn. of herbicides, fungicides and dyestuffs, and its 2HCl salt is used in photography as a developing agent. Cpd. (I) and its 2HCl salt are obtd. in high yields.