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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Catalysis
- نوع مقاله: Journal Article
- کلمات کلیدی: Oxidation,Heteropolyacid,Magnetic nanoparticles,Supported catalyst
- چکیده:
- چکیده انگلیسی: In this research, Keggin-type polyoxometalate, H5PMoV2O40 (denoted as PMoV) was immobilized on modified NiFe2O4 nanoparticles to produce a magnetically separable catalyst. This catalyst was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), cyclic voltummetry (CV), energy dispersive X-ray (EDX) and UV-vis diffuse reflectance spectroscopy (UV-DRS). The catalytic activity of synthesized catalyst in oxidation of dibenzothiophene (DBT) to dibenzothiophene sulfone (DBTO2) was investigated using H2O2 as an oxidant and acetonitrile as an extractant. The catalyst could be readily separated from the catalytic system using the magnetic field; and loss of activity was negligible when the catalyst was recovered in five consecutive runs. The effects of main process variables including H2O2 amount (mmol), reaction temperature (°C) and reaction time (min) were analyzed by response surface methodology (RSM) based on the central composite design (CCD). The optimal condition for conversion of DBT was found to be H2O2 2.8 mmol, reaction temperature 42°C and reaction time 57 min for 0.1 g of catalyst dosage. The conversion of DBT to DBTO2 under optimized conditions was 85.9 %. Moreover, the dibenzothiophene sulfone product was characterized by NMR, FT-IR, Mass and GC analysis.
- انتشار مقاله: 01-03-1396
- نویسندگان: Hossein Salavati,Abbas Teimouri,Shahnaz Kazemi
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Heterocyclic Chemistry
- نوع مقاله: Journal Article
- کلمات کلیدی: Zeolite,Green synthesis,Sulfated zirconia,arylaminotetrazoles
- چکیده:
- چکیده انگلیسی: The [3+2] cycloaddition between various nitriles and sodium azide proceeds smoothly in the presence of zeolite and sulfated Zircona as effective catalyst and in the water and DMF/MeOH, to give the corresponding arylaminotetrazoles in good to high yields. The reaction most probably precedes through the in situ formation of a catalyst azide species, followed by a successive [3+2] cycloaddition with the nitriles. This method has the advantages of high yields, simple methodology,and easy work-up. The catalyst can be recovered by simple filtration and reused in good yields.
- انتشار مقاله: 19-04-1394
- نویسندگان: Abbas Teimouri,Alireza Najafi Chermahini
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Heterocyclic Chemistry
- نوع مقاله: Journal Article
- کلمات کلیدی: Zeolite,Green synthesis,Sulfated zirconia,arylaminotetrazoles
- چکیده:
- چکیده انگلیسی: The [3+2] cycloaddition between various nitriles and sodium azide proceeds smoothly in the presence of zeolite and sulfated Zircona as effective catalyst and in the water and DMF/MeOH, to give the corresponding arylaminotetrazoles in good to high yields. The reaction most probably precedes through the in situ formation of a catalyst azide species, followed by a successive [3+2] cycloaddition with the nitriles. This method has the advantages of high yields, simple methodology,and easy work-up. The catalyst can be recovered by simple filtration and reused in good yields.
- انتشار مقاله: 05-03-1395
- نویسندگان: Abbas Teimouri,Alireza Najafi Chermahini
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Heterocyclic Chemistry
- نوع مقاله: Journal Article
- کلمات کلیدی: Zeolite,Green synthesis,Sulfated zirconia,arylaminotetrazoles
- چکیده:
- چکیده انگلیسی: The [3+2] cycloaddition between various nitriles and sodium azide proceeds smoothly in the presence of zeolite and sulfated Zircona as effective catalyst and in the water and DMF/MeOH, to give the corresponding arylaminotetrazoles in good to high yields. The reaction most probably precedes through the in situ formation of a catalyst azide species, followed by a successive [3+2] cycloaddition with the nitriles. This method has the advantages of high yields, simple methodology,and easy work-up. The catalyst can be recovered by simple filtration and reused in good yields
- انتشار مقاله: 25-03-1393
- نویسندگان: Abbas Teimouri,Alireza Najafi Chermahini
- مشاهده
- جایگاه : پژوهشی
- مجله: Chemical Methodologies
- نوع مقاله: Journal Article
- کلمات کلیدی: Methylene blue,Degradation,Heteropolyacid,Photocatalytic
- چکیده:
- چکیده انگلیسی: this project, keggin-type polyoxometalate, cationic exchange Q5PMoV2O40 (denoted as TBA-PMoV) was synthesized to produce a recoverable catalyst. This catalyst was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Field Emission scanning electron microscopy (FESEM) and UV-vis diffuse reflectance spectroscopy (UV-DRS). The synthesized catalyst showed high photocatalytic activity in the degradation of methylene blue as a pollutant under UV light irradiation. The effect of various factors such as catalyst amount, contact time and pH on degradation of methylene blue (denoted as MB) were investigated. Formal batch adsorption studies was applied for investigation of effects of various parameters, such as initial solution pH, initial dye concentration, catalyst amount, temperature, etc. Optimization results for 20 mg/L methylene blue showed that maximum degradation efficiency 96.8 % at the optimum conditions was found to be: catalyst amount 25 mg, pH= 7.6 and time 60 min at ambient pressure and temperature.
- انتشار مقاله: 20-05-1396
- نویسندگان: Hossein Salavati,Abbas Teimouri,Shahnaz Kazemi
- مشاهده
- جایگاه : پژوهشی
- مجله: Chemical Methodologies
- نوع مقاله: Journal Article
- کلمات کلیدی: Graphene Oxide,Nanocomposite,polyethylene glycol,Photocatalytic
- چکیده:
- چکیده انگلیسی: This research reports the synthesis, characterization and catalytic properties ofnovel supported catalyst based on nickel acetate hydrate (denoted as NiOAC) immobilized on graphene oxide (denoted as GO) modified polyethylene glycol (abbreviated as PEG). The supported catalyst was characterized by X-ray diffraction spectroscopy (XRD), Scanning electron microscopy (FESEM), Furrier transforms infrared spectroscopy (FT-IR) and diffuse reluctance spectroscopy (DRS). In addition, under mild reaction conditions, the mentioned catalyst exhibited high photocatalytic activity and reusability in photocatalytic degradation of dyes as pollutants. For this research, a statistical method called Response Surface Methodology (RSM) has been used to economize the number of experiments and their meaningful interpretation.The effect of various factors such as catalyst amount, time, pH on degradation of methylene blue were investigated. Optimization results for 20 ppm methylene blue showed that maximum degradation efficiency 92.9% was achieved at the optimum conditions: catalyst amount 24.6 mg, pH= 7.6 and time 23.3 min.
- انتشار مقاله: 03-04-1396
- نویسندگان: Mehrnaz Alem,Abbas Teimouri,Hossein Salavati,Shahnaz Kazemi
- مشاهده
- جایگاه : پژوهشی
- مجله: Chemical Methodologies
- نوع مقاله: Journal Article
- کلمات کلیدی: Photocatalytic degradation,Polymer,Phthalocyanines,Heterogenous Catalyst
- چکیده:
- چکیده انگلیسی: In this study, Copper-tetraaminophthalocyanine (CuTAP) was supported on polyvinylcholoride by reflux condition to produce heterogeneous recovarable catalyst. This catalyst was characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and UV-vis spectroscopy. The results showed that the photocatalytic degradation of methyl orange was performed in mild conditions at ambient pressure and temperature under visible light. The synthesized catalyst could be readily separated from the catalytic system by centrifuging and loss of activity was negligible when the catalyst was recovered in four consecutive cycles. The effects of operational various factors such as catalyst amount, initial dye concentration and contact time on degradation of methyl orange were investigated. Optimization results showed that maximum degradation of methyl orange efficiency 98.6 % was achieved at the optimum conditions.
- انتشار مقاله: 02-04-1396
- نویسندگان: Hossein Salavati,Abbas Teimouri,Shahnaz Kazemi
- مشاهده
- جایگاه : پژوهشی
- مجله: Asian Journal of Green Chemistry
- نوع مقاله: Journal Article
- کلمات کلیدی: Graphene Oxide,Catalytic,Green Oxidation,Nanocomposite polyethylene glycol
- چکیده:
- چکیده انگلیسی: This study reports the synthesis, characterization and catalytic properties of a novel supported catalyst on the basis of nickel acetate hydrate (NiOAC) immobilized on graphene oxide (GO) modified polyethylene glycol (PEG). The catalyst was characterized by scanning electron microscopy (FESEM), X-ray diffraction spectroscopy (XRD), furrier transforms infrared spectroscopy (FT-IR) and diffuse reluctance spectroscopy (DRS). It showed a high activity in the green oxidation of thioanisole as a model substrate to sulfoxide product at ambient temperature and presurre. To establish the general applicability of the process, various sulfides were subjected to the oxidation system using the synthesized catalyst. The reactivities of the sulfur compounds were influenced by two main factors, i.e., the electron density on the S atom and the steric hindrance of the sulfur compound. In addition, ethanol was selected as a green solvent for this procedure. The effects of the main process variables including H2O2 amount (mmol), reaction time (min) and catalyst amount (mg) were analyzed by response surface methodology (RSM) based on the central composite design (CCD). The optimal condition for conversion of thioanisole was found to be O/S ratio 3.4, reaction time 31 min for 21 mg of catalyst amount.
- انتشار مقاله: 26-05-1397
- نویسندگان: Mehrnaz Alem,Shahnaz Kazemi,Abbas Teimouri,Hossein Salavati
- مشاهده
- جایگاه : پژوهشی
- مجله: Asian Journal of Green Chemistry
- نوع مقاله: Journal Article
- کلمات کلیدی: Oxidation,Heteropolyacid,Polymer,Alkenes,Support
- چکیده:
- چکیده انگلیسی: Polyphosphotungstate (denoted as PPT) was supported on polypyrrol as organic support (abbreviated as PTT@Ppy) to produce catalytic active supported catalyst. This catalyst was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FESEM) and UV-vis diffuse reflectance spectroscopy (UV-DRS). The catalyst showed high catalytic activity in the oxidation of alkenes under optimized conditions. In this work, cyclooctene was selected as model alkene for investigation of oxidation procedure, and then under optimized condition, other alkenes were examined. The catalyst could be readily separated from the catalytic system using the centrifuging and loss of activity was negligible when the catalyst was recovered in five consecutive cycles. For this research, a statistical method called response surface methodology (RSM) has been used to economize the number of experiments and their meaningful interpretation. The effect of various factors such as catalyst amount, time, oxidant amount and temperature on oxidation of alkenes were investigated. Optimization results for 0.2 mmol cyclooctene showed that maximum oxidation efficiency 88% was achieved at the optimum conditions: catalyst amount 200 mg, temperature 63, time 5 h and oxidant = 2.15 mmol.
- انتشار مقاله: 15-05-1396
- نویسندگان: Hossein Salavati,Abbas Teimouri,Shahnaz Kazemi
- مشاهده