RATES OF ADSORPTION OF HYDROGEN ON PALLADIUM AND ON RHODIUM

1960 ◽  
Vol 38 (4) ◽  
pp. 588-595 ◽  
Author(s):  
Manfred J. D. Low
Keyword(s):  
Gas Pressure ◽  
General Effect ◽  
Pressure Sensitive ◽  
Early Appearance ◽  
Elovich Equation ◽  
Supported Palladium ◽  
Effects Of Temperature ◽  
Temperature And Pressure ◽  
Increasing Temperature ◽  
Kinetics Of

A study of the effects of temperature and initial gas pressure on the kinetics of chemisorption of hydrogen on alumina-supported palladium and rhodium catalysts revealed, for both gas–solid systems, that the adsorption proceeded via three distinct and consecutive kinetic stages. Each stage could be described by the Elovich equation. The temporal range of existence of each kinetic stage was temperature- and pressure-sensitive, low initial pressures and high temperatures favoring early appearance of each stage. On increasing the temperatures from 0° to 400 °C, the amounts of hydrogen adsorbed on both solids decrease. Over that temperature range the rates of adsorption on Pd decrease, while those on Rh increase, with increasing temperature. The general effect of increasing the initial gas pressure over the range 10–60°mm Hg is to increase both rates and extents of adsorption.

PRESSURE AND TEMPERATURE EFFECTS ON THE KINETICS OF THE ALKALINE FADING OF ORGANIC DYES IN AQUEOUS SOLUTION

1959 ◽  
Vol 37 (3) ◽  
pp. 599-612 ◽  
Author(s):  
David T. Y. Chen ◽  
Keith J. Laidler
Keyword(s):  
Malachite Green ◽  
Crystal Violet ◽  
Atmospheric Pressure ◽  
Organic Dyes ◽  
Back Reaction ◽  
Bromphenol Blue ◽  
Effects Of Temperature ◽  
Temperature And Pressure ◽  
Pressure And Temperature Effects ◽  
Kinetics Of

The rates of the alkaline fading of bromphenol blue, phenolphthalein, crystal violet, and malachite green have been studied from atmospheric pressure to 16,000 pounds per square inch. The rates for phenolphthalein and malachite green were also measured over a range of temperatures in order to determine the activation energies and entropies. The reactions went essentially to completion with the exception of the fading of phenolphthalein, for which the effects of temperature and pressure on the back reaction and equilibrium constant were also studied. No effect of pressure was found for the fading of crystal violet, but the reactions of the other three dyes were accelerated by pressure, so that there are negative volumes of activation. These are correlated with the entropies of activation and are interpreted in terms of the reaction mechanisms.

scholarly journals Effect of Temperature and Pressure of Supercritical CO2 on Dewatering, Shrinkage and Stresses of Eucalyptus Wood

2021 ◽  
Vol 11 (18) ◽  
pp. 8730
Author(s):  
Lin Yang
Keyword(s):  
Residual Stress ◽  
Supercritical Co2 ◽  
Tangential Direction ◽  
Effect Of Temperature ◽  
Eucalyptus Wood ◽  
Conventional Kiln Drying ◽  
Effects Of Temperature ◽  
Temperature And Pressure ◽  
Capillary Tension ◽  
Increasing Temperature

Supercritical CO2 (SuCO2) dewatering can mitigate capillary tension and reduce wood collapse. In this study, Eucalyptus urophylla × E. grandis specimens were dewatered by SuCO2 at temperatures of 35, 40 and 55 °C, in pressures of 10 and 30 MPa, respectively, for 1h. Effects of temperature and pressure on dewatering rate, moisture content (MC) distribution and gradient, shrinkage and residual stress of wood after dewatering were investigated. The results indicate that the SuCO2 dewatering rate is much faster than that of conventional kiln drying (CKD). The dewatering rate increases with increasing of temperature and pressure; however, pressure has a significant influence, especially for the high-temperature dewatering process; the MC distribution after 1 h dewatering is uneven and MC gradients decrease with reducing of mean final MC of wood. MC gradients along radial direction are much smaller than that in tangential direction; collapse of wood significantly reduces after dewatering due to SuCO2 decreasing the capillary tension, and residual stress of wood during dewatering is mainly caused by pressure of SuCO2, which decreases with increasing temperature. SuCO2 dewatering has great potential advantages in water-removal of wood prone to collapse or deformation.

THE KINETICS OF HYDROGEN CHEMISORPTION ON AN IRIDIUM CATALYST

1959 ◽  
Vol 37 (5) ◽  
pp. 915-921 ◽  
Author(s):  
Manfred J. D. Low ◽  
H. Austin Taylor
Keyword(s):  
Gas Pressure ◽  
Hydrogen Chemisorption ◽  
Iridium Catalyst ◽  
Elovich Equation ◽  
Kinetics Of

The kinetics of the chemisorption of hydrogen on an iridium catalyst have been studied at various temperatures and pressures. The rate of adsorption is well defined by the Elovich equation. Isothermal anomalies have been observed and were found to be a function of temperature and initial gas pressure.

Palladium-catalyzed carbonylation of 1,5-cyclooctadiene. Effects of temperature and pressure

1991 ◽  
Vol 56 (3) ◽  
pp. 663-672 ◽  
Author(s):  
Curtis B. Anderson ◽  
Rade Marković
Keyword(s):  
Carbon Monoxide ◽  
Oxidative Carbonylation ◽  
Influence Of Temperature ◽  
Carbonylation Reaction ◽  
Palladium Catalyzed ◽  
Effects Of Temperature ◽  
Temperature And Pressure

The influence of temperature and carbon monoxide pressure on the course of oxidative carbonylation reaction of 1,5-cyclooctadiene in the presence of the palladium(II) salts as a catalyst, was investigated.

scholarly journals Some Thermodynamic Relationships for Soils at or Below the Freezing Point: 2. Effects of Temperature and Pressure on Unfrozen Soil Water

1968 ◽  
Vol 4 (3) ◽  
pp. 541-544 ◽  
Author(s):  
Philip F. Low ◽  
Pieter Hoekstra ◽  
Duwayne M. Anderson
Keyword(s):  
Soil Water ◽  
Freezing Point ◽  
Thermodynamic Relationships ◽  
Effects Of Temperature ◽  
Temperature And Pressure

scholarly journals Lead Recovery from Solid Residues of Copper Industry Using Triethylenetetramine Solution

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 546
Author(s):  
Mateusz Ciszewski ◽  
Andrzej Chmielarz ◽  
Zbigniew Szołomicki ◽  
Michał Drzazga ◽  
Katarzyna Leszczyńska-Sejda
Keyword(s):  
Lead Extraction ◽  
Pressure Leaching ◽  
Base Metals ◽  
Lead Carbonate ◽  
Pure Lead ◽  
Industrial Processing ◽  
High Temperature And Pressure ◽  
Lead Recovery ◽  
Temperature And Pressure ◽  
Increasing Temperature

Industrial processing of mineral ores and concentrates generates large amounts of solid residues, which can be landfilled or further processed to recover selected elements depending on its economical profitability. Pressure leaching is a technology enabling high recovery of base metals like copper and zinc, transferring others like lead and iron to the solid residue. High temperature and pressure of such leaching leads to formation of sparingly soluble lead jarosite (plumbojarosite). The load of lead landfilled as solid residues resulting from such operation is so big that its recovery is perspective and crucial for waste-limiting technologies. This paper is devoted to lead extraction from pressure leaching residues using triethylenetetramine solution and then its precipitation as a commercial lead carbonate. The highest obtained recovery of lead was 91.3%. Additionally, presented technology allows to manage and recycle amine solution and reuse solid products. Produced pure lead carbonate can be directly added to smelting, not increasing temperature within the furnace.

scholarly journals Interaction of hsp70 with unfolded proteins: effects of temperature and nucleotides on the kinetics of binding.

1991 ◽  
Vol 88 (13) ◽  
pp. 5719-5723 ◽  
Author(s):  
D. R. Palleros ◽  
W. J. Welch ◽  
A. L. Fink
Keyword(s):  
Unfolded Proteins ◽  
Effects Of Temperature ◽  
Kinetics Of

scholarly journals Comparative Study of Chemical Stability of Two H1Antihistaminic Drugs, Terfenadine and ItsIn VivoMetabolite Fexofenadine, Using LC-UV Methods

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Anna Gumieniczek ◽  
Anna Berecka-Rycerz ◽  
Rafał Pietraś ◽  
Izabela Kozak ◽  
Karolina Lejwoda ◽  
...  
Keyword(s):  
Comparative Study ◽  
Chemical Stability ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of Degradation ◽  
Effects Of Temperature ◽  
High Doses ◽  
Antihistaminic Drugs ◽  
Kinetics Of

A comparative study of chemical stability of terfenadine (TER) and itsin vivometabolite fexofenadine (FEX) was performed. Both TER and FEX were subjected to high temperature at different pH and UV/VIS light at different pH and then quantitatively analyzed using new validated LC-UV methods. These methods were used to monitor the degradation processes and to determine the kinetics of degradation for both the compounds. As far as the effects of temperature and pH were concerned, FEX occurred more sensitive to degradation than TER. As far as the effects of UV/VIS light and pH were concerned, the both drugs were similarly sensitive to high doses of light. Using all stress conditions, the processes of degradation of TER and FEX followed the first-order kinetics. The results obtained for these two antihistaminic drugs could be helpful in developing their new derivatives with higher activity and stability at the same time.

scholarly journals Effects of temperature and pressure on the glass transitions of plastic bonded explosives

2000 ◽  
Vol 357-358 ◽  
pp. 89-95 ◽  
Author(s):  
Mary Stinecipher Campbell ◽  
Danielle Garcia ◽  
Deanne Idar
Keyword(s):  
Glass Transitions ◽  
Effects Of Temperature ◽  
Temperature And Pressure
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