Кафедра хімії

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Browsing Кафедра хімії by Author "Golub, Alexander"

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    Commercial Silica Materials Functionalized with a Versatile Organocatalyst for the Catalysis Of Acylation Reactions in Liquid Media
    (2024) Brand, Raoul; Maass, Mareike; Grebenyuk, Anatoliy; Golub, Alexander; Smarsly, Bernd
    Silica materials, natural and synthetic variants, represent a promising material for the application in heterogeneous organocatalysis due to their readily modifiable surface and chemical inertness. To achieve high catalyst loadings, usually, porous carriers with high surface areas are used, such as silica monoliths or spherical particles for packed bed reactors. While these commercial materials were shown to be efficient supports, their synthesis is elaborate, and thus less complex and cheaper alternatives are of interest, especially considering scaling up for potential applications. In this work, two commercial silica materials functionalized with the organocatalyst 4-(dimethylamino)pyridine (DMAP) were used in catalytic acylation reactions: a mesoporous silica gel (Siliabond-DMAP) and non-porous silica nanoparticles (Ludox). While both were successfully used in the acylation of phenylethanol, the latter required significantly longer reaction times, presumably due to the lack of mesopores and the associated spatial confinement, as well as agglomeration that limits the active amount of catalyst. Furthermore, we find that the influence of the linker molecule is negligible, since for two different linker motifs the reaction yields and activation energy remain largely similar. Lastly, as main result the commercial material Siliabond-DMAP, despite the non-uniform particles, were employed in a flow setup, thus demonstrating the potential as support material for application in heterogeneous organocatalysis.
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    Ornidazol-based application sorbent with nano silica and its antimicrobial activity
    (2023) Bilyayeva, Olga; Karol, Ivan; Demianenko, Eugeniy; Gaidai, Alina; Kryzhevskyi, Yevhenii; Vakuliuk, Polina; Golub, Alexander
    The aim: To investigate the effect of application sorbent based on ornidazole with nanosilicon in experiment and clinic. Materials and methods: In order to study the effectiveness of the Ornidasil application sorbent for the treatment of purulent wounds, we conducted an experimental study in rats. Also, we studied the effectiveness of the Ornidasil in the clinic for the treatment of patients with diabetic foot syndrome and to prevent the suppuration of postoperative wounds in patients with purulent peritonitis in toxic and terminal stages. Results: The formation of active substance complexes with hydroxylated matrices is due to hydrogen bonds between the oxygen atom of the silanol group of the silica surface and the hydrogen atom of the alcohol group of the ornidazole molecule. This promotes the gradual release of ornidazole from the surface of such a matrix into the wound exudate. Thus, on day 13, 9 experimental rats of group I healed completely, 11 rats had a small wound surface, complete healing occurred on day 15. We also investigated the effectiveness Ornidasil in the clinic. In the comparison group, postoperative wound suppuration occurred in 6 patients (31.6%), and in the main group - in 3 patients (12.5%). Conclusions: A study of the effectiveness Ornidasil in the complex treatment of Diabetic foot syndrome showed that in the experimental groups, wound healing occurred 1.6 -1.9 times faster. The use of polyurethane wound protector in combination with Ornidasil reduced the suppuration of postoperative wounds in patients of the main group by 2.5 times relative to patients in the comparison group.