Search for: heterogeneous-catalyst
Total 54 records
Efficient fatty acid esterification using silica supported Brønsted acidic ionic liquid catalyst: Experimental study and DFT modeling, Article Chemical Engineering Journal ; Vol. 250 , 2014 , Pages 35-41 ; ISSN: 13858947 ; Hashemi, M. M ; Sharif University of Technology
A task-specific Brønsted acidic ionic liquid (BAIL), 1-benzyl-3-methylimidazolium hydrogensulfate ([BnMIm]HSO4), was prepared and confined onto the high surface area silica gel. The catalyst has shown extraordinary activity in comparison of homogeneous ionic liquid (IL) system for Fischer esterification of fatty acid with ethanol. The ester derivatives were synthesized in high yields and catalyst was easily separated from the reaction mixture by simple filtration. The structure of the catalyst is theoretically modelized to investigate the unusual catalytic activity. Hence, a hydroxylated cage-like nano-cluster, H6Si8O12(OH)2, was selected to mimic the surface of silica gel. The interactions...
Transesterification of waste cooking oil to biodiesel using KOH/γ-Al2O3 catalyst in a new two-impinging-jets reactor, Article Industrial and Engineering Chemistry Research ; Vol. 53, Issue. 31 , 2014 , Pages 12238-12248 ; ISSN: 08885885 ; Molaei Dehkordi, A ; Sharif University of Technology
In this article, the transesterification of waste cooking oil (WCO) to biodiesel fuel (BDF) has been studied using KOH loaded on millimetric γ-Al2O3 particles in a novel type of two-impinging-jets reactor (TIJR). The effects of various parameters such as KOH loading (wt %), catalyst loading, and methanol-to-oil molar ratio on the BDF yield were studied. The catalyst particles with a KOH loading of 25 wt % at appropriate reaction conditions (i.e., catalyst loading = 4 wt % and methanol-to-oil molar ratio = 15:1) and at 65 °C were used in the TIJR. The influences of various operating and design parameters such as jet Reynolds number value, feed flow rate, jet diameter, and the internozzle...
Synthesis, characterizations and catalytic studies of a new two-dimensional metal-organic framework based on Co-carboxylate secondary building units, Article Journal of Solid State Chemistry ; Volume 223, March , 2014 , Pages 32-37 ; ISSN: 00224596 ; Ashouri, F ; Dakovic, M ; Sharif University of Technology
A metal-organic framework [Co3(BDC)3(DMF)2(H2O)2] was synthesized and structurally characterized. X-ray single crystal analysis revealed that the framework contains a 2D polymeric chain through coordination of 1,4-benzenedicarboxylic acid linker ligand to cobalt centers. The polymer crystallize in monoclinic P21 /n space group with a=13.989(3) Å, b=9.6728(17) Å, c=16.707(3) Å, and Z=2. The polymer features a framework based on the perfect octahedral Co-O6 secondary building units. The catalytic activities of [Co3(BDC)3(DMF)2(H2O)2]n for olefins oxidation was conducted. The heterogeneous catalyst could be facilely separated from the reaction mixture, and reused three times without significant...
Supported Pd nanoparticles on Mn-based metal-organic coordination polymer: Efficient and recyclable heterogeneous catalyst for Mizoroki-Heck cross coupling reaction of terminal alkenes, Article Inorganic Chemistry Communications ; Vol. 44 , 2014 , Pages 10-14 ; ISSN: 13877003 ; Ashouri, F ; Hashemi, L ; Morsali, A ; Sharif University of Technology
Supported palladium nanoparticles on Mn-carboxylate coordination polymer (Pd/MnBDC) were prepared using solution impregnation method. This new catalyst was characterized by XRD, SEM, TEM, EDX, XPS, FTIR and TGA analysis. The Pd/MnBDC exhibits efficient catalytic activity for the Mizoroki-Heck coupling reaction between iodobenzene and either aromatic or aliphatic terminal alkenes and reuses up to four runs without significant loss of activities
Immobilization of dioxomolybdenum(VI) complex bearing salicylidene 2-picoloyl hydrazone on chloropropyl functionalized SBA-15: A highly active, selective and reusable catalyst in olefin epoxidation, Article Applied Catalysis A: General ; Vol. 475 , April , 2014 , pp. 55-62 ; ISSN: 0926860X ; Zare, M ; Salemnoush, T ; Ozkar, S ; Akbayrak, S ; Sharif University of Technology
A novel organic-inorganic hybrid heterogeneous catalyst system was obtained from the reaction of the molybdenum(VI) complex of salicylidene 2-picoloyl hydrazone with mesoporous silica containing 3-chloropropyl groups prepared by a direct synthetic approach involving hydrolysis and co-condensation of tetraethylorthosilicate (TEOS) and 3-chloropropyltrimethoxysilane in the presence of the triblock copolymer P123 as template under acidic conditions. Characterization of the functionalized materials by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), N2 adsorption/desorption, FT-IR and UV-Vis spectroscopy, and thermogravimetric...
Synthesis, structural characterization and application of a 2D coordination polymer of Mn-terephthalate as a heterogeneous catalyst for olefin oxidation, Article Polyhedron ; Volume 69 , 17 February , 2014 , Pages 167-173 ; ISSN: 02775387 ; Ashouri, F ; Crossed D Signakovic, M ; Sharif University of Technology
A metal-organic coordination polymer of [Mn3(1,4- benzenedicarboxylate)3(DMF)4] ([Mn3(BDC) 3(DMF)4]n) was synthesized and characterized by IR spectra, elemental analysis (CHN), thermal gravimetric analysis (TGA) and single crystal X-ray diffraction analysis. The structure of [Mn 3(BDC)3(DMF)4]n is a 2D-periodic framework based on Mn(II)-terephthalate secondary building units (SBUs). The catalytic oxidation of various olefins was effectively carried out with [Mn 3(BDC)3(DMF)4]n. Moreover, the influence of key reaction parameters, including the solvents, reaction temperatures and nature of oxidant were studied. The optimized conditions were achieved by TBHP as the efficient oxidant in...
Interaction of ionic liquids with the surface of silica gel using nanocluster approach: A combined density functional theory and experimental study, Article Journal of Physical Organic Chemistry ; Vol. 27, issue. 2 , 2014 , pp. 163-167 ; ISSN: 08943230 ; Fattahi, A ; Sharif University of Technology
Silica gel-confined ionic liquid (IL) is a class of heterogeneous catalysts with broad catalytic applications. Leaching of the IL from the surface of the support is the major drawback of these catalysts, which reduce the catalyst efficiency during the chemical reactions. To investigate the effect of the hydrogen bonding on the leaching phenomena, the interaction between the 1-ethyl-3-methylimidazolium-based IL with various anions (Cl-, Br-, HSO4 -, NO3 -, BF 4 -, and PF6 -) and the surface of the silica gel were studied using density functional theory. Hence, a hydroxylated cage-like cluster of silica gel, Si4O6(OH), was selected to mimic the surface. The values of ÎEinteraction show that...
Thermokinetic study of Fischer-Tropsch synthesis on Fe2Cu 1 and FeCu surfaces with comparison to Fe(110) and Cu(111) catalysts by the UBI-QEP method, Article Journal of the Iranian Chemical Society ; Vol. 11, issue. 5 , 2014 , pp. 1305-1310 ; SSN: 1735-207X ; Sajjadifar, S ; Sharif University of Technology
The purpose of this study is to predict the activation barriers and enthalpy for elementary steps in the process of Fischer-Tropsch (F-T) on the surfaces of Fe(110), Cu(111) and Fe/Cu alloys catalyst using "Unity Bond Index-Quadratic Exponential Potential" method aimed at predicting the activity and selectivity on the basis of energy criteria. The elementary steps, such as dissociation of CO, hydrogenation of carbidic carbon, C-C chain growth by insertion of CH2 versus CO into the metal-alkyl bonds, and chain termination, which lead to hydrocarbons (alkanes versus α-olefins) or oxygenates are discussed in detail. The results show that metallic Fe(110) is necessary to produce the carbidic...
Gadolinium triflate immobilized on magnetic nanocomposites as recyclable Lewis acid catalyst for acetylation of phenols, Article Nanoscience and Nanotechnology Letters ; Vol. 6, issue. 4 , 2014 , p. 309-313 ; Kim, A ; Shokouhimehr, M ; Sharif University of Technology
The acetylation of phenols with acetic anhydride proceeded in excellent yields when it was catalyzed by gadolinium triflate immobilized on magnetically recyclable nanocomposites. This heterogeneous catalyst provided high catalytic activity with low loading level (1 mol%), because the Lewis acid catalyst was grafted on the surface of the nanocomposites. The catalysts were also easily recovered from the reaction mixture using a magnet and reused for six consecutive cycles
Molybdenum liquid salts immobilized on ionic liquid-modified silica as efficient heterogeneous catalysts for sulfoxide reduction, Article Tetrahedron Letters ; Volume 54, Issue 29 , 2013 , Pages 3765-3768 ; 00404039 (ISSN) ; Ghazali Esfahani, S ; Sharif University of Technology
Two room temperature liquid salts containing molybdenum(VI), [BMIM] 2[MoO2(NCS)4] (1) and [DMIM] 2[MoO2(NCS)4] (2), were immobilized on ionic liquid-modified silica leading to materials which showed notable catalytic activity for the reduction of sulfoxides into sulfides with triphenylphosphine (PPh3). The molybdenum liquid salts immobilized on the supported ionic liquid phase could be reused at least for three catalytic cycles without significant loss of activity
Article Journal of Molecular Catalysis A: Chemical ; Volume 365 , 2012 , Pages 55-59 ; 13811169 (ISSN) ; Hosseini, S. H ; Soleyman, R ; Sharif University of Technology
A dual acidic heterogeneous organocatalyst was synthesized by copolymerization of acidic ionic liquid monomer (vinyl-3-(3-sulfopropyl) imidazolium hydrogen sulfate [VSim][HSO 4]) and ionic liquid crosslinker (1,4-butanediyl-3,3′-bis-l-vinyl imidazolium dihydrogen sulfate). The resulting ionic heterogeneous catalyst is shown to be an efficient dual acidic organocatalyst for synthesis of dihydropyrimidines using the Biginelli synthetic route under mild reaction conditions in high yields. Since monomers make the catalyst bed, crosslinked poly(ionic liquid) will have high loading level of acidic groups comparing to other heterogeneous acid catalysts. Despite of conventional heterogeneous ionic...
Synthesis of some new 1,4-distyrylbenzenes using immobilized palladium nanoparticles on silica functionalized morpholine as a recyclable catalyst, Article Synthesis ; Issue 10 , 2011 , Pages 1609-1615 ; 00397881 (ISSN) ; Gharavi, A ; Nezhad, M. R. H ; Panahi, F ; Sharbati, M. T ; Sharif University of Technology
Some new 1,4-distyrylbenzene derivatives were synthesized by using immobilized palladium nanoparticles on silica-bonded N-propyl morpholine (PNP-SBNPM) as a heterogeneous catalyst. These one-pot reactions afforded a range of stereoselective, symmetrical (E)-1,4-distyrylbenzene derivatives with high yields (78-90%). The green catalyst system is recyclable and allows facile product isolation. The recycled catalyst could be reused six times without appreciable loss of catalytic activity
Manganese and cobalt-terephthalate metal-organic frameworks as a precursor for synthesis of Mn
Inorganic Chemistry Communications
; Zare, M
; Bagherzade, M
Sharif University of Technology
2O 3, Mn 3O 4 and Co 3O 4 nanoparticles: Active catalysts for olefin heterogeneous oxidation
The thermal decomposition of manganese and cobalt-terephthalate Metal-Organic Framework precursors was utilized as a synthetic route for fabrication of Co
3O 4, Mn 3O 4 and Mn 2O 3 nanoparticles. The prepared metal oxide nanoparticles of Co 3O 4, Mn 3O 4 and Mn 2O 3 possess average size diameter of 40, 60 and 80 nm respectively. The findings demonstrate that spinel structure nanoparticles of Co 3O 4 and Mn 3O 4 exhibit efficient catalytic activity toward heterogeneous olefin epoxidation in the presence of tert-butyl hydroperoxide. In...
Silver nanoparticles supported on silica-coated ferrite as magnetic and reusable catalysts for oxidant-free alcohol dehydrogenation, Article RSC Advances ; Volume 5, Issue 29 , Jan , 2015 , Pages 22503-22509 ; 20462069 (ISSN) ; Shakourian Fard, M ; Ehyaei, N ; Mahmoodi Hashemi, M ; Sharif University of Technology
Royal Society of Chemistry 2015
Silver (0) nanoparticles supported on silica-coated ferrite were synthesized to be used as an efficient and recyclable heterogeneous catalyst for oxidant-free dehydrogenation of alcohols to the corresponding carbonyl compounds. The catalyst can be easily recovered and reused for 8 reaction cycles without considerable loss of activity. The facile recovery of the catalyst is carried out by applying an external magnetic device. The catalyst was fully characterized by the techniques of TEM, SEM, XRD, EDS, ICP-AES, and VSM. This journal is
Synthesis, characterizations and catalytic studies of a new two-dimensional metal-organic framework based on Co-carboxylate secondary building units, Article Journal of Solid State Chemistry ; Volume 223 , March , 2015 , Pages 32-37 ; 00224596 (ISSN) ; Ashouri, F ; Daković, M ; Sharif University of Technology
Academic Press Inc 2015
A metal-organic framework [Co3(BDC)3(DMF)2(H2O)2] was synthesized and structurally characterized. X-ray single crystal analysis revealed that the framework contains a 2D polymeric chain through coordination of 1,4-benzenedicarboxylic acid linker ligand to cobalt centers. The polymer crystallize in monoclinic P21/n space group with a=13.989(3) Å, b=9.6728(17) Å, c=16.707(3) Å, and Z=2. The polymer features a framework based on the perfect octahedral Co-O6 secondary building units. The catalytic activities of [Co3(BDC)3(DMF)2(H2O)2]n for olefins oxidation was conducted. The heterogeneous catalyst could be facilely separated from the reaction mixture, and reused three times without significant...
Article RSC Advances ; Volume 5, Issue 38 , 2015 , Pages 29609-29617 ; 20462069 (ISSN) ; Hosseini, S. H ; Matloubi Moghaddam, F ; Ayati, S. E ; Sharif University of Technology
Royal Society of Chemistry 2015
A novel heterogeneous copper catalyst was synthesized in which poly(1-vinyl imidazole-co-ionic liquid) was used as a solid heterogeneous support. The catalyst was readily synthesized in a large scale amount. The catalyst has a high loading level of copper ions and can be used in low weight percentages. The resulting catalyst was highly active in the preparation of triazoles by the Huisgen 1,3-dipolar cycloaddition method. In some cases the catalytic turnover number and frequency reached 70 002 and 3889 h-1, respectively. The catalyst was recycled many times without significant loss of activity. This journal is
Immobilized tungstate on magnetic poly(2-ammonium ethyl acrylamide): A high loaded heterogeneous catalyst for selective oxidation of sulfides using H2O2, Article Journal of Industrial and Engineering Chemistry ; Volume 44 , 2016 , Pages 73-81 ; 1226086X (ISSN) ; Hosseini, S. H ; Pourjavadi, A ; Soleyman, R ; Bennett, C ; Sharif University of Technology
Korean Society of Industrial Engineering Chemistry 2016
A heterogeneous tungstate-based catalyst has been prepared for selective oxidation of sulfides to sulfoxides in the presence of 30% H2O2. The catalyst was prepared via immobilization of high amounts of WO4 2− onto the cross-linked poly(ammonium ethyl acrylamide) coated magnetic nanoparticles (MNP). FT-IR, TEM, TGA, VSM, XRD, EDX, and CHN analysis were used for characterization of catalyst. Variety of sulfides successfully converted to the related sulfoxides using 1 mol% of catalyst at room temperature in high yields. The catalyst was easily recovered and reused up to 6 times without loss of activity
Vanadium–Schiff base complex-functionalized SBA-15 as a heterogeneous catalyst: synthesis, characterization and application in pharmaceutical sulfoxidation of sulfids, Article Research on Chemical Intermediates ; Volume 42, Issue 12 , 2016 , Pages 8201-8215 ; 09226168 (ISSN) ; Karimi, H ; Sadeghi Abandansari, H ; Sharif University of Technology
VO2(picolinichydrazone) complex as a catalyst was stabilized on a SBA-15 mesoporous silica as a catalytic support by using (3-chloropropyl)triethoxysilane as a connector. SBA-15 is nanoporous and has a high ratio of surface area to volume. The immobilization of a metal–Schiff base complex to the surface area of SBA-15 can improve its catalytic effects by increasing the catalytic surface area. Unlike homogeneous catalysts, heterogeneous catalysts can be recovered and reused several times without any significant loss of catalytic activity. A vanadium–Schiff base complex-functionalized SBA-15 was synthesized by covalency connected by a pre-synthesised VO2(picolinichydrazone) complex to...
Synthesis, characterization, and catalytic activity of supported molybdenum Schiff base complex as a magnetically recoverable nanocatalyst in epoxidation reaction, Article Journal of Coordination Chemistry ; Volume 69, Issue 4 , 2016 , Pages 668-677 ; 00958972 (ISSN) ; Zare, M ; Bagherzadeh, M ; Ozkar, S ; Akbayrak, S ; Sharif University of Technology
Taylor and Francis Ltd 2016
A heterogeneous nanocatalyst was prepared via covalent anchoring of dioxomolybdenum(VI) Schiff base complex on core-shell structured Fe3O4@SiO2. The properties and the nature of the surface-fixed complex have been identified by a series of characterization techniques such as SEM, EDX, XRD, TGA, FT-IR, and VSM. The synthesized hybrid material was an efficient nanocatalyst for selective oxidation of olefins to corresponding epoxides with t-BuOOH in high yields and selectivity. The catalyst could be conveniently recovered by applying an external magnetic field and reused several times without significant loss of efficiency. © 2016 Taylor and Francis
Magnetic starch nanocomposite as a green heterogeneous support for immobilization of large amounts of copper ions: Heterogeneous catalyst for click synthesis of 1,2,3-triazoles, Article RSC Advances ; Volume 6, Issue 23 , 2016 , Pages 19128-19135 ; 20462069 (ISSN) ; Motamedi, A ; Hosseini, S. H ; Nazari, M ; Sharif University of Technology
Royal Society of Chemistry
A new magnetic heterogeneous copper catalyst was prepared by immobilization of copper ions onto a cross-linked polymeric nanocomposite composed of starch grafted polyacrylamide and functionalized Fe3O4 magnetic nanoparticles. The resulting support was loaded with large amounts of copper ions (1.6 mmol g-1). The prepared catalyst is highly active in Huisgen 1,3-dipolar cycloaddition reactions of different azides and alkynes at low catalyst amounts. Various corresponding 1,2,3-triazoles were produced with high yields in mild conditions. The catalyst was easily recovered and reused for ten cycles of reaction and no significant loss of catalytic activity was observed