Pd- and Au-Induced Circular and Fibrous Polymer Gelation via Thiocarbonyl Groups and High Pd Catalyst Activity

2020 ◽  
Vol 2 (6) ◽  
pp. 2211-2219 ◽  
Author(s):  
Daisuke Nagai ◽  
Ayaka Kubo ◽  
Moeko Morita ◽  
Naoyuki Shimazaki ◽  
Yasuyuki Maki ◽  
...  
Keyword(s):  
Catalyst Activity ◽  
Pd Catalyst ◽  
Fibrous Polymer

scholarly journals METHOD FOR THE PREPARATION OF 2,4,6-TRIHYDROXYTOLUENE FROM 2,4,6-TRINITROTOLUENE

2021 ◽  
pp. 143-147
Author(s):  
И.А. Щурова ◽  
Н.А. Алексеева ◽  
С.В. Сысолятин ◽  
В.В. Малыхин
Keyword(s):  
Sulfuric Acid ◽  
Azo Dyes ◽  
Catalyst Activity ◽  
Amino Derivative ◽  
Synthetic Method ◽  
Pd Catalyst ◽  
Concentrated Sulfuric Acid ◽  
Hydrolysis Of ◽  
Chemical Reactant ◽  
Dyes And Pigments

Статья посвящена усовершенствованию способа получения 2,4,6-тригидрокситолуола, востребованного химического реагента в синтезе азокрасителей и пигментов, а также химико-фармацевтических препаратов и различных полимеров. Основным сырьем для его получения является 2,4,6-тринитротолуол, который подвергают каталитическому гидрированию с последующим гидролизом образовавшегося 2,4,6-триаминотолуола. В данной работе предложены условия многоциклового использования палладиевого катализатора гидрирования 2,4,6-тринитротолуола, позволяющие сохранять активность катализатора и повысить выход 2,4,6-триаминотолуола выше 98 %. Аминопроизводное выделяется в виде дисульфата действием концентрированной серной кислоты. Кроме того, изучено влияние соотношения вода/дисульфат 2,4,6-триаминотолуола на выход 2,4,6-тригидрокситолуола; найдены условия, в которых выход на стадии гидролиза увеличен до 83-84 %. Проведен сравнительный анализ различных способов выделения 2,4,6-тригидрокситолуола из реакционной массы. The paper is concerned with upgrading the synthetic method for 2,4,6-trihydroxytoluene, an in-demand chemical reactant in the synthesis of azo-dyes and pigments, as well as chemical pharmaceuticals and various polymers. The basic feedstock for the synthesis thereof is 2,4,6-trinitrotoluene, which is subjected to catalytic hydrogenation followed by hydrolysis of the resulting 2,4,6-triaminotoluene. Here we suggest conditions for the multicycle use of Pd catalyst employed for the hydrogenation of 2,4,6-trinitrotoluene, which allow the catalyst activity to be retained and the yield of 2,4,6-triaminotoluene to be enhanced above 98%. The amino derivative is liberated as the disulfate by concentrated sulfuric acid. Moreover, we examined how the ratio of water / 2,4,6-triaminotoluene disulfate influences the yield of 2,4,6-trihydroxytoluene. Conditions were found in which the yield from hydrolysis is 83-84 %. Different methods for the isolation of 2,4,6-trihydroxytoluene from the reaction mixture were comparatively analyzed.

Study of Catalytic Methane Oxidation Over Pd Supported on Nanocrystalline CeO2: Effects of Calcination and Pd Loading

2001 ◽  
Vol 676 ◽  
Author(s):  
Seung H. Oh ◽  
Michael L. Everett ◽  
Gar B. Hoflund ◽  
Johannes Seydel ◽  
Horst W. Hahn
Keyword(s):  
Catalytic Oxidation ◽  
Methane Oxidation ◽  
Catalyst Activity ◽  
Pd Catalyst ◽  
Oxidation Of Methane ◽  
Heating And Cooling ◽  
Enhanced Activity ◽  
Nanocrystalline Ceria ◽  
Catalytic Methane Oxidation

ABSTRACTThe catalytic oxidation of methane was studied over palladium supported on nanocrystalline ceria. Three palladium weight loadings (1, 5, and 10 wt%) were tested after calcining at 500 °C, at 280 °C and after no calcination at all. For the 5 and 10 wt% loadings, the 280 °C-calcined and non-calcined catalysts exhibit enhanced activity after several heating and cooling cycles. Calcining these same catalysts at 500 °C results in a systematic decline in activity. For all pretreatments the 1 wt% Pd catalyst exhibits decreasing activity. For the 5 and 10 wt% Pd loadings, the non-calcined catalysts are more active than the 280 °C-calcined catalysts, which are more active than the 500 °C-calcined catalysts. For the 1 wt% Pd catalyst, the opposite is true. The catalyst activity improves as the Pd loading is increased.

Preparation and Evaluation of Skeletal Cobalt-Molybdenum Hydrodesulfurization Catalysts

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.

Kinetics of carbon monoxide methanation on a Ni/SiO2 catalyst

1990 ◽  
Vol 55 (7) ◽  
pp. 1678-1685
Author(s):  
Vladimír Stuchlý ◽  
Karel Klusáček
Keyword(s):  
Carbon Monoxide ◽  
Reaction Rate ◽  
Catalyst Activity ◽  
Adsorbed Hydrogen ◽  
Reaction Products ◽  
Co Methanation ◽  
Molar Ratios ◽  
Rate Determining Step ◽  
Higher Temperature ◽  
Kinetics Of

Kinetics of CO methanation on a commercial Ni/SiO2 catalyst was evaluated at atmospheric pressure, between 528 and 550 K and for hydrogen to carbon monoxide molar ratios ranging from 3 : 1 to 200 : 1. The effect of reaction products on the reaction rate was also examined. Below 550 K, only methane was selectively formed. Above this temperature, the formation of carbon dioxide was also observed. The experimental data could be described by two modified Langmuir-Hinshelwood kinetic models, based on hydrogenation of surface CO by molecularly or by dissociatively adsorbed hydrogen in the rate-determining step. Water reversibly lowered catalyst activity and its effect was more pronounced at higher temperature.

ChemInform Abstract: A Simple and Facile Heck-Type Arylation of Alkenes with Diaryliodonium Salts Using Magnetically Recoverable Pd-Catalyst.

ChemInform ◽  
2012 ◽  
Vol 43 (50) ◽  
pp. no-no
Author(s):  
Buchi Reddy Vaddula ◽  
Amit Saha ◽  
John Leazer ◽  
Rajender S. Varma
Keyword(s):  
Pd Catalyst ◽  
Diaryliodonium Salts

scholarly journals Au-modified Pd catalyst exhibits improved activity and stability for NO direct decomposition

2021 ◽  
Author(s):  
Taha Elgayyar ◽  
Josefine Schnee ◽  
Alain Tuel ◽  
Laurence Burel ◽  
Françoise Bosselet ◽  
...  
Keyword(s):  
Noble Metals ◽  
Direct Decomposition ◽  
Pd Catalyst

The direct decomposition of NOx at moderate temperatures is a challenge because of the poisoning of the surface of noble metals by oxygen, yet the modification of Pd with Au...

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