Selective Synthesis of Primary Anilines from NH3 and Cyclohexanones by Utilizing Preferential Adsorption of Styrene on the Pd Nanoparticle Surface

Dehydrogenative aromatization is one of the attractive alternative methods for directly synthesizing primary anilines from NH₃ and cyclohexanones. However, the selective synthesis of primary anilines is quite difficult because the desired primary aniline products and the cyclohexanone substrates readily undergo condensation affording the corresponding imines (i.e., N‐cyclohexylidene‐anilines), followed by hydrogenation to produce N‐cyclohexylanilines as the major products. In this study, primary anilines were selectively synthesized in the presence of supported Pd nanoparticle catalysts (e.g., Pd/HAP, HAP=hydroxyapatite, Ca₁₀(PO₄)₆(OH)₂) by utilizing competitive adsorption unique to heterogeneous catalysis; in other words, when styrene was used as a hydrogen acceptor, which preferentially adsorbs on the Pd nanoparticle surface in the presence of N‐cyclohexylidene‐anilines, various structurally diverse primary anilines were selectively synthesized from readily accessible NH₃ and cyclohexanones. The Pd/HAP catalyst was reused several times though its catalytic performance gradually declined.     

Polarographische Bestimmung von ?thylendiamin in Gegenwart von Ammoniak

Ohne Zusammenfassung

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Polarographic determination of ethylene diamine in the presence of ammonia

     

Comparison of two electrodes for the determination of ammonia and nitrogen compounds

Summary Two types of electrodes for the determination of ammonia are compared: one of the liquid membrane and one of the gas detecting type. Important electrode characteristics as response time, sensitivity and selectivity are commented. The ammonia electrode was tested in practice by analysis of ammonia and nitrate in canal water. The precision of the methods described was tested by analysis of synthetic samples, and by comparison with a volumetric and colorimetric method.

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Vergleich zweier Elektroden für die Bestimmung von Ammoniak und von Stickstoffverbindungen

Zusammenfassung Zwei Elektrodentypen (Flüssig-Membran und Gasdetektor) für die Ammoniakbestimmung wurden einem Vergleich unterzogen. Wichtige Charakteristiken (Ansprechzeit, Empfindlichkeit und Selektivität) werden diskutiert. Die praktische Prüfung erfolgte an Hand der Bestimmung von Ammoniak und Nitrat in Kanalwasser. Die Präzision wurde mit synthetischen Proben getestet sowie durch Vergleich mit einer volumetrischen und einer colorimetrischen Methode.