Performance of MFI Zeolite Catalysts in n-heptane Conversion Reaction Test

2018 ◽  
Vol 69 (9) ◽  
pp. 2420-2424
Author(s):  
Iuliean Vasile Asaftei ◽  
Neculai Catalin Lungu ◽  
Ioan Gabriel Sandu ◽  
Adrian Florin Spac ◽  
Maria Ignat
Keyword(s):  
Aqueous Solution ◽  
Catalytic Activity ◽  
Pulse Method ◽  
Zeolite Catalysts ◽  
Activity Measurement ◽  
Zinc Ions ◽  
Mfi Zeolite ◽  
Reaction Test ◽  
Main Components ◽  
Heptane Conversion

The aromatization of n-heptane, one of the main components of light naphtha, has been investigated over HZSM-5 (Si/Al = 33.9) and Zn-HZSM-5: Zn1-HZSM-5 (0.86% Zn); Zn2-HZSM-5 (1.35% Zn) and Zn3-HZSM-5 (2.89% Zn) catalysts prepared by the ion exchange with 10M aqueous solution of Zn(NO3)2. The catalytic activity measurement was performed by the chromatographic pulse method in the temperature range of 673 - 823K. The presence of zinc in Zn-HZSM-5 catalysts provided a significant increase in total aromatics selectivity due to the improvement of dehydrogenation activity by Zn incorporation. The Zn species facilitated the aromatization by converting paraffin�s into corresponding olefins which, in turn, were the aromatics precursors. Therefore, both acidity and zinc incorporation played important roles in the aromatization of n-heptane. Over 773 K the activity and selectivity of the Zn-HZSM-5 catalysts decrease very probably due to the loss of zinc ions.

Performance of Ag-HZSM-5 Zeolite Catalysts in n-heptane Conversion

2017 ◽  
Vol 68 (1) ◽  
pp. 116-120
Author(s):  
Iuliean Vasile Asaftei ◽  
Neculai Catalin Lungu ◽  
Lucian Mihail Birsa ◽  
Ioan Gabriel Sandu ◽  
Laura Gabriela Sarbu ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Metal Content ◽  
Pulse Method ◽  
Acid Strength ◽  
Strength Distribution ◽  
Zeolite Catalysts ◽  
Benzene Toluene ◽  
Acid Strength Distribution ◽  
Silver Cations ◽  
Heptane Conversion

The conversion of n-heptanes into aromatic hydrocarbons benzene, toluene and xylenes (BTX), by the chromatographic pulse method in the temperature range of 673 - 823K was performed over the HZSM-5 and Ag-HZSM-5 zeolites modified by ion exchange with AgNO3 aqueous solutions. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ag-HZSM-5 (Ag1-HZSM-5 wt. % Ag1.02, Ag2-HZSM-5 wt. % Ag 1.62; and Ag3-HZSM-5 wt. % Ag 2.05 having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The yield of aromatic hydrocarbons BTX appreciably increased by incorporating silver cations Ag+ into HZSM-5.

Study on n-heptane Conversion Over Ni-HZSM-5 Zeolite Catalysts

2017 ◽  
Vol 68 (4) ◽  
pp. 715-719
Author(s):  
Iuliean Vasile Asaftei ◽  
Neculai Catalin Lungu ◽  
ion Sandu ◽  
Maria Ignat
Keyword(s):  
Ion Exchange ◽  
Metal Content ◽  
Pulse Method ◽  
Acid Strength ◽  
Strength Distribution ◽  
Zeolite Catalysts ◽  
Acidic Properties ◽  
Mfi Zeolites ◽  
Acid Strength Distribution ◽  
Heptane Conversion

The conversion of n-heptanes by the chromatographic pulse method in the temperature range of 673 - 823K on the MFI zeolites modified by ion exchange with Ni(NO3)2 aqueous solutions was studied. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ni-HZSM-5 (wt. % Ni, 0.57, 1.09, 1.34,) having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The highest selectivity for n-heptanes aromatization was obtained on the catalyst Ni3-HZSM-5 (wt. % Ni 1.34) at 823K. The metal actions and the acidic properties of zeolites have an important effect on the aromatization of n-heptanes.

Decomposition of hydrogen peroxide on a two-component NiO-CdO catalyst and the effect of ionizing radiation on its catalytic properties

1979 ◽  
Vol 44 (4) ◽  
pp. 1015-1022 ◽  
Author(s):  
Viliam Múčka
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Nickel Oxide ◽  
Catalytic Properties ◽  
Cadmium Oxide ◽  
Chemisorb Oxygen ◽  
Composition Region ◽  
Chemisorbed Oxygen ◽  
Two Component

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.

scholarly journals Selective Production of Aromatics from 2-Octanol on Zinc Ion-Exchanged MFI Zeolite Catalysts

Catalysts ◽  
2015 ◽  
Vol 5 (4) ◽  
pp. 2122-2133 ◽  
Author(s):  
Masakazu Iwamoto ◽  
Ryota Takezawa ◽  
Masao Morimoto
Keyword(s):  
Zinc Ion ◽  
Zeolite Catalysts ◽  
Mfi Zeolite

The catalytic activity of microporous and mesoporous NiCoBeta zeolite catalysts in Fischer–Tropsch synthesis

2021 ◽  
Vol 47 (1) ◽  
pp. 397-418
Author(s):  
Karolina A. Chalupka ◽  
Renata Sadek ◽  
Lukasz Szkudlarek ◽  
Pawel Mierczynski ◽  
Waldemar Maniukiewicz ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Tropsch Synthesis ◽  
Zeolite Catalysts ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis

scholarly journals A diffusion anisotropy descriptor links morphology effects of H-ZSM-5 zeolites to their catalytic cracking performance

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiaoliang Liu ◽  
Jing Shi ◽  
Guang Yang ◽  
Jian Zhou ◽  
Chuanming Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Cracking ◽  
Catalytic Performance ◽  
Zeolite Catalysts ◽  
Time Resolved ◽  
Cracking Performance ◽  
Morphology Effect ◽  
Ft Ir ◽  
The Difference ◽  
Dynamics Simulations

AbstractZeolite morphology is crucial in determining their catalytic activity, selectivity and stability, but quantitative descriptors of such a morphology effect are challenging to define. Here we introduce a descriptor that accounts for the morphology effect in the catalytic performances of H-ZSM-5 zeolite for C4 olefin catalytic cracking. A series of H-ZSM-5 zeolites with similar sheet-like morphology but different c-axis lengths were synthesized. We found that the catalytic activity and stability is improved in samples with longer c-axis. Combining time-resolved in-situ FT-IR spectroscopy with molecular dynamics simulations, we show that the difference in catalytic performance can be attributed to the anisotropy of the intracrystalline diffusive propensity of the olefins in different channels. Our descriptor offers mechanistic insight for the design of highly effective zeolite catalysts for olefin cracking.

Study of active sites on the MFI zeolite catalysts for the transformation of ethanol into propylene

2010 ◽  
Vol 328 (1-2) ◽  
pp. 114-118 ◽  
Author(s):  
Wei Xia ◽  
Atsushi Takahashi ◽  
Isao Nakamura ◽  
Hiromichi Shimada ◽  
Tadahiro Fujitani
Keyword(s):  
Active Sites ◽  
Zeolite Catalysts ◽  
Mfi Zeolite

scholarly journals Molecular modeling of post-diffusion stage of biotissue optical clearing under effect of iohexol aqueous solution

2021 ◽  
Vol 2103 (1) ◽  
pp. 012048
Author(s):  
I T Shagautdinova ◽  
A M Likhter ◽  
K V Berezin ◽  
K N Dvoretsky ◽  
V V Nechaev ◽  
...  
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Aqueous Solution ◽  
Molecular Modeling ◽  
Biological Tissues ◽  
Optical Clearing ◽  
X Ray ◽  
Diffusion Stage ◽  
Collagen Peptide ◽  
Main Components

Abstract Interaction of iohexol (Omnipaque), an X-Ray contrast agent, with a mimetic peptide of collagen (GPH)3 as one of the main components of biological tissues has been studied with the use of methods of classical molecular dynamics (GROMACS). Complex molecular modeling of the post-diffusion stage of optical clearing allowed to evaluate such parameters as the average number of hydrogen bonds, formed between the clearing agent and collagen per unit time, and the immersion agent’s effect on changes in the collagen peptide volume. The obtained results are compared with similar results for glycerol, a polyatomic alcohol, and with the existing experimental data on the efficiency of optical clearing of these immersion agents.

scholarly journals Understanding the Catalytic Activity of Microporous and Mesoporous Zeolites in Cracking by Experiments and Simulations

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1114
Author(s):  
Shih-Cheng Li ◽  
Yen-Chun Lin ◽  
Yi-Pei Li
Keyword(s):  
Catalytic Activity ◽  
Active Site ◽  
Petrochemical Industry ◽  
Molecular Level ◽  
Shape Selectivity ◽  
Zeolite Catalysts ◽  
Hydrocarbon Cracking ◽  
Mesoporous Zeolites ◽  
Secondary Reactions ◽  
Pros And Cons

Porous zeolite catalysts have been widely used in the industry for the conversion of fuel-range molecules for decades. They have the advantages of higher surface area, better hydrothermal stability, and superior shape selectivity, which make them ideal catalysts for hydrocarbon cracking in the petrochemical industry. However, the catalytic activity and selectivity of zeolites for hydrocarbon cracking are significantly affected by the zeolite topology and composition. The aim of this review is to survey recent investigations on hydrocarbon cracking and secondary reactions in micro- and mesoporous zeolites, with the emphasis on the studies of the effects of different porous environments and active site structures on alkane adsorption and activation at the molecular level. The pros and cons of different computational methods used for zeolite simulations are also discussed in this review.

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