Preparation of Bimetallic Oxide Catalysts on Carbon Supports: The Effect of the Support on the Stability of Catalysts to Thermal Decomposition

2021 ◽  
Vol 29 (5) ◽  
pp. 582-588
Author(s):  
L. B. OKHLOPKOVA ◽  
L. M. KHITSOVA ◽  
Z. R. ISMAGILOV
Keyword(s):  
Thermal Decomposition ◽  
Oxide Catalysts ◽  
Carbon Supports ◽  
The Stability ◽  
Effect Of The Support

The Decomposition of Perchloric Acid on Metal Oxide Catalysts

1971 ◽  
Vol 49 (17) ◽  
pp. 2827-2831 ◽  
Author(s):  
R. Gilbert ◽  
P. W. M. Jacobs
Keyword(s):  
Thermal Decomposition ◽  
Metal Oxide ◽  
Proton Transfer ◽  
Ammonium Perchlorate ◽  
Perchloric Acid ◽  
Catalyst Surface ◽  
Copper Chromite ◽  
Oxide Catalysts ◽  
The Other ◽  
Metal Oxide Catalysts

The thermal decomposition of perchloric acid has been investigated on five Harshaw catalysts: copper chromite, alumina, iron(III) oxide, copper(II) oxide, and manganese(IV) oxide (the last three being supported on alumina). Manganese(IV) oxide gave complex kinetics which were not fully analyzed but on the other four catalysts the reaction was.first order. Activation energies were: copper chromite, 54 kcal/mol; alumina, 28.8 kcal/mol; iron(III) oxide, 28.6 kcal/mol; copper(II) oxide, 39.0 kcal/mol. A mechanism is proposed for the decomposition which involves proton transfer to an accepter (typically an O2− ion) in the catalyst surface followed by decomposition of the ClO4− anion formed in this process. Some observations on the catalyzed thermal decomposition of ammonium perchlorate are presented.

scholarly journals The influence of the nature and textural properties of different supports on the thermal behavior of Keggin type heteropolyacids

2006 ◽  
Vol 71 (3) ◽  
pp. 235-249 ◽  
Author(s):  
Alexandru Popa ◽  
Viorel Sasca ◽  
Mircea Stefanescu ◽  
Erne Kis ◽  
Radmila Marinkovic-Neducin
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Solid Phase ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Active Phase ◽  
Support Surface ◽  
Sem Images ◽  
The Stability

In order to obtain highly dispersed heteropolyacids (HPAs) species, H3PMo12O40 and H4PVMo11O40 were supported on various supports: silica (Aerosil - Degussa and Romsil types) and TiO2. The structure and thermal decomposition of supported and unsupported HPAs were followed by different techniques (TGA-DTA, FTIR, XRD, low temperature nitrogen adsorption, scanning electron microscopy). All the supported HPAs were prepared by impregnation using the incipient wetness technique with a 1:1 mixture of water-ethanol. Samples were prepared with different concentrations to examine the effect of loading on the thermal behavior of the supported acid catalysts. The thermal stability was evaluated with reference to the bulk solid acids and mechanical mixtures. After deposition on silica types supports, an important decrease in thermal stability was observed on the Romsil types and a small decrease on the Aerosil type. The stability of the heteropolyacids supported on titania increased due to an anion-support interaction, as the thermal decomposition proceeded in two steps. The structure of the HPAs was not totally destroyed at 450 ?C as some IR bands were still preserved. A relatively uniform distribution of HPAs on the support surface was observed for all compositions of the active phase. No separate crystallites of solid phase HPAs were found in the SEM images.

Theoretical Study on Thermal Hazardous Properties of C18H10O11 and C18H18O7 Organic Peroxides

2013 ◽  
Vol 787 ◽  
pp. 301-305
Author(s):  
Yun Bo He ◽  
Wei Wang ◽  
Shi Xiong Wang ◽  
Xiang Jun Yang ◽  
Hong Guo
Keyword(s):  
Molecular Structure ◽  
Thermal Decomposition ◽  
Quantum Chemistry ◽  
Organic Compounds ◽  
Theoretical Study ◽  
Organic Peroxides ◽  
Quantum Chemistry Calculation ◽  
The Past ◽  
Chemistry Calculation ◽  
The Stability

The thermal decomposition of organic peroxides are widely used as coagulant for organic compounds, however, its thermal hazardous characteristics have already caused serious accidents in chemical industries, which limited its application in much more strict conditions. Organic peroxides of C18H10O11 and C18H18O7 are two new candidates fitted for industrial explosive. However, as we best known there is little reports available on the geometry structure in the past decades. In this work, by means of quantum chemistry calculation, the relation of safety with molecular structure of C18H10O11 and C18H18O7 are discussed. The molecules with more activity O and the activity part more dispersedly exhibit higher stable, and the configuration has good safety. All the energy of molecule b is higher than that of molecule a. The stability of different configurations are 6a>7a>8a>9a>5a>1a>4a>3a=2a and 1b>7b>5b>6b>4b>2b>3b>8b, respectively, suggesting the structures of 6a,3a,2a,1b,8b exhibit high safety.

Nitrogen-doped carbon supports with terminated hydrogen and their effects on active gold species: a density functional study

2014 ◽  
Vol 16 (46) ◽  
pp. 25498-25507 ◽  
Author(s):  
Junjie Gu ◽  
Qian Du ◽  
You Han ◽  
Zhenghua He ◽  
Wei Li ◽  
...  
Keyword(s):  
Valence State ◽  
Density Functional ◽  
Functional Study ◽  
Carbon Supports ◽  
Acetylene Hydrochlorination ◽  
Density Functional Study ◽  
Nitrogen Doped ◽  
Doped Graphene ◽  
The Stability ◽  
Nitrogen Doped Carbon

The stabilities of gold species on N-doped graphene increase with its valence state. Au2Cl6 interacts preferentially with HCl on N-doped supports, enhancing the stability of Au catalysts for acetylene hydrochlorination.

Synthesis of vanadium-phosphorus oxide catalysts deposited onto silica-carbon supports

2008 ◽  
Vol 81 (8) ◽  
pp. 1325-1331 ◽  
Author(s):  
V. V. Sidorchuk ◽  
J. Skubiszewska-Zięba ◽  
S. V. Khalameida ◽  
V. A. Zazhigalov ◽  
R. Leboda
Keyword(s):  
Oxide Catalysts ◽  
Phosphorus Oxide ◽  
Carbon Supports ◽  
Vanadium Phosphorus Oxide

scholarly journals The thermal decomposition of the pyridine saccharinates of Co, Ni and Cu: A correlation of the structural and the infrared data

1999 ◽  
Vol 64 (10) ◽  
pp. 609-620 ◽  
Author(s):  
Pance Naumov ◽  
Gligor Jovanovski ◽  
Vera Jordanovska ◽  
Boyan Boyanov
Keyword(s):  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Ambient Temperature ◽  
Spectral Characteristics ◽  
Structural Data ◽  
Oxidizing Atmosphere ◽  
Air Atmosphere ◽  
Infrared Spectral ◽  
The Stability ◽  
Infrared Data

In order to investigate the differences in the stability of the isomorphous pyridine saccharinates [Co(H2O)4(C5H5N)2](C7H4NO3S)2.4H2O and [Ni(H2O)4(C5H5N)2] (C7H4NO3S)2.4H2O, their thermal behavior (TG, DTG and DTAcurves) from ambient temperature up to 1000 ?C in a static air atmosphere was studied. For comparative purposes, the thermoanalytical curves of [Cu(H2O)(C5H5N)2(C7H4NO3S)2] were recorded as well. The decomposition pathways and the stability of the compounds are interpreted in the terms of the structural data. A possible mechanism for the decomposition of the saccharinato ion/ligand in an oxidizing atmosphere is proposed.The infrared spectral characteristics of the complexes are also discussed.

The thermal decomposition of aromatic compounds - II. Dichlorobenzenes

1954 ◽  
Vol 224 (1159) ◽  
pp. 544-551 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Thermal Stabilities ◽  
Carbonaceous Deposit ◽  
Chain Processes ◽  
Composition And Structure ◽  
Gaseous Decomposition Product ◽  
Molecular Reaction ◽  
Complete Exclusion ◽  
The Stability ◽  
Kinetic Features

A kinetic study of the thermal decomposition of the dichlorobenzenes shows that the three isomers behave similarly. The compounds differ strikingly from chlorobenzene, inasmuch as the rate of decomposition is not reduced by nitric oxide or ammonia. Other kinetic features suggest that the reaction is unimolecular, and that chain processes do not occur to an appreciable extent. The main gaseous decomposition product is hydrogen chloride, and nearly all the combined chlorine can be accounted for as this product. Very small amounts of gaseous hydrogen are also found, but the balance of the combined hydrogen remains in the carbon deposited on the walls of the reaction vessel; this carbonaceous deposit is of similar composition and structure to that formed from chlorobenzene. Comparison of the thermal stabilities of benzene, chlorobenzene and the dichlorobenzenes shows that the stability is dependent on the extent of substitution of the aromatic ring but is little influenced by the relative positions of the substituents. The increased rate of decomposition caused by a second chlorine atom is evidently due to its ability to facilitate a molecular reaction, which apparently operates to the complete exclusion of chain processes.

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