110-71-4Relevant articles and documents
EFFECT OF MODIFIED ADDITIVES ON THE SELECTIVITY OF TRANSFORMATION OF METHANOL INTO AROMATIC HYDROCARBONS OR LOWER OLEFINS IN THE PRESENCE OF PENTASILS
Vasina, T. V.,Isaev, S. A.,Preobrazhenskii, A. V.,Rostanin, N. N.,Konoval'chikov, L. D.,et al.
, (1987)
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CONVERSION OF METHANOL INTO HYDROCARBONS IN THE PRESENCE OF MODIFIED HIGH-SILICON ZEOLITE CATALYSTS
Vasina, T. D.,Khelkovskaya-Sergeeva, E. G.,Rostanin, N. N.,Konoval'chikov, B. K.,Nefedov, B. K.,Bragin, O. V.
, p. 1347 - 1351 (1986)
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Niobia-modified aluminas prepared by impregnation with niobium peroxo complexes for dimethyl ether production
Rocha, Angela S.,Da S. Forrester, Aline M.,Lachter, Elizabeth R.,Faro Jr., Arnaldo C.,Sousa-Aguiar, Eduardo F.
, p. 104 - 111,8 (2012)
Use of a water-soluble niobium peroxo complex allowed the preparation of niobium-modified aluminas containing up to 90% of the theoretical niobia monolayer in one impregnation step. There was a maximum in the density of surface Lewis acid sites at 45% of the theoretical monolayer. FTIR of adsorbed pyridine and adsorbed CO2 suggest the vertical growth of the Nb 2O5 layer for the largest niobium contents. The addition of 22.5% of the theoretical monolayer eliminated about 80% of the basic surface hydroxyls, inhibiting the adsorption of gas phase CO2 by the samples. The niobia/alumina catalysts suffered less inhibition by CO2 than the pure alumina in the methanol dehydration reaction, confirming that Nb 2O5 is mainly deposited on sites where the CO2 adsorption is stronger, leaving free sites that are active in catalytic dehydration and less inhibited by CO2, however none of the niobia/aluminas was more active than the pure alumina. Nevertheless, in the direct syngas to DME conversion using a mixed catalyst system comprised of a CuZnAl methanol synthesis catalyst and a methanol dehydration component, the activity was significantly larger with a niobia/alumina as a dehydrating component than with the pure alumina.
Carbonylation of methanol to acetic acid using homogeneous Ru complex catalyst
Kelkar, Ashutosh A.,Kolhe, Devidas S.,Chaudhari, Raghunath V.
, p. 111 - 116 (1992)
Carbonylation of methanol to give acetic acid catalysed by Ru complexes such as trans-Ru(CO)2Cl2(PPh3)2, cis-Ru(CO)2Cl2(PPh3)2 and H2Ru(CO)(PPh3)3 is reported.The highest activity and selectivity were obtained with H2Ru(CO)(PPh3)3 as the catalyst precursor.Hydrogen increases the activity and selectivity of catalysts such as trans-Ru(CO)2Cl2(PPh3)2, cis-Ru(CO)2Cl2(PPh3)2, but has no influence on the activity and selectivity in the case of H2Ru(CO)(PPh3)3.
Marcus,Darwent,Steacie
, p. 993 (1948)
C-C Bond Formation from Dimethil Ether via a Radical Mechanism in the Presence of Strong Acid
Choukroun, Henri,Brunel, Daniel,Germain, Alain
, p. 6 - 7 (1986)
The selective radical dimerization of dimethyl ether by peroxodisulphuryl difluoride in fluorosulphuric acid, suggests that a radical intermediate for initial C-C bond formation in the conversion of methanol into hydrocarbons is a possibility.
Visualizing Element Migration over Bifunctional Metal-Zeolite Catalysts and its Impact on Catalysis
Cheng, Kang,Wang, Genyuan,Wang, Ye,Wang, Yuhao,Zhang, Qinghong,de Jong, Krijn P.,van der Wal, Lars I.
, p. 17735 - 17743 (2021)
The catalytic performance of composite catalysts is not only affected by the physicochemical properties of each component, but also the proximity and interaction between them. Herein, we employ four representative oxides (In2O3, ZnO, Cr2O3, and ZrO2) to combine with H-ZSM-5 for the hydrogenation of CO2 to hydrocarbons directed by methanol intermediate and clarify the correlation between metal migration and the catalytic performance. The migration of metals to zeolite driven by the harsh reaction conditions can be visualized by electron microscopy, meanwhile, the change of zeolite acidity is also carefully characterized. The protonic sites of H-ZSM-5 are neutralized by mobile indium and zinc species via a solid ion-exchange mechanism, resulting in a drastic decrease of C2+ hydrocarbon products over In2O3/H-ZSM-5 and ZnO/H-ZSM-5. While, the thermomigration ability of chromium and zirconium species is not significant, endowing Cr2O3/H-ZSM-5 and ZrO2/H-ZSM-5 catalysts with high selectivity of C2+ hydrocarbons.
Synthesis, characterization and molecular structures of barium(II) trichloroacetate DME/1,4-dioxane compounds
Singh, Sukhjinder,Saini, Deepika,Mehta,Kaur, Ravneet,Ferretti, Valeria
, p. 202 - 209 (2012)
Two new barium(II) trichloroacetate compounds, [Ba(H2O)(DME) (μ-O2CCCl3)2]n (1) and [{Ba(H2O)2(diox)0.5(μ-O2CCCl 3)2}(diox)]n (2) were synthesized and characterized by elemental analyses, physiochemical studies, FT-IR, 1H NMR, thermogravimetric analyses (TG/DTG/DSC) and single crystal X-ray studies. The reaction of hydrated barium(II) trichloroacetate monohydrate with excess DME (1,2-dimethoxyethane) and diox (1,4-dioxane) in methanol at room temperature led to the isolation of the novel compounds 1 and 2, respectively. Bridging trichloroacetate groups are anticipated on the basis of FT-IR studies and this was confirmed by the X-ray studies. Both compounds dissociate to produce ions in water, as shown by molar conductance values. 1H NMR spectroscopy confirms that DME and 1,4-dioxane are coordinated to the metal ion in these compounds. Single crystal X-ray diffraction studies reveal that the barium cation is coordinated to nine O atoms in a deformed coordination polyhedron in both compounds. Structural data of barium(II) trichloroacetates compounds have been obtained for the first time in the present investigation.
The Ionic Hydrogen Bond. 2. Multiple NH+...O and CH?+...O Bonds. Complexes of Ammonium Ions with Polyethers and Crown Ethers
Meot-Ner (Mautner), Michael
, p. 4912 - 4915 (1983)
Complexes of ammonium ions RNH3+ (R = CH3, c-C6H11), (CH3)3NH+, and pyridineH+ with polyethers and crown ethers are observed in the gas phase in the abscence of the solvent effects.The dissociation energies, ΔH0D, of the RNH3+ polyether complexes range from 29.4 kcal mol-1 (for RNH3+*CH3OCH2CH2OCH3) to 46 kcal mol-1 (RNH3+*18-crown-6).The large ΔH0D values for complexes of polydentate ligands indicate multiple -NH+...O-hydrogen bonding.Such mutiple bonding can contribute up to 18 kcal mol-1 to the bonding in RNH3+*CH3(OCH2CH2)3OCH3 and 21 kcal mol-1 in RNH3+*18-crown-6.Multiple interactions are also evident in the (CH3)3NH+*polyether complexes where -CH?+...O-hydrogen bonding seems to occur; and consecutive -CH?+...O-bonds contribute approximately 6, 4, and 2 kcal/mol-1 respectively for up to three such bonds.Total ΔH0D values in the (CH3)3NH+*polyether complexes thus range from 26.7 kcal mol-1 in (CH3)3NH+*CH3O(CH2)2OCH3 to 41 kcal mol-1 in (CH3)3NH+*18-crown-6.Multiple interaction effects, possibly including van der Waals dispersion forces, are observed also in pyridineH+*polyether complexes.Large negative entropies in RNH3+*acyclic polyether complexes vs.RNH3+*cyclic crown ethers make the acyclic polyethers less efficient ligands.
The promoting role of Ga in ZnZrOx solid solution catalyst for CO2 hydrogenation to methanol
Han, Zhe,Li, Can,Sha, Feng,Tang, Chizhou,Tang, Shan,Wang, Jijie,Wang, Qingnan
, p. 383 - 392 (2021/11/09)
Catalytic conversion of CO2 into methanol utilizing green hydrogen produced from renewable energy is a promising route to realize carbon neutrality. Although ZnZrOx solid solution catalyst displays excellent catalytic performance, it is still highly desired to make any further improvement. Herein, we found the promoting effect of incorporating Ga into ZnZrOx solid solution catalyst in CO2 hydrogenation to methanol. Ga promoted ZnZrOx (GaZnZrOx) solid solution catalyst exhibits CO2 conversion of 8.8% and methanol space time yield of 630 mg gcat?1 h?1 that are higher than those of ZnZrOx solid solution catalyst (7.7%, 556 mg gcat?1 h?1) at 320 °C, while the highly selectivity toward methanol remains unchanged. Chemisorption and H2-D2 exchange results show that GaZnZrOx solid solution catalyst displays higher capacity for the adsorption and activation of H2 than ZnZrOx solid solution catalyst. Electron paramagnetic resonance result suggests that more oxygen vacancies are derived after incorporating Ga into ZnZrOx solid solution catalyst. In situ diffuse reflectance infrared Fourier transform spectra indicate that the HCOO* and CH3O* species are the main intermediate species. The higher IR intensity of intermediate species and lower CH3O*/HCOO* ratio on GaZnZrOx solid solution catalyst suggest that the hydrogenation of HCOO* to CH3O* is boosted. These results reveal the promoting effect of incorporated Ga into ZnZrOx solid solution catalyst that improves the adsorption and activation of H2 and CO2, thus enhancing catalytic performance of methanol synthesis from CO2 hydrogenation.
Simple and Strong Dative Attachment of α-Diimine Nickel (II) Catalysts on Supports for Ethylene Polymerization with Controlled Morphology
Kianfar, Ehsan,Azimikia, Reza,Faghih, Seyed Mohammad
, p. 2322 - 2330 (2020/02/25)
Abstract: In this article, preparation of novel spherical MgCl2 supported α-diimine nickel (II) catalysts for ethylene polymerization in slurry phase is reported. α-Diimine ligands were synthesized by condensation reaction of 2, 6-disubstituted alkyls or aryls anilines and Ace naphthoquinone Which have hydroxyl functionality in their para-position. Hydroxyl functionalized α-diimine attached strongly on to the spherical MgCl2 support surface by dative bonding. No linker was needed to attach the complexes onto the support surface and the amount of loaded Nickel was controllable to improve morphology and especially bulk density of polymer powder. A significant reduction in catalysts activity has happened when homogeneous catalysts were supported onto silica but this reduction was decreased when they were supported onto thermally treated spherical MgCl2. As homogeneous bis(N,N′-(4-(3-hydroxyl-propyl)-2,6-di[(4-tert-butyl-phenyl)-phenyl) amino] Ace naphthoquinone Nickel dibromide(d) showed the highest activity among other evaluated homogeneous catalysts, its MgCl2 supported catalyst (d/S-MgCl2) has shown the highest activity among MgCl2 supported catalysts too. These MgCl2 supported catalysts were pre-polymerized in presence of ethylene monomer in the mild polymerization condition to yield a pre-polymerized catalyst with polymer/catalyst weight ratio equal to six. Ethylene polymerization was carried out to make spherical particles of polyethylene without reactor fouling by these pre-polymerized catalysts. Clearly, it is shown in SEM images that the spherical morphology of MgCl2 support is replicated in the produced polymer. The molecular weight and molecular weight distribution of produced polymer with MgCl2 supported catalysts were higher than those produced by homogeneous catalysts. Graphic Abstract: α–Diimine nickel (II) complexes have hydroxy functionality where produce strong dative bonding onto spherical MgCl2. This bonding is strong enough that these catalysts are suitable for slurry polymerization of ethylene without reactor fouling due to catalyst leaching from support. The chemical structure of MgCl2 leads to high active supported catalysts. The molecular weight and polydispersity index of produced polymrers using these supported catalysts are higher than those produced by equivalent homogeneous catalysts and are controllable by selection of appropriate ligand for used α–diimine nickel (II) complex or hydrogen concentration in ethylene polymerization.[Figure not available: see fulltext.].