Gas phase hydrolysis of sulfur tetrafluoride: A comparison of the gaseous and liquid phase rate constants

The ratio of the rate constants for disproportionation and combination for ethyl radicals, kd/kc[Formula: see text]has been measured over the temperature range 298–173 K in the gas phase. Ethyl radicals were produced by direct photolysis of ethylene followed by addition of hydrogen atoms to ethylene. At low temperatures the only important reactions of the radicals were combination and disproportionation. The ratio kd/kc was obtained from measurements of the rates of formation of ethane, butane, and butene. No change in the ratio kd/kc was observed over the temperature range studied, leading to the conclusion that Ed − Ec = 0, within the experimental error. The significance of this result is discussed in relation to other measurements in both gas and liquid phase and to the nature of the transition state for this reaction.

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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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Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19811229 ◽

1981 ◽

Vol 46 (5) ◽

pp. 1229-1236 ◽

Cited By ~ 7

Author(s):

Jan Balej ◽

Milada Thumová

Keyword(s):

Ionic Strength ◽

Rate Constants ◽

Acidic Medium ◽

Measured Data ◽

Molar Ratios ◽

Starting Solution ◽

Kinetics Of Hydrolysis ◽

Rate Of Hydrolysis ◽

Kinetics Of ◽

Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

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Salt effect in hydrolysis of 3-acyl-1,3-diphenyltriazenes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19813104 ◽

1981 ◽

Vol 46 (12) ◽

pp. 3104-3109 ◽

Cited By ~ 2

Author(s):

Miroslav Ludwig ◽

Oldřich Pytela ◽

Miroslav Večeřa

Keyword(s):

Sodium Chloride ◽

Temperature Dependence ◽

Potassium Chloride ◽

Rate Constants ◽

Zinc Sulphate ◽

Salt Effect ◽

Sodium Sulphate ◽

Potassium Sulphate ◽

Lithium Sulphate ◽

Hydrolysis Of

Rate constants of non-catalyzed hydrolysis of 3-acetyl-1,3-diphenyltriazene (I) and 3-(N-methylcarbamoyl)-1,3-diphenyltriazene (II) have been measured in the presence of salts (ammonium chloride, potassium chloride, lithium chloride, sodium chloride and bromide, ammonium sulphate, potassium sulphate, lithium sulphate, sodium sulphate and zinc sulphate) within broad concentration ranges. Temperature dependence of the hydrolysis of the substrates studied has been measured in the presence of lithium sulphate within temperature range 20° to 55 °C. The results obtained have been interpreted by mechanisms of hydrolysis of the studied substances.

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Kinetics of esterification of monoisopropylphenols with phosphoryl trichloride

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19891311 ◽

1989 ◽

Vol 54 (5) ◽

pp. 1311-1317

Author(s):

Miroslav Magura ◽

Ján Vojtko ◽

Ján Ilavský

Keyword(s):

Liquid Phase ◽

Rate Constants ◽

Reaction Rates ◽

Activation Energies ◽

The Individual ◽

Kinetics Of

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.

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