Mechanism of the acetonitrile hydrogenation to amines over a platinum catalyst investigated by in situ infrared spectroscopy and DFT modeling

The mechanism of the hydrogenation of acetonitrile (CH3CN and CD3CN) to amines over a platinum filmand Pt/Al2O3 catalyst was investigated by in situ infrared spectroscopy. The reaction was studied under realisticconditions -liquid phase with toluene as solvent- using a flow-through cell-microreactor in attenuated total reflection(ATR) mode developed in our research group. Reaction intermediates were identified combining infrared spectra withtheoretical modeling by DFT. A sequential hydrogenation mechanism is proposed. Acetonitrile linearly and 2-foldchemisorbed on platinum sites is hydrogenated to form an imine surface intermediate (CH3CH=NH), which ishydrogenated to ethylamine. In turn, this imine intermediate can condense producing diethylamine and triethylamineand ammonia as a by-product. The time-evolution of the IR signals were modeled using a proposed microkineticmechanism and intrinsic kinetic constants were obtained under chemical control.Fil: Vogt, Lautaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Quaino, Paola Monica. Universidad Nacional del Litoral. Facultad de Ingeniería Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Calaza, Florencia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Collins, Sebastián Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina255th American Chemical Society National Meeting and ExpositionNew OrleansEstados UnidosAmerican Chemical Societ

Theoretical and FTIR Investigations of the Acetonitrile Hydrogenation Pathways on Platinum

The hydrogenation reaction of acetonitrile adsorbed on a platinum surface to produce amines has been investigated by theoretical and in situ infrared studies. An energetic, kinetics and vibrational analysis have been performed to unravel the elementary steps of the reaction and to clarify the mechanism. The comparison with the experiments allows us to identify an imine as a crucial intermediate for this reaction.Fil: Vogt, Lautaro. Universidad Nacional del Litoral; ArgentinaFil: Schulte, Erica Daniela. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Electroquímica Aplicada e Ingeniería Electroquímica; ArgentinaFil: Collins, Sebastián Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Quaino, Paola Monica. Universidad Nacional del Litoral. Instituto de Química Aplicada del Litoral. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Química Aplicada del Litoral.; Argentin

Mechanochemical Synthesis of a Multicomponent Solid Form: The Case of 5‑Fluorocytosine Isoniazid Codrug

Mechanochemistry synthesis was applied to the supramolecular synthesis and green scale-up production of a 1:1 drug–drug cocrystal involving the antimetabolite prodrug 5-Fluorocytosine (5-FC) and the tuberculostatic drug Isoniazid (INH), namely, 5FC-INH. Crystalline material, also obtained by traditional slow evaporation methods, was analyzed by single-crystal X-ray diffraction (XRD). The crystal packing is stabilized by a classical N–H···N hydrogen-bond interaction between the amine moiety of 5-FC and the INH pyridine nitrogen. IR and Raman data provided spectroscopic evidence about the hydrogen atom positions, thereby confirming the neutral nature of the cocrystal. Furthermore, 5FC-INH codrug was also evaluated by a range of analytical techniques such as powder XRD and thermal (thermogravimetric analysis, differential scanning calorimetry, hot stage microscopy) analyses. A physical stability study was performed in high relative humidity conditions to verify possible 5-FC solid-state hydration and/or INH degradation. The equilibrium solubility of this codrug was compared to the anhydrous 5-FC and INH raw materials, in pH 1.2 buffer media, and it was found to be similar to that of 5-FC, a biopharmaceutics classification system class I drug. The results show that the cocrystal has superior phase stability properties against moisture when compared to the starting pharmaceutical ingredients, so it could be considered as a potential candidate for the treatment of concomitant fungal infections, tuberculosis, and cancer