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دسترسی آزاد مقاله
1 - The kinetic parameters of drug compounds adsorption onto mesoporous materials
Masoud. Giahi Abdollah. Falah Shojaie Farkhondeh. Mirsfa MoqadamThe discovery of mesoporous molecular sieves, MCM-41, which possesses a regular hexagonalarray of uniform pore openings, aroused a worldwide resurgence in this field. This is not onlybecause it has brought about a series of novel mesoporous materials with various compos چکیده کاملThe discovery of mesoporous molecular sieves, MCM-41, which possesses a regular hexagonalarray of uniform pore openings, aroused a worldwide resurgence in this field. This is not onlybecause it has brought about a series of novel mesoporous materials with various compositionswhich may find applications in catalysis, adsorption, and guest-host chemistry, but also it hasopened a new avenue for creating of the zeotype materials. This paper presents a comprehensiveoverview of recent advances in the field of MCM-41. Adsorption of drug molecules such asPseudeoephedrine hydrochloride onto mesoporous molecular sieves (MCM-41) from aqueoussolution has been investigated systematically using batch experiments in this study. Resultsindicate that Pseudeoephedrine hydrochloride adsorption is initially rapid and the adsorptionprocess reaches a steady state after 2 min. The adsorption isotherms are well described by theLangmuir model. Based on the results, it suggests that the adsorption is primarily brought about byhydrophobic interaction between drug molecules and MCM-41 surface. پرونده مقاله -
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2 - Fast Monitoring of the Phosphate Ions at Sub-mg L level with the Aim of Diamine-grafted MCM-41 Mesoporous silica and Ion Chromatography
Leila Hajiaghababaei Sima DjamIn this work, an innovative method is described for the preconcentration of phosphate ions using ethylenediamine functionalized mesopor (MCM-41). Functionalized MCM-41 was synthesized and the presence of organic groups in the silica framework was demonstrated by FTIR چکیده کاملIn this work, an innovative method is described for the preconcentration of phosphate ions using ethylenediamine functionalized mesopor (MCM-41). Functionalized MCM-41 was synthesized and the presence of organic groups in the silica framework was demonstrated by FTIR spectrum. The amount of organic groups immobilized on silica surface was determined by elemental analysis and TGA. The functionalized product showed the BET surface area 804 m2g-1, BJH pore diameter 3.28 nm and pore volume 0.27 cm3g-1, based on adsorption- desorption of N2at 77 K. The phosphate ions were identified by ion chromatography (IC). The enrichment factor of the proposed method was 100 and detection limit was found to be 0.3μg L-1 . The time of extraction, pH, the optimum amount of the sorbent and amount of sodium hydroxide solution for stripping were investigated. The maximum capacity the adsorbent was found to be 12.0 (±1.4) μg phosphate/mg diamine-grafted MCM-41. The method was applied successfully for the determination of trace amounts of phosphate ions in water samples. پرونده مقاله -
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3 - Asymmetric Synthesis of Modafinil and its Derivatives by using the Functionalized Silica-based Mesoporous MCM-41
Mohammad javad TaghizadehModafinil [2-[(diphenylmethyl)sulfinyl]acetamide] is used clinically in the treatment of narcolepsy and sleeping disorders. The synthesis of modafinil, begins with the reaction of benzhydrol and thioglycolic acid in trifluoroacetic acid to afford benzhydrylsulfinyl ac چکیده کاملModafinil [2-[(diphenylmethyl)sulfinyl]acetamide] is used clinically in the treatment of narcolepsy and sleeping disorders. The synthesis of modafinil, begins with the reaction of benzhydrol and thioglycolic acid in trifluoroacetic acid to afford benzhydrylsulfinyl acetic acid. The reaction of acid with thionyl chloride in benzene followed by treatment with ammonium hydroxide gave acetamide. Synthesis of novel heterogeneous chiral catalyst by a simple and efficient method has been reported. The first, a new derivative of chiral ligand (containing amine group) in 6 steps from a cheap and readily available substrate (4-aminobenzoic acid) were synthesized in good yield. Then, this chiral ligand immobilized on silica-based mesoporous MCM-41 through its amine group. The obtained catalysts were characterized with FT-IR, XRD, BET, SEM, IR, 1H NMR,13C NMR and mass spectral and used for the first time in oxidation of benzhydrylsulfinyl acetic acid and its derivatives. The reaction using this catalysts exhibits very good yield. پرونده مقاله -
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4 - Synthesis and characterization of bifunctional basic mesoporous organosilica catalyst as an efficient and ecofriendly nanocomposite in Biginelli condensation reaction
Fatemeh Ghalambaz Asadollah Farhadi Ali Reza Kiasat Rashid BadriAn organic–inorganic hybrid nanocomposite was prepared by immobilizing β-cyclodextrin (β-CD) and amino groups onto mesoporous MCM-41 via surfactant-templated sol-gel procedure and post-modification method. The heterogeneous hybrid nanocomposite, MCM-41-& چکیده کاملAn organic–inorganic hybrid nanocomposite was prepared by immobilizing β-cyclodextrin (β-CD) and amino groups onto mesoporous MCM-41 via surfactant-templated sol-gel procedure and post-modification method. The heterogeneous hybrid nanocomposite, MCM-41-β-CD/NH2, was characterized by SEM, TEM, XRD, TGA, BET and FT-IR. The potential application of this covalently linked basic catalyst was also investigated as an efficient, heterogeneous and recyclable stationary micro-vessel and basic heterogeneous catalyst in Biginelli multicomponent condensation reaction. High yield, high efficiency and reusability are among the advantages of this environmentally friendly method. The nano catalyst can be easily separated from the reaction mixture and reused after washing for several runs without less in activity. پرونده مقاله -
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5 - Removal of Neodymium from Aqueous Solutions Using a New Fe-modified Nanoporous Adsorbent of Fe-MCM-41
Seyedeh Aseman Lajevardi Roghayeh Madadi Hamzeh Khanlou Mahboobeh ManoochehriIn our study a new Fe-modified nano porous of MCM-41 was synthezied hydrothermally with cetyltrimethylammoniumbromide (C16TAB) as surfactant and charactrizied using XRD, SEM, FT-IR and BET. This work reports the adsorption of Neodymium from aqueous solution onto Fe-M چکیده کاملIn our study a new Fe-modified nano porous of MCM-41 was synthezied hydrothermally with cetyltrimethylammoniumbromide (C16TAB) as surfactant and charactrizied using XRD, SEM, FT-IR and BET. This work reports the adsorption of Neodymium from aqueous solution onto Fe-MCM-41.100 ml of stock solution of Neodymium was prepared.Various factors such as pH,the amount of adsorbent were considered. The optimium conditions obtained were: pH value= 5-8,the amount of Fe-MCM-41=0.0025gr.The Langmuir, Freundlich, Temkin and Dubinin-Rudeshkuvich models have been applied and the equilibrium adsorption was found fit the Freundlich isotherm model(R2= 0.98). The removal amount of adsorbed Neodymium was obtained 97% and charactrizied by Inductivity coupled optical emission spectroscopy (ICP-OES). پرونده مقاله -
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6 - An Efficient One-Pot Synthesis of 1H-Pyrazolo[1,2-b]phthalazine-5,10-dione Derivatives using MCM-41
Adel Ghasemi Haleh SanaeishoarAza heterocyclic compounds are major interest for organic chemists because of their mainly pharmacological activities and clinical applications such as antianxiety, antitumor, anticonvulsant, cardiotonic and vasorelaxant. This work a new and efficient synthesis of phtha چکیده کاملAza heterocyclic compounds are major interest for organic chemists because of their mainly pharmacological activities and clinical applications such as antianxiety, antitumor, anticonvulsant, cardiotonic and vasorelaxant. This work a new and efficient synthesis of phthalazine drivatives from the three-component condensation reaction of malononitrile, phthalhydrazide and aromatic aldehydes using MCM-41 as catalyst. The features of this procedure are mild reaction conditions, good to excellent yields, short reaction times and operational simplicity.Mesoporous solids synthesized using micelles as structure directing agents have been found to posses’ large specific surface area, large pore volume, regular order of pore structure and tuneable pore characteristics Recently, the discovery of a new family of mesoporous molecular sieves designated as MCM-41 has been reported by researchers at the Mobil Corporation [3]. The MCM-41 material possesses a uniform hexagonal array of cylindrical pores embedded within a silica-based matrix. The material is synthesized through a hydrothermal reaction of silicate gel in the presence of a surfactant. پرونده مقاله -
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7 - Synthesis and characterization of Nanoparticles Poly Ethylene Imine-Functionalized MCM-41by Covalent Anchoring as a Solid Catalyst for Multi-Component Reactions
Hosein Hamadi Maryam Gholami Mehdi KhoobiA novel magnetically immobilized polyethyleneimine (PEI) fabricated by covalently anchoring on MCM-41 (MCM-41@PEI) was prepared. The synthesized catalyst was characterized by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction چکیده کاملA novel magnetically immobilized polyethyleneimine (PEI) fabricated by covalently anchoring on MCM-41 (MCM-41@PEI) was prepared. The synthesized catalyst was characterized by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The immobilized PEI was shown to be an efficient heterogeneous catalyst for the synthesis of spiro-oxindole and benzopyranes derivatives via multi-component reaction (MCR), in ethylene glycol as a green solvent. No leaching problem was observed after several runs, while the catalyst can be recovered and reused without loss of reactivity under the described reaction conditions. پرونده مقاله -
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8 - Microwave-assisted thioacetalization of carbonyl compounds using Al-MCM-41 as an efficient heterogeneous catalyst
Marzieh Abedini Soheil SayyahiIn this project various types of carbonyl compounds were efficiently converted to their corresponding 1,3-oxathiolanes with 2-mercaptoethanol in the presence of catalytic amount of Al-MCM-41 with microwave energy. The catalyst can be reused several times without loss of چکیده کاملIn this project various types of carbonyl compounds were efficiently converted to their corresponding 1,3-oxathiolanes with 2-mercaptoethanol in the presence of catalytic amount of Al-MCM-41 with microwave energy. The catalyst can be reused several times without loss of its catalytic activity. Very short reaction times, reusability of the catalyst, and easy workup are noteworthy advantages of this method. پرونده مقاله -
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9 - The Growth of Multilayer Graphene over MCM-41 by CVD Method in Atmospheric Pressure: metal–Free Nanocatalyst
Majid Masoumi Alimorad Rashidi Saeed Sadeghpour Mohammad Mehdi ChoolaeiGraphene films were fabricated over synthesized MCM-41 nanocatalyst by chemical vapor deposition method, and the reaction was carried in atmospheric pressure at 750˚C . Acetylene gas used as carbon precursor and the synthesis reaction took place at hydrogen atmosphere . چکیده کاملGraphene films were fabricated over synthesized MCM-41 nanocatalyst by chemical vapor deposition method, and the reaction was carried in atmospheric pressure at 750˚C . Acetylene gas used as carbon precursor and the synthesis reaction took place at hydrogen atmosphere . Mesoporous MCM-41 was synthesized at room temperature using wet chemical method . The synthesized metal free catalyst was characterized by XRD and N2 adsorption isotherms. The catalytically synthesized graphene layers were characterized by Raman spectroscopy, scanning electron microscopy ( SEM ), and transmission electron microscopy ( TEM ) . The results indicated the favorable effect of MCM-41 with high BET surface area ( 908.76 m2/g ) as an active metal free nanocatalyst for fabricating graphene layers with high level of purity and homogeneity . Because of simplicity, easy purification, and high yield of graphene synthesis offered by this method , it is possible to use it in larger scales . پرونده مقاله -
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10 - Solvent Selection in Impregnation of Zinc Oxide Nanoparticles into MCM-41 Investigation of Its Ability Toward H2S Removal from Crude Oil
Ali Akbar Miran Beigi Nastaran Hazrati Majid Abdouss Amir VahidSilicate mesoporous materials are of the main interesting adsorbents for decreasing of hydrogen sulfide (H2S) from crude oil. In this work zinc impregnated highly ordered MCM-41 was synthesized via post-synthesis functionalization and was used as adsorbent for removal o چکیده کاملSilicate mesoporous materials are of the main interesting adsorbents for decreasing of hydrogen sulfide (H2S) from crude oil. In this work zinc impregnated highly ordered MCM-41 was synthesized via post-synthesis functionalization and was used as adsorbent for removal of H2S from crude oil. Also the variation of solvents was mainly adjusted. In order to determine the ideal solvent for the synthesis of zinc incorporated MCM-41, a few solvents (water, ethanol and THF) has been tried in these experiments. The experiments showed that THF is a better solvent to get better materials. پرونده مقاله -
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11 - The Growth of Multilayer Graphene over MCM-41 by CVD Method in Atmospheric Pressure: metal–Free Nanocatalyst
Majid Masoumi Ali Morad Rashidi Mohammadmehdi Choolaei Saeed SadeghpourGraphene films were fabricated over synthesized MCM-41 nanocatalyst by chemical vapordeposition method, and the reaction was carried in atmospheric pressure at 750˚C. Acetylenegas used as a carbon precursor and the synthesis reaction took place in hydrogen atmosphere.Me چکیده کاملGraphene films were fabricated over synthesized MCM-41 nanocatalyst by chemical vapordeposition method, and the reaction was carried in atmospheric pressure at 750˚C. Acetylenegas used as a carbon precursor and the synthesis reaction took place in hydrogen atmosphere.Mesoporous MCM-41 was synthesized at room temperature, using wet chemical method. Thesynthesized metal free catalyst was characterized by XRD and N2 adsorption isotherms. Thecatalytically synthesized graphene layers were characterized by Raman spectroscopy, scanningelectron microscopy (SEM), and transmission electron microscopy (TEM). The results indicatedthat the favorable effect of MCM-41 with high BET surface area (908.76 m2/g) as an activemetal free nanocatalyst for fabricating graphene layers with high level of purity and homogeneity.Because of simplicity, easy purification, and high yield of graphene synthesis offered bythis method, it is possible to use it in larger scales. پرونده مقاله -
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12 - Highly efficient multicomponent Biginelli’s synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by Al-MCM-41 under solvent-free conditions
Soheil Sayyahi Mehdi Behvandi BehvandiIn this study, an efficient and green process for the synthesis of dihydropyrimidin-2(1H)-ones from aromatic benzaldehydes, ethyl acetoacetate and urea using Al-MCM-41 as heterogeneous catalyst and microreactor under solvent-free conditions has been developed. The advanta چکیده کاملIn this study, an efficient and green process for the synthesis of dihydropyrimidin-2(1H)-ones from aromatic benzaldehydes, ethyl acetoacetate and urea using Al-MCM-41 as heterogeneous catalyst and microreactor under solvent-free conditions has been developed. The advantages of this method are easy work-up procedure, regeneration of the catalyst, clean and neutral reaction conditions. پرونده مقاله -
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13 - Mn(II)-Schiff base complex immobilized onto MCM-41 matrix as a heterogeneous catalyst for epoxidation of alkenes
Hassan Zakeri Saeed Rayati Goldasteh Zarei Ali Parsa Forogh AdhamiA heterogeneous catalyst containing manganese Schiff base complex (derived from 2,4-dihydroxybenzadehyde and 1,2-phenylenediamine) is produced by covalent anchoring in MCM-41 matrix. The synthesized catalyst was characterized by X-ray diffraction pattern (XRD), inductiv چکیده کاملA heterogeneous catalyst containing manganese Schiff base complex (derived from 2,4-dihydroxybenzadehyde and 1,2-phenylenediamine) is produced by covalent anchoring in MCM-41 matrix. The synthesized catalyst was characterized by X-ray diffraction pattern (XRD), inductivity coupled plasma (ICP), Fourier transform infrared (FT-IR) spectroscopy, N2 sorbtion-desorbtion isotherm and by transmission electron microscopy (TEM). The obtained catalyst was used in the epoxidation of alkenes with hydrogen peroxide. Furthermore, the effect of various parameters such as reaction time, temperature, amount of catalyst, oxidant and imidazole has been investigated. The catalyst reusability was investigated. Our result reveals that this catalyst shows high catalytic activity in the epoxidation of alkenes. پرونده مقاله -
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14 - CO Hydrogenation over functionalized AlMCM-41 materials and ZSM-11/5 zeolites as catalysts
B. Smili M. Sakmeche A. Belhakem L. Belgacem C. TabtiWe studied the reaction in which carbon monoxide is converted to hydrocarbons, and investigated the behaviors and the combination system of catalysts exchanged with platinum and ammonium ions. Experiments were conducted at 1.2 MPa, 523K, and CO/H2=1 ratio. The structure چکیده کاملWe studied the reaction in which carbon monoxide is converted to hydrocarbons, and investigated the behaviors and the combination system of catalysts exchanged with platinum and ammonium ions. Experiments were conducted at 1.2 MPa, 523K, and CO/H2=1 ratio. The structure and the texture of the catalysts, assessed by XRD, BET/BJH, and SEM, exhibited a microporosity for ZSM-5/11 and a micro/mesoporosity for AlMCM-41, which implies a direct effect on the catalytic properties of these materials. The conversions obtained were 60%, 55%, and 50% for Ptn+/H+-catalysts, Ptn+-catalysts, and H+-catalysts respectively. Such conversions could be attributed to the good acidity resulting from the simultaneous presence of Ptn+/H+ at different oxidation states of platinum, which was revealed by XANES PtLIII analysis, and their uniform dispersion within the inner surface and its grain size average conducted by the titration of adsorbed H2-O2. FTIR analysis showed a better distribution of acid sites for bi-exchanged catalysts over mono-exchanged ones, which resulted in a good catalytic activity. These results suggest a strong correlation between the high selectivity of light hydrocarbon products, the ions, and the catalyst types. These differences depended mainly on the facility of forming different products, such as n/iso-alkanes and alkenes. Skeletal isomerization was the main transformation observed on exchanged catalysts, particularly those with Ptn+/H+ ions. A deactivation process of catalysts, versus time-on-stream, begins after 70 minutes, especially for combined exchanged materials. پرونده مقاله -
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15 - Preparation, characterization and determination of photocatalytic activity of MCM-41/ZnO and MCM-48/ZnO nanocomposites
Hamid Reza Pouretedal Mina AhmadiThe direct and indirect methods in solvent media and grinding method in a solvent-free media were used to prepare the MCM-41/ZnO and MCM-48/ZnO photocatalysts. The X-ray diffraction (XRD) patterns showed that zinc oxide nanoparticles were put into MCM-41 and MCM-48 subs چکیده کاملThe direct and indirect methods in solvent media and grinding method in a solvent-free media were used to prepare the MCM-41/ZnO and MCM-48/ZnO photocatalysts. The X-ray diffraction (XRD) patterns showed that zinc oxide nanoparticles were put into MCM-41 and MCM-48 substrates and there were ZnO crystallites as secondary phase in the extra framework of mesoporous materials. The decrease of surface areas, pore volume and average pore size of mesoporous materials with incorporation of ZnO nanoparticles were confirmed by N2 adsorption and desorption isotherms. The FT-IR spectra showed an absorption peak at 490 cm-1 that was related to formation of ZnO in the substrate of MCMs. The photocatalytic activity of MCM-41/ZnO and MCM-48/ZnO were studied in photodegradation reaction of Congo red as a dye pollutant. The photocatalysts of MCM-41/ZnO and MCM-48/ZnO which were prepared by grinding method showed the highest photocataltyic activity with pseudo first-order kinetic rate constants of 34.6 and 27.810-3 min-1, respectively. The obtained results indicated complete incorporation of zinc ions in mesoporous material of MCMs in a solvent-free media. The elimination of solvent and facility of proposed method were the advantages of grinding method in preparation of MCM/ZnO photocatalyst. پرونده مقاله -
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16 - حذف رنگزاهای بازی بنفش 10 و زرد 13 از پساب دو کارخانه داروسازی و آرایشی با MCM-41 اصلاح شده با N-(2-آمینو اتیل)-3-آمینوپروپیلتریمتوکسیسیلان و پیریدین کربالدهید
شبنم ششمانی گلدسته زارعی وحید علی اکبری ممقانیاین پژوهش، با هدف به‎کارگیری مزوحفره MCM-41 اصلاح شده بهعنوان جاذب در حذف رنگزاهای بازی بنفش 10 و زرد 13 انجام شد. مرحله نخست، اصلاح شیمیایی با ترکیب N-(2-آمینو اتیل)-3- آمینوپروپیلتریمتوکسیسیلان و مرحله دوم، اصلاح شیمیایی با پیریدین کربالدهید انجام شد. به منظو چکیده کاملاین پژوهش، با هدف به‎کارگیری مزوحفره MCM-41 اصلاح شده بهعنوان جاذب در حذف رنگزاهای بازی بنفش 10 و زرد 13 انجام شد. مرحله نخست، اصلاح شیمیایی با ترکیب N-(2-آمینو اتیل)-3- آمینوپروپیلتریمتوکسیسیلان و مرحله دوم، اصلاح شیمیایی با پیریدین کربالدهید انجام شد. به منظور دستیابی به شرایط مطلوب حذف، اثر عامل‎هایی مانند مقدار جاذب، pH، زمان تماس و دما در مقدار حذف بررسی شد. جاذب در مقدارهای 1 تا 8 میلیگرم، pH در گستره 2 تا 10، زمان در 10، 30، 60، 90 و 120دقیقه و دما در 25، 35، 45، 55 و C° 65 تغییر داده شد. نتایج نشان داد که با افزایش مقدار جاذب از 1 به 6 میلیگرم، زمان تماس از 10 تا 90 دقیقه و دما از 25 تا C° 65 مقدار جذب از 60 تا 100% افزایش یافته است. شرایط بهینه حذف رنگزاها به ازای 5 میلیگرم جاذب، زمان 90 دقیقه، دمای 55 و C° 65، pH برابر با 5 برای حذف بنفش 10 و pH برابر با 8 برای حذف زرد 13 تعیین شد. پس از تعیین شرایط بهینه، حذف رنگزاهای بنفش 10 و زرد 13 مربوط به پساب دو کارخانه داروسازی و نساجی بررسی شد. بیشینه مقدار درصد حذف بنفش 10 و زرد 13 در پساب با جاذب MCM-41 اصلاح شده به ترتیب 97/15 و 95/55 % به‎دست آمد. پرونده مقاله -
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17 - تهیه نانوکاتالیست Cr/MCM-41 به روش آب گرمایی یک مرحلهای و بررسی فعالیت کاتالیستی آن در هیدروژن گیری از اتان به اتیلن در حضور کربن دیاکسید
المیرا اصغری محمد حقیقی فرهاد رحمانیدر این مقاله تأثیر روش هیدروترمال یک مرحلهای در سنتز نانوکاتالیست Cr(8%)/MCM-41 بهمنظور استفاده در فرایند هیدروژنگیری اکسایشی تبدیل اتان به اتیلن در حضور کربن دیاکسید مطالعه و نتیجههای بهدست آمده با روش سنتز تلقیح مقایسه شد. برای بررسی ویژگیهای فیزیکی- شیمیایی ن چکیده کاملدر این مقاله تأثیر روش هیدروترمال یک مرحلهای در سنتز نانوکاتالیست Cr(8%)/MCM-41 بهمنظور استفاده در فرایند هیدروژنگیری اکسایشی تبدیل اتان به اتیلن در حضور کربن دیاکسید مطالعه و نتیجههای بهدست آمده با روش سنتز تلقیح مقایسه شد. برای بررسی ویژگیهای فیزیکی- شیمیایی نانوکاتالیستها، از روشهای XRD ،BET ،FESEM ،FT-IR و EDX استفاده شد. الگوهای XRD تشکیل فازهای بلوری MCM-41 و Cr2O3 را اثبات کرد. بررسی تصویرهای FESEM ذرات یکنواخت و کوچک در مقیاس نانومتری و توزیع اندازهی ذرات باریکی را بر روی سطح کاتالیستها نشان داد. نتیجههای بهدست آمده از تجزیهی EDX نشان داد در اثر بهکارگیری روش آب گرمایی مستقیم، فاز فعال کروم بهطور یکنواخت روی سطح کاتالیست پخش شده است. بر اساس نتیجههای بهدست آمده روش آب گرمایی یک مرحلهای باعث سنتز کاتالیستی با اندازهی ذرات کوچکتر و یکنواختتر در راستای بهبود ویژگی جذب و پخش شوندگی بیشتر نسبت به نمونهی بهدست آمده از روش تلقیح شد. همچنین نانوکاتالیستها در فشار اتمسفری و گستره دمایی 550 تا C°700 با ترکیب خوراک 10% اتان، 50% کربن دیاکسید و 40% نیتروژن در یک سامانه آزمایشگاهی مورد ارزیابی قرار گرفتند. نانوکاتالیستهای سنتز شده به روش آب گرمایی یک مرحلهای فعالیت کاتالیستی معقول و پایداری را حتی پس از گذشت ده ساعت با بازده و انتخابپذیری نسبت به اتیلن به ترتیب برابر با 42% و 97% در دمای C°700 از خود نشان داد. این نمونه انتخابپذیری بهتر و بازده قابلرقابتی با نمونهی سنتز شده به روش تلقیح از خود نشان داد. پرونده مقاله -
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18 - Isothermal and thermodynamic studies of the adsorption of safranine on MCM-41
Ghazaleh Koutchakzadeh Zohreh DerikvandThe uses of MCM-41 as adsorbent have been studied as an alternative substitution of activated carbon for theremoval dyes. This adsorbent was prepared at laboratory by authors. Adsorption of safranine on MCM-41was studied to examine adsorption thermodynamics. In this stu چکیده کاملThe uses of MCM-41 as adsorbent have been studied as an alternative substitution of activated carbon for theremoval dyes. This adsorbent was prepared at laboratory by authors. Adsorption of safranine on MCM-41was studied to examine adsorption thermodynamics. In this study was investigated the effect of proccesparameters like pH, initial dye concentration, temperature and adsorbent mass. MCM-41, as adsorbent, ischaracterized by high surface area and high pore volume to adsorbed dye very well. In this study, bothLangmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. Langmuirmodel being has found to provide the best fit of experimental data. Results of thermodynamic evaluationindicated that adsorption reaction was spontaneous because Gibs energy was negative. This reaction wasexothermic with negative enthalpy and reducing entropy. پرونده مقاله -
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19 - MCM-41 functionalized sulfonic acid catalyzed one-pot synthesis of 1,8- dioxo-octahydroxanthenes
Gholam Hossein Mahdavinia Mohammad Mehdi Ghanbari Hamid Sepehrian Fatemeh KootiMCM-41-R-SO3H catalyzed one-pot synthesis of 1,8-dioxo-octahydroxanthenes is reportedunder reflux conditions. The catalyst is easily prepared, highly stable, very simple to handle andrecycled for five times without loss of significant activityMCM-41-R-SO3H catalyzed one-pot synthesis of 1,8-dioxo-octahydroxanthenes is reportedunder reflux conditions. The catalyst is easily prepared, highly stable, very simple to handle andrecycled for five times without loss of significant activity پرونده مقاله -
دسترسی آزاد مقاله
20 - Synthesis of open chain analogue of 1,8-dioxooctahydroxanthene catalyzed by aluminosilicate MCM- 41
Soheil Sayyahi Vali Zare-Shahabadi Maryam Rastroshan Rashid BadriIn this study, aluminosilicate MCM-41 has been found to be an efficient catalyst for reaction betweendifferent benzaldehyde derivatives and 5,5-dimethyl-1,3-cyclohexanedione to give open chain analogue of1,8-dioxo-octahydroxanthene in excellent yields. No evidence for t چکیده کاملIn this study, aluminosilicate MCM-41 has been found to be an efficient catalyst for reaction betweendifferent benzaldehyde derivatives and 5,5-dimethyl-1,3-cyclohexanedione to give open chain analogue of1,8-dioxo-octahydroxanthene in excellent yields. No evidence for the formation of cyclization products wasobserved. The catalyst can be used several times after recovery. پرونده مقاله
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