Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

LOW-TEMPERATURE DIRECT ROUTE TO ANILINE VIAAMINATION OF BENZENE IN THE PRESENCEOF OXYGEN AND HYDROGENN.I. Kuznetsova a , V.A. Likholobov b , G. Pez cOP-III-24a Boreskov Institute of Catalysis SB RAS, Pr. Akad. Lavrentieva, 5, Novosibirsk, 630090,Russia, Fax: +7 383 333 16 06, E-mail: kuznina@catalysis.rub Institute of Hydrocarbon Processing, Omsk, 644040, RFc Air Products and Chemicals, Inc., Allentown, PA 18195-1501 USAIntroductionAniline is produced from benzene in two-stage routes of (1) nitration of benzene followedby reduction of nitrobenzene, and (2) amination of phenol obtained by hydroxylation ofbenzene. One-stage vapor-phase amination of benzene with ammoniaC 6 H 6 + NH 3 = C 6 H 5 NH 2 + H 2is strongly exothermal reaction [1]. An appreciable equilibrium concentration of aniline canbe obtained over metal catalysts at extremely high temperature. Addition of oxidantsconsuming hydrogen shifts equilibrium to aniline. However, the noble metal catalysts operateat the temperature as higher as 350-500 °C even in the presence of oxidants, such asmolecular oxygen [2-3] or reducible metal oxides [4-5].In the present study, it was found that the temperature of amination can be hundreddegrees lower when a mixture of oxygen and hydrogen is used as oxidant.ExperimentalThe Pt/γ-Al 2 O 3 samples were prepared by incipient wetness impregnation of alumina witha solution of H 2 PtCL 6 , followed by drying in air, calcination at 450 °C and reduction with H 2 .X-Ray photoelectron spectra (XPS) of the samples were recorded on ES-300 (KRATOSAnalytical) spectrometer.The amination of benzene with ammonia was performed in a fixed-bed flow reactor atambient and elevated pressure. Oxygen, hydrogen (or premixed O 2 /H 2 /N 2 gas in experimentsat elevated pressure) were controlled by mass-flow controllers, the liquid benzene (and liquidammonia in experiments at elevated pressure) were introduced by a syringe pump. Thereactor was supplied with an on-line GC for an analysis of O 2 , H 2 (NaX molecular sieves),CO 2 and NH 3 (Hausep C + 4.5% KOH) and aniline, phenol, benzonitrile and biphenyl (0.4%1-nitroanilinoanthraquinone on carbon black) in the stream.137