F:Flammable;
108-20-3Relevant articles and documents
Dehydration of 2-propanol over molybdenum oxide treated with hydrogen
Matsuda, Takeshi,Hirata, Yasuyoshi,Sakagami, Hirotoshi,Takahashi, Nobuo
, p. 1261 - 1262 (1997)
Dehydration of 2-propanol was carried out at 398 K using molybdenum oxides as a catalyst. The parent MoO3 exhibited a low activity. H2 reduction at 623 K increased the dehydration activity. After the reduction for 4 h, the MoO3 became more active than USY zeolites, although the catalytic activity of MoO3 declined with time on stream. We suggest that the acidity of MoO3 was enhanced by H2 reduction at 623 K.
Study of acid-base properties of supported heteropoly acids in the reactions of secondary alcohols dehydration
Hernández-Cortez,Manríquez, Ma.,Lartundo-Rojas,López-Salinas
, p. 32 - 38 (2014)
The dehydration of secondary alcohols (propan-2-ol and 4-methylpentan-2-ol) was catalyzed by heteropolyacids (HPAs) supported on different solids. Catalysts prepared with 20 wt.% of HPAs were calcined at 400 C and characterized by X-ray diffraction, Raman spectroscopy, XPS and N2 adsorption measurements. Stability of the Keggin structure of supported HPAs and changes in textural properties of catalysts were analyzed. The catalytic conversion of alcohols to olefins and ethers has been studied over the catalysts prepared. All catalysts presented activity in the reactions, but only molybdophosphoric acid supported on ZrO2 (MoP-Z) showed selectivity in the formation of acetone and methyl isobutyl-ketone (MIBK). Catalysts with tungstosilicic acid (WSi) and Tungstophosphoric acid (WP) were active in the formation to DIPE. The acid-base properties of the catalysts play a key role in route of the reaction mechanism.
A FTIR spectroscopy study of isopropanol reactivity on alkali-metal-doped MoO3/TiO2 catalysts
Martin, Cristina,Martin, Ines,Rives, Vicente,Grzybowska, Barbara,Gressel, Irena
, p. 733 - 740 (1996)
The transformation of isopropanol on MoO3/TiO2 catalysts doped with alkali-metal cations has been studied by the pulse technique. The FTIR studies have provided evidence of the dissociative adsorption of isopropanol and the formation of isopropoxide species which decompose at higher temperatures to acetone. Catalytic measurements have shown that the addition of alkali-metal cations leads to a drastic decrease in the yield of propene, owing to the elimination of Bronsted centres originally existing on the catalyst surface, whereas the rate of dehydrogenation to acetone is affected only slightly. The extent of the changes observed depends on the nature of the doping alkali-metal cation.
Effect of the CuAl2O4 and CuAlO2 Phases in Catalytic Wet Air Oxidation of ETBE and TAME using CuO/γ-Al2O3 catalysts
Sánchez-Trinidad, Cecilia,del Angel, Gloria,Torres-Torres, Gilberto,Cervantes-Uribe, Adrián,Pavón, A. Abiu Silahua,Guerra-Que, Zenaida,Arévalo-Pérez, Juan Carlos,Tzompantzi-Morales, Fancisco J.
, p. 1143 - 1150 (2019)
This paper studies Cu/Al2O3 catalysts, synthesized in two ways: copper deposit in the synthesis of alumina (sol gel) and incipient impregnation stabilized at 400 °C. The materials were characterized by X-ray diffraction studies, nitrogen physisorption, temperature programmed reduction of H2, dehydration of isopropanol, scanning electronic microscopy, transmission electronic microscopy, which were evaluated in the liquid phase oxidation reaction of ethyl tert-butyl ether and tert-amyl methyl ether. The formation of CuAl2O4 and CuAlO2 in the samples synthesized by sol gel, led to a modification of the texture, thus resulting in an expansion of the specific area of the materials. CuAl2O4 and CuAlO2 have been identified by DRX from a content of 10 % Copper, the first showed the highest intensity with this technique. In the same way, these species favor the presence of Lewis acid sites; this is reflected in the materials with (Di-isopropyl Ether) DIPE of 96.7 % and 91.1 % for the samples SAlCu5 and SAlCu15 respectively. The catalytic activity of the materials prepared by sol gel is in the function of the number of surface acid sites, the smaller particle size of the Cu and the surface of the contact, in the case of the ETBE meanwhile for TAME the activity was based mainly on the strength of the present acid sites. With impregnated materials, the activity is attributed to the smaller particle size of the Cu and the greater strength of the surface acid sites in the solid. The formation of spinel species inhibits the leaching phenomenon in the reaction milieu.
Catalytic dehydration of propan-2-ol by lanthanum-Y zeolite
Rudham, Robert,Spiers, Andrew I.
, p. 1445 - 1448 (1997)
Catalytic dehydration of propan-2-ol has been investigated over the range 353 to 407 K on a series of LaY zeolites containing up to 9.5 lanthanum atoms per unit cell. Zero-order kinetics were obeyed, with mean activation energies of 128.5 and 139.5 kJ mol-1, respectively, for diisopropyl ether and propene formation. These activation energies, which were independent of both the temperature of catalyst activation and the extent of lanthanum exchange, are identical to those for the reaction on HY zeolites made from the same NaY starting material. Reaction is thus considered in terms of the same single Bronsted acid-site mechanism, where differences in activity arise from differences in the concentration of active sites. Progressive poisoning experiments with pyridine assess the total concentration of acid sites, which generally exceeds that which is accessible to propan-2-ol and active in catalysis.
Oxidative alkoxylation of phosphine in alcohol solutions of copper halides
Polimbetova,Borangazieva,Ibraimova, Zh. U.,Bugubaeva,Keynbay
, p. 1539 - 1544 (2016)
The phosphine oxidation reaction with oxygen in alcohol solutions of copper (I, II) halides is studied. Kinetic parameters, intermediates, and by-products are studied by means of NMR 31Р-, IR-, UV-, and ESR- spectroscopy; and by magnetic susceptibility, redox potentiometry, gas chromatography, and elemental analysis. A reaction mechanism is proposed, and the optimum conditions are found for the reaction of oxidative alkoxylation phosphine.
Catalytic properties of carbon nanotubes-supported heteropolyacids in isopropanol conversion
Kirpsza,Lalik,Mordarski,Micek-Ilnicka
, p. 254 - 262 (2018)
The technique of catalytic flow microreactor has been combined with the gas flow-through microcalorimetry to correlate the catalytic activity of supported heteropolyacids with both the acid strength of protons as well as the protons’ accessibility. Multiwall carbon nanotubes (CNT) were used as a support for Keggin (H3PW12O40) and Wells-Dawson (H6P2W18O62) structured heteropolyacids, in order to produce catalysts combining high acidity from the parent acids with the inherent microporosity of the support. Prior to the catalytic tests, the obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and Raman spectroscopies as well as by the nitrogen adsorption-desorption analysis (BET). The latter technique confirmed overall improved porosity of the obtained materials. Upon testing for activity in the isopropyl alcohol dehydration, the supported Wells-Dawson catalysts turned out to be superior to both the Keggin-based materials, as well as to the unsupported H6P2W18O62. It has been found that the improvement of catalytic performance in the isopropanol conversion is mostly related to the increase of the accessibility of protons, rather than to the changes in the acid strengths.
Amino-grafted metallosilicate MCM-41 materials as basic catalysts for eco-friendly processes
Blasco-Jiménez, Davinia,Sobczak, Izabela,Ziolek, Maria,López-Peinado, Antonio J.,Martín-Aranda, Rosa M.
, p. 119 - 125 (2010)
Thecompounds3-aminopropyl-trimethoxysilane (APMS), [3-(2-aminoethylamino) propyl]trimethoxysilane (2APMS) and 3-[2-(2-aminoethylamino)ethylamino]propyl- trimethoxysilane (3APMS) were loaded by grafting on MCM-41 matrices of various chemical compositions, aluminosilicate (AlMCM-41; Si/Al = 64) and niobosilicate (NbMCM-41; Si/Nb = 64). The materials prepared were characterized using XRD, N2 adsorption/desorption, thermogravimetric analysis, FTIR spectroscopy and elemental analysis. Thermal stability of APMS was found not to depend on the chemical composition of the support. The higher stability of 2APMS and 3APMS was related to the hydrogen bonding between amine groups and surface hydroxyls. The models of amine grafted in MCM-41 materials were proposed. Basic activity in 2-propanol dehydrogenation and Knoevenagel reactions was found strongly dependent on the nature of the support and changed in the following order: APMS/AlMCM-41> APMS/NbMCM-41. The acidity of the support is considered for the explanation of the activity sequence.
Catalytic properties of H2-reduced MoO3 with noble metal for the conversions of heptane and propan-2-ol
Uchijima, Fumiko,Takagi, Tomoaki,Itoh, Hidenobu,Matsuda, Takeshi,Takahashi, Nobuo
, p. 1077 - 1083 (2000)
Effects of H2 reduction on the catalytic properties of MoO3 with Pt, Pd, Rh, Ir, or Ru for the conversions of heptane and propan-2-ol were studied. The catalytic activity of MoO3 with noble metal for the isomerization of heptane was strongly dependent on the period of H2 reduction at 623 K. This behavior was almost the same as that of MoO3 without noble metal. Among the catalysts tested, Pt/MoO3 was the most active for this reaction. The catalytic activities of MoO3 for dehydration and dehydrogenation of propan-2-o1 also increased in proportion with the period of H2 reduction. In the case of MoO3 with noble metal, a higher dehydration activity was obtained by a longer period of H2 reduction, while the dehydrogenation activity was almost independent of the reduction period. Pt/MoO3 exhibited a high dehydration activity compared with the other catalysts, indicating the most acidic property of Pt/MoO3. We conclude from these results that the high isomerization activity of Pt/MoO3 can be attributed to its high acidity as well as to the hydrogenative and dehydrogenative properties of Pt metal.
Infrared Study of the Adsorption of Propan-2-ol on Rutile at the Solid/Vapour and Solid/Heptane Interfaces
Rochester, Colin H.,Graham, John,Rudham, Robert
, p. 2459 - 2466 (1984)
Infrared spectra of propan-2-ol adsorbed on rutile have shown that non-dissociatively adsorbed propan-2-ol is coordinatively liganded to Lewis-acidic surface sites.Dissociative chemisorption occurs at exposed Ti(4+) cations, particularly for dehydroxylated rutile, and generates isopropoxide anions.Surface hydroxyl groups on rutile were replaced by isopropoxide anions with the concomitant formation of water.Hydroxyl groups at sub-surface lattice sites were unaffected by propanol adsorption.Multilayer adsorption of propan-2-ol at high surface coverages involved the formation of molecular aggregates which were weakly bound by hydrogen-bonding interactions and which contained water molecules resulting from the chemisorptive reactions.Heat treatment of adsorbed propan-2-ol resulted in the formation of adsorbed carboxylate and possibly carbonate species.The implications of the results with respect to the dehydration of propan-2-ol catalysed by rutile are briefly discussed.
