Catalytic systems for oxidative chlorination of hydrocarbons Communication 3. Properties of catalysts containing copper salts on an aluminum oxide support

Author(s):  
I. G. Solomonik ◽  
I. I. Kurlyandskaya ◽  
V. I. Yakerson ◽  
T. F. Kudryavtseva ◽  
G. A. Ashavskaya ◽  
...  
1997 ◽  
Vol 497 ◽  
Author(s):  
L. L. L. Prado ◽  
P. A. P. Nascente ◽  
S. C. de Castro ◽  
Y. Gushikem

ABSTRACTThe synthesis of aluminum oxide grafted on silica gel surface was carried out by the reaction of a suitable aluminum precursor with the surface hydrolysis of the oxide support. The chemical and physical properties of the attached oxide, SiO2/ Al2O3, can be quite different than those found for bulk Al2O3. The advantage of this preparation method, compared to the conventional ones (impregnation, precipitation and calcination), is that the oxide is highly dispersed on the surface (monolayer or submonolayer). We characterized the surface oxides treated at the temperature range of 423 to 1573 K employing X-ray photoelectron spectroscopy (XPS), solid state nuclear magnetic resonance spectroscopy (NMR), and diffuse reflectance spectroscopy (DRS). XPS was used to identify the oxidation states and atomic ratios. Al27 NMR detected two species for samples heated up to 1023 K, and another one above this temperature. DRS, using pyridine as a molecular probe, showed that both Lewis and Brönsted acid sites are stable up to 1023 K. We concluded that the aluminum oxide is highly dispersed on the silica gel surface and it remains stable up to 1023 K.


Author(s):  
Alexander P. Savostyanov ◽  
Roman E. Yakovenko ◽  
Grigory B. Narochny ◽  
Vera G. Bakun ◽  
Alexander A. Merkin

The compositions, methods of preparation and specific technological parameters of the production processes of cobalt catalysts for the synthesis of long chain hydrocarbons from synthesis gas were justified. To obtain C35+ selective catalysts by coprecipitation of active components, the carrier must provide a polydisperse distribution of the pore volume along the radii. This is achieved by hydrothermal treatment of the aluminosilicate carrier. To increase the strength of catalysts, it is possible to incorporate natural bentonites and diatomite of Roctov region deposits into the composition of coprecipitated catalysts. Effective catalytic systems are impregnated catalysts on Al2O3 and SiO2 supports with aluminum oxide promotion. The insertion of 5% - Al2O3 of cobalt metal mass allows to form crystallites of Co-CoO system with a size of 8 nm on the SiO2 surface, which provides high activity and selectivity for ceresin. Aluminum oxide is stabilized with Co3O4 in a structure with a high degree of ordering, without hindering its reduction, with the formation of cobalt predominantly with the crystalline structure of hexagonal close packing. Catalyst technologies are implemented in industry. The catalysts underwent continuous continuous testing (1000 h) in laboratory and industrial conditions, showed high stability of operation. During the entire operation, the yield of C5+ hydrocarbons was 159-171 g/Nm3 based on the processed synthesis gas. The long-chain hydrocarbons C35+ (ceresin) obtained are of high quality: the dropping point was 114-116 °C (37-40% ceresin content). Operation during the year of two industrial reactors at the Novocherkassk plant of synthetic products with a total volume of catalyst loading of 18 m3 confirmed the results of laboratory tests. For citation: Savostyanov A.P., Yakovenko R.E., Narochny G.B., Bakun V.G., Merkin A.A. Development and industrial approbation of technologies of cobalt catalysts for synthesis of long chain hydrocarbons from synthesis gas. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 9-10. P. 53-58


2020 ◽  
Vol 23 (22) ◽  
pp. 2489-2503 ◽  
Author(s):  
Saeideh Ebrahimiasl ◽  
Farnaz Behmagham ◽  
Shahrzad Abdolmohammadi ◽  
Rahman N. Kojabad ◽  
Esmail Vessally

: Synthesis of symmetrical 1,3-diynes from terminal alkynes through an oxidative process is generally called Glaser coupling. The classic Glaser coupling is catalyzed by copper salts under an atmosphere of molecular oxygen as an oxidant. Over the past years, different metal catalysts and oxidants were successfully used in this atom economical C-C coupling reaction. Moreover, several procedures for the preparation of unsymmetrical 1,3-diynes by coupling two different alkyne substrates have been developed. In this review, we will highlight the usefulness of transition metal nanoparticles as efficient catalysts in homo- and hetero-coupling of alkynes by hoping that it will be beneficial to the development of novel and extremely efficient catalytic systems for this fast-growing and important reaction.


2014 ◽  
Vol 605 ◽  
pp. 593-596
Author(s):  
Y.N. Parkhomenko ◽  
A.I. Belogorokhov ◽  
A.P. Bliev ◽  
V.G. Sozanov ◽  
A.G. Kaloeva ◽  
...  

The structural and photoinduced properties of silicon nanoparticles obtained by plasmachemical and electrolytic techniques and the nickel particles deposited on aluminum oxide film in ultra-high vacuum are investigated by Auger electron spectroscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy and time-of-flight spectroscopy. It is found that substantial increase of silicon nanoparticle photoinduced luminescence can be attributed to particle specific structure, as well as to the SiO2thin film which is formed on the nanocrystalline silicon surface. In case of Ni particles deposited on aluminum oxide film at low mean coverage of about 0.04 monolayers, when the film can be viewed as consisting of separated single adsorbed atoms or very small clusters, the photon irradiation by nanosecond pulsed laser leads to NO desorption. At monolayer Ni coverage formed at a substrate temperature of 80 K laser irradiation causes dissociation of NO molecules. Efficiency of this process at the initial stage is notably enhanced compared to that of NO on the bulk Ni (111) crystal. This enhancement can be attributed to the effect of underlying aluminum oxide support.


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