Electrical control of synthesis conditions for locally grown CNTs on polysilicon microstructure

Author(s):  
Bao Quoc Ta ◽  
Nils Hoivik ◽  
Einar Halvorsen ◽  
Knut E. Aasmundtveit
2017 ◽  
pp. 471-482
Author(s):  
Knut E. Aasmundtveit ◽  
Bao Quoc Ta ◽  
Nils Hoivik ◽  
Einar Halvorsen

2020 ◽  
pp. 1-18
Author(s):  
Yu.V. Bilokopytov ◽  
◽  
S.L. Melnykova ◽  
N.Yu. Khimach ◽  
◽  
...  

CO2 is a harmful greenhouse gas, a product of chemical emissions, the combustion of fossil fuels and car exhausts, and it is a widely available source of carbon. The review considers various ways of hydrogenation of carbon dioxide into components of motor fuels - methanol, dimethyl ether, ethanol, hydrocarbons - in the presence of heterogeneous catalysts. At each route of conversion of CO2 (into oxygenates or hydrocarbons) the first stage is the formation of CO by the reverse water gas shift (rWGS) reaction, which must be taken into account when catalysts of process are choosing. The influence of chemical nature, specific surface area, particle size and interaction between catalyst components, as well as the method of its production on the CO2 conversion processes is analyzed. It is noted that the main active components of CO2 conversion into methanol are copper atoms and ions which interact with the oxide components of the catalyst. There is a positive effect of other metals oxides additives with strong basic centers on the surface on the activity of the traditional copper-zinc-aluminum oxide catalyst for the synthesis of methanol from the synthesis gas. The most active catalysts for the synthesis of DME from CO2 and H2 are bifunctional. These catalysts contain both a methanol synthesis catalyst and a dehydrating component, such as mesoporous zeolites with acid centers of weak and medium strength, evenly distributed on the surface. The synthesis of gasoline hydrocarbons (≥ C5) is carried out through the formation of CO or CH3OH and DME as intermediates on multifunctional catalysts, which also contain zeolites. Hydrogenation of CO2 into ethanol can be considered as an alternative to the synthesis of ethanol through the hydration of ethylene. High activation energy of carbon dioxide, harsh synthesis conditions as well as high selectivity for hydrocarbons, in particular methane remains the main problems. Further increase of selectivity and efficiency of carbon dioxide hydrogenation processes involves the use of nanocatalysts taking into account the mechanism of CO2 conversion reactions, development of methods for removing excess water as a by-product from the reaction zone and increasing catalyst stability over time.


2015 ◽  
Vol 37 (4) ◽  
pp. 402-407
Author(s):  
S.V. Zhil’tsova ◽  
◽  
V.M. Mikhal’chuk ◽  
N.G. Leonova ◽  
R.I. Lyga ◽  
...  

2017 ◽  
Vol 58 (8) ◽  
pp. 1543-1552
Author(s):  
N.I. Fainer ◽  
◽  
R.V. Pushkarev ◽  
V.A. Shestakov ◽  
A.K. Gutakovsky ◽  
...  

2020 ◽  
Vol 5 (443) ◽  
pp. 85-91
Author(s):  
Ibrayev M.K., ◽  
◽  
Takibayeva A.T., ◽  
Fazylov S.D., ◽  
Rakhimberlinova Zh.B., ◽  
...  

This article presents studies on the targeted search for new derivatives of azoles, such as benzthiazole, 3,5-dimethylpyrazole, 1,3,4-oxadiazole-2-thione, 1,3,4-thiadiazole. The possibility of combining in one molecule of the azole ring with other cyclic compounds: the alkaloid cytisine, morpholine, furan and some arenes has been studied. To obtain new compounds, the reactions of bromination, acylation, and interaction with isothiocyanates were studied. Optimal synthesis conditions were studied for all reactions. It was found that the reaction of 4-bromo-3,5-dimethylpyrazole with isothiocyanates, in contrast to the previously written derivatives of anilines, takes a longer time and requires heating the reaction mixture. The combination of a pirasol fragment with halide substituents often results in an enhanced therapeutic effect. The synthesized 2-bromine-N-(6-rodanbenzo[d]thiazole-2-yl)acetamide, due to the alkylbromide group, is an important synth in the synthesis of new benzthiazole derivatives. Its derivatives combine in one molecule the rest of rhodanbenzthiazole with alkaloid cytisine and biogenic amine morpholine and are potentially biologically active compounds, since the molecule structure contains several pharmacophoric fragments: benzthiazole and alkaloid (amine) heterocycles, rhodane and urea groups. The mechanism of formation of 1,3,4-oxadiazole-2-tyons from hydrazides under action on them by carbon disulfide was studied and assumed. It was shown that dithiocarbamates in acidic medium decompose with the release of hydrogen sulfide and the formation of highly reactive isothiocyanate group. Then, intra-molecular cyclization occurs, with the formation of end products - 1,3,4-oxadiazole-2-thions. The structures of the synthesized compounds were studied by 1H and 13C NMR spectroscopy. All synthesized substances are potentially biologically active compounds, since they contain several pharmacophore fragments in their structure.


2018 ◽  
Vol 10 (3) ◽  
pp. 03029-1-03029-6
Author(s):  
L. V. Mokhnatska ◽  
◽  
V. O. Kotsyubynsky ◽  
A. B. Hrubiak ◽  
S. V. Fedorchenko ◽  
...  

2017 ◽  
Vol 14 (8) ◽  
Author(s):  
Mohammad Kazem Khoeeniha ◽  
Mehdi Esfandyari-Manesh ◽  
Hossein Behrouz ◽  
Mohsen Amini ◽  
Behrang Shiri Varnamkhasti ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document