Post-synthesis incorporation of Al into germanosilicate ITH zeolites: the influence of treatment conditions on the acidic properties and catalytic behavior in tetrahydropyranylation

Post-synthesis alumination of germanosilicate medium-pore ITH zeolites was shown to be an effective procedure for tuning their acidity. Treatment of ITH zeolites synthesized with different chemical compositions (i.e. Si/Ge = 2.5, 4.4 and 5.8) with aqueous Al(NO3)(3) solution led to the formation of strong Bronsted and Lewis acid sites and an increasing fraction of ultramicro- and meso-pores in Ge-rich ITH samples (Si/Ge = 2.5 and 4.4). The concentration of Al incorporated into the framework increases with decreasing Si/Ge ratio of the parent ITH. The increasing temperature of alumination from 80 to 175 degrees C (HT conditions) resulted in (1) a 1.5-2-fold increase in the concentration of Bronsted acid sites formed and (2) a decreasing fraction of framework Al atoms detectable with base probe molecules (i.e. pyridine, 2,6-di-tert-butylpyridine), i.e. an increased concentration of the "inner" acid sites. The activity of prepared Al-substituted ITH zeolites in tetrahydropyranylation of alcohols is enhanced with increasing amount of accessible acid sites in bulky crystals (e.g. alumination at lower temperature) or with increasing total concentration of acid centres within tiny ITH crystals (e.g. alumination under HT conditions). This trend became more prominent with increasing kinetic diameter of the substrate molecules under investigation (methanol < 1-propanol < 1-hexanol).Post-synthesis alumination of germanosilicate medium-pore ITH zeolites was shown to be an effective procedure for tuning their acidity. Treatment of ITH zeolites synthesized with different chemical compositions (i.e.Si/Ge = 2.5, 4.4 and 5.8) with aqueous5529732984Czech Science Foundation [14-30898P, 13-17593P

Annulation of phenols with methylbutenol over MOFs: The role of catalyst structure and acid strength in producing 2,2-dimethylbenzopyran derivatives

The catalytic behavior of metal-organic frameworks of different structures (Fe(BTC), MIL-100(Fe), MIL-100(Cr) and Cu-3(BTC)(2)) was investigated in annulation reaction between 2-methyl-3-buten-2-ol and phenols differing in size (phenol, 2-naphthol). MIL-100(Fe) possessing intermediate Lewis acidity, perfect crystalline structure, and the highest S-BET surface area showed the highest activity (TOF = 0.7 and 1.4h(-1) for phenol and 2-naphthol, respectively) and selectivities to target benzopyran (45% and 65% at 16% of phenol and 2-naphthol conversion, respectively). The increasing strength of Lewis acid centers for MIL-100(Cr) was found to result in the dramatically decreased activity of the catalyst, while negligible conversion of phenols was found over Fe(BTC), characterized by a less ordered framework.M.O. and J.C. acknowledge the Czech Science Foundation for the support (14-07101S) and RNDr. Libor Brabec, CSc. for SEM images.Shamzhy, MV.; Opanasenko, MV.; García Gómez, H.; Cejka, J. (2015). Annulation of phenols with methylbutenol over MOFs: The role of catalyst structure and acid strength in producing 2,2-dimethylbenzopyran derivatives. Microporous and Mesoporous Materials. 202:297-302. doi:10.1016/j.micromeso.2014.10.003S29730220

Greener Method to Obtain a Key Intermediate of Vitamin E over Cu-ZSM-5

The catalytic oxidation of 2,3,5-trimethylphenol was performed over transition metals modified ZSM-5 zeolites employing hydrogen peroxide as oxidant under mild reaction conditions. Catalysts samples were characterized by several techniques (XRD, FTIR, BET, AA) and cristallinity and orthorhombic symmetry were confirmed for all of them. Best catalytic results were obtained for Cu-ZSM-5 sample, so further activity studies were done over this material. 2,3,5-trimethyl-1,4-benzoquinone was obtained as the main product of the selective oxidation. Reaction parameters (nature of the solvent, hydrogen peroxide concentration, reaction time, catalyst mass, substrate initial concentration and reaction temperature) were evaluated to reach the optimum reaction conditions. According to the obtained results, an apparent activation energy of 52.33 kJ/mol was calculated.Fil: Saux, Clara. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; ArgentinaFil: Renzini, Maria Soledad. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; ArgentinaFil: Gómez, Silvina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; ArgentinaFil: Pierella, Liliana Beatriz. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; Argentin

Current trend in synthesis, Post-Synthetic modifications and biological applications of Nanometal-Organic frameworks (NMOFs)

Since the early reports of MOFs and their interesting properties, research involving these materials has grown wide in scope and applications. Various synthetic approaches have ensued in view of obtaining materials with optimised properties, the extensive scope of application spanning from energy, gas sorption, catalysis biological applications has meant exponentially evolved over the years. The far‐reaching synthetic and PSM approaches and porosity control possibilities have continued to serve as a motivation for research on these materials. With respect to the biological applications, MOFs have shown promise as good candidates in applications involving drug delivery, BioMOFs, sensing, imaging amongst others. Despite being a while away from successful entry into the market, observed results in sensing, drug delivery, and imaging put these materials on the spot light as candidates poised to usher in a revolution in biology. In this regard, this review article focuses current approaches in synthesis, post functionalization and biological applications of these materials with particular attention on drug delivery, imaging, sensing and BioMOFs

Ensuring quality control during determination of PBC in beer, using statistic control of surrogate standard.

In the framework of a good laboratory praxis the emphasis is placed to the quality of reproducible results. For this reason are very useful methods of mathematical statistics, which in the form of regulating diagrams, can help to the speed identification of that results, which are outside the required tolerances. There are a lot of various samples used for statistical regulation. One possibility how to control the efficiency of whole analytic process, from prepearing to the final determination, is using of surrogate standard. For PCB determination in various types of water were found as a surrogate standard following two compounds: 2,4,5,6-tetrachlor-m-xylen and decachlorbifenyl. Above mentioned compounds were examined during relativly complicated of PCB in beer. The concentration was determined by Shewhart's diagrams for individual values and sliding span according to standard ČSN ISO 8258. This example of PCB determination in beer indicates the possibility to use surrogate standards as a powerful instrument for determination of results quality.In the framework of a good laboratory praxis the emphasis is placed to the quality of reproducible results. For this reason are very useful methods of mathematical statistics, which in the form of regulating diagrams, can help to the speed identification of that results, which are outside the required tolerances. There are a lot of various samples used for statistical regulation. One possibility how to control the efficiency of whole analytic process, from prepearing to the final determination, is using of surrogate standard. For PCB determination in various types of water were found as a surrogate standard following two compounds: 2,4,5,6-tetrachlor-m-xylen and decachlorbifenyl. Above mentioned compounds were examined during relativly complicated of PCB in beer. The concentration was determined by Shewhart's diagrams for individual values and sliding span according to standard ČSN ISO 8258. This example of PCB determination in beer indicates the possibility to use surrogate standards as a powerful instrument for determination of results quality

Satatystyczna analiza jakości kontroli i zanieczyszczeń piwa za pomocą standardów zastępczych

In the framework of good laboratory praxis the emphasis is placed on the quality of reproducible results. Methods of mathematic statistics are very useful for this reason. In the form of regulating diagrams they can help to quick identification of that results which are outside the required tolerances. There are a lot of various samples used for statistical regulation. One possibility how to control the efficiency of whole analytic process, from preparing to the final determination, is using of surrogate standard. 2,4,5,6-tetrachloro-m-xylene and decachlorobiphenyl were used as surrogate standards for the determination of PCB in various types of water. These compounds were examined during relatively complicate determination of PCB in beer. The concentration was determined by Shewhart’s diagrams for individual values and sliding span according to standard ČSN ISO 8258. This example of PCB determination in beer indicates the possibility of using surrogate standards as a powerful tool for determination of quality results.W ramach dobrej praktyki laboratoryjnej kładzie się nacisk na jakość uzyskanych wyników. Do ich oceny wykorzystuje się matematyczne metody statystyczne. Za pomocą schematycznych diagramów można szybko zidentyfikować wyniki pozostające poza wymaganymi granicami tolerancji. Istnieje wiele różnych metod statystycznych używanych do tych celów. Jedną z możliwości kontroli efektywności całego procesu analitycznego, od przygotowania próbki do końcowego oznaczenia, jest użycie standardów zastępczych. Do oznaczania PCB w różnych rodzajach wody użyto 2,4,5,6-tetrachloro-m-ksylenu i dekachlorobifenylu jako wzorców zastępczych. Związki te zostały zbadane podczas stosunkowo skomplikowanego oznaczania PCB w piwie. Stężenie zostało określone za pomocą schematów Shewharta dla poszczególnych wartości, zgodnie z normą ČSN ISO 8258. Ten przykład oznaczania PCB w piwie wskazuje na możliwość korzystania ze standardów zastępczych jako istotnego narzędzia do określenia jakości wyników

Application of Gel-Permeation Chromatography for Determination of Organic Pollutants in Brewing Barley.

A  method   was  developed  that   enables,  within  one extraction  step,  to  determine  nine  polycyclic  aromatic hydrocarbons    (PAH)   -    benzo(a)anthracene,   chrysene, benzo(b)fluoranthene,  benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene,    indeno(1,2,3-cd)pyrene,dibenzo(a, i)pyrene,   dibenzo(a,h)pyrene   -   and   seven  indicating congeners of polychlorinated biphenyls  (PCB) - congeners of No. 28, 52, 101, 118, 138, 153, 180 - in vegetable matrixes, mainly in  barley and malt.  The assay process  includes the description of  extraction and purification  of the acquired extract by means of the gel-permeation chromatography method with   the  use   of  gel   on  the   basis  of  polymer  of styrenedivinylbenzene   (Bio-Beads  SX-3).In   this  way  an extract   is   obtained   of   sufficient   purity  for  the determination of  both PAH and  PCB. The final  assay of PAH was  carried  out  by  the  method  of high-efficient liquid chromatography and  the assay of  PCB by gas  chromatography using the electron capture detector. All analytes can be set in microgram amounts with a relative authoritative deviation < 25 %.     The study contains characteristics of the method for all stipulated substances and speciment chromatograms.A  method   was  developed  that   enables,  within  one extraction  step,  to  determine  nine  polycyclic  aromatic hydrocarbons    (PAH)   -    benzo(a)anthracene,   chrysene, benzo(b)fluoranthene,  benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene,    indeno(1,2,3-cd)pyrene,dibenzo(a, i)pyrene,   dibenzo(a,h)pyrene   -   and   seven  indicating congeners of polychlorinated biphenyls  (PCB) - congeners of No. 28, 52, 101, 118, 138, 153, 180 - in vegetable matrixes, mainly in  barley and malt.  The assay process  includes the description of  extraction and purification  of the acquired extract by means of the gel-permeation chromatography method with   the  use   of  gel   on  the   basis  of  polymer  of styrenedivinylbenzene   (Bio-Beads  SX-3).In   this  way  an extract   is   obtained   of   sufficient   purity  for  the determination of  both PAH and  PCB. The final  assay of PAH was  carried  out  by  the  method  of high-efficient liquid chromatography and  the assay of  PCB by gas  chromatography using the electron capture detector. All analytes can be set in microgram amounts with a relative authoritative devia

Positive Contributions of Beer to Consumer's Health.

This synoptical work summarizes different findings, including  the brand-new ones, on the positive effect of beer, when  consumed in reasonable and adecuate quantity, upon health of  the population. It resumes influences of small rations of  alcohol over the incidence of cardiovascular diseases, the  tranquillizing effect on psyche, the stress reduction, and  the effect on blood pressure. The work discusses problems of  antioxidant matters present in beer and of their incidence,  putting emphasis on polyphenol matters both from malt and  hop. Attention is paid to the content of vitamins. Discussed  is even the relationship of concentration of some vitamins  and homocysteine that begins to be an important marker of  civilization illnesses, as well as abundance of  phytoestrogens in beer, their effects and contribution to the  coverage of the necessary day dose that comes from beer.  Mentioned is even the sphere of minerals and trace elements.  It is emphasized the very low concentration of heterogeneous  substances in comparison with other foodstuff. Despite of  a wide summary on findings on health effect of beer in  professional literature, we have to accept that there are  still many other substances, not discovered yet, with  important positive influence on health.This synoptical work summarizes different findings, including  the brand-new ones, on the positive effect of beer, when  consumed in reasonable and adecuate quantity, upon health of  the population. It resumes influences of small rations of  alcohol over the incidence of cardiovascular diseases, the  tranquillizing effect on psyche, the stress reduction, and  the effect on blood pressure. The work discusses problems of  antioxidant matters present in beer and of their incidence,  putting emphasis on polyphenol matters both from malt and  hop. Attention is paid to the content of vitamins. Discussed  is even the relationship of concentration of some vitamins  and homocysteine that begins to be an important marker of  civilization illnesses, as well as abundance of  phytoestrogens in beer, their effects and contribution to the  coverage of the necessary day dose that comes from beer.  Mentioned is even the sphere of minerals and trace elements.  It is emphasized the very low concentration of heterogeneous  substances in comparison with other foodstuff. Despite of  a wide summary on findings on health effect of beer in  professional literature, we have to accept that there are  still many other substances, not discovered yet, with  important positive influence on health