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1
Content available Charakterystyka struktury elektronowej heteropolikwasu fosforowolframowego H3PW12O40 modyfikowanego kationem Fe2+
Niemiec Piotr Jan
Science, Technology and Innovation
|
2020
|
Vol. 11, no. 4
24--32
PL
W pracy zbadano wpływ podstawienia atomu wolframu atomem żelaza w pierwszorzędowej strukturze heteropolikwasu fosforowolframowego o budowie anionu Keggina. Charakterystykę struktury elektronową zmodyfikowanego heteropolikwasu przeprowadzono za pomocą: analizy populacyjnej NBO, całkowitych (PDOS) i parcjalnych (PDOS) widm gęstości stanów, energetyki i charakteru chemicznego orbitali granicznych (HOMO/LUMO) oraz rozmiaru przerwy wzbronionej (gap). Dodatkowo zbadano mechanizm oddziaływania modyfikowanego kationem Fe2+ heteropolikwasu fosforowolframowego z cząsteczką H2O pełniącą rolę środowiska reakcji chemicznej. W większości charakterystyk stwierdzono istotny wpływ wprowadzonego metalu przejściowego na ww. właściwości w stosunku do heteropolikwasu wyjściowego H3PW12O40.
EN
In this paper the influence of substituting the tungsten atom with an iron ion in the primary structure of the phosphotungstic heteropolyacid with the Keggin anion structure was investigated. Characterization of the electronic structure of the modified heteropolyacid was performed using: population analysis according to NBO scheme, total (TDOS) and partial (PDOS) density of states spectra, energy and chemical character of frontier orbitals (HOMO/LUMO) and the size of the HOMO-LUMO band gap. Additionally, the mechanism of interaction between the Fe2+ with H2O molecule, acting as a chemical reaction medium, was investigated. Most cases showed a significant effect of the introduced transition metal ion (Fe2+) on the above-mentioned properties in relation to the nonmodified heteropolyacid H3PW12O40.
2
Content available Novel catalytic method synthesis of calix[4]pyrroles using Preyssler and Wells-Dawson heteropolyacids
Gharib A., Jahangir M., Scheeren J.(H.)W.
Polish Journal of Chemical Technology
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2011
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Vol. 13, nr 2
70-73
EN
A catalytic synthesis of calix[4]pyrroles and N-confused calix[4]pyrroles by reaction of dialkyl or cycloalkyl ketones with pyrrole was performed using Preyssler, sodium30-tungsto pentaphosphate, [NaP5W30O110]14- and Wells-Dawson heteropolyacids as acidic catalysts. The process occurred under mild, eco-friendly and environmental friendly conditions and as a reusable, green catalyst at room temperature for 6 hours. The results showed that the yield for this synthesis is excellent with the use of Preyssler and Wells-Dawson type tungstophosphoric heteropolyacid, H6[P2W18O62], catalysts. The synthesis reaction of calix[4]pyrroles and N-confused calix[4]pyrroles was developed using different solvents and the best yields were obtained in chloroform.
3
Content available Acylation of aromatic compounds by acid anhydrides using Preyssler's anion [NaP5W30O110]14- and heteropolyacids as green catalysts
Gharib A., Jahangir M., Scheeren J.(H.)W.
Polish Journal of Chemical Technology
|
2011
|
Vol. 13, nr 2
11-17
EN
The Preyssler, Wells-Dowson and Keggin heteropolyacids are efficient and eco-friendly solid acid catalysts for the acylation of electron-rich aromatic compounds with acid anhydrides. The performance of different forms of heteropolyacids was compared. In all the cases, the best results were obtained using the Preyssler heteropolyacid as the catalyst. In the presence of 25 mol% (with respect to H+ equivalency) Preyssler catalyst, highly para-selective acetylation of anisole occurs using two equivalents of acetic anhydride, in 15 min at room temperature. The isolated yield of the p-methoxyacetophenone product is 98%.
4
Content available Epoxidation of 1,5,9-cyclododecatriene with H2O2 in the presence of tungstophosphoric acid (H3PW12O40)
Wołosiak A., Lewandowski G.
Polish Journal of Chemical Technology
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2010
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Vol. 12, nr 3
40-44
EN
The influence of the technological parameters on the epoxidation of 1,5,9-cyclododecatriene (CDT) to 1,2- epoxy-5,9-cyclododecadiene (ECDD) by the phase-transfer catalysis method (PTC) in the presence of tungstophosphoric heteropolyacid (H3PW12O40) and hydrogen peroxide as the oxidizing agent has been presented. The phase-transfer catalyst was AliquatŽ 336 (methyltrioctylammonium chloride). The epoxidation of CDT to ECDD in the PTC system proceed under the relatively mild condition: low temperature, lack of solvent, short reaction time. The effect of: the mixing velocity, the molar ratio of CDT:H2O2 and H2O2:H3PW12O40, the nature of the solvent and its concentration, was studied. The most advantageous technological parameters were: the mixing rate 400 – 600 rpm, the molar ratio of CDT:H2O2= 3:1 – 1.5:1, the molar ratio of H2O2:H3PW12O40= 200:1 – 400:1, the temperature 40 – 50°C, solvent: dichloromethane or lack of the solvent, dichloromethane concentration: 10 – 50 vol%, reaction time 35 – 50 min. The application of the above-mentioned parameters allows to achieve the yield of 44 – 47% ECDD in relation to introduced CDT.
5
Content available One-pot synthesis of (S)-2-(6-methoxynaphtalen-2-yl)propanoic acid, (S)-Naproxen using Preyssler and Keggin-type heteropolyacids as green and reusable catalysts
Gharib A., Daneshtalab M., Scheeren J.(H.)W., Bamoharram F.F., Roshani M., Jahangir M.
Polish Journal of Chemical Technology
|
2009
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Vol. 11, nr 3
8-14
EN
A simple, clean and environmentally benign route to the enantioselective synthesis of (S)-2-(6-methoxynaphtalen-2-yl)propanoic acid, (S)-Naproxen 3 is described by using Preyssler heteropolyacid, H14[NaP5W30O110], as a green and reusable catalyst in water and in the presence of 1-(6-methoxynaphthalen-2-yl)propan-1-one 1, D-mannitol 2. The products were obtained in very good yields.
6
Content available Novel catalytic synthesis of 6,7-dimethoxyisatin with the use of heteropolyacids (HPAs) as acid solid catalyst
Gharib A., Daneshtalab M., Scheeren J.(H.)W., Bamoharram F.F., Roshani M., Jahangir M.
Polish Journal of Chemical Technology
|
2009
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Vol. 11, nr 3
5-7
EN
An efficient method for the preparation of 6,7-dimethoxyisatin and its derivatives was developed with good yield by using Preyssler-type heteropolyacid (HPA) as acid catalyst under green conditions. The comparison between Keggin type heteropolyacids, H3[PW12O40], H4[SiW12O40] and H4[SiMo12O40], H3[PMo12O40] and mineral acids with Preyssler's anion shows that the latter possess better catalytical activity than the other heteropolyacids and no degradation of the structure was observed.
7
Content available Acetylation of p-aminophenol by Preyssler's anion [NaP5W30O110]14-, [NaP5 W29MoO110]14- with green condition at room temperature
Gharib A., Scheeren J.(H.)W., Bamoharram F.F., Roshani M., Jahangir M.
Polish Journal of Chemical Technology
|
2009
|
Vol. 11, nr 2
31-35
EN
Synthesis of acetaminophen at green condition and room temperature in the presence of the Preyssler type heteropolyacids has been investigated in order to contribute toward clean technology, which is the most important need of the society. All of the catalysts are recyclable and reusable.
8
Content available remote Heteropolikwasy jako współczesne katalizatory reakcji estryfikacji
Witczak T., Grzesik M., Witczak M., Skrzypek J.
Przemysł Chemiczny
|
2007
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T. 86, nr 1
42-47
9
Content available The influence of the catalyst on the kinetics of ethyl metacrylate synthesis
Grzesik M., Witczak T.
Polish Journal of Chemical Technology
|
2007
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Vol. 9, nr 1
7-9
EN
The synthesis of ethyl metacrylate in the liquid phase was studied. Tungstophosphoric and molybdophosphoric acids, which belong to heteropolyacids group, were used as a catalyst. The chemical compounds from this group are often utilized in the catalysis with regard to their activity and selectivity. The rate equations, reaction rate constants and equilibrium constants have been determined. The reaction order and the kinetic parameters of the kinetic relations were determined by the integral method. All rate equations are formulated with activities taking the non ideal effects of the compounds into consideration. It was found that the kinetics of the esterification of the presented reactions was non-elementary.
10
Content available remote Zależności miedzy równoległymi reakcjami dehydratacji alkoholu izopropylowego na centrach kwasowych Bronsteda
Turek W., Krowiak A., Dębiec J., Śniechota A.
Chemik
|
2005
|
Vol. 58, nr 6
312-314
PL
Przedmiotem badań było określenie zależności miedzy reakcjami dehydratacji do propenu i do eteru diizopropylowego podczas konwersji alkoholu izopropylowego. Badania prowadzono na grupie krystalicznych heteropolikwasów: H3PMo12O14, H4PMo11VO40, H4SiMo12O40 i H3PW12O40. Badania przeprowadzono w temperaturach, w których wszystkie procesy katalityczne przebiegają w obszarze dyfuzyjnym. Stwierdzono, ze że wzrostem temperatury selektywność reakcji dehydratacji do eteru maleje, podczas gdy do propenu rośnie. Wynika z tego, iż elementarna reakcja dehydratacji alkoholu izopropylowego do eteru jest reakcją wolniejszą niż reakcja dehydratacji do propenu.
EN
The subject of the studies is determination of the relation between dehydratation to propene and diisopropyll ether during conversion of isopropyl alcohol. The experiments were performed for a group of crystalline heteropolyacids: H3PMo12O14, H4PMo11VO40, H4SiMo12O40 i H3PW12O40 in the temperature range, in which the catalytic processes are diffusion-controled. It was found that higher temperatures, the selectivity of dehydratation to diisopropyl ether increases, while the selectivity to propene increases. This observation proves that the elementary rection of isopropyl alcohol dehydratation to diisopropyl ether is slower than dehydratation of propene.
11
Content available remote A new heterogeneous catalyst for the oxidation of organic compounds by hydrogen peroxide
Łukasiewicz M., Pielichowski J.
Polish Journal of Chemical Technology
|
2004
|
Vol. 6, nr 1
31-33
EN
A series of new heterogeneous catalysts for the oxidation of aromatic and alkyl aromatic compound using hydrogen peroxide as a catalyst were prepared. The described catalytic system is based on the introduction of heteropolyacids containing tungsten atoms into the polymeric chain. Polyaniline (PANI) was chosen as a matrix for its interesting properties (conductivity, insolubility in most common organic solvents). The catalyst was synthesized in both one-step or two step methods resulting in getting materials with different catalytic properties. The whole catalyst was characterized by UV-VIS and FTIR method. The thermal properties in both neutral and oxidative conditions were also investigated during the research. The resulting heterogeneous catalyst was tested in the oxidation of anthracene by the hydrogen peroxide. The reaction was proceeding in both the microwave and conventional conditions.
12
Kinetyka syntezy akrylanu n-oktylu w obecności heteropolikwasów
Grzesik M., Gumuła T., Witczak M., Skrzypek J.
Inżynieria Chemiczna i Procesowa
|
2004
|
T. 25, z. 3/1
909-914
PL
Przedstawiono wyniki badań kinetycznych homogenicznego procesu estryfikacji kwasu akrylowego n-oktanolem w obecności kwasu wolframofosforowego i molibdenofosforowego jako katalizatorów. Eksperymenty wykonano w izotermicznym reaktorze półokresowym, z ciągłym usuwaniem wody. Równania kinetyczne i ich parametry wyznaczono na podstawie danych doświadczalnych z wykorzystaniem aktywności reagentów w fazie ciekłej. Współczynniki aktywności obliczono metodą UNIFAC.
EN
Esterification of acrylic acid with n-octanol has been studied in a homogeneous reaction system using tungstophosphoric and molybdophosphoric acid as catalysts. Experiments were carried out in an isothermal semibatch reactor with the continuous removal of water. Using the experimental data the kinetic equation and their parameters were estimated. To include a nonideality of the system, UNIF AC method was employed.
13
Content available remote New heterogeneous catalyst for oxidation of organic compounds by hydrogen peroxide
Łukasiewicz M., Pielichowski J.
Polish Journal of Chemical Technology
|
2003
|
Vol. 5, nr 3
12-14
EN
A series of new heterogeneous catalysts for oxidation of aromatic and alkyl aromatic compound using hydrogen peroxide as a catalyst were prepared. Described catalytic system is based on introduction of heteropolyacids containing tungsten atoms into the polymeric chain. Polyaniline (PANI) was chosen as a matrix in order to its interesting properties (conductivity, insolubility in most common organic solvents). The catalyst was synthesized in both one-step or two step methods resulting in materials with different catalytic properties. All catalyst was characterized by UV-VIS and FTIR method. The thermal properties in both neutral and oxidative conditions were also investigated during the research. The resulting heterogeneous catalyst was tested in oxidation of anthracene by hydrogen peroxide. The reaction was proceeding in both microwave and conventional conditions.
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