scholarly journals Epoxidation of Alkenes with Molecular Oxygen Catalyzed by Immobilized Co(acac)2and Co(bpy)2Cl2Complexes within Nanoreactors of Al-MCM-41

2012 ◽  
Vol 9 (4) ◽  
pp. 2205-2212 ◽  
Author(s):  
F. Farzaneh ◽  
M. Jalalian ◽  
L. Tayebi
Keyword(s):  
Molecular Oxygen ◽  
Cobalt Complexes ◽  
Trans Stilbene ◽  
Ft Ir ◽  
Adsorption Desorption ◽  
Epoxidation Of Alkenes ◽  
Immobilized Complexes ◽  
Mcm 41

Cobalt complexes with different ligands such as bipyridine, and acetylacetonate were immobilized within nanoreactors of Al-MCM-41, designated as Co(acac)2/Al-MCM-41 and Co(bipy)22+/Al-MCM41. The immobilized complexes were characterized by XRD, N2-adsorption desorption, FT-IR and UV-Vis techniques. It was found that Co(bipy)22+/Al-MCM41 and Co(acac)2/Al-MCM-41 successfully catalyze the oxidation of norbornene, styrene, cis-stilbene, trans-stilbene, and cyclohexene with 68% to 100% conversion and 41% to 90% selectivity toward the corresponding epoxides. No desorption was observed during the course of reactions.

Synthesis of Al-Containing Mesoporous Molecular Sieves and their Catalytic Performance to Isomerization Reaction of Endo-Tetrahydrodicyclo-Pentadiene

2011 ◽  
Vol 233-235 ◽  
pp. 234-237 ◽  
Author(s):  
Sa Liu ◽  
Jian Wei Guo ◽  
Chu Fen Yang ◽  
Long Huan Li ◽  
Yi Hua Cui
Keyword(s):  
Catalytic Activity ◽  
Molecular Sieves ◽  
Catalytic Performance ◽  
Mesoporous Molecular Sieves ◽  
Isomerization Reaction ◽  
Inorganic Acid ◽  
Ft Ir ◽  
Desorption Isotherms ◽  
Adsorption Desorption ◽  
Mcm 41

Al-containing mesoporous molecular sieves(Al-MCM-41) were synthesized at ambient temperature. The structures of samples were characterized by XRD, N2-adsorption/desorption isotherms and FT-IR, etc. The evaluation results showed that Al-MCM-41 had higher catalytic activity for isomerization conversion of endo-tetrahydrodicyclo-pentadiene (endo-TCD) into exo-tetrahydrodicyclo-pentadiene (exo-TCD) and adamantane (AdH). Loading inorganic acid on the surface of Al-MCM-41 led increase of its catalytic activity and the yield of adamantane.

Epoxidation of alkenes with molecular oxygen and isobutyraldehyde catalyzed by immobilized vitamin B12 within Al-MCM-41

2007 ◽  
Vol 91 (2) ◽  
pp. 333-340 ◽  
Author(s):  
Faezeh Farzaneh ◽  
Leila Tayebi ◽  
Mehdi Ghandi
Keyword(s):  
Vitamin B12 ◽  
Molecular Oxygen ◽  
Epoxidation Of Alkenes ◽  
Mcm 41

Synthesis and Characterization of MCM-41 Molecular Sieves Nanoparticals

2013 ◽  
Vol 662 ◽  
pp. 214-217 ◽  
Author(s):  
Li Qin Wang ◽  
Yang Han ◽  
Xiu Jun Fu ◽  
Hai Tao Wu ◽  
E Chang ◽  
...  
Keyword(s):  
Molecular Sieves ◽  
Room Temperature ◽  
Mesoporous Structure ◽  
Decomposition Temperature ◽  
Surface Areas ◽  
Type Iv ◽  
Typical Type ◽  
Ft Ir ◽  
Adsorption Desorption ◽  
Mcm 41

Nanoparticals of MCM-41 molecular sieves were synthesized at near room temperature with cetyltrimethylammonium bromide (CTAB) as template agent. The prepared samples were characterized by the means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), N2 adsorption tests, thermogravimetric and differential thermal analysis (TG-DTA). The results suggested that morphology of MCM-41 molecular sieves samples with high crystallinity was almost uniform spherical, and the particles size was almost less than 100 nm. The adsorption-desorption isotherms were corresponded to typical type IV isotherms with the hysteresis loop of type H2, which showed the samples had mesoporous structure. The pore size distribution of samples were 1.69 nm and 3.58 nm, and the specific surface areas was up to 752.23 m2/g. The decomposition temperature of template agent CTAB was around 327 °C, while the framework for MCM-41molecular sieves was stable. So MCM-41 molecular sieve samples synthesized at near room temperature had excellent physical properties.

Rice Straw and Rice Straw Ash as Precursor for Synthesis of Mesoporous Molecular Sieves MCM-41

2012 ◽  
Vol 550-553 ◽  
pp. 1391-1394
Author(s):  
Xiao Hong Tang ◽  
Bao Jun Li ◽  
Cheng Wei Li
Keyword(s):  
Rice Straw ◽  
Molecular Sieves ◽  
Mesoporous Structure ◽  
Mesoporous Molecular Sieves ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Adsorption Desorption ◽  
Straw Ash ◽  
Mcm 41

In this paper, rice straw (RS) and rice straw ash (RSA) were employed to synthesize mesoporous molecular sieves MCM-41 in an open-vessel. The structure of as-synthesized MCM-41 was characterized by X-ray diffraction (XRD) pattern, Fourier transform infrared (FT–IR) spectrum, NH3-Temperature Programmed Desorption (TPD), and N2 adsorption-desorption isotherms. RS-MCM-41 and RSA-MCM-41 possess the same typical hexagonal mesoporous structure with high long-range order and crystalline degree as those of MCM-41 from water glass (SDS-MCM-41).

scholarly journals Synthesis of MCM-41 Immobilized (Phenoxy)Imine Palladium(II) Complexes as Recyclable Catalysts in the Methoxycarbonylation of 1-Hexene

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 143 ◽  
Author(s):  
Saphan Akiri ◽  
Stephen Ojwach
Keyword(s):  
Electron Microscopy ◽  
Active Species ◽  
X Ray ◽  
Transmission Electron ◽  
Recyclable Catalysts ◽  
Ir Transmission ◽  
Ft Ir ◽  
Immobilized Compounds ◽  
Immobilized Complexes ◽  
Mcm 41

The immobilization of 2-phenyl-2-((3(tryethoxysicyl)propyl)imino)ethanol (HL1) and 4-methyl-2-(((3(triethoxysilyl)propyl)imino)methyl)phenol (HL2) on MCM-41 afforded the respective ligands HL1-MCM-41 (HL3) and HL2-MCM-41 (HL4). The treatment of complexes Pd(L1)2 and Pd(L2)2 with MCM-41 afforded the immobilized complexes (Pd(L1)2)-MCM-41 (1) and (Pd(L2)2)-MCM-41 (2) respectively. Separately, the reactions of HL3 and HL4 with Pd(NCMe)2Cl2 produced the immobilized complexes Pd(HL3)Cl2 (3) and Pd(HL4)Cl2 (4) respectively. The immobilized compounds were characterized by FT-IR, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), energy-dispersive X-ray (EDX), Thermogravimetric Analysis (TGA) and X-ray Powder Diffraction (XRD). All the complexes (1–4) formed active catalysts in the methoxycarbonylation of 1-hexene to give linear and branched esters. The catalysts were recycled four times without the loss of catalytic activity. Hot filtration experiments established the absence of leaching, and the heterogeneous nature of the active species was derived from mercury drop experiments.

scholarly journals Light olefin production using the mixture of HZSM-5/MCM-41 and γ-Al2O3 as catalysts for catalytic pyrolysis of waste tires

2020 ◽  
pp. 25-25 ◽  
Author(s):  
Ruru Fu ◽  
Zhuangzhang He ◽  
Shikai Qin ◽  
Qingze Jiao ◽  
Caihong Feng ◽  
...  
Keyword(s):  
Light Olefins ◽  
Light Olefin ◽  
Waste Tires ◽  
Size Constraints ◽  
Olefin Production ◽  
Silica Alumina ◽  
Ft Ir ◽  
Adsorption Desorption ◽  
Silica Alumina Ratio ◽  
Mcm 41

In this paper, micro-mesoporous HZSM-5/MCM-41 zeolites were prepared by a two-step hydrothermal method using commercial HZSM-5 with two different silica/alumina ratios (38 and 50) as starting materials. The structures, morphologies and acidity of as-prepared zeolites were analyzed using XRD, FT-IR, SEM, N2-adsorption/desorption and NH3-TPD. The HZSM-5/MCM-41 zeolites combined the acidity of microporous HZSM-5 with the pore advantages of mesoporous MCM-41. Mesopores and microspores of 3.34 and 0.95 nm in diameter were found to be present in HZSM-5/MCM-41 zeolites. When they were used to catalyze the pyrolysis of waste tires, the selectivity of light olefins for HZSM-5/MCM-41 prepared using HZSM-5 with the silica/alumina ratio of 50 as starting materials was 21.42%, higher than 18.43% of HZSM-5/MCM-41synthesized using HZSM-5 with the silica/alumina ratio of 38. In order to further overcome the pore size constraints and mass transfer limitations of HZSM-5/MCM-41 zeolites for catalyzing pyrolysis of waste tires, macroporous ?-Al2O3 were mixed with HZSM-5/MCM-41 and used as catalysts. The selectivity to light olefins for the mixture of ?-Al2O3 and HZSM-5/MCM-41 prepared using HZSM-5 with the silica/alumina ratio of 50 as starting materials was 33.65%, which was obviously enhanced by the introduction of ?-Al2O3.

Preparation of Mesoporous MCM-41 in Open-Vessel for Catalytic Synthesis of Geranyl Propionate

2012 ◽  
Vol 550-553 ◽  
pp. 358-361
Author(s):  
Xiao Hong Tang ◽  
Bao Jun Li ◽  
Chun Liang Han ◽  
Jin Wang ◽  
Cheng Wei Li
Keyword(s):  
Molecular Sieves ◽  
Mesoporous Structure ◽  
Mesoporous Molecular Sieves ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Geranyl Propionate ◽  
Adsorption Desorption ◽  
Mcm 41

In this paper, the synthesis of mesoporous molecular sieves MCM-41 was carried out in an open-vessel. The mesoporous structure of as-synthesized MCM-41 was characterized by X-ray diffraction (XRD) pattern, Fourier transform infrared (FT–IR) spectrum, NH3-Temperature Programmed Desorption (TPD), and N2 adsorption-desorption isotherms. The catalytic performances of MCM-41 for the synthesis of geranyl propionate (GP) with geraniol and propionic acid as reagents also were investigated. The characterization results show that the as-synthesized MCM-41 possesses typical hexagonal mesoporous structure with high long-range order and crystalline degree. The high GP selectivity of 64.25% with geraniol conversion of 17.21% was achieved under optimum conditions.

scholarly journals Release of toxic methylene blue from water by mesoporous silicalite-1: characterization, kinetics and isotherm studies

2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Sabarish Radoor ◽  
Jasila Karayil ◽  
Aswathy Jayakumar ◽  
Jyotishkumar Parameswaranpillai ◽  
Suchart Siengchin
Keyword(s):  
Electron Microscopy ◽  
Contact Time ◽  
Dye Removal ◽  
Batch Adsorption ◽  
Aqueous Environment ◽  
Order Kinetic ◽  
Adsorption Method ◽  
X Ray ◽  
Ft Ir ◽  
Adsorption Desorption

AbstractIn the present work, we have developed a mesoporous silicalite-1 using CMC as a template for the removal of MB from aqueous solution. The synthesized silicalite-1 were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Energy-dispersive X-ray spectroscopy (EDAX) and N2 adsorption–desorption isotherm (BET). XRD and FT-IR analysis confirmed the formation of crystallinity and development of MFI structure in the mesoporous silicalite-1. The adsorption of MB dye on mesoporous silicalite-1 was conducted by batch adsorption method. The effect of various parameters such as adsorbent dosage, initial dye concentration, contact time and temperature on the dye uptake ability of silicalite-1 was investigated. The operating parameters for the maximum adsorption are silicalite-1 dosage (0.1 wt%), contact time (240 min), initial dye concentration (10 ppm) and temperature (30 ℃). The MB dye removal onto mesoporous silicalite-1 followed pseudo-second-order kinetic and Freundlich isotherm. The silicalite-1 exhibits 86% removal efficiency even after six adsorption–desorption cycle. Therefore, the developed mesoporous silicalite-1 is an effective eco-friendly adsorbent for MB dye removal from aqueous environment.

MeAPO4 Berlinite as an Effective Catalyst for Mild Oxidation of Cyclohexane

2013 ◽  
Vol 709 ◽  
pp. 102-105 ◽  
Author(s):  
Da Lei Sun ◽  
Zi Sheng Chao
Keyword(s):  
Molecular Oxygen ◽  
Atmospheric Pressure ◽  
Molecular Sieve ◽  
Catalytic Performance ◽  
Synergic Effect ◽  
Mild Oxidation ◽  
Effective Catalyst ◽  
Ft Ir

Cobalt and/or manganese incorporated berlinites (CoMnAPO4) and aluminophosphate molecule sieve (CoMnAPO-5) were hydrothermally synthesized, characterized by XRD, FT-IR, XPS and SEM, and employed as catalysts in the oxidation of cyclohexane with molecular oxygen at 348 K under atmospheric pressure. It was found that the berlinite-based catalysts were more selective for the production of KA oil, stable during the reaction, but slightly less active for the conversion of cyclohexane, when compared to their molecular sieve counterparts. The CoMnAPO4exhibited a better catalytic performance, due to a synergic effect, than the CoAPO4or MnAPO4.

Preparation of Immobilized Chromium Schiff Base Complexes and their Catalytic Performance for Olefins Epoxidation

2014 ◽  
Vol 692 ◽  
pp. 240-244
Author(s):  
Gong De Wu ◽  
Xiao Li Wang ◽  
Zhi Li Zhai
Keyword(s):  
Hydrogen Peroxide ◽  
Schiff Base ◽  
Elemental Analysis ◽  
Catalytic Performance ◽  
Schiff Base Complexes ◽  
Metal Centers ◽  
Chemical Measurements ◽  
Physico Chemical ◽  
Immobilized Complexes ◽  
Mcm 41

A series of transition metal alanine-salicylaldehyde Schiff base chromium (III) complexes immobilized on MCM-41 were prepared and characterized by various physico-chemical measurements such as FIIR, XRD, HRTEM, N2 sorption and elemental analysis. The immobilized complexes were effective and stable catalysts for the epoxidation of styrene and cyclohexene with 30% hydrogen peroxide. Moreover, the metal centers were found to play important roles in the catalytic performance of immobilized complex catalysts.

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