The Hydrogenation of Allene. IV. The Reaction of Allene with Hydrogen Catalyzed by Palladium, Platinum, Iridium, Rhodium, Ruthenium, and Osmium Catalysts

1972 ◽  
Vol 50 (12) ◽  
pp. 1793-1796 ◽  
Author(s):  
R. S. Mann ◽  
A. M. Shah
Keyword(s):  
Activation Energies ◽  
Constant Volume ◽  
Catalytic Activities ◽  
Wide Range ◽  
Apparent Activation Energies ◽  
Palladium Platinum

The reaction between allene and hydrogen over unsupported palladium, platinum, iridium, rhodium, ruthenium, and osmium catalysts has been investigated in a static constant volume system between 70 and 149 °C for a wide range of reactant ratios. The orders of reaction with respect to hydrogen and allene were one and zero, respectively, and temperature independent. The overall apparent activation energies for unsupported platinum, iridium, palladium and rhodium were 17.7, 9.1, 6.4, and 17.4 kcal/mol, respectively. The catalytic activities of the unsupported metals were in the sequence Pd > Ir > Rh > Pt > Ru, Os. Selectivity was highest with palladium and rhodium, and least with iridium. The polymerization was highest with platinum and least with indium.

scholarly journals Catalytic hydrogenation of allene

1968 ◽  
Vol 46 (2) ◽  
pp. 161-166 ◽  
Author(s):  
R. S. Mann ◽  
D. E. To
Keyword(s):  
Catalytic Hydrogenation ◽  
Hydrogenation Reaction ◽  
Activation Energies ◽  
Constant Volume ◽  
Kcal Mole ◽  
Catalytic Activities ◽  
Pressure Time ◽  
Wide Range ◽  
Apparent Activation Energies ◽  
Selective Formation

The reaction between allene and hydrogen over pumice-supported metals of the eighth group has been investigated in a constant volume reactor for a wide range of temperature and reactant ratios. The shape of the pressure–time curves were found to be dependent upon the reactant ratios and their order of admission. The reaction over nickel–pumice is principally a selective formation of propylene with small yields of propane and reduced polymers of allene. The orders of hydrogenation reaction are first, or slightly higher, and zero with respect to hydrogen and allene respectively. The apparent activation energies for Pd, Pt, Co, Fe, Ni, Rh, Ir, Ru, and Os are 13, 17.4, 10.8, 9.4, 7.8, 9.6, 5.3, 3.0, and 4.6 kcal/mole respectively. The catalytic activities of the metals are in the sequence[Formula: see text]While selectivity was found to decrease with increasing initial hydrogen pressures, it increased with increasing temperatures.

Hydrogenation of methylacetylene. IV. The reaction of methylacetylene with hydrogen catalyzed by palladium, platinum, iridium, rhodium, and ruthenium catalysts

1969 ◽  
Vol 47 (2) ◽  
pp. 215-221 ◽  
Author(s):  
R. S. Mann ◽  
K. C. Khulbe
Keyword(s):  
Activation Energies ◽  
Ruthenium Catalysts ◽  
Kcal Mole ◽  
Wide Range ◽  
Apparent Activation Energies ◽  
Palladium Platinum

The reaction between methylacetylene and hydrogen over pumice supported and unsupported palladium, platinum, iridium, rhodium, and ruthenium catalysts has been investigated between 12 and 160 °C for a wide range of reactant ratios. The order of reaction with respect to hydrogen was one and with respect to methylacetylene was zero to slightly negative. The overall apparent activation energies for supported and unsupported palladium, platinum, iridium, and rhodium were 10.5, 9.5, 12.4, 14.7, 8.6, 6.2, 10.7, and 11.7 kcal/mole respectively.

The hydrogenation of allene. II. The reaction of allene with hydrogen catalyzed by nickel, cobalt, and iron

1968 ◽  
Vol 46 (20) ◽  
pp. 3249-3254 ◽  
Author(s):  
R. S. Mann ◽  
D. E. Tiu
Keyword(s):  
Activation Energies ◽  
Constant Volume ◽  
Cobalt Catalysts ◽  
Kcal Mole ◽  
Nickel Iron ◽  
Early Stages ◽  
Nickel Cobalt ◽  
Wide Range ◽  
Apparent Activation Energies ◽  
Selective Formation

The reaction between allene and hydrogen over unsupported nickel, iron, and cobalt catalysts has been studied in a static constant volume system for a wide range of temperature and reactant ratios. The reaction over metals is largely simple hydrogenation, the early stages being principally a selective formation of propylene with small yields of reduced polymers of allene. The orders of the hydrogenation were 1 and 0 with respect to hydrogen and allene respectively, and were temperature independent. The overall apparent activation energies for nickel, iron, and cobalt were 6.5, 7.6, and 6.9 kcal/mole respectively. Selectivity was highest with nickel, and least with cobalt.

The hydrogenation of methylacetylene. II. The reaction of methylacetylene with hydrogen catalyzed by nickel, iron, and cobalt

1967 ◽  
Vol 45 (22) ◽  
pp. 2755-2760 ◽  
Author(s):  
R. S. Mann ◽  
K. C. Khulbe
Keyword(s):  
Cobalt Catalyst ◽  
Activation Energies ◽  
Constant Volume ◽  
Kcal Mole ◽  
Nickel Iron ◽  
Early Stages ◽  
Wide Range ◽  
Apparent Activation Energies

The reaction between methylacetylene and hydrogen over unsupported nickel, iron, and cobalt catalyst has been investigated in a static constant volume system for a wide range of temperature and reactant ratios. The reaction over metals is largely simple hydrogenation, the early stages being principally a selective production of propylene with small yields of reduced polymers of methylacetylene. The orders of the hydrogenation were first and zero to slightly negative with respect to hydrogen and methylacetylene. The overall apparent activation energies for nickel, iron, and cobalt were 12.2, 8.1, and 7.3 kcal/mole respectively. Selectivity was highest with iron and least with nickel.

scholarly journals Catalytic Hydrogenation of Methylacetylene

1967 ◽  
Vol 45 (10) ◽  
pp. 1023-1030 ◽  
Author(s):  
R. S. Mann ◽  
S. C. Naik
Keyword(s):  
Compensation Effect ◽  
Nickel Catalysts ◽  
Hydrogenation Reaction ◽  
Activation Energies ◽  
Reaction Vessel ◽  
Kcal Mole ◽  
Pressure Time ◽  
Wide Range ◽  
Exponential Factors ◽  
Apparent Activation Energies

The reaction between methylacetylene and hydrogen over supported and unsupported nickel catalysts has been investigated in a static constant volume system for a wide range of temperature and reactant ratios. The pressure–time curves consist of two linear portions of different slopes. The reaction over nickel is largely simple hydrogenation, the early stages being principally a selective production of propylene with small yields of reduced polymers of methylacetylene. The orders of the hydrogenation reaction are first and zero with respect to hydrogen and methylacetylene respectively. The overall apparent activation energies for nickel–pumice and nickel–kieselguhr are 16.8 and 14.0 kcal/mole and for unsupported nickel catalysts vary between 17.2 and 20.0 kcal/mole. A satisfactory "compensation effect" exists between the activation energies and logarithmic values of the pre-exponential factors. The unsupported catalysts were not poisoned when methylacetylene was added first to the reaction vessel.

Growth Rate Distributions during Recrystallization of Copper

2004 ◽  
Vol 467-470 ◽  
pp. 197-202 ◽  
Author(s):  
R.A. Vandermeer ◽  
Erik M. Lauridsen ◽  
Dorte Juul Jensen
Keyword(s):  
Pure Copper ◽  
Activation Energies ◽  
Individual Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Apparent Activation Energies ◽  
Diffraction Microscopy ◽  
Purity Copper

New 3D X-ray diffraction microscopy (3DXRD) experiments on recrystallizing bulk grains that nucleated and grew in a 92% cold deformed pure copper during in situ annealing at both 150° C and 160° C are described. Nucleation times, growth velocities and apparent activation energies were determined for each grain. A wide range of apparent activation energies was observed but the average of 123 kJ/mol agreed well with earlier recrystallization experiments on a similar purity copper. It was clear that each recrystallized grain had its own individual characteristics; the grains do not all behave alike as various models would suppose.

scholarly journals Effect of CaO on catalytic combustion of semi-coke

2021 ◽  
Vol 10 (1) ◽  
pp. 011-020
Author(s):  
Luyao Kou ◽  
Junjing Tang ◽  
Tu Hu ◽  
Baocheng Zhou ◽  
Li Yang
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Combustion Rate ◽  
Activation Energies ◽  
Combustion Reaction ◽  
Tg Analysis ◽  
Conversion Rates ◽  
Apparent Activation Energies ◽  
Ozawa Integral Method ◽  
Addition Amount

Abstract Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.

Hydrogenation of methylacetylene. III. The reaction of methylacetylene with hydrogen catalyzed by nickel, copper, and their alloys

1968 ◽  
Vol 46 (4) ◽  
pp. 623-633 ◽  
Author(s):  
R. S. Mann ◽  
K. C. Khulbe
Keyword(s):  
Activation Energy ◽  
Nickel Catalyst ◽  
Hydrogen Pressure ◽  
Constant Volume ◽  
Temperature Dependent ◽  
Nickel Copper ◽  
Wide Range ◽  
Initial Hydrogen Pressure

The reaction between methylacetylene and hydrogen over unsupported nickel, copper, and their alloys has been investigated in a static constant volume system between 20 and 220 °C for a wide range of reactant ratios. The order of reaction with respect to hydrogen was one and nearly independent of temperature. While the order of reaction with respect to methylacetylene over nickel catalyst was slightly negative and temperature dependent, it was always positive and nearly independent of temperature for copper and copper-rich alloys. Selectivity was independent of initial hydrogen pressure for nickel and copper only; for others it decreased rapidly with increasing hydrogen pressure. The overall activation energy varied between 9 and 21.2 kcal/g mole. Selectivity and extent of polymerization increased with increasing amount of copper in the alloy.

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