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Wyświetlanie 1-2 z 2
Tytuł:
Palladium Catalyst in the HBIW Hydrodebenzylation Reaction. Deactivation and Spent Catalyst Regeneration Procedure
Autorzy:
Maksimowski, P.
Gołofit, T.
Tomaszewski, W.
Powiązania:
https://bibliotekanauki.pl/articles/358843.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
HBIW hydrodebenzylation
palladium-based catalyst
Pd/C deactivation
spent Pd/C catalyst regeneration
Opis:
The polycyclic nitramine 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12- hexaazaisowurtzitane (HNIW, CL-20) is synthesized via hydrodebenzylation of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (HBIW) over a palladium-based catalyst. This process is the key step in the synthesis of CL-20, a compound with unique energetic and explosive characteristics. The use of CL-20 is restricted at present by the high cost of the hydrodebenzylation process, during which the palladium-based catalyst becomes rapidly deactivated. The catalyst deactivation has now been shown to consist of deposition of the reaction products on the carbon support with simultaneous blocking of the active centers by these products. The HBIW decomposition products can permanently combine with palladium, thereby reducing the number of the active centers on the catalyst. Other byproducts clog the pores of the active carbon and reduce both the surface area of the active carbon and the pore volume. The reaction yield is also reduced by aggregation of palladium particles. A palladium catalyst regeneration procedure which has now been developed, consists of heating the catalyst for a specific time at 350 °C in a nitrogen and water vapour stream, and allows partial recovery of the activity of the palladium catalyst in a subsequent HBIW hydrodebenzylation reaction. The specific area and overall pore volume of the regenerated catalyst are also enhanced. The yield from the HBIW hydrodebenzylation reaction using the regenerated catalyst was ca. 42%.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 2; 333-348
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical Optimization of a Novel Approach for the Reductive Debenzylation of 2,4,6,8,10,12-Hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane Using Pd@SiO2 Nano Catalyst
Autorzy:
Zarandi, M.
Bayat, Y.
Zebardasti, A.
Khayrabadi, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/358766.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
Pd@SiO2
reductive debenzylation
nano
catalyst
Taguchi
Opis:
The synthesis of 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (TADB), from 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane(HBIW) is a key step in the preparation of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW or CL-20). In this study, a novel highly efficient nano catalyst based on Pd@SiO2 was used for the reductive debenzylation of HBIW. It is notable that an orthogonal array design OA9 was applied as a statistical optimization method for the synthesis of TADB. The current application of the Taguchi method in optimizing the experimental parameters of the TADB synthetic procedure was successful. TADB was synthesized by investigating the effect of the reaction conditions, such as catalyst percentage, time (h) and temperature (°C). The effects of these factors on the yield of TADB were evaluated quantitavely by the analysis of variance (ANOVA). The Pd@SiO2 nano catalyst, consisting of a palladium core with SiO2 monolayer shells, was synthesized and characterized by SEM, TEM and IR spectroscopy. The optimum condition indicated that the use of fresh Pd@SiO2 nano catalyst provides a high yield (90%). The use of Pd@SiO2 nano catalyst after recovery gave a yield of 65%.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 4; 984-995
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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