Study on Macro Kinetics of the Desulfurization Processes of Heteropoly Compounds in Ionic Liquids and Aqueous Solutions

The kinetics of oxidation of alkenes by thallic sulphate in aqueous solutions, involving the two reaction steps-the hydroxythallation and the dethallation - was studied, and the effect of salts on the kinetics was examined; this made it possible to specify more precisely the reaction mechanism and to suggest a qualitative model of the reaction coordinate. It was found that in homogeneous as well as in heterogeneous reaction conditions, the reaction can be accelerated appreciably by adding tetraalkylammonium salts. These salts not only operate as catalysts of the phase transfer, but also exert a significant kinetic effect, which can be explained with a simplification in terms of a stabilization of the transition state of the reaction.

Download Full-text

Preparation and Evaluation of Skeletal Cobalt-Molybdenum Hydrodesulfurization Catalysts

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19950568 ◽

1995 ◽

Vol 60 (4) ◽

pp. 568-575

Author(s):

Karel Sporka ◽

Jiří Hanika ◽

Vladimír Jůn

Keyword(s):

Aqueous Solutions ◽

Active Component ◽

Catalyst Activity ◽

Gas Oil ◽

Gamma Alumina ◽

Molybdenum Sulfides ◽

Hydrodesulfurization Catalysts ◽

Hds Catalysts ◽

Kinetics Of ◽

Preparation And Evaluation

Preparation of skeletal Co-Mo catalysts by controlled impregnation of aluminosilicate skeletons containing deposited gamma-alumina with aqueous solutions of active component precursors has been investigated. The activity of the laboratory catalysts in gas oil hydrodesulfurization has been determined. Kinetics of impregnation of skeletal supports, the effect of their type, and the dependence of catalyst activity on the content of cobalt and molybdenum sulfides are reported. HDS skeletal catalysts prepared were compared with the extruded types. It was found that skeletal HDS catalysts show the higher activity (related to the content of alumina and Co-Mo sulfides) than the extruded ones due to the less significant effect of internal diffusion. However, if the activity is related to the same volume of catalyst bed, the activity of skeletal catalysts is only one fourth of that of the extruded types.

Download Full-text

Study of potential oscillations during reaction of an aluminium single crystal with an aqueous KOH solution

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19900345 ◽

1990 ◽

Vol 55 (2) ◽

pp. 345-353 ◽

Cited By ~ 4

Author(s):

Ivan Halaša ◽

Milica Miadoková

Keyword(s):

Aqueous Solutions ◽

Single Crystal ◽

Single Crystals ◽

Periodic Potential ◽

Optimum Conditions ◽

Potential Oscillations ◽

Dilute Aqueous Solutions ◽

Experimental Findings ◽

Kinetics Of

The authors investigated periodic potential changes measured on oriented sections of Al single crystals during spontaneous dissolution in dilute aqueous solutions of KOH, with the aim to find optimum conditions for the formation of potential oscillations. It was found that this phenomenon is related with the kinetics of the reaction investigated, whose rate also changed periodically. The mechanism of the oscillations is discussed in view of the experimental findings.

Download Full-text

Enhancing Artemisinin Solubility in Aqueous Solutions: Searching for Hydrotropes based on Ionic Liquids

Fluid Phase Equilibria ◽

10.1016/j.fluid.2021.112961 ◽

2021 ◽

Vol 534 ◽

pp. 112961

Author(s):

Isabela Sales ◽

Dinis O. Abranches ◽

Pedro Costa ◽

Tânia E. Sintra ◽

Sónia P.M. Ventura ◽

...

Keyword(s):

Ionic Liquids ◽

Aqueous Solutions

Download Full-text

Thermal Stability and Decomposition Kinetics of 1-Alkyl-2,3-Dimethylimidazolium Nitrate Ionic Liquids: TGA and DFT Study

Materials ◽

10.3390/ma14102560 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2560

Author(s):

Jianwen Meng ◽

Yong Pan ◽

Fan Yang ◽

Yanjun Wang ◽

Zhongyu Zheng ◽

...

Keyword(s):

Thermal Stability ◽

Density Functional Theory ◽

Ionic Liquids ◽

Density Functional ◽

Density Functional Theory Calculations ◽

Nitrogen Atmosphere ◽

Decomposition Kinetics ◽

Heating Rates ◽

Functional Theory ◽

Kinetics Of

The thermal stability and decomposition kinetics analysis of 1-alkyl-2,3-dimethylimidazole nitrate ionic liquids with different alkyl chains (ethyl, butyl, hexyl, octyl and decyl) were investigated by using isothermal and nonisothermal thermogravimetric analysis combined with thermoanalytical kinetics calculations (Kissinger, Friedman and Flynn-Wall-Ozawa) and density functional theory (DFT) calculations. Isothermal experiments were performed in a nitrogen atmosphere at 240, 250, 260 and 270 °C. In addition, the nonisothermal experiments were carried out in nitrogen and air atmospheres from 30 to 600 °C with heating rates of 5, 10, 15, 20 and 25 °C/min. The results of two heating modes, three activation energy calculations and density functional theory calculations consistently showed that the thermal stability of 1-alkyl-2,3-dimethylimidazolium nitrate ionic liquids decreases with the increasing length of the alkyl chain of the substituent on the cation, and then the thermal hazard increases. This study could provide some guidance for the safety design and use of imidazolium nitrate ionic liquids for engineering.

Download Full-text