CATALYSISAt present, elementary germanium is the purest substance. Germanium is widely used in micro-and nanoelectronics for fabrication of pulse, parametric, and tunnel diodes, microwave converters and in IR engineering for fabrication of optical elements: lenses, refl ecting mirrors, windows, and lasers. High-purity germanium doped with special impurities retains its dominant position as one of the most promising materials for fabrication of high-sensitivity IR photodetectors. One of the most important practical application areas of high-purity single-crystal germanium is the fabrication of ionizing radiation detectors. High-purity germanium, semiconducting germanium layers, germanium dioxide, and fiber-optic light-emitting diodes containing germanium are produced from its high-purity volatile compounds, germanium tetrachloride and germanium hydride (monogermane) [1].The industry widely employs the "chloride" method for obtaining high-purity germanium [2]. The main problem of the chloride technology is the low yield of germanium (≤70%) and also the substantial loss with chloride sewage water and the contamination of the fi nal product in the stage of hydrolysis of germanium tetrachloride. In addition, chlorides are toxic and corrosion-active substances, which, in turn, makes the "chloride technology" rather labor consuming as regards its instrumentation. Up to 70% of capital expenditure and maintenance expenses are constituted by the expenditure for purifi cation of wastewater and effl uent gases and appreciation of equipment [3].Monogermane is produced by the reaction in which germanium tetrachloride is reduced by simple and complex metal hydrides. Germanium oxide and magnesium germanide served as germanium-containing reagents. Lithium and potassium hydrides, lithium and sodium borohydrides, lithium aluminohydride, and diisobutylaluminum hydride [4] in solutions with organic solvents and in the gas phase were used as reducing agents.Abstract-Effect of a catalyst based on multi-walled carbon nanotubes modifi ed with copper nanoparticles on the kinetics of the catalytic reduction of germanium tetrachloride by hydrogen was studied in the temperature range 423-723 K. Results of experiments were used to determine the reaction order and activation energy. A mechanism of the occurring reaction is suggested on the basis of the data obtained. The introduction of catalysts based on multi-walled carbon nanotubes modifi ed with copper nanoparticles made it possible to lower the reaction temperature and achieve a germanium tetrachloride conversion of about 98%.
The synthesis of biologically active coordination compounds and the design on their basis of effective pharmacological preparations is currently the promising area. This paper presents the results of the toxicological studies on digermanium and its complex derivatives. It should be noted that the positive medical properties of organometallic compounds of germanium are confirmed by numerous studies, therefore, the development of the methods of synthesis, as well as investigations of physicochemical and pharmacological properties of these compounds are at the center of attention.