Gas phase vs. liquid phase: monitoring H2 and CO adsorption phenomena on Pt/Al2O3 by IR spectroscopy

Cycloalkylidenselenoketene durch Pyrolyse von 1,2,3-Selenadiazolen — Untersuchungen mit der temperaturabhängigen PE-Spektroskopie und Matrix-IR-Spektroskopie [1]

Zeitschrift für Naturforschung B ◽

10.1515/znb-1984-1113 ◽

1984 ◽

Vol 39 (11) ◽

pp. 1536-1540 ◽

Cited By ~ 11

Author(s):

Reinhard Schulz ◽

Armin Schweig

Keyword(s):

Liquid Phase ◽

Ir Spectroscopy ◽

Ir Spectra ◽

Gas Phase ◽

Photoelectron Spectroscopy ◽

Variable Temperature ◽

Matrix Ir Spectroscopy

Abstract The gas-phase pyrolysis of cyclohexeno-1,2,3-selenadiazole and cycloocteno-1,2,3-selenadiazole has been investigated by variable temperature photoelectron spectroscopy and matrix IR spectroscopy. The ring contracted, highly reactive products cyclopentylidenselenoketene (cyclopentylidenmethanselone) and cycloheptylidenselenoketene (cycloheptylidenmethanselone) - which had not been found in liquid phase thermolysis experiments - have been detected. Additionally HeI photoelectron and IR spectra of analogous ketenes and thioketenes are presented for comparative reasons.

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Pyridine hydrodenitrogenation over industrial NiMo/γ-Al2O3 catalyst: Application of gas phase kinetic models to liquid phase reactions

Fuel ◽

10.1016/j.fuel.2014.02.017 ◽

2014 ◽

Vol 125 ◽

pp. 206-218 ◽

Cited By ~ 12

Author(s):

C.S. Raghuveer ◽

J.W. Thybaut ◽

R. De Bruycker ◽

K. Metaxas ◽

T. Bera ◽

...

Keyword(s):

Liquid Phase ◽

Gas Phase ◽

Kinetic Models ◽

Al2o3 Catalyst

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Kinetics of Liquid - Phase Hydrogenation of Straight Chain C10 to C13 Di-Olefins Over Ni/Al2O3 Catalyst

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1244 ◽

2006 ◽

Vol 4 (1) ◽

Author(s):

D. Rajeshwer ◽

G. Sreenivasa Rao ◽

K.R. Krishnamurthy ◽

G. Padmavathi ◽

N. Subrahmanyam ◽

...

Keyword(s):

Liquid Phase ◽

Power Law ◽

Fixed Bed Reactor ◽

Process Conditions ◽

Straight Chain ◽

Marquardt Algorithm ◽

Hydrogenation Reactions ◽

Solid Liquid ◽

Kinetics Of ◽

Al2o3 Catalyst

Straight chain C10 to C13 di-olefins were selectively hydrogenated to increase the mono-olefins content in the feed to alkylation reactor in the process of production of Linear Alkyl Benzene (LAB). The reaction was carried out in a liquid phase up-flow fixed bed reactor at temperature of 448-503 °K and pressure of 1.08-1.96 MPa, which keeps hydrogen dissolved in the hydrocarbon feed. Under the above process conditions the reactor will be virtually two phase (solid-liquid) instead of three phase (solid-liquid-vapour). Kinetics of hydrogenation of straight chain C10 to C13 di-olefins on nickel alumina (Ni/Al2O3) catalyst was studied in the temperature range of 458-488 °K. The reaction scheme considered includes two consecutive hydrogenation reactions. Various rate models based on the modified Power Law, Horiuti-Polanyi mechanism & proposed by Somers. A.; were derived for the two consecutive hydrogenation reactions and subjected to model discrimination. Parameter estimation was done utilizing the Levenberg-Marquardt Algorithm for global convergence using MATLAB software. Out of the various models tested, rate model based on power law with modification fitted the data well. The estimated rate constants of the best model are thermodynamically sound and statistically consistent.

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Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

Water Science & Technology ◽

10.2166/wst.1991.0211 ◽

1991 ◽

Vol 24 (7) ◽

pp. 277-284 ◽

Cited By ~ 2

Author(s):

E. Gomólka ◽

B. Gomólka

Keyword(s):

Carbon Dioxide ◽

Liquid Phase ◽

Gas Phase ◽

Flue Gas ◽

Carbonic Acid ◽

Low Cost ◽

Flue Gases ◽

Carbon Dioxide Content ◽

Patent Claim ◽

Phase Dispersion

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

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Modeling of aerated upflow fixed bed reactors for nitrification

Water Science & Technology ◽

10.2166/wst.1999.0193 ◽

1999 ◽

Vol 39 (4) ◽

pp. 85-92 ◽

Cited By ~ 7

Author(s):

J. Behrendt

Keyword(s):

Mathematical Model ◽

Mass Transfer ◽

Liquid Phase ◽

Gas Phase ◽

Fixed Bed ◽

Fixed Bed Reactor ◽

Bulk Liquid ◽

Initial Value ◽

Fixed Bed Reactors ◽

Number Of Cells

A mathematical model for nitrification in an aerated fixed bed reactor has been developed. This model is based on material balances in the bulk liquid, gas phase and in the biofilm area. The fixed bed is divided into a number of cells according to the reduced remixing behaviour. A fixed bed cell consists of 4 compartments: the support, the gas phase, the bulk liquid phase and the stagnant volume containing the biofilm. In the stagnant volume the biological transmutation of the ammonia is located. The transport phenomena are modelled with mass transfer formulations so that the balances could be formulated as an initial value problem. The results of the simulation and experiments are compared.

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Theoretical analysis of counter-current absorption of a poorly soluble gas based on the PDE-AD model

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19861222 ◽

1986 ◽

Vol 51 (6) ◽

pp. 1222-1239 ◽

Cited By ~ 1

Author(s):

Pavel Moravec ◽

Vladimír Staněk

Keyword(s):

Experimental Data ◽

Liquid Phase ◽

Gas Phase ◽

Transfer Functions ◽

Packed Bed ◽

Packed Bed Column ◽

Interfacial Transport ◽

Gaseous Component ◽

Poorly Soluble ◽

Counter Current

Expression have been derived in the paper for all four possible transfer functions between the inlet and the outlet gas and liquid steams under the counter-current absorption of a poorly soluble gas in a packed bed column. The transfer functions have been derived for the axially dispersed model with stagnant zone in the liquid phase and the axially dispersed model for the gas phase with interfacial transport of a gaseous component (PDE - AD). calculations with practical values of parameters suggest that only two of these transfer functions are applicable for experimental data evaluation.

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Reesterification of ethyl acetate by propanol catalysed by glycidyl methacrylate copolymers containing sulphonic acid groups

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19811941 ◽

1981 ◽

Vol 46 (8) ◽

pp. 1941-1946 ◽

Cited By ~ 2

Author(s):

Karel Setínek

Keyword(s):

Liquid Phase ◽

Ethyl Acetate ◽

Kinetic Study ◽

Gas Phase ◽

Nonlinear Regression ◽

Kinetic Data ◽

Glycidyl Methacrylate ◽

Kinetic Equations ◽

Methacrylate Copolymers ◽

Styrene Divinylbenzene

A series of differently crosslinked macroporous 2,3-epoxypropyl methacrylate-ethylenedimethacrylate copolymers with chemically bonded propylsulphonic acid groups were used as catalysts for the kinetic study of reesterification of ethyl acetate by n-propanol in the liquid phase at 52 °C and in the gas phase at 90 °C. Analysis of kinetic data by the method of nonlinear regression for a series of equations of the Langmuir-Hinshelwood type showed that kinetic equations which describe best the course of the reaction are the same as for the earlier studied sulphonated macroporous styrene-divinylbenzene copolymers. Compared types of catalysts differ, however, in the dependence of their activity on the degree of crosslinking of the copolymer used.

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The Properties of Cu Ions in Zeolites CuY Studied by IR Spectroscopy

Molecules ◽

10.3390/molecules26154686 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4686

Author(s):

Jerzy Podobiński ◽

Mariusz Gackowski ◽

Grzegorz Mordarski ◽

Katarzyna Samson ◽

Michał Śliwa ◽

...

Keyword(s):

Ir Spectroscopy ◽

Positive Charge ◽

Co Adsorption ◽

The Other ◽

Probe Molecules ◽

Adsorption And Desorption ◽

Other Hand ◽

Close Proximity ◽

No And Co Adsorption ◽

Cu Ions

The properties of both Cu2+ and Cu+ ions in zeolite CuY were followed with NO and CO as probe molecules. Cu2+ was found to be located in SII, SII*, and SIII sites, whereas Cu+ was found in SII and SII* sites. The fine analysis of the spectra of Cu2+-NO and Cu+-CO adducts suggests that both in SII and in SII* sites two kinds of Cu cations exist. They differ in the positive charge, which may be related to the varying numbers of AlO4− in close proximity. The experiments of NO and CO adsorption and desorption evidenced that both Cu2+ and Cu+ sites of highest positive charge bind probe molecules most strongly but activate them to a lesser extent than the Cu sites of lowest positive charge. The experiments of reduction with hydrogen evidenced that the Cu ions of higher positive charge are first reduced by hydrogen. On the other hand, Cu sites of the lowest positive charge are first oxidized by oxygen. The experiments with CuNaY zeolites of various Cu contents suggest that the first introduced Cu (at low Cu contents) created Cu+, which was the most neutralized by framework oxygens. Such Cu cations are the most stabilized by framework oxygens.

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Radiolysis of methylcyclopentane. III. Liquid phase mechanism and comparison of cycloalkanes

Canadian Journal of Chemistry ◽

10.1139/v68-536 ◽

1968 ◽

Vol 46 (20) ◽

pp. 3235-3240 ◽

Cited By ~ 11

Author(s):

Gordon R. Freeman ◽

E. Diane Stover

Keyword(s):

Liquid Phase ◽

Gas Phase ◽

Bond Cleavage ◽

Open Chain ◽

Methyl Substitution ◽

Product Yields ◽

Total Ionization ◽

Gamma Radiolysis ◽

G Value

The initial yields of the major products of the gamma radiolysis of liquid methylcyclopentane (MCP) at 25° are: G(H2) = 4.2, G(1-methylcyclopentene plus methylenecyclopentane) = 2.7, G(3- plus 4-methyl-cyclopentene) = 1.0, G(open chain hexene) = 1.0, and G(bimethylcyclopentyl) = 0.9. The effects of scavengers on the product yields are reported and the mechanism is discussed.The liquid phase radiolytic decompositions of cyclohexane (CH), methylcyclohexane (MCH), cyclopentane (CP), and MCP are compared. The net amount of C—C bond cleavage is much greater in the five-membered than in the six-membered rings. Methyl substitution on the ring reduces G(H2) by about one unit, mainly because of the formation of a type of ion (QH+) that does not yield hydrogen when neutralized by an electron. The QH+ type ions are formed in MCH and MCP, but not in CH and CP. In all the systems, another type of ion (N+) that does not yield hydrogen when neutralized by an electron is formed with a G value of about unity. The type of ion (PH+) that does yield hydrogen when neutralized by an electron has a G value of 3.4 in CH and CP, but only 2.0 in MCP. It is concluded that G(total ionization) is in the vicinity of 4.4 in the liquid compounds, virtually the same as the gas phase values.

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