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    Metal promoted mordenite catalyst for methanol conversion into light olefins

    , Article Petroleum Science and Technology ; Vol. 32, Issue. 11 , 2014 , Pages 1349-1356 ; ISSN: 10916466 Shareh, F. B ; Kazemeini, M ; Asadi, M ; Fattahi, M ; Sharif University of Technology
    Abstract
    Methanol conversion was investigated on dealuminated mordenite (DM) as well as a series of promoted DM (i.e., metal/DM) catalysts prepared by impregnation. Prepared catalysts characterized by the powder XRD, BET, and NH3-TPD techniques. Chemical analysis was performed using induced coupled plasma (ICP) method. The conversion of methanol over different metal/mordenite catalysts was compared at 460C and WHSV of 1 h-1. Several metals including Fe, La, and Ca had been used to prepare metal/DM catalysts, which displayed high selectivity toward propylene production. Ultimately, La/DM catalyst was determined to be the best material amongst those investigated for methanol conversion based upon its... 

    Chemoselective and convenient preparation of 1,1-diacetates from aldehydes, mediated by solid lithium perchlorate under solvent-free conditions

    , Article Journal of Molecular Catalysis A: Chemical ; Volume 238, Issue 1-2 , 2005 , Pages 138-141 ; 13811169 (ISSN) Ziyaei, A ; Azizi, N ; Saidi, M. R ; Sharif University of Technology
    2005
    Abstract
    A simple, efficient, and general method has been developed for the conversion of aldehydes to 1,1-diacetates with the use of acetic anhydride and solid LiClO4 under first solvent-free and mild conditions in good yields. This method applies to not only simple but also to conjugated aldehydes. © 2005 Elsevier B.V. All rights reserved  

    Oxovanadium(IV) complexes as homogeneous catalyst-aerobic epoxidation of olefins

    , Article Applied Catalysis A: General ; Volume 278, Issue 2 , 2005 , Pages 263-267 ; 0926860X (ISSN) Mohebbi, S ; Boghaei, D. M ; Sarvestani, A. H ; Salimi, A ; Sharif University of Technology
    2005
    Abstract
    The novel N2O2 unsymmetrical tetradentate Schiff bases complexes are used as catalysts for the selective aerobic oxidation of cyclohexene. In general, conversion percentages decrease with increasing ΔEp and decreasing Eredox 0′. Catalytic activity increases with decrease of the number of electron-donating groups and the catalytic selectivity varies according to the types of substituents in the ligands. The catalytic system described here is an inexpensive method for selective oxidation of olefins, with advantages of high activity, selectivity, re-usability and short reaction times. Analysing GC and redox potential results shows a moderate correlation between selectivity and activity. © 2004... 

    Ethylbenzene dehydrogenation to styrene over fresh and used commercial catalysts

    , Article AIChE Annual Meeting, Conference Proceedings ; 2011 ; 9780816910670 (ISBN) Baghalha, M ; Ebrahimpour, O ; Sharif University of Technology
    2011
    Abstract
    Dehydrogenation of ethylbenzene (EB) to produce styrene (ST) monomer is commercially performed over potassium-promoted iron oxide catalysts. Catalyst deactivation due to coke deposition and loss of potassium is a major operation and economic drawback in this process. To better evaluate the performance change of these catalysts over their life-cycle, dehydrogenation of EB to ST over the fresh and used commercial catalysts was experimentally investigated at temperatures from 590 to 639°C under atmospheric pressure. The fresh and the used catalysts were obtained from a styrene plant. The used catalyst had been continuously operated for two years under severe plant conditions. The catalyst... 

    Hydro-purification of crude terephthalic acid using palladium catalyst supported on multi-wall carbon nanotubes

    , Article Journal of Industrial and Engineering Chemistry ; 2015 ; ISSN: 1226086X Tourani, S ; Khorasheh, F ; Rashidi, A. M ; Safekordi, A. A ; Sharif University of Technology
    Abstract
    Palladium catalysts supported on functionalized multi-wall carbon nanotubes were synthesized for hydro-purification of crude terephthalic acid containing 2100ppm 4-carboxybenzaldehyde (4-CBA) as impurity. PdCl2 and Pd(OAc)2 were used as precursors. Palladium loadings were 0.05 to 0.6wt.% with catalysts reduced at 200 to 400°C. Catalysts prepared from both precursors with least 0.3wt.% palladium resulted in 99%+ removal of 4-CBA. The most desired selectivity was obtained for the catalyst with PdCl2 as precursor, reduction temperature of 300°C, and palladium loading of 0.3wt.%. This catalyst had slightly better performance than the commercial catalyst (0.5wt.% of palladium on activated carbon)... 

    Supported iron oxide nanoparticles: Recoverable and efficient catalyst for oxidative S-S coupling of thiols to disulfides

    , Article Catalysis Communications ; Volume 40 , 2013 , Pages 13-17 ; 15667367 (ISSN) Rajabi, F ; Kakeshpour, T ; Saidi, M. R ; Sharif University of Technology
    2013
    Abstract
    Supported iron oxide nanoparticles are found to be efficient and recoverable catalyst in the selective oxidation of thiols to their corresponding disulfides using hydrogen peroxide as green oxidant at room temperature. The protocol features an easy work-up, simplicity and the utilizing mild reaction conditions, as well as high selectivity toward disulfides, are highly advantageous compared to alternative reported methodologies. The supported iron oxide nanoparticles could be easily recovered and reused several times without any loss of activity. ICP-MS results prove that there is no metal leaching observed, and demonstrating the stability of the catalyst under the reaction conditions  

    Effect of lanthanum doping on the lifetime of Co/γ-Al 2O 3 catalysts in Fischer-Tropsch synthesis

    , Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 43, Issue 5 , September , 2012 , Pages 704-710 ; 18761070 (ISSN) Hemmati, M. R ; Kazemeini, M ; Zarkesh, J ; Khorasheh, F ; Sharif University of Technology
    Elsevier  2012
    Abstract
    Cobalt-based catalysts were prepared on gamma alumina supports, and their behaviour for different Fischer-Tropsch synthesis (FTS) conditions was assessed. Although Co/γ-Al 2O 3 is a well-known FTS catalyst, its durability ought to be improved to make the industrial process economically feasible. The effect of lanthanum doping on the catalyst lifetime was examined utilising reactor tests and catalyst characterization techniques including TPR, ICP and N 2 porosimetry. Reactor test results revealed that an optimum amount of lanthanum improved catalyst activity and selectivity. Increasing amounts of lanthanum doping up to about 1.1wt% seemed to modify the chemical composition of the support... 

    A high performance multi-walled carbon nanotube-supported palladium catalyst in selective hydrogenation of acetylene-ethylene mixtures

    , Article Applied Catalysis A: General ; Volume 399, Issue 1-2 , May , 2011 , Pages 184-190 ; 0926860X (ISSN) Bazzazzadegan, H ; Kazemeini, M ; Rashidi, A. M ; Sharif University of Technology
    2011
    Abstract
    In this research, a palladium nanocatalyst was synthesised over a multi-walled carbon nanotube (MWCNT) support and then applied for selective hydrogenation of acetylene in an ethylene-richflow stream. This material displayed a very promising selectivity toward ethylene production with increasing temperature, and also suppressed oligomer formation during acetylene hydrogenation. New operating conditions for selective hydrogenation of acetylene in an ethylene-richflow were introduced. This nanocatalyst gave a considerably higher yield, as high as 93%, than that previously obtained for ethylene production. It was postulated that the governing mechanism for acetylene hydrogenation over 0.5 wt.%... 

    Hydro-purification of crude terephthalic acid using palladium catalyst supported on multi-wall carbon nanotubes

    , Article Journal of Industrial and Engineering Chemistry ; Volume 28 , August , 2015 , Pages 202-210 ; 1226086X (ISSN) Tourani, S ; Khorasheh, F ; Rashidi, A. M ; Safekordi, A. A ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2015
    Abstract
    Palladium catalysts supported on functionalized multi-wall carbon nanotubes were synthesized for hydro-purification of crude terephthalic acid containing 2100ppm 4-carboxybenzaldehyde (4-CBA) as impurity. PdCl2 and Pd(OAc)2 were used as precursors. Palladium loadings were 0.05 to 0.6wt.% with catalysts reduced at 200 to 400°C. Catalysts prepared from both precursors with least 0.3wt.% palladium resulted in 99%+ removal of 4-CBA. The most desired selectivity was obtained for the catalyst with PdCl2 as precursor, reduction temperature of 300°C, and palladium loading of 0.3wt.%. This catalyst had slightly better performance than the commercial catalyst (0.5wt.%... 

    In situ generation of highly active bis(N-heterocyclic)carbene palladium as an efficient catalyst in direct S-arylation of methylphenyl sulfoxide and the Heck reaction: Ligand steric effects in product selectivity

    , Article Applied Organometallic Chemistry ; 2016 ; 02682605 (ISSN) Bagherzadeh, M ; Mousavi, N ; Jamali, S ; Sharif University of Technology
    John Wiley and Sons Ltd 
    Abstract
    The use of 1,3-bis(N-heterocyclic)carbene ligands with different alkyl wingtip groups (alkyl = methyl, isopropyl and tert-butyl) is an effective method for the palladium-catalysed direct S-arylation of methylphenyl sulfoxide and C-C coupling of various of aryl halides with alkenes. The reactions proceed in moderate to good yields. Interestingly, it is shown experimentally that, by using bulkier bidentate N-heterocyclic carbene ligands, more selective catalytic systems towards cis products in Heck coupling reactions can be achieved  

    Synthesis and characterization of magnetic silica-supported Mn(II)-substituted polyoxophosphotungstate as catalyst in sulfoxidation reaction

    , Article Journal of Nanoparticle Research ; Volume 18, Issue 10 , 2016 ; 13880764 (ISSN) Moradi Shoeili, Z ; Zare, M ; Bagherzadeh, M ; Sharif University of Technology
    Springer Netherlands  2016
    Abstract
    Abstract: Polyoxometalate-functionalized magnetic nanoparticles (Fe3O4@SiO2–MnPOW) were successfully synthesized via covalent anchoring of Mn(II)-substituted phosphotungstate on ammonium-modified Fe3O4@SiO2 nanoparticles. The complete characterization of nanoparticles has been carried out by scanning electron microscope, energy-dispersive X-ray, X-ray diffraction, Fourier transform infrared and elemental analysis. The resulting nanocomposites were efficient catalysts for the selective oxidation of sulfides with different green oxidants in good to excellent yields and also high selectivity. Leaching and recycling tests showed that the nanocatalyst can be reused several times without... 

    In situ generation of highly active bis(N-heterocyclic)carbene palladium as an efficient catalyst in direct S-arylation of methylphenyl sulfoxide and the Heck reaction: Ligand steric effects in product selectivity

    , Article Applied Organometallic Chemistry ; Volume 31, Issue 8 , 2017 ; 02682605 (ISSN) Bagherzadeh, M ; Mousavi, N. A ; Jamali, S ; Sharif University of Technology
    John Wiley and Sons Ltd  2017
    Abstract
    The use of 1,3-bis(N-heterocyclic)carbene ligands with different alkyl wingtip groups (alkyl = methyl, isopropyl and tert-butyl) is an effective method for the palladium-catalysed direct S-arylation of methylphenyl sulfoxide and C–C coupling of various of aryl halides with alkenes. The reactions proceed in moderate to good yields. Interestingly, it is shown experimentally that, by using bulkier bidentate N-heterocyclic carbene ligands, more selective catalytic systems towards cis products in Heck coupling reactions can be achieved. Copyright © 2016 John Wiley & Sons, Ltd  

    Formation of a catalytically active intermediate for oxidation in H2O2/ionic liquid system: experimental and theoretical investigations

    , Article Research on Chemical Intermediates ; Volume 43, Issue 4 , 2017 , Pages 2615-2625 ; 09226168 (ISSN) Alinezhad, H ; Vafaeezadeh, M ; Mahmoodi Hashemi, M ; Sharif University of Technology
    Springer Netherlands  2017
    Abstract
    Abstract: A metal-free method for activation of hydrogen peroxide (H2O2) is introduced using piperidinium trifluoroacetate (PPHTFA) ionic liquid as catalyst. The catalyst has been used for selective oxidation of thioanisole to its corresponding sulfoxide at room temperature. It was found that the selectivities were reduced by increasing the reaction temperature. In this work, no organic solvents or metallic salts were used for activation of H2O2. Mechanistic studies suggested that the reaction proceeds via in situ formation of trifluoro hydroperoxy species as an active catalytic intermediate. Formation of the catalytic intermediate was screened by NMR, IR and Mass Spectroscopy analysis.... 

    Heterogeneous SBA-15-supported oxoperoxomolybdenum(VI) complex for enhanced olefin epoxidation

    , Article Catalysis Communications ; Volume 88 , 2017 , Pages 9-12 ; 15667367 (ISSN) Zare, M ; Moradi Shoeili, Z ; Ashouri, F ; Bagherzadeh, M ; Sharif University of Technology
    Abstract
    Heterogeneous nanoscale catalyst was successfully synthesized via anchoring of oxoperoxo molybdenum(VI) complex on the chloro-functionalized SBA-15. The mesoporous nanomaterials, MoO3(sal-phz)/SBA-15 (where sal-phz is salicylidene 2-picoloyl hydrazine) were identified by several characterization techniques. MoO3(sal-phz)/SBA-15 and MoO3(sal-phz) were also treated as catalysts in the olefins epoxidation reactions. Both homogenous and heterogeneous catalysts exhibit outstanding activity and selectivity for epoxide with tert-BuOOH in decane as oxidant at 95 °C. In addition, the heterogeneous nanocatalyst was chemically stable and can be efficiently reused for at least six cycles without a... 

    A study on the effect of SiO2/Al2O3 ratio on the structure and performance of nano-sized ZSM-5 in methanol to propylene conversion

    , Article Reaction Kinetics, Mechanisms and Catalysis ; Volume 121, Issue 2 , 2017 , Pages 763-772 ; 18785190 (ISSN) Jabbari, A ; Abbasi, A ; Zargarnezhad, H ; Riazifar, M ; Sharif University of Technology
    Abstract
    The effect of SiO2/Al2O3 ratio on high silica content nano-sized HZSM-5 stability and selectivity in conversion of methanol to propylene (MTP) has been investigated in a continuous flow isotherm fixed-bed reactor. Highly crystalline HZSM-5 zeolite samples with SiO2/Al2O3 ratios ranging 150–200 have been prepared and characterized using XRD, ICP-AES analytical techniques, NH3-TPD, BET surface area and SEM imaging for studying their physical and chemical behavior. The reaction was conducted at 480 °C and 1bar with WHSV = 1 h−1 and a solution with 1:1 wt% of methanol and water as feed. Over thoroughly monitoring the catalyst synthesis conditions, the nanocrystal ZSM-5 zeolite samples were... 

    Oxazine containing molybdenum(VI)–oxodiperoxo complex immobilized on SBA-15 as highly active and selective catalyst in the oxidation of alkenes to epoxides under solvent-free conditions

    , Article Microporous and Mesoporous Materials ; Volume 251 , 2017 , Pages 173-180 ; 13871811 (ISSN) Zare, M ; Moradi Shoeili, Z ; Esmailpour, P ; Akbayrak, S ; Özkar, S ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    Molybdenum(VI)–oxodiperoxo complex containing an oxazine ligand, ([MoO(O2)2(phox)], phox: 2-(2′-hydroxyphenyl)-5,6-dihydro-1,3-oxazine) was conveniently synthesized and immobilized onto chloro-functionalized mesoporous silica SBA-15 by covalent bonding between the chloropropyl group on the internal surface of the pores and the nitrogen atom of oxazine ligand yielding [MoO(O2)2(phox)]/SBA-15. The resulting material was characterized by FT-IR, TGA, XRD, SEM, TEM, EDX, ICP-AES, BET and UV–vis spectroscopy. The heterogeneous catalyst [MoO(O2)2(phox)]/SBA-15 was employed in the epoxidation of alkenes, exhibiting high catalytic performance and selectivity for epoxide similar to that of homogeneous... 

    Green and selective oxidation of alcohols by immobilized Pd onto triazole functionalized Fe 3O 4 magnetic nanoparticles

    , Article Journal of Chemical Sciences ; 2018 ; 09743626 (ISSN) Dadras, A ; Naimi Jamal, M. R ; Matloubi Moghaddam, F ; Ayati, S. E ; Sharif University of Technology
    Abstract
    Abstract: Carbonyl compounds were prepared by selective oxidation of alcohols in the presence of recoverable Fe 3O 4@ SiO 2@ Pd magnetic nanocatalyst in aqueous media as a green solvent. Molecular oxygen served as an oxidant. The catalyst was removed from the reaction media by external magnetic field, washed with methanol, and reused for six more times without any considerable reduction in its reactivity. The chemoselectivity and regioselectivity of the catalyst can serve for selective oxidation of primary alcohols in the presence of secondary ones, and for oxidation of unhindered alcohols in the presence of hindered ones. Graphical Abstract: Selective and facile oxidation of alcohols to... 

    Mg–Al layered double hydroxide intercalated with manganese(III) 5,10,15,20-tetrakis(4-benzoate)porphyrinacetate as a highly reusable catalyst for epoxidation

    , Article Applied Organometallic Chemistry ; 2018 ; 02682605 (ISSN) Bagherzadeh, M ; Mesbahi, E ; Sharif University of Technology
    John Wiley and Sons Ltd  2018
    Abstract
    The preparation and characterization are presented of a new catalytic material comprising Mg–Al layered double hydroxide and intercalated manganese(III) 5,10,15,20-tetrakis(4-benzoate)porphyrinacetate. Characterization was realized via various techniques. The prepared composite exhibited excellent catalytic activity in the selective epoxidation of various olefins with tetra-n-butylammonium hydrogen monopersulfate as an oxidant under mild reaction conditions. Furthermore, the catalytic system could be reused nine times without significant reduction in conversion percentage and any special care or additional treatment of the catalyst. © 2018 John Wiley & Sons, Ltd  

    Mg–Al layered double hydroxide intercalated with manganese(III) 5,10,15,20-tetrakis(4-benzoate)porphyrinacetate as a highly reusable catalyst for epoxidation

    , Article Applied Organometallic Chemistry ; Volume 33, Issue 1 , 2019 ; 02682605 (ISSN) Bagherzadeh, M ; Mesbahi, E ; Sharif University of Technology
    John Wiley and Sons Ltd  2019
    Abstract
    The preparation and characterization are presented of a new catalytic material comprising Mg–Al layered double hydroxide and intercalated manganese(III) 5,10,15,20-tetrakis(4-benzoate)porphyrinacetate. Characterization was realized via various techniques. The prepared composite exhibited excellent catalytic activity in the selective epoxidation of various olefins with tetra-n-butylammonium hydrogen monopersulfate as an oxidant under mild reaction conditions. Furthermore, the catalytic system could be reused nine times without significant reduction in conversion percentage and any special care or additional treatment of the catalyst. © 2018 John Wiley & Sons, Ltd  

    Mg–Al layered double hydroxide intercalated with manganese(III) 5,10,15,20-tetrakis(4-benzoate)porphyrinacetate as a highly reusable catalyst for epoxidation

    , Article Applied Organometallic Chemistry ; Volume 33, Issue 1 , 2019 ; 02682605 (ISSN) Bagherzadeh, M ; Mesbahi, E ; Sharif University of Technology
    John Wiley and Sons Ltd  2019
    Abstract
    The preparation and characterization are presented of a new catalytic material comprising Mg–Al layered double hydroxide and intercalated manganese(III) 5,10,15,20-tetrakis(4-benzoate)porphyrinacetate. Characterization was realized via various techniques. The prepared composite exhibited excellent catalytic activity in the selective epoxidation of various olefins with tetra-n-butylammonium hydrogen monopersulfate as an oxidant under mild reaction conditions. Furthermore, the catalytic system could be reused nine times without significant reduction in conversion percentage and any special care or additional treatment of the catalyst. © 2018 John Wiley & Sons, Ltd