Physico-Chemical nanomaterials science
Composites of Co nanoparticles and N-doped carbon on porous carriers for reductive amination p-methoxybenzaldehyde 
at presence of gaseous hydrogen  

Asaula V. M.,1 Omelyan I. V.,1 Gavrilenko K. S.,2,3 Pariiska O. O.,1 
Ryabukhin S. V.,2,3 Volochnyuk D. M.,2,3,4 Kolotilov S. V.1,3

1 L.V. Pisarzhevskii Institute of Physical Chemistry of the NAS of Ukraine. Prospect Nauki, 31, Kyiv-03028, Ukraine. 
E-mail : vitaliy.asaula@gmail.com
2 Enamine Ltd, 78 Chervonotkatska str., Kyiv 02660, Ukraine
3 National Taras Shevchenko University of Kyiv, 60 Volodymyrska str., Kyiv, 01033, Ukraine
4 Institute of Organic Chemistry of the National Academy of Sciences of Ukraine, Murmanska str., 5, Kyiv, 02000, Ukraine

The reaction of reductive amination of carnonyl compounds is widely used for preparation a number of amines, which are important building blocks for medicinal chemistry. The efficient catalysts of this process contain platinum group metals (PGM). Search of PGM-free catalysts for such transformations is important task of modern physical chemistry. The composites containing 3d metals in combination with carboneous species are promising candidates for reductive amination as alternative to PGM-systems. 
The aim of this study was to develop new PGM-free catalysts for reductive amination of p-methoxybenzaldehyde with aliphatic amines and to reveal the factors which influence the catalytic activity of the composites, based on N-doped carboneous particles, in such process.
A series of composites was prepared by pyrolysis the Co(II) complexes with N-containing organic ligands deposited on several zeolites (mordenite and NaX-zeolite) and aerosil. The composites contained only metallic Co as crystalline phase, as shown by powder XRD. The cobalt nanoparticles had the size of ca. 5-20 nm, as shown by TEM. On the results of Raman spectra analysis the composites contained graphene-like carboneous species.
The catalytic activity of the obtained composites was tested in reactions of p-methoxybenzaldehyde with di-iso-propylamine under H2 pressure (30 atm, 100-150 °C). The reaction products were analyzed by 1H NMR and gas chromatography. The composites prepared by pyrolysis of Co(II) complex with imidazole on aerosil and Co(II) complex with 1,2-diaminobenzene on mordenite were the most active. The yields of N-(p-methoxybenzyl)-N-di-iso-propylamine reached 88 %. It was found that the product yield significantly depended on the reaction temperature.