Diethyl ether sorption on titanium trichloride and its correlation with catalytic activity in the polymerization of propene

1983 ◽  
Vol 48 (10) ◽  
pp. 2798-2804
Author(s):  
Luboš Pololáník ◽  
Jiří Mejzlík ◽  
Oldřich Hamřík ◽  
Jan Blatný
Keyword(s):  
Catalytic Activity ◽  
Partial Pressure ◽  
Diethyl Ether ◽  
Sorption Properties ◽  
Propene Polymerization ◽  
Titanium Trichloride ◽  
Order Of Magnitude

A series of samples exhibiting different catalytic activity and sorption properties was obtained by grinding two basic types of titanium trichloride (TiCl3.1/3 AlCl3 and TiCl3). The samples with co-crystallized AlCl3 can sorb, under otherwise identical conditions, by an order of magnitude more diethyl ether than those of pure TiCl3. The amount of sorbed ether increases with its partial pressure and decreases when elevating the temperature of sorption. There is a correlation between the quantity of ether sorbed on TiCl3 and the catalytic activity of the latter in the propene polymerization. This correlation is, however, different for both examined catalyst types.

Catalytic activity of titanium trichloride prepared by different methods in combination with organo-aluminium compounds for propylene polymerization

1969 ◽  
Vol 11 (8) ◽  
pp. 2068-2079 ◽  
Author(s):  
V.I. Tsvetkova ◽  
A.N. Plyusnin ◽  
R.F. Bol'shakova ◽  
B.A. Uvarov ◽  
N.M. Chirkov
Keyword(s):  
Catalytic Activity ◽  
Propylene Polymerization ◽  
Titanium Trichloride

A Homochiral Metal–Organic Material with Permanent Porosity, Enantioselective Sorption Properties, and Catalytic Activity

2006 ◽  
Vol 45 (6) ◽  
pp. 916-920 ◽  
Author(s):  
Danil N. Dybtsev ◽  
Alexey L. Nuzhdin ◽  
Hyungphil Chun ◽  
Konstantin P. Bryliakov ◽  
Evgeniy P. Talsi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Organic Material ◽  
Sorption Properties ◽  
Metal Organic

Humidity-Dependent Cold Cells on the Antenna of the Stick Insect

2007 ◽  
Vol 97 (6) ◽  
pp. 3851-3858 ◽  
Author(s):  
Harald Tichy
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Partial Pressure ◽  
Systematic Study ◽  
Water Vapor Pressure ◽  
Ambient Air ◽  
Stick Insect ◽  
Proper Choice ◽  
Impulse Frequency ◽  
Order Of Magnitude

We present the first systematic study of the response of insect “cold cells” to a variation in the partial pressure of water vapor in ambient air. The cold cells on the antenna of the stick insect respond with an increase in activity when either the temperature or the partial pressure of water vapor is suddenly reduced. This double dependency does not in itself constitute bimodality because it could disappear with the proper choice of parameters involving temperature and humidity. In this study, we demonstrate that the evaporation of a small amount of water from the sensillum surface resulting from a drop in the water vapor pressure—leading to a transient drop in temperature and thus to a brief rise in impulse frequency—is the most plausible explanation for this bimodal response. We also show with an order-of-magnitude calculation that this mechanism is plausible and consistent with the amounts of water vapor potentially present on the sensillum. We hypothesize that a film of moisture collects on the hygroscopic sensillum surface at higher humidity and then tends to evaporate when humidity is lowered. The water might even be bound loosely within the cuticular wall, a situation conceivable in a sensillum that contains two hygroreceptive cells in addition to the cold cell.

scholarly journals Kinetics Study of Propene Polymerization with Porous Titanium Trichloride.

2000 ◽  
pp. 495-500
Author(s):  
Hiroshi UENO ◽  
Kunihiko IMANISHI ◽  
Satoshi UEKI ◽  
Tadanao KOHARA
Keyword(s):  
Porous Titanium ◽  
Kinetics Study ◽  
Propene Polymerization ◽  
Titanium Trichloride

NO reduction utilizing complex oxide catalysts

RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 85434-85439 ◽  
Author(s):  
Kimber L. Stamm Masias ◽  
Torin C. Peck ◽  
Paul T. Fanson
Keyword(s):  
Catalytic Activity ◽  
Precious Metal ◽  
No Reduction ◽  
Precious Metals ◽  
Complex Oxide ◽  
Oxide Catalysts ◽  
Order Of Magnitude ◽  
Metal Doped

Precious metal doped BaCeO3 compounds show catalytic activity toward NO an order of magnitude higher than traditional supported precious metals.

Diffusion of Sr in Bi2Sr2Can–1CunO2n+4

1993 ◽  
Vol 8 (10) ◽  
pp. 2465-2470 ◽  
Author(s):  
Nan Chen ◽  
S.J. Rothman ◽  
J.L. Routbort
Keyword(s):  
Diffusion Equation ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Pressure Range ◽  
Tracer Diffusion ◽  
Concentration Profiles ◽  
Measured Temperature ◽  
Serial Sectioning ◽  
Measured Temperature Range ◽  
Order Of Magnitude

Tracer diffusion of 85Sr in polycrystalline Bi2Sr2Can-1CunO2n+4 has been investigated for n = 1, 2, and 3 in an oxygen atmosphere between 775 and 850 °C. A radiotracer serial-sectioning technique was used to measure the concentration profiles, which were fit to a solution of the diffusion equation to calculate the diffusivities. The activation energies were 403, 553, and 519 kJ/mole, for n = 1, 2, and 3, respectively. However, the absolute values of D for the various layered superconductors did not differ by more than an order of magnitude over the measured temperature range. The diffusivity of Sr at 800 °C for n = 1 or 2 over an oxygen partial pressure range of 103 to 105 Pa increased as the pressure decreased.

Über den Einfluß äußerer Magnetfelder auf die Aktivität ferromagnetischer Katalysatoren

1953 ◽  
Vol 8 (9) ◽  
pp. 538-546 ◽  
Author(s):  
E. Justi ◽  
G. Vieth
Keyword(s):  
Catalytic Activity ◽  
Nickel Powder ◽  
Catalytic Effect ◽  
Theoretical Treatment ◽  
High Catalytic Activity ◽  
Experimental Proof ◽  
Apparent Lack ◽  
Low Field ◽  
Order Of Magnitude ◽  
Catalytic Effects

J.A. Hedvall has discovered “internal” magneto-catalytic effects; the activity of ferromagnetic catalyst changes upon transgressing the Curie-interval. The present publication deals with finding an “external” magneto-catalytic effect consisting of the influence of external magnetic fields upon the activity of ferromagnetic catalysts. This can be shown quite clearly in capillaries of high purity ferromagnetic nickel by experiments applying the o-p-hydrogen conversion. In this reaction the conversion rises so steeply with relatively low field strengths that even the magnetic earth field should enhance the catalytic activity of nickel in compact form; a few hundred oersted may suffice for doubling the conversion and at some 1000 or 10.000 oersted a saturation value of the conversion is reached. The connection between catalytic activity and magnetism finds further support by a corresponding catalytic retentivity.From the theory of ferromagnetism, especially the studies of Néel, it is known that extremely small ferromagnetic particles of the order of magnitude of Blochs walls, i. e. some 10—4 mm, posses high permanent magnetism. This fact appears significant in this connection for the high catalytic activity of finely divided powder catalysts such as Raney catalysts. This permanent magnetism explains also the apparent lack of the external magneto-catalytic effect when using a nickel powder catalyst. The theoretical treatment of the results cannot yet give a definite explanation; before this can be given the experiments must be extended to ordinary chemical reactions. To this end the prerequisits for such experiments are being established.Independently thereof the experimental proof for the external catalytic effect serves to ascertain that the internal Hedvall effects are primarily correlated to the ferromagnetic and paramagnetic states of matter.

Catalytic activity of synthesized nanosized molybdenum disulfide for the hydrodesulfurization of dibenzothiophene: Effect of H2S partial pressure

2009 ◽  
Vol 91 (1-2) ◽  
pp. 189-197 ◽  
Author(s):  
Hamdy Farag ◽  
Abdel-Nasser A. El-Hendawy ◽  
Kinya Sakanishi ◽  
Masahiro Kishida ◽  
Isao Mochida
Keyword(s):  
Catalytic Activity ◽  
Partial Pressure ◽  
Molybdenum Disulfide

scholarly journals Coupled inter-subunit dynamics enable the fastest CO2-fixation by reductive carboxylases

2019 ◽  
Author(s):  
Hasan DeMirci ◽  
Yash Rao ◽  
Gabriele M. Stoffel ◽  
Bastian Vögeli ◽  
Kristina Schell ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Molecular Mechanisms ◽  
Co2 Fixation ◽  
Catalytic Domains ◽  
Catalytically Active ◽  
Key Enzyme ◽  
Order Of Magnitude ◽  
Conformational Coupling ◽  
Substrate Binding Sites ◽  
Half Site

AbstractEnoyl-CoA carboxylases/reductases (ECRs) are the most efficient CO2-fixing enzymes described to date, outcompeting RubisCO, the key enzyme in photosynthesis in catalytic activity by more than an order of magnitude. However, the molecular mechanisms underlying ECR’s extraordinary catalytic activity remain elusive. Here we used different crystallographic approaches, including ambient temperature X-ray Free Electron Laser (XFEL) experiments, to study the dynamic structural organization of the ECR from Kitasatospora setae. K. setae ECR is a homotetramer that differentiates into a dimer of dimers of open- and closed-form subunits in the catalytically active state, suggesting that the enzyme operates with “half-site reactivity” to achieve high catalytic rates. Using structure-based mutagenesis, we show that catalysis is synchronized in K. setae ECR across the pair of dimers by conformational coupling of catalytic domains and within individual dimers by shared substrate binding sites. Our results provide unprecedented insights into the dynamic organization and synchronized inter- and intra-subunit communications of nature’s most efficient CO2-fixing enzyme during catalysis.

scholarly journals Further experimental evidence that condensation is a major cause of airflow

DYNA ◽  
2019 ◽  
Vol 86 (209) ◽  
pp. 56-63
Author(s):  
Peter Paul Bunyard ◽  
Martin Hodnett ◽  
Carlos Peña ◽  
Javier D. Burgos-Salcedo
Keyword(s):  
Kinetic Energy ◽  
Partial Pressure ◽  
Small Proportion ◽  
Considerable Proportion ◽  
P Value ◽  
Water Condensation ◽  
Air Density ◽  
Order Of Magnitude ◽  
Pressure Changes ◽  
Experimental Structure

This paper further explores the physics of water condensation, using an experimental structure designed for that purpose. The data show a highly significant correlation (R2 >0.94, p value <0.001) between observed airflows and partial pressure changes from condensation, when the results of different experiments are pooled. Changes in air density on cooling provide insufficient energy to account for the airflow. The finding is that the kinetic energy of the chilled air falls short by an order of magnitude, even to move a relatively small proportion of the 20 kg of air contained within the structure. Meanwhile the physics of condensation indicate a surplus of kinetic energy is made available from the air surrounding the locus of condensation. At low rates of condensation a considerable proportion of the available kinetic energy in the enclosed air is absorbed in friction and turbulence. That proportion reduces with higher rates of condensation.

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