Resource-efficient technology to produce 4-aminodiphenylamine

A critical analysis of the existing and emerging methods for preparation of 4-aminodiphenylamine has been conducted. It is noted that, in economic and environmental terms, the promising methods are based on condensation of aniline with nitrobenzene in an alkaline medium, followed by hydrogenation of the resulting intermediates. Using the above method for industrial production of 4-ADPA will help eliminate
principal shortcomings inherent in the existing industrial methods: reduce unit operations of the process, use more accessible, inexpensive raw materials, increase product yield, eliminate formation of carcinogenic substances, significantly decrease the formation of waste products and, most importantly, decrease the volume of waste water. The most promising methods for industrial production are recent discoveries that use heterogeneous catalysts during condensation of aniline with nitrobenzene, e.g., zeolite ZSM-5 treated with tetramethylammonium hydroxide or highly basic anions which considerably simplify production technology and process control, lower costs and comply with strict environmental requirements.