scholarly journals Dependence of Activity and Selectivity upon the Catalysts of Multi-component System in Vapor Phase Oxidation of Acrolein

1972 ◽  
Vol 14 (1) ◽  
pp. 94-99 ◽  
Author(s):  
Hidemu Inoue ◽  
Kunihiko Mizutani ◽  
Hiroo Ito
Keyword(s):  
Vapor Phase ◽  
Component System ◽  
Phase Oxidation ◽  
Multi Component System

scholarly journals Vapor Phase Modification for Selective Enrichment of Grafted Styrene/Acrylonitrile onto Carbon Nanotubes Via ATRP

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 459
Author(s):  
Maryam Azadbakht ◽  
Elnaz Esmizadeh ◽  
Ali Vahidifar ◽  
Tizazu H. Mekonnen ◽  
Mehdi Salami-Kalajahi
Keyword(s):  
Carbon Nanotubes ◽  
1H Nmr ◽  
Vapor Phase ◽  
Proton Nuclear Magnetic Resonance ◽  
Acid Vapor ◽  
Selective Enrichment ◽  
Pristine Mwcnts ◽  
Morphological Studies ◽  
Phase Oxidation ◽  
Multi Walled Carbon Nanotubes

Nitric acid vapor phase oxidation of multi-walled carbon nanotubes (MWCNTs) was proposed as a promising technique to fabricate poly styrene-co-acrylonitrile (SAN)-grafted-CNTs via atom transfer radical polymerization (ATRP). The in-situ ATRP grafting approach was successfully employed to graft polystyrene (PS), SAN and polyacrylonitrile (PAN), onto the convex surfaces of pristine MWCNTs (PCNT) and acid-functionalized MWCNTs (FCNT). Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), and thermogravimetric analysis (TGA) confirmed the effectiveness of the modification via the ATRP grafting approach. The molar composition of acrylonitrile in the synthesized copolymer on the surface of CNTs for an FCNTs was calculated to be about 80% and 67.5% by 1H-NMR and TGA respectively, whereas the value is lower for PCNTs. Morphological studies showed that SAN-grafted FCNTs exhibit rougher surface morphology compared to the SAN-grafted PCNTs. Moreover, the higher diameter of the FCNTs indicated the higher polymer content, which was coated onto CNTs functionalized by vapor-phase oxidation. Therefore, the vapor phase oxidation strategy employed in this study could be utilized as a general method to prepare CNTs which can serve as an ATRP macroinitiator for the fabrication of various polymer grafted CNTs.

Vapor-phase oxidation of propylene glycol-methanol mixture to methyl lactate on CeO2/Al2O3 catalyst

2021 ◽  
pp. 92-97
Author(s):  
M.E. Sharanda ◽  
◽  
A.M. Mylin ◽  
O.Yu. Zinchenko ◽  
V.V. Brei ◽  
...  
Keyword(s):  
Propylene Glycol ◽  
Vapor Phase ◽  
Flow Reactor ◽  
Aldol Condensation ◽  
Ethyl Lactate ◽  
Molar Ratio ◽  
Methyl Lactate ◽  
Reactor Inlet ◽  
Phase Oxidation ◽  
Al2o3 Catalyst

The vapor-phase oxidation of mixtures of propylene glycol with methanol and ethanol to methyl and ethyl lactate, respectively, on supported CeO2/Al2O3 catalyst with 10 wt.% CeO2 content was studied. The steel flow reactor with a fixed catalyst bed (4 cm3) was used. 20 wt.% solution of propylene glycol in alcohol was fed to the reactor inlet by Waters 950 pump at LHSV= 0.5-0.8 h-1. Reaction temperature and pressure were varied in the interval of 190-250 0C and 1.3-1.8 bars respectively. Compressed air was given to the reactor inlet at the molar ratio of propylene glycol/O2 = 1. The reaction products were analyzed using gas chromatography (Agilent 7820A) and 3C NMR (Bruker Avance 400) methods. Studied oxidation of propylene glycol in the presence of methanol describes by total reaction CH3CHOHCH2OH +O2 + СН3OH = CH3CHOHCOOСН3 +2H2O At first, hydroxyacetone is formed that is further oxidized to pyruvic aldehyde, which attaches alcohol to form hemiacetal. Then, hemiacetal of methyl glyoxal rearranges into methyl lactate by Cannizzaro. At 220 0C and load on a catalyst of < 2 mmol PG/gcat/h, the selectivity towards methyl lactate reaches 70 wt.% at 100 % propylene glycol conversion. The main by-products are formed as the result of acetaldehyde transformation. Acetaldehyde could be formed at hydroxyacetone aldol decondensation. In the presence of ethanol, the formation of a significant amount of acetaldehyde and its aldol condensation products as well as the formation of diethoxyethane are observed. Therefore, ethyl lactate selectivity at 100 % propylene glycol conversion does not exceed 45 %. Supported CeO2/SiO2 contact was tested in this oxidation reaction also. However, CeO2/SiO2 provides the low, up to 25%, selectivity towards methyl lactate at full propylene glycol conversion. It was shown that at the same conditions methyl lactate is formed with higher selectivity then ethyl lactate. The high methyl lactate yield up to 70 wt.% could be obtained via vapor-phase oxidation of 20% mixture of propylene glycol with methanol by air oxygen on supported CeO2/Al2O3 catalyst at 210 - 220°С and at time contact of 3-4 seconds.

Multiponental Model Of Education According To The New Paradigm

2021 ◽  
Vol 03 (03) ◽  
pp. 365-370
Author(s):  
Ashurova Dilfuza Nabiyevna ◽  
◽  
Abjalilov Sanakul Xujamovich ◽  
Toshtemirova Kamola Ergashevna ◽  
◽  
...  
Keyword(s):  
Educational System ◽  
Modern Society ◽  
Educational Process ◽  
New Paradigm ◽  
Component System ◽  
Educational Processes ◽  
Multi Component System

In this work on the example of educational system of Uzbekistan the new paradigm of education is substantiated in the following edition: education through all life. It is demonstrated that the proposed in correspondence to this paradigm the formalized model reflects multi-component system, multi-variant approaches and cyclist of educational process in a modern society. The examples of educational processes which are modeled within the framework of proposed formalized model of education are presented.

Vapor-phase Oxidation of Cyclohexane over Supported Fe-Mn Catalysts: In-Situ DRIFTS studies

2021 ◽  
Author(s):  
Vijendra Kumar Yadav ◽  
Taraknath Das
Keyword(s):  
Surface Area ◽  
Raman Spectra ◽  
Vapor Phase ◽  
Oxide Catalysts ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Mn Oxide ◽  
Phase Oxidation

Alumina-supported Fe-Mn oxide catalysts were synthesized by the incipient wetness impregnation method. The catalysts were characterized by using various characterization techniques such as surface area, XRD, H2-TPR, and Raman spectra...

scholarly journals Statistical physics of fracture and earthquakes

2018 ◽  
Vol 377 (2136) ◽  
pp. 20180202
Author(s):  
Soumyajyoti Biswas ◽  
Lucas Goehring ◽  
Bikas K. Chakrabarti
Keyword(s):  
Complex System ◽  
Stress Field ◽  
Statistical Physics ◽  
Disordered Materials ◽  
Emergent Properties ◽  
Theme Issue ◽  
Component System ◽  
Playing Field ◽  
Collective Response ◽  
Multi Component System

Manifestations of emergent properties in stressed disordered materials are often the result of an interplay between strong perturbations in the stress field around defects. The collective response of a long-ranged correlated multi-component system is an ideal playing field for statistical physics. Hence, many aspects of such collective responses in widely spread length and energy scales can be addressed by the tools of statistical physics. In this theme issue, some of these aspects are treated from various angles of experiments, simulations and analytical methods, and connected together by their common base of complex-system dynamics. This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’ .

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