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A simple, economical, and catalyst-free oxidation of thiols to disulfides
, Article Journal of Sulfur Chemistry ; Volume 30, Issue 6 , 2009 , Pages 578-580 ; 17415993 (ISSN) ; Hashemi, M. M ; Sharif University of Technology
Abstract
A simple, rapid, and highly efficient method for the preparation of symmetrical aliphatic, aromatic, and heteroaromatic disulfides is reported. Addition of NBS to an alkyl- or arylthiol under catalyst-free conditions in dichloromethane solution produces the corresponding disulfides in nearly quantitative yields
Transesterification of canola oil to biodiesel using CaO/Talc nanopowder as a mixed oxide catalyst
, Article Chemical Engineering and Technology ; Volume 40, Issue 10 , 2017 , Pages 1923-1930 ; 09307516 (ISSN) ; Kazemeini, M ; Bastan, F ; Sharif University of Technology
Abstract
A series of heterogeneous catalysts including different molar ratios of CaO/talc was synthesized to study the transesterification reaction of canola oil and methanol under different reaction conditions. Characterization and kinetic results revealed that the activity of this catalyst was enhanced due to the increase of CaO/talc molar ratio value leading to an improvement in the biodiesel production. Moreover, the effect of various parameters on the activity of the undertaken catalysts was studied in order to determine the optimum process conditions. Leaching measurements and the durability of the CaO/talc catalyst under several reaction cycles were evaluated and proved it to be a stable...
Organocopper-based magnetically recoverable and reusable nanocatalyst for efficient synthesis of novel 1,2,3-triazole-based sulfonamides in green medium
, Article Research on Chemical Intermediates ; Volume 44, Issue 1 , 2018 , Pages 601-612 ; 09226168 (ISSN) ; Sadighian, H ; Arabgari, M ; Mirjafary, Z ; Ayati, S. E ; Najafi, E ; Matloubi Moghaddam, F ; Sharif University of Technology
Springer Netherlands
2018
Abstract
Abstract: We report robust green synthesis of novel 1,2,3-triazole-based sulfonamides bearing different motifs such as fluorine under click conditions in presence of a copper-based magnetically recoverable and reusable heterogeneous nanocatalyst. The organocopper catalyst at 0.5 mol.% was highly recyclable (up to five times) when recovered using an external magnet without significant loss in catalytic activity. The mild reaction conditions and excellent yields (69–95 %) make this protocol an attractive method for efficient synthesis of the title compounds. The structure of product 3a was determined by Röntgen crystal structure analysis. Graphical Abstract: [Figure not available: see...
A catalyzed method to remove polychlorinated biphenyls from contaminated transformer oil
, Article Environmental Science and Pollution Research ; 2021 ; 09441344 (ISSN) ; Gholipour Zanjani, N ; Khorasheh, F ; Arjmand, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
The disposal of polychlorinated biphenyls (PCBs) as persistent organic pollutants from the environment has been normally performed by isolation from soil or water because of their biological activity and toxic potential. In the present investigation, catalytic hydrodehalogenation was used to detoxify PCBs-contaminated transformer oil. All reactions were directed on an oil containing 11.09 wt% of PCBs utilizing palladium supported on multi-walled carbon nanotubes (Pd/MWCNTs). The amount of hexa-chlorine homologues reduced considerably from 5.07% to less than 800 ppm utilizing HDC at the atmosphere of argon. Moreover, the amounts of long half-lives and bioaccumulative congener of PCB 153...
Poly(basic ionic liquid) coated magnetic nanoparticles: High-loaded supported basic ionic liquid catalyst
, Article Comptes Rendus Chimie ; Volume 16, Issue 10 , 2013 , Pages 906-911 ; 16310748 (ISSN) ; Hosseini, S. H ; AghayeeMeibody, S. A ; Hosseini, S. T ; Sharif University of Technology
2013
Abstract
A novel poly(ionic liquid) (PIL) coated magnetic nanoparticle was synthesized by distillation-precipitation-polymerization of 1-vinyl-3- ethyl imidazolium in the presence of surface modified magnetic nanoparticles. The resulting catalyst was used as magnetic heterogeneous base catalyst for the synthesis of 4H-benzo[b]pyrans in water. The separation of the catalyst from the reaction mixture was readily achieved by simple magnetic decantation and the catalyst could be easily recycled without appreciable loss of catalytic activity. Because of polymer layers coated the surface of the magnetic nanoparticles, the catalyst has a high loading level of ionic liquid
Tungstate-loaded triazine-based magnetic poly(Bis-imidazolium ionic liquid): An effective bi-functional catalyst for tandem selective oxidation/Knoevenagel condensation in water
, Article Polymer (United Kingdom) ; Volume 112 , 2017 , Pages 342-350 ; 00323861 (ISSN) ; Tavakolizadeh, M ; Hosseini, S. H ; Pourjavadi, A ; Bennett, C ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
A novel bi-functional polymeric catalyst was synthesized by immobilization of tungstate anions onto the nitrogen rich poly(ionic liquid)/magnetic nanocomposite. The resulting catalyst has two types of catalytic sites: (i) immobilized WO4 anions with bis-imidazolium ionic liquid cation for selective oxidation of alcohols and (ii) basic amine groups for Knoevenagel condensation between produced aldehyde and malononitrile. Due to the polymeric nature of the catalyst, large amounts of tungstate and basic nitrogen groups were presented on the solid surface which led to a decrease in the applied catalyst mass for catalytic reaction. High catalytic activity and excellent selectivity of catalyst in...
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) ; 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...
Studies on the catalyst preparation methods and kinetic behavior of supported cobalt catalysts for the complete oxidation of cyclohexane
, Article Reaction Kinetics, Mechanisms and Catalysis ; Volume 114, Issue 2 , Jan , 2015 , Pages 611-628 ; 18785190 (ISSN) ; Khorasheh, F ; Shayegan, J ; Sharif University of Technology
Springer Netherlands
2015
Abstract
Low cost dispersed supported cobalt oxide nanocatalysts on activated carbon (AC) were prepared by two different methods: (1) combined impregnation and deposition–precipitation (IMP-DP) and (2) heterogeneous deposition–precipitation (HDP). XRD, TEM, FESEM, BET and Boehm techniques were used for the characterization of the support and the catalysts. Characterization analyses indicated the negative effect of the wet impregnation method on the IMP-DP technique for the preparation of catalysts for the total oxidation of cyclohexane in air. The catalysts prepared by HDP and IMP-DP methods were found to have significant differences in oxidation activity, morphology, particle size, and shape of...
Highly selective doped Pt[sbnd]MgO nano-sheets for renewable hydrogen production from APR of glycerol
, Article International Journal of Hydrogen Energy ; Volume 41, Issue 39 , 2016 , Pages 17390-17398 ; 03603199 (ISSN) ; Kazemeini, M ; Khorasheh, F ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
A series of M-doped Pt[sbnd]MgO (M = Pd, Ir, Re, Ru, Rh and Cr) sheet-shaped nano-catalysts were synthesized by the controlled co-precipitation method. The effects of M-doping on both the physicochemical and the chemisorption characteristics of Pt[sbnd]MgO catalysts were examined. The performance of the catalysts for the aqueous phase reforming (APR) of glycerol was also investigated. The APR activity of Pt[sbnd]M[sbnd]MgO catalysts depended on the type of the M dopant used. The APR activity varied in the following order: Rh > Pd > Cr > Ir > undoped ≈ Ru > Re, with the Rh-promoted catalyst having an activity of about one order of magnitude higher than the Re-promoted catalyst at 250 °C. It...
Heterogeneous SBA-15-supported oxoperoxomolybdenum(VI) complex for enhanced olefin epoxidation
, Article Catalysis Communications ; Volume 88 , 2017 , Pages 9-12 ; 15667367 (ISSN) ; 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...
Effects of catalyst loading gradient in catalyst layers on performance of polymer electrolyte membrane fuel cells
, Article Renewable Energy ; Volume 50 , February , 2013 , Pages 921-931 ; 09601481 (ISSN) ; Ahmadi, F ; Sharif University of Technology
2013
Abstract
In this paper, numerical and analytical approaches are presented to evaluate the effect of catalyst loading gradient in the catalyst layer (CL) of a polymer electrolyte membrane (PEM) fuel cell. The model is developed based on agglomerate catalyst and accounts for reactant spices and charge (ion and electron) transport in the cathode side of a PEM fuel cell. The special variation of catalyst loading is considered in two direction, "across the layer" from membrane/CL interface to gas diffusion layer (GDL) and "in catalyst plane" under the channels and land areas in the channel direction. A fuel cell test stand is designed and built to facilitate experimental validation of the model. The...
Transesterification of waste cooking oil to biodiesel using Ca and Zr mixed oxides as heterogeneous base catalysts
, Article Fuel Processing Technology ; Volume 97 , 2012 , Pages 45-51 ; 03783820 (ISSN) ; Ghasemi, M ; Sharif University of Technology
2012
Abstract
Heterogeneous solid catalysts comprising CaO and ZrO 2 mixed oxides with various Ca-to-Zr molar ratios were synthesized by means of coprecipitation method. These synthesized mixed oxide catalysts were used for the transesterification of waste cooking oil (WCO) as feedstock with methanol to produce biodiesel fuel (BDF) at 65 °C and 1 atm. The influences of Ca-to-Zr molar ratio, catalyst loading, methanol-to-oil molar ratio, and the reaction time on the BDF yield were carefully investigated. In addition, the stability of prepared solid catalysts was studied. These catalysts were characterized by using techniques of X-ray diffraction, X-ray florescence, X-ray photoelectron spectroscopy, surface...
Ethylbenzene dehydrogenation to styrene over fresh and used commercial catalysts
, Article AIChE Annual Meeting, Conference Proceedings ; 2011 ; 9780816910670 (ISBN) ; 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...
Effect of recycle gas composition of the performance of Fischer-Tropsch catalyst
, Article Petroleum Science and Technology ; Volume 28, Issue 5 , 2010 , Pages 458-468 ; 10916466 (ISSN) ; Khorashe, F ; Safekordi, A. A ; Tavassoli, A ; Sharif University of Technology
Abstract
In this study, the influence of CO2 and CH4 on the performance and selectivity of Co-Ru/Al2O3 catalyst is investigated by injection of these gases (0-20 vol.% of feed) to the feed stream. The effect of temperature and feed flow rate are also inspected. The results show that low amounts of CO2 in the feed stream do not change the catalyst activity, but increasing the amount of CO2 (more than 10 vol.%), causes the CO conversion to decrease and the selectivity of heavy components to increase. Methane acts as an inert gas and does not affect the catalyst performance. Increasing feed flow rate has a negative effect on both CO conversion and heavy component selectivity. By raising the temperature,...
Hydrogenation of crude terephthalic acid by supported Pd and Pd-Sn catalysts on functionalized multiwall carbon nanotubes
, Article Chemical Engineering Research and Design ; Volume 109 , 2016 , Pages 41-52 ; 02638762 (ISSN) ; Safekordi, A. A ; Rashidzadeh, M ; Rashidi, A. M ; Khorasheh, F ; Sharif University of Technology
Institution of Chemical Engineers
2016
Abstract
Liquid phase hydro-purification of crude terephthalic acid (CTA) was performed using supported Pd and Pd-Sn catalysts on functionalized multi-wall carbon nanotubes (FMWCNT). Pd/FMWCNT catalysts were prepared by wet impregnation with Pd loadings of 0.05 to 0.6 wt.%. Pd-Sn/FMWCNT catalysts were prepared by co-impregnation (CI) and successive impregnation (SI) using 0.3 wt.% Pd loading and Sn/Pd molar ratios of 0.1 and 0.35 for the CI method and 0.05 to 0.35 for the SI method. Pd loading of 0.3 wt.% for Pd/FMWCNT was sufficient to decrease the 4-carboxybenzaldehyde (4-CBA) content of CTA from 2100 ppm to 5.5 ppm without excessive hydrogenation of terephthalic acid (TA). The commercial catalyst...
Effect of recycle gas on activity and selectivity of Co-Ru/Al2O3 catalyst in fischer- Tropsch synthesis
, Article World Academy of Science, Engineering and Technology ; Volume 37 , 2009 , Pages 587-591 ; 2010376X (ISSN) ; Hatami, B ; Jokar, L ; Khorasheh, F ; Safekordi, A. A ; Sharif University of Technology
2009
Abstract
In industrial scale of Gas to Liquid (GTL) process in Fischer-Tropsch (FT) synthesis, a part of reactor outlet gases such as CO2 and CH4 as side reaction products, is usually recycled. In this study, the influence of CO2 and CH4 on the performance and selectivity of Co-Ru/Al2O3 catalyst is investigated by injection of these gases (0-20 vol. % of feed) to the feed stream. The effect of temperature and feed flow rate, are also inspected. The results show that low amounts of CO2 in the feed stream, doesn't change the catalyst activity significantly but increasing the amount of CO2 (more than 10 vol. %) cause the CO conversion to decrease and the selectivity of heavy components to increase....
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
Abstract
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
Graphene oxide/poly(vinyl imidazole) nanocomposite: An effective support for preparation of highly loaded heterogeneous copper catalyst
, Article Applied Organometallic Chemistry ; Volume 29, Issue 9 , June , 2015 , Pages 601-607 ; 02682605 (ISSN) ; Safaie, N ; Hosseini, S. H ; Bennett, C ; Sharif University of Technology
John Wiley and Sons Ltd
2015
Abstract
A heterogeneous polymeric catalyst was synthesized by immobilization of copper ions in a graphene oxide/poly(vinyl imidazole) nanocomposite. This catalyst has proven to be highly active in a practical protocol for click synthesis of 1,2,3-triazole via one-pot three-component cycloaddition of halides, terminal alkynes and sodium azide. The reaction was carried out in water medium and good to excellent yields of products were obtained using only 1.0 mol% of catalyst. The catalyst can be readily recovered and reused eight times under the described reaction conditions without significant loss of activity. The reaction also proceeded well with only 0.002 mol% of catalyst, which shows the high...
Copper loaded cross-linked poly(ionic liquid): Robust heterogeneous catalyst in ppm amount
, 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
Abstract
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
A novel highly dispersive magnetic nanocatalyst in water : Glucose as an efficient and green ligand for the immobilization of copper(II) for the cycloaddition of alkynes to azides
, Article RSC Advances ; Volume 6, Issue 83 , 2016 , Pages 80234-80243 ; 20462069 (ISSN) ; Saberi, V ; Kalhor, S ; Ayati, S. E ; Sharif University of Technology
Royal Society of Chemistry
Abstract
A new heterogeneous and highly dispersive nanocatalyst in water was prepared by the immobilization of Cu2+ onto glucose on Fe3O4. The catalyst was fully characterized by FT-IR, TGA, CHN, SEM, EDX, and atomic absorption spectroscopy. The synthesized catalyst was used in the synthesis of different derivatives of 1,2,3-triazole via a one-pot three-component reaction of alkynes, alkyl halides, and sodium azide. To the best of our knowledge, this novel catalyst adheres to the principles of green chemistry. The nanocatalyst could be recycled and reused in several runs without significant loss of activity