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Abstract  

β-MCM41 composite molecular sieves were hydrothermally synthesized using NaOH treated β zeolite as precursors, and Pt/β-MCM41 bifunctional catalysts were prepared by impregnation. Hβ, desilicated Hβ by NaOH treatment (Dβ), and the physical mixture of Hβ and MCM41 (β+MCM41) were also used as control supports for bifunctional catalysts. All the catalysts were characterized by ICP, XRD, BET, nitrogen adsorption–desorption isotherm and NH3-TPD, and evaluated in the hydroisomerization of n-heptane using an atmospheric fixed bed flow reactor. Dβ, β+MCM41, or β-MCM41 supported Pt catalysts showed higher selectivity to isoheptanes than the counterpart Pt/Hβ did due to the presence of mesopores in addition to the zeolite micropores. Moreover, Pt/β-MCM41 was demonstrated to be a much more selective catalyst among them because the connection between mesopores and micropores accelerated the diffusion of larger molecules of isoheptanes. Under optimal conditions, Pt/β-MCM41 provided a very high selectivity to isomerization of 96.5%, coupled with a considerable high conversion of n-heptane of 56.0%.

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Abstract  

Interaction between 1-methylnaphthalene and alkali-metal X and Y zeolites has been investigated using TPD. All spectra show only a single peak, the temperature of which changes with the nature and amount of the alkali-metal cation and the Si/Al ratio of the faujasite. A correlation between peak temperature and average charge of structural oxygen atoms of the zeolite is shown. On the basis of the atomic charge distribution in the 1-methylnaphthalene molecule, it is, suggested that adsorption is initiated by interaction between the alkali-metal cation and the carbon atom of the methyl group. Simultaneously, an interaction involving hydrogens atoms of the aromatic rings and structural oxygen atoms of the zeolite occurs, except for X samples containing high amounts of large alkali-metal cations.

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according to the BET equation. The basicity of the samples was measured by CO 2 temperature-programmed desorption (CO 2 -TPD) on Quantachrome CHEMBET-3000. 0.200 g sample was pre-treated at 550 °C for 1 h in dry He flow (50 ml/min), and cooled

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) applying the same temperature program. Thus, carbon yield could be calculated as a balance between residual masses determined after TG analyses in argon and in air. The temperature programmed desorption (TPD) measurements were carried out with use of

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aromatization of the intermediates [ 2 ]. A lot of work on NH 3 -TPD, XPS, FTIR, ESR, NMR and EXAFS [ 15 – 19 ] done by several groups showed that impregnated Mo species are mainly located on the external zeolite surface. After calcination, part of Mo species

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/customer-demand-leads-the-way-to-digitalized-banking-in-asia-pacific/ , accessed 25 / 07 / 2019 . Touchpoint Dashboard ( 2014 ): A Guide to Customer Journey Mapping . http://www.touchpointdashboard.com/wp-content/uploads/2014/03/TPD-Mapping-Guide-2014.pdf

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-programmed desorption of ammonia (NH 3 –TPD) experiments. About 100 mg of sample was used in each measurement. The samples were pretreated at 500 °C for 1 h under argon stream (20 mL min −1 ). After that, the sample was cooled down to 100 °C, and pulse NH 3 (99

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FID detector. Catalyst characterization The surface area and acidity characteristics of H-beta were obtained, respectively, by N 2 adsorption and temperature programmed desorption (TPD) of NH 3 . The catalyst

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The catalyst alkalinity was measured on a quartz microreactor (TP-5080, Tianjin-Xianquan, China) through a temperature-programmed desorption of carbon dioxide (CO 2 -TPD) experiment. About 50 mg of sample was used in each measurement. The samples were

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CO 2 conversion with time on stream. The promotional effect of CeO 2 –ZrO 2 was verified by measuring the changes of nickel crystallite size, reducibility and the extent of CO 2 activation with the help of TPR, H 2 -chemisorption, CO 2 -TPD and XRD

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