Search results for "catalyst"
showing 10 items of 516 documents
Ibuprofen degradation using a Co-doped carbon matrix derived from peat as a peroxymonosulphate activator
2021
The wider presence of pharmaceuticals and personal care products in nature is a major cause for concern in society. Among pharmaceuticals, the anti-inflammatory drug ibuprofen has commonly been found in aquatic and soil environments. We produced a Co-doped carbon matrix (Co-P 850) through the carbonization of Co2+ saturated peat and used it as a peroxymonosulphate activator to aid ibuprofen degradation. The properties of Co-P 850 were analysed using field emission scanning electron microscopy, energy filtered transmission electron microscopy and X-ray photoelectron spectroscopy. The characterization results showed that Co/Fe oxides were generated and tightly embedded into the carbon matrix …
Studies on ethylene/1-hexene copolymerization over the zirconocene catalyst supported on MAO-modified MgCl2(THF)2. The effect of copolymerization con…
2002
Badania dotyczą układu katalitycznego MgCl2(THF)2/MAO/Cp2ZrCl2/MAO (MAO — metyloaluminoksan). Stwierdzono, że zarówno aktywność tego układu katalitycznego, jak i właściwości kopolimerów w znacznym stopniu zależą od stosunku molowego Al:Zr (zmienianego w przedziae 1500—7000) i od temperatury kopolimeryzacji (tabele 1 i 2), natomiast wpływ czasu kopolimeryzacji jest mniejszy (tabela 3). Aktywność katalizatora oraz zawartość 1-heksenu wbudowanego do kopolimeru zwiększają się ze wzrostem temperatury i stosunku Al:Zr, a jednocześnie maleje ciężar cząsteczkowy i temperatura topnienia produktów. Ustalono także, że osadzenie katalizatora cyrkonocenowego na stosowanym nośniku powoduje zwiększenie je…
Titanium-magnesium catalysts containing tetrahydrofuran and ethyl acetate for ethylene polymerization
2000
A complex [TiCl3(THF)2(CH3CO2C2H5] (I) was used as a pre-cursor of titanium-magnesium catalysts for ethylene polymerization. The complex was ball-milled in hexane with [MgCl2(THF)2] and activated with AlEt3 used as cocatalyst for 15 min at 323 K. Ethylene was polymerized at 323 K in hexane at a pressure of 0.5 MPa. The reaction was quenched with methanolic 5% HCl and the polymer was washed with methanol and dried at 303 K for 12 h at 5 hPa. The catalyst was found to be very active. Depen-ding on the nature of the cocatalyst used, the catalyst activity varied within a range of 21.5–93.0 kg PE/(g Ti ź h) and the resulting polymer was cha-racterized by specific gravity 0.955–0.968 g/cm3, bulk …
Racemization of Secondary-Amine-Containing Natural Products Using Heterogeneous Metal Catalysts
2018
The complementary structural studies of the double metal cyanide type catalysts for the ring opening polymerization of the oxiranes
2016
Przeprowadzono badania strukturalne katalizatorów dimetalocyjankowych (DMC) z dwoma rodzajami ligandów organicznych. Zaproponowano wyjaśnienie etapów przebiegu krzywych otrzymanych metodą analizy termograwimetrycznej i różnicowej kalorymetrii skaningowej (TG/DSC) badanych katalizatorów. Wykazano obecność kilku stopni związania ligandów w kompleksach DMC. Na podstawie wyników badań z wykorzystaniem absorpcji rentgenowskiej (XAS) stwierdzono, że centrum aktywne katalizatora stanowi atom cynku. W bezpośrednim sąsiedztwie atomów Zn wykryto obecność atomów Cl, natomiast w najbliższych sferach koordynacyjnych atomu Zn nie wykryto atomów tlenu.
New substituted imidazolidinone as low loading catalyst for α-alkylation of aldehydes
2013
Recyclable Chiral Imidazolidinone Catalyst for α-Alkylation of Aldehydes
2014
Rola chlorku magnezu jako nośnika katalizatorów Zieglera-Natty
2000
Structural examination data are presented for various supports. Porosimetry (Table 2) and particle size distribution studies on MgCl 2, MgCl 2(THF) 2, Al 2O 3 as supports, carried out prior to and after ball-milling (Figs. 1, 3), suggest that MgCl 2 is beneficial as carrier because it is more liable to pretreatment (ball-milling, presence of a Lewis base) and allows its mass to be better utilized and its surface to produce catalytically active centers. Prolonged ball-milling of MgCl 2 was found to result not only in comminuted particles but also in increased specific area and larger pore volume. Studies on synthesis conditions of a vanadium precursor supported on MgCl 2(THF) 2 showed prolon…
Brookite, the least known TiO2 photocatalyst, Catalysts
2013
Brookite is the least studied TiO2 photocatalyst due to the difficulties usually encountered in order to obtain it as a pure phase. In this review, a comprehensive survey of the different methods available for preparing brookite powders and films is reported. Attention has been paid both to the most traditional methods, such as hydrothermal processes at high temperatures and pressures, and to environmentally benign syntheses using water soluble compounds and water as the solvent. Papers reporting the photocatalytic activity of pure and brookite-based samples have been reviewed.
(Photo)electrocatalytic Versus Heterogeneous Photocatalytic Carbon Dioxide Reduction
2021
The present review summarizes some of the main results achieved in electrochemical, photocatalytic, and (photo)-electrocatalytic systems for the reduction of carbon dioxide. After a preliminary survey of the electrocatalytic and photocatalytic systems in terms of materials used, efficiencies, operating conditions, and product distribution, it is shown how the combination of the two approaches affords often higher efficiency than the single technologies and allows better control of the product distribution. In fact, the peculiar energetic distribution at the interface of irradiated semiconductors under opportune electrical bias enables enhancement of the spatial separation of the photogenera…