Synthesis and Catalytic Properties of FeZSM-35 Zeolites Directed by Alkyl-polyamine Triethylene-tetramine

2011 ◽  
Vol 284-286 ◽  
pp. 909-912
Author(s):  
Bo Wei ◽  
Bing Shi Li ◽  
Hong Ding ◽  
Yuan Gao

Using a long alkyl-polyamine triethylene-tetramine as structure-directing agent, FeZSM-35 zeolites were synthesized and characterized by XRD, SEM, FTIR and TG-DTA techniques. EDS and ICP-AES indicate that the transition metal iron ions were framework elements and the mass fraction was 0.48%. The catalytic activity of as-synthesized crystals was examined for the aqueous hydroxylation of phenol with hydrogen peroxide. The phenol conversion was 18.8% and the selectivity on catechol and hydroquinone wasca.69.1% and 30.9%, respectively. The as-synthesized FeZSM-35 zeolites show relative high selectivity towards catechol and could be a promising catalyst.

1979 ◽  
Vol 44 (4) ◽  
pp. 1015-1022 ◽  
Author(s):  
Viliam Múčka

The catalytic properties of two-component catalyst nickel oxide-cadmium oxide with the proportions of the components covering the whole composition region 0-100% were examined by studying the decomposition of hydrogen peroxide in aqueous solution on it. In the range 0-25 mol.% CdO, cadmium oxide is found to affect infavourably the ability of nickel oxide to chemisorb oxygen. The amount of the chemisorbed oxygen increases several times on gamma irradiation of the samples. The effect of cadmium oxide on the catalytic activity of the system shows up in fresh samples only indirectly via the changed amount of the oxygen chemisorbed. In older samples the initial catalytic activity of the system is changed, which can be explained based on the concept of bivalent catalytic centres in terms of the co-action of the catalytic centres of the two oxides, which are in equilibrium. The irradiation of the system under study speeds up the processes leading to the establishing of this equilibrium which is thermally very stable, and results in a substantial increase of the catalytic activity of the samples investigated.


1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.


RSC Advances ◽  
2014 ◽  
Vol 4 (55) ◽  
pp. 28848-28851 ◽  
Author(s):  
Yanhui Zhang ◽  
Dongdi Zhang ◽  
Zhiyuan Huo ◽  
Pengtao Ma ◽  
Jingyang Niu ◽  
...  

The novel undecatungstoarsenate-supported carbonyl rhenium derivative exhibits prominent catalytic activity and high selectivity in the cycloaddition of epoxides.


Polyhedron ◽  
2017 ◽  
Vol 124 ◽  
pp. 77-85 ◽  
Author(s):  
Paranthaman Vijayan ◽  
Panneerselvam Anitha ◽  
Mani Rajeshkumar ◽  
Periasamy Viswanathamurthi ◽  
Paramasivam Sugumar ◽  
...  

2007 ◽  
Vol 124-126 ◽  
pp. 1793-1796 ◽  
Author(s):  
Gun Dae Lee ◽  
Sung Gab Kim ◽  
Hee Hoon Jeong ◽  
Seong Soo Park ◽  
Seong Soo Hong

The photo-catalytic hydroxylation of phenol with hydrogen peroxide was carried out over TS-1 and Ti-MCM-41 catalysts. For comparison, the dark (thermal)-catalytic hydroxylation of phenol was also performed. The difference in catalytic behaviors of TS-1 and Ti-MCM-41 and product distribution in both the reactions were investigated. The TS-1 and Ti-MCM-41 catalysts having the Si/Ti ratio of 50 were prepared by in-situ crystallization and characterized using XRD, UV-DRS. In the all reactions, the main products were catechol (CAT), hydroquinone (HQ) and benzoquinone (BQ). In dark (thermal)-reaction, TS-1 showed a higher catalytic activity than Ti- MCM-41. In photo-reaction, however, the activity of Ti-MCM-41 was comparable to that of TS-1. The conversion of phenol and the selectivity to CAT in the photo-catalytic reaction were higher than those in dark (thermal)-reaction. In the all reactions, the selectivity to CAT increased remarkably when the selectivities to HQ and BQ decreased with reaction time.


2007 ◽  
Vol 62 (3) ◽  
pp. 331-338 ◽  
Author(s):  
Juanita L. van Wyk ◽  
Selwyn Mapolie ◽  
Anders Lennartson ◽  
Mikael Håkansson ◽  
Susan Jagner

The synthesis of copper(II) salicylaldiminato complexes and their application in the catalytic hydroxylation of phenol is reported. Tetracoordinated copper complexes (Cu(Ln)2) were obtained by reacting the N-phenylsalicylaldimine ligands (HL1 -HL7) with copper acetate in a 2 : 1 mole ratio. The reaction of N-(2,6-diisopropyl)phenyl-3,5-di-tert-butylsalicylaldimine (HL7) with copper acetate in a 1 : 1 mole ratio afforded a dinuclear complex, which was not obtained with the other ligand systems. All complexes were characterized using FT-IR and elemental analysis. X-Ray crystal structures of complexes 2, 5 and 8 have also been obtained. The catalytic activity of these complexes was evaluated in the hydroxylation of phenol using oxygen and hydrogen peroxide as co-oxidants in aqueous media in the pH range 3 - 6. All complexes studied were found to be active for the hydroxylation process over the pH range studied with higher selectivity for catechol formation.


1984 ◽  
Vol 49 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Viliam Múčka

Some physical and catalytic properties of cerium dioxide-nickel oxide two-component catalysts have been studied over the entire composition region, employing the decomposition of hydrogen peroxide in aqueous solution as a model catalytic process. The two oxides have been found to affect each other, particularly for NiO contents of 9.1 and 96.7 mol%; the mutual influencing, the nature of which in the conditions applied remains unaffected by heat treatment of the sample or by its exposition to ionizing radiation, is manifested by the nonmonotonic dependences of the oxidation power and of the specific activity of the catalysts on their composition. This can be interpreted in terms of the concept of bivalent catalytic centres, assuming that for nickel oxide the centres consist of Ni2+-Ni3+ ion pairs, for cerium dioxide they consist of Ce3+-Ce4+ ion pairs, and that in the region of the mutual influencing , Ni2+-Ce4+ ion pairs play a major role. Within the scope of this concept, the increase in the oxidation power of all the catalysts in question and a simultaneously decrease in the specific activity of the pure nickeloxide exposed to ionizing radiation can be explained in terms of the ionization effect.


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