The Experts below are selected from a list of 28659 Experts worldwide ranked by ideXlab platform
Daniel E Resasco - One of the best experts on this subject based on the ideXlab platform.
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regeneration and oxidation reduction cycles of vapor phase and incipient wetness impregnation pt kl catalysts
Studies in Surface Science and Catalysis, 2000Co-Authors: Firoz Ghadiali, Gary Jacobs, Adriana Pisanu, Armando Borgna, Walter E Alvarez, Daniel E ResascoAbstract:The regeneration of three different Pt/KL catalysts has been studied after the n-hexane Aromatization reaction in the presence of sulfur. It has been found that regeneration in air of poisoned catalysts does not result in recovery of the Aromatization activity. After this regeneration, growth of Pt particles outside the channels of the zeolite is observed. By contrast, regeneration with addition of a halo-alcohol results in Pt redispersion and significant recovery of Aromatization activity. The preparation method employed and the presence of Tm as a promoter plays an important role in the efficiency of the regeneration procedure.
Yueqin Song - One of the best experts on this subject based on the ideXlab platform.
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an effective method to enhance the stability on stream of butene Aromatization post treatment of zsm 5 by alkali solution of sodium hydroxide
Applied Catalysis A-general, 2006Co-Authors: Yueqin Song, Yi Song, Qingxia Wang, Longya XuAbstract:The catalytic stability of ZSM-5 zeolite in butene Aromatization was improved by the treatment of ZSM-5 zeolite with sodium hydroxide solution of appropriate concentration. By characterizing pore structures, the acidity of the catalyst and the coke amount, we found that alkali-treatment of ZSM-5 led to a formation of new mesopores resulting from a preferential removal of silicon species, while the intrinsic micropores remained unchanged. As for the acidity, the amount and properties of acid sites exhibited a slight change on the alkali-treated ZSM-5 zeolites. In addition, the alkali-treatment to ZSM-5 zeolite led to only a little reduction in the amount of coke during the butene Aromatization. But a portion of coke was deposited in the newly created mesopores because of the alkali-treatment and the formation of coke in the micropores was found to be reduced. These changes can suppress the channel blockage of ZSM-5 zeolite by the coke deposits during butene Aromatization. The variation of the coking location was the main reason for the favorable enhancement in the reaction stability during butene Aromatization.
Longya Xu - One of the best experts on this subject based on the ideXlab platform.
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an effective method to enhance the stability on stream of butene Aromatization post treatment of zsm 5 by alkali solution of sodium hydroxide
Applied Catalysis A-general, 2006Co-Authors: Yueqin Song, Yi Song, Qingxia Wang, Longya XuAbstract:The catalytic stability of ZSM-5 zeolite in butene Aromatization was improved by the treatment of ZSM-5 zeolite with sodium hydroxide solution of appropriate concentration. By characterizing pore structures, the acidity of the catalyst and the coke amount, we found that alkali-treatment of ZSM-5 led to a formation of new mesopores resulting from a preferential removal of silicon species, while the intrinsic micropores remained unchanged. As for the acidity, the amount and properties of acid sites exhibited a slight change on the alkali-treated ZSM-5 zeolites. In addition, the alkali-treatment to ZSM-5 zeolite led to only a little reduction in the amount of coke during the butene Aromatization. But a portion of coke was deposited in the newly created mesopores because of the alkali-treatment and the formation of coke in the micropores was found to be reduced. These changes can suppress the channel blockage of ZSM-5 zeolite by the coke deposits during butene Aromatization. The variation of the coking location was the main reason for the favorable enhancement in the reaction stability during butene Aromatization.
Firoz Ghadiali - One of the best experts on this subject based on the ideXlab platform.
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regeneration and oxidation reduction cycles of vapor phase and incipient wetness impregnation pt kl catalysts
Studies in Surface Science and Catalysis, 2000Co-Authors: Firoz Ghadiali, Gary Jacobs, Adriana Pisanu, Armando Borgna, Walter E Alvarez, Daniel E ResascoAbstract:The regeneration of three different Pt/KL catalysts has been studied after the n-hexane Aromatization reaction in the presence of sulfur. It has been found that regeneration in air of poisoned catalysts does not result in recovery of the Aromatization activity. After this regeneration, growth of Pt particles outside the channels of the zeolite is observed. By contrast, regeneration with addition of a halo-alcohol results in Pt redispersion and significant recovery of Aromatization activity. The preparation method employed and the presence of Tm as a promoter plays an important role in the efficiency of the regeneration procedure.
Siriporn Jungsuttiwong - One of the best experts on this subject based on the ideXlab platform.
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local structure elucidation and reaction mechanism of light naphtha Aromatization over ga embedded h zsm 5 zeolite combined dft and experimental study
Microporous and Mesoporous Materials, 2020Co-Authors: Yutthana Wongnongwa, Pinit Kidkhunthod, Usa Sukkha, Sitthiphong Pengpanich, Kaewarpha Thavornprasert, Jakkrapong Phupanit, Nawee Kungwan, Gang Feng, Tinnagon Keawin, Siriporn JungsuttiwongAbstract:Abstract Local structures and mechanisms for n-pentane Aromatization on Ga embedded H-ZSM-5 zeolite (Ga/ZSM-5) were elucidated using Synchrotron-based X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations to understand the role of Ga/ZSM-5 zeolite in aromatics synthesis. XAS data suggests that Ga ligates with four oxygen or four hydrogen atoms. Catalytic tests results suggest that conversion by Ga/ZSM-5 catalyst cannot occur via C6–C8 non-aromatic intermediates, while the availability of Ga metal sites promotes the Aromatization of C2 and C3 species. Therefore, conversion of n-pentane to benzene or toluene comprises four steps, i) cracking, ii) GaH2 activation, iii) cyclization, and iv) dehydrogenation. Our model predicts the key intermediate in n-pentane Aromatization on Ga/ZSM-5 zeolite to be a five-membered Ga-C4 ring structure. The ring undergoes expansion to form a seven-membered Ga-C6 ring. Moreover, we discuss thermodynamics and kinetic results for the benzene and toluene formation pathways. Our results provide new finding for the role of Ga/ZSM-5 zeolites in n-pentane Aromatization processes.