136 research outputs found

    Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide

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    The results of both chemical and XPS analysis pointed out that desilication of highly siliceous ZSM-5 of Si/Al = 164 was more effective in the surface zone than in the bulk, contrary to zeolite ZSM-5 of Si/Al = 31.6. According to the IR studies in parent zeolite the concentration of protonic sites was very close to the concentration of Al indicating that all Al atoms can form Si-OH-Al. The results of our quantitative IR studies strongly support the realumination thesis, i.e. some Al atoms extracted in basic solutions are subsequently reinserted forming new acidic hydroxyls. In desilicated zeolites all Al atoms were able to form protonic sites, however part of them dehydroxylated during the activation of zeolite producing Lewis acid sites according to the stoichiometry: one protonic site was transformed into one Lewis site. Low temperature nitrogen adsorption revealed that the alkaline treatment of highly siliceous zeolite with 0.2 M NaOH/TBAOH mixture produced mesopores of smaller diameter and narrower pore size distribution than in the case of zeolite of medium Si/Al ratio. This result can be explained by low concentration of Al which similarly as TBA(+) cations plays the role of pore directing agents (PDA). Contrary to TEA(+), the presence of Al in desilication mixture, led to the formation of larger pores. Therefore, in highly siliceous zeolite TBA(+) played dominant role as PDA producing narrower pores. Highly siliceous zeolite with uniform distribution of relatively narrow pores may be useful catalyst or catalyst support. The influence of desilication temperature on porosity development was also investigated. The increase of desilication temperature from 338 to 353 K resulted in both more extensive demetalation (more Si and Al is extracted) and the distinct increase of the volume and surface of mesopores. Both lower concentration of protonic sites and higher concentration of Lewis sites confirmed partial zeolite destruction upon desilication at elevated temperature. The experiments of pivalonitrile sorption followed by IR spectroscopy showed a significant increase of accessibility of acid sites to bulky pivalonitrile molecules. (C) 2012 Elsevier Inc. All rights reserved.The research was partially carried out with the equipment purchased thanks to the financial support of the European Regional Development Fund in the framework of the Polish Innovation Economy Operational Program (Contract No. POIG.02.01.00-12-023/08).Sadowska, K.; Góra-Marek, K.; Drozdek, M.; Kustrowski, P.; Datka, J.; Martínez-Triguero, J.; Rey Garcia, F. (2013). Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide. Microporous and Mesoporous Materials. 168:195-205. https://doi.org/10.1016/j.micromeso.2012.09.033S19520516

    Attitude towards pharmacotherapy in the course of psychotherapy : pilot study of women-psychotherapists in urban medical and psychotherapeutic centre

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    Wstęp: Nastawienia psychoterapeutów do stosowania leków psychotropowych w trakcie trwania psychoterapii, rzadko były dotychczas badane. Mogą one mieć znaczenie dla postaw i zachowań pacjentów wobec przyjmowanych przez nich leków. Może to wynikać zarówno z jawnych, jak i niejawnych komunikatów ze strony psychoterapeutów co do przyjmowania leków, a także założeń danej modalności psychoterapii. Z tego powodu nastawienia psychoterapeutów do leczenia psychofarmakologicznego powinny stać się przedmiotem świadomej refleksji. Materiał i metody: Opracowano kwestionariusz wypełniany on-line dotyczący liczby pacjentów przyjmujących leki w trakcie psychoterapii oraz nastawień psychoterapeutów do prowadzenia psychofarmakoterapii w trakcie psychoterapii. Badanie przeprowadzono w dużym ośrodku psychiatryczno-psychoterapeutycznym w Warszawie. Wyniki: Uzyskano odpowiedzi 36 psychoterapeutów, wyłącznie kobiet. Leki w trakcie psychoterapii przyjmowało jednocześnie 55,5% pacjentów, w tym 68,5% osób w trakcie terapii poznawczo behawioralnej i 47,5% osób w trakcie psychoterapii psychoanalitycznych i psychodynamicznych. Nazwy leków psychotropowych przyjmowanych przez pacjentów znało ponad 61% terapeutów. Terapeuci sami inicjowali rozmowę na ten temat leków w 52,8% przypadków lub w 36% podejmowali temat, jeśli zainicjował go pacjent. Wprowadzanie farmakoterapii w leczeniu zaburzeń niepsychotycznych za wskazane uznało 97% osób. Psychoterapeuci uważali także, że przyjmowanie przez pacjenta ma znaczenie dla procesu terapii, i może zarówno przeszkadzać jak i pomagać w jej prowadzeniu. Zdaniem osób badanych stosowanie leków jest przeważnie korzystne dla pacjenta (66% odpowiedzi twierdzących), jednak zdaniem 33% badanych możliwe są różne warianty, może być ono korzystne lub niekorzystne dla osób leczonych. Wnioski: Potrzebne są dalsze badania nad nastawieniami psychoterapeutów do leczenia psychofarmakologicznego w zmieniającej się rzeczywistości klinicznej i społecznej.Introduction: Attitudes of psychotherapist toward psychopharmacotherapy in the course of psychotherapy rarely was the subject of systematic research. Nevertheless they can have important impact on patients’ attitudes to medication and ultimately on adherence to pharmacotherapy. Psychotherapists attitudes can be expressed directly or indirectly and may by connected to psychotherapeutic modality and its theoretical assumptions. Those attitudes should be consciously reflected. Material and methods: Special questionnaire available on line was designed for the purpose of this study and mailed to psychotherapists in one urban psychiatric and psychotherapeutic centre. Results: Data were obtained from 36 psychotherapists, only women. In the course of psychotherapy 55.5% of patients was simultaneously on medication, 68,%% in the course of cognitive-behavioral therapy and 47.5% in the course of psychodynamic or psychoanalytic psychotherapy. Drug names were known to 61% of therapists. In 52.8% conversation abut medication was initiated by psychotherapist and in 36% was sustained if it was initiated by the patient. According to 97% of psychotherapists medication is indicated in some cases of non-psychotic disorders. Psychopharmacotherapy was considered as important for the psychotherapy, not neutral and both with positive and negative effects 33% of opinions. According to 66% of responders it is mostly helpful. Conclusions: More systematic researches of psychotherapists attitudes to psychopharmacotherapy are needed in the ever-changing clinical and socio-economic conditions

    Catalytic cracking performance of alkaline-treated zeolite Beta in the terms of acid sites properties and their accessibility

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    The zeolite Beta is considered as a promising additive for FCC catalyst in diesel oil production. In this article, it is shown that hierarchical zeolite Beta obtained by an optimized desilication procedure increases diesel and propylene yields during gas oil cracking reaction. The alkaline treatment of zeolite Beta (Si/Al = 22) by desilication with NaOH and NaOH&TBAOH was investigated. The catalytic performance improvement of desilicated zeolite Beta has been rationalized by deep characterization of the samples including X-ray diffraction, low-temperature adsorption of nitrogen, solid-state 29Si MAS NMR and IR studies of acidity. Finally, the catalytic performance of the zeolites Beta was evaluated in the cracking of n-decane, 1,3,5-tri-iso-propylbenzene, and vacuum gas oil. It was found that desilication with NaOH&TBAOH ensures the more uniform intracrystalline mesoporosity with the formation of narrower mesopores, while preserving full crystallinity resulting in catalysts with the most appropriated acidity and then with better catalytic performance.Also, M.C.I.L., J.M.T. and F.R. thank financial support from the Spanish Ministry of Economy and Competitiveness through the Severo Ochoa program (SEV-2012-0267) as well as operating grants Consolider Ingenio Multicat (CSD-2009-00050) and MAT-2012-3856-0O2-01.Tarach, K.; Gora-Marek, K.; Tekla, J.; Brylewska, K.; Datka, J.; Mlekodaj, K.; Makowski, W.... (2014). Catalytic cracking performance of alkaline-treated zeolite Beta in the terms of acid sites properties and their accessibility. Journal of Catalysis. 312:46-57. https://doi.org/10.1016/j.jcat.2014.01.009S465731

    Translational and rotational mobility of methanol-d(4) molecules in NaX and NaY zeolite cages: A deuteron NMR investigation

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    Nuclear magnetic resonance (NMR) provides means to investigate molecular dynamics at every state of matter. Features characteristic for the gas phase, liquid-like layers and immobilized methanol-d(4) molecules in NaX and NaY zeolites were observed in the temperature range from 300 K down to 20 K. The NMR spectra at low temperature are consistent with the model in which molecules are bonded at two positions: horizontal (methanol oxygen bonded to sodium cation) and vertical (hydrogen bonding of hydroxyl deuteron to zeolite framework oxygen). Narrow lines were observed at high temperature indicating an isotropic reorientation of a fraction of molecules. Deuteron spin-lattice relaxation gives evidence for the formation of trimers, based on observation of different relaxation rates for methyl and hydroxyl deuterons undergoing isotropic reorientation. Internal rotation of methyl groups and fixed positions of hydrogen bonded hydroxyl deuterons in methyl trimers provide relaxation rates observed experimentally. A change in the slope of the temperature dependence of both relaxation rates indicates a transition from the relaxation dominated by translational motion to prevailing contribution of reorientation. Trimers undergoing isotropic reorientation disintegrate and separate molecules become localized on adsorption centers at 166.7 K and 153.8 K for NaX and NaY, respectively, as indicated by extreme broadening of deuteron NMR spectra. Molecules at vertical position remain localized up to high temperatures. That indicates the dominating role of the hydrogen bonding. Mobility of single molecules was observed for lower loading (86 molecules/uc) in NaX. A direct transition from translation to localization was observed at 190 K. (C) 2012 Elsevier Inc. All rights reserved
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