Thermodynamic characteristics used for estimating the relative catalytic activity of oxides

1972 ◽  
Vol 5 (5) ◽  
pp. 475-476 ◽  
Author(s):  
V. V. Popovskii
Keyword(s):  
Catalytic Activity ◽  
Thermodynamic Characteristics ◽  
Relative Catalytic Activity

The relative catalytic activity of acids in hydrolytic caprolactam polymerization

1973 ◽  
Vol 5 (3) ◽  
pp. 339-340
Author(s):  
L. N. Mizerovskii ◽  
Yu. S. Paikachev ◽  
B. G. Silanteva ◽  
N. V. Sholichev
Keyword(s):  
Catalytic Activity ◽  
Caprolactam Polymerization ◽  
Relative Catalytic Activity

DECOMPOSITION OF SODIUM HYPOCHLORITE: THE CATALYZED REACTION

1956 ◽  
Vol 34 (4) ◽  
pp. 479-488 ◽  
Author(s):  
M. W. Lister
Keyword(s):  
Catalytic Activity ◽  
Sodium Hypochlorite ◽  
Small Extent ◽  
Copper Oxides ◽  
Iron Cobalt ◽  
First Order ◽  
Cobalt Nickel ◽  
Nickel Copper ◽  
Relative Catalytic Activity ◽  
Mechanism Of The Reaction

The catalyzed decomposition of sodium hypochlorite has been examined; the catalysts tried were manganese, iron, cobalt, nickel, and copper oxides. It was shown that in no case was the decomposition to chlorate and chloride accelerated, only the reaction to chloride and oxygen. Manganese and iron did not catalyze even the latter reaction, or only to a very small extent; this was in fairly concentrated sodium hypochlorite containing some sodium hydroxide. The manganese and iron are largely oxidized to permanganate and ferrate under these conditions. It was found that copper could catalyze the formation of permanganate and ferrate, and nickel the formation of permanganate. Cobalt catalyzed the reaction going to oxygen, and the rate was proportional to the cobalt added, but little dependent on the hypochlorite concentration; the same is true of nickel. Copper (as reported earlier) gives a catalyzed reaction not far from first order in hypochlorite. The activation energies were measured, and were consistent with the relative catalytic activity of these metals. The mechanism of the reaction is briefly discussed.

Complex iron catalytic systems: relative catalytic activity of various components

1994 ◽  
Vol 8 (1) ◽  
pp. 53-55 ◽  
Author(s):  
Malvina Farcasiu ◽  
Patricia A. Eldredge ◽  
Steven C. Petrosius
Keyword(s):  
Catalytic Activity ◽  
Catalytic Systems ◽  
Relative Catalytic Activity

High resolution electron microscopy of lanthanum phosphate crystals

1978 ◽  
Vol 36 (1) ◽  
pp. 274-275
Author(s):  
J. C. Wheatley ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
High Resolution ◽  
Petroleum Industry ◽  
High Resolution Electron Microscopy ◽  
Lanthanum Phosphate ◽  
Good Catalyst ◽  
Resolution Electron ◽  
Good Catalytic Activity ◽  
Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

Prolonged Expression of Procoagulant Activity of Human Platelets Degranulated by Thrombin

1995 ◽  
Vol 74 (03) ◽  
pp. 958-961 ◽  
Author(s):  
Raelene L Kinlough-Rathbone ◽  
Dennis W Perry
Keyword(s):  
Catalytic Activity ◽  
Thrombus Formation ◽  
Annexin V ◽  
Human Platelets ◽  
Procoagulant Activity ◽  
Prothrombinase Complex ◽  
Arterial Thrombus ◽  
Flowing Blood

SummaryPlatelets are exposed to thrombin when they take part in arterial thrombus formation, and they may return to the circulation when they are freed by fibrinolysis and dislodged by flowing blood. Thrombin causes the expression of procoagulant activity on platelets, and if this activity persists, the recirculating platelets may contribute to subsequent thrombosis. We have developed techniques to degranulate human platelets by treatment with thrombin, and recover them as single, discrete platelets that aggregate in response to both weak and strong agonists. In the present study we examined the duration of procoagulant activity on the surface of thrombin-degranulated platelets by two methods: a prothrombinase assay, and the binding of 125I-labeled annexin. Control platelets generated 0.9 ± 0.4 U thrombin per 107 platelets in 15 min. Suspensions of thrombin-degranulated platelets formed 5.4 ± 0.1 U thrombin per 107 platelets in this time. Binding of 125I-annexin V was also greater with thrombin-treated platelets than with control platelets (controls: 1.7 ±0.1 ng annexin/107 platelets; thrombin-degranulated platelets: 6.8 ± 0.2 ng annexin/107 platelets). With thrombin-degranulated platelets, increased procoagulant activity and annexin binding persisted for at least 4 h after degranulation and resuspension, indicating that the catalytic activity for the prothrombinase complex is not reversed during this time. These platelets maintained their ability to aggregate for 4 h, even in response to the weak agonist, ADP. Thus, platelets that have taken part in thrombus formation and returned to the circulation may contribute to the promotion of further thrombotic events because of the persistence of procoagulant activity on their surface.

ABOUT HEAT CAPACITY OF TITANIUM CARBIDE TiCx

2019 ◽  
pp. 56-66
Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Titanium Carbide ◽  
Temperature Dependence ◽  
Carbon Concentration ◽  
Room Temperature ◽  
Thermodynamic Characteristics ◽  
Liquid Nitrogen Temperature ◽  
Analysis Data ◽  
Thermal Excitation

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration  range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.

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