Application of combinatorial catalysis for the direct amination of benzene to aniline

Principles of Heterogeneous Catalysis

“…In this respect, catalyst development studies involve examining a large number of catalysts, for which recent advances in high-throughput testing have attracted considerable attention [82][83][84][85][86][87]. Catalyst development through the testing of a wide range of materials was first practiced in 1909 by Mittasch at BASF who, according to Timm [88], issued the following directive to his team who at the time were developing the synthesis of ammonia:…”

Der isotherme Labor‐Festbettreaktor mit quantitativer schneller Online‐Analytik als vielseitiges Instrument in der Redoxkatalyse

“…Insbesondere der Einsatz einer temperaturprogrammierten Fahrweise erlaubt eine genaue Festlegung der engen Grenzen des Temperaturfensters zwischen dem Einsetzen der Reaktion und der Benzol-zersetzung und auch eine klare Identifikation, welche Funktionen die Reaktanten Benzol, Ammoniak und NiO haben [19]. Damit lassen sich deutlich umfassendere Erkenntnisse gewinnen, als es in einer kürzlich veröffent-lichten herkömmlichen High-ThroughputExperimentation-Studie mit 25000 Proben in Miniaturautoklaven möglich war, die das DuPont-System NiO/ZrO 2 nur unwesentlich verbessern konnte [20]. [21,23].…”

On the Nature of the Active Site for the Oxidative Amination of Benzene to Aniline over NiO/ZrO2 as Cataloreactant

“…Recently, the Dow Chemical Company asked for the submission of research proposals on cost-effective one-step routes to aniline based on benzene. [13] In a combinatorial approach by Hagemeyer et al, [14] about 25 000 samples were tested in batch reactors leading to the result that NiO is indeed the most active oxidant and that ZrO 2 and K x TiO 2 are the most suitable carriers. To improve the system developed by DuPont, the authors suggested the addition of a noble metal such as Rh to enhance the reducibility and a dopant such as Mn to stabilize NiO for improved regenerability.…”

“…To improve the system developed by DuPont, the authors suggested the addition of a noble metal such as Rh to enhance the reducibility and a dopant such as Mn to stabilize NiO for improved regenerability. [14] It was speculated that nickel metal is essential to activate the CÀH bond of benzene and the NÀH bond of ammonia to initiate the formation of aniline without, however, providing any evidence for this hypothesis. [14,15] In a recent knowledge-based approach, we were able to obtain information on the reaction mechanism and on the degree of coking by establishing continuous oxidative synthesis of aniline at atmospheric pressure using DuPont's NiO/ZrO 2 cataloreactant under isothermal conditions.…”

“…[14] It was speculated that nickel metal is essential to activate the CÀH bond of benzene and the NÀH bond of ammonia to initiate the formation of aniline without, however, providing any evidence for this hypothesis. [14,15] In a recent knowledge-based approach, we were able to obtain information on the reaction mechanism and on the degree of coking by establishing continuous oxidative synthesis of aniline at atmospheric pressure using DuPont's NiO/ZrO 2 cataloreactant under isothermal conditions. [16] We deduced that the reaction temperature is a crucial parameter for the selectivity to aniline: at temperatures below 610 K, aniline is detected as the only aromatic product.…”