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1
Content available remote Synthesis of polyaniline nanotubes through UV light catalytic method
Sun C., Wang Y.
Materials Science Poland
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2015
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Vol. 33, No. 1
193--197
EN
In this study, nitrocellulose (NC) fiber blanket prepared by electrostatic spinning method has been used as a template, and copper nitrate (Cu(NO3)2)) as an oxidant to synthesise polyaniline nanotubes doped with heteropolyacid (H4)SiW12)O40), SiW12) using UV light catalytic method. Infrared spectroscopy (IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) technologies were applied to characterize the prepared samples of polyaniline nanotubes. The results show that the external diameter of the tube is about 200 nm, and the internal diameter about 170 nm. We also give a reasonable speculation and explanation about the formation mechanism of the nanotubes.
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 Catalytic synthesis of warfarin acetals by using different heteropolyacid catalysts
Gharib A., Jahangir M., Roshani M., Scheeren J. W., Mohadeszadeh S., Bakhtiari L., Lagzian S.
Polish Journal of Chemical Technology
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2011
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Vol. 13, nr 3
5-11
EN
In this research, we report on the synthesis of warfarin acetals by using Preyssler's anion, [NaP5W30O110]-14 and heteropolyacids (HPAs) catalysts. This reaction was performed using methanol and ethanol at reflux temperature conditions. Under these conditions we have excellent yields and high selectivity. Preyssler heteropolyacid catalyst were easily recycled recovery and reused without the loss of its catalytic activities. The synthesis of warfarin acetals has been achieved using the catalytic amounts of green, inexpensive and eco-friendly Keggin types heteropolyacids. The products were obtained in high yields.
4
Content available Dinitrotoluene Synthesis Using Solid State Catalysts - MoO3/SiO2 and H3PO4/MoO3/SiO2
Adamiak J., Skupiński W.
Central European Journal of Energetic Materials
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2010
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Vol. 7, nr 3
301-311
EN
Dinitrotoluene (DNT) has a lot of applications. It is mainly used in the production of polyurethane forms. Other uses include the explosives industry. It is converted to trinitrotoluene (TNT), or used as an additive in propellants. The main aim of these researches was to obtain DNT in one stage process with solid acid catalyst and nitric acid. The solid catalysts were composed of transition metal oxide (MoO3) and silica gel. One of them was modifed by phosphoric acid (H3PO4/MoO3/SiO2). The addition of phosphoric acid to these catalysts enhances catalytic properties and gives new structures on the surface – mixture of MoO3 and 12-molybdophosphoric acid. The activity of two catalysts in toluene nitration was compared. Higher yields of DNT were obtained in shorter time and with lower excess of HNO3 using modifed catalyst H3PO4/MoO3/SiO2 than using catalyst MoO3/SiO2. The very high yield of DNT (85%) was obtained in the reaction with only tenfold excess of nitric acid with 10 g of H3PO4/MoO3/SiO2. The way of regeneration of the catalyst system H3PO4/MoO3/SiO2 was found and time of storing was examined.
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
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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
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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
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2009
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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 Kinetics of esterification of methacrylic acid with n-butanol and butanol-2 in the presence of some heteropolyacids as catalysts
Witczak T.
Chemical and Process Engineering
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2008
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Vol. 29, z. 4
869-882
EN
The results of investigations of kinetics of esterification of methacrylic acid with n-butanol and butanol- 2 in the presence of some heteropolyacids as catalysts have been presented. In the study, the effects of temperature, initial concentration and concentration of the catalyst on the course of the esterification process have also been determined. The parameters of kinetic equations and the equlibrium constants have been established. It was found that the kinetics investigate reactions is non-elementary.
PL
Przedstawiono wyniki badań kinetycznych estryfikacji kwasu metakrylowego n-butanolem i butanolem- 2, w obecności wybranych heteropolikwasów jako katalizatorów. Oceniono wpływ temperatury, początkowego stosunku molowego reagentów oraz stężenia katalizatora na przebieg procesu. Wyznaczono parametry równań kinetycznych oraz stałe równowagi chemicznej. Dla badanych reakcji uzyskano nieelementarną postać równania kinetycznego.
9
Content available remote Zależności miedzy równoległymi reakcjami dehydratacji alkoholu izopropylowego na centrach kwasowych Bronsteda
Turek W., Krowiak A., Dębiec J., Śniechota A.
Chemik
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2005
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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.
10
Influence of heteropoly acid and USY zeolite on activity of ZSM-5 containing catalysts.
Grzechowiak J. R., Masalska A.
Prace Naukowe Instytutu Chemii i Technologii Nafty i Węgla Politechniki Wrocławskiej. Konferencje
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2002
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Vol. 10, nr 57
343-348
EN
Activity and selectivity of Ni/ZSM-5+Al2O3 catalyst (8 wt.% NiO) containing 30 wt.% Ni,H-ZSM-5 were compared to those of catalysts to which USY zeolite, Ni,H-ZSM-5 zeolite, and heteropoly acid were added (20%). The ZSM-5 containing catalyst modified with heteropoly acid was less active than those modified by zeolite (USY, ZSM-5). N-Hexane conversion was highest for the catalyst contg. 50 wt.% zeolite. The yield of hydrocracking products was higher for the catalyst contg. 50 wt.% ZSM-5 than that of catalyst containing 30 wt.% ZSM-5 and 20 wt.% USY zeolites. Modification of the ZSM-5 containing catalyst did not result in higher yield of isomerization products.
11
Solid acids as catalysts for cumene cracking: heteropolyacids as compared with zeolites. Part. 1. Reaction and coke formation
Małecka-Lubańska A., Poźniczek J.
Bulletin of the Polish Academy of Sciences. Chemistry
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2002
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Vol. 50, No.2
219-236
EN
The catalytic properties of dodecatungstosilicic acid H(4)SiW(12)O(40 (HPA) and NaHY-88 zeolite in cumene cracking reaction were compared. HPA exhibits catalytic activity at temperatures lower (below 160° C) than NaHY-88 (above 170°C) but its deacti-vation is faster. Mass balance shows that in both cases a certain deficit exists due to the formation of carbonaceous deposits. It has been shown that in the formation of deposits both chain hydrocarbons ("propylene deposit") and aromatic ones ("cumene deposit") participate. In the case of both catalysts the course of catalytic reaction and deposit formation were influenced by the contact time. The results enabled us also to propose some conclusions concerning the geometry of deposit distribution in both catalysts.
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