Synthesis of Fructone and Acylal Using Hexagonally Ordered Mesoporous Aluminosilicate Catalyst

2008 ◽  
Vol 73 (8-9) ◽  
pp. 1112-1124 ◽  
Author(s):  
Ajayan Vinu ◽  
Josena Justus ◽  
Veerappan Vaithilingam Balasubramanian ◽  
Shivappa Basappa Halligudi ◽  
Katsuhiko Ariga ◽  
...  
Keyword(s):  
Carbonyl Compounds ◽  
Phase Reaction ◽  
Reaction Conditions ◽  
Structure Directing Agent ◽  
Pluronic P123 ◽  
Ordered Mesoporous ◽  
Temperature Programmed ◽  
Hexagonally Ordered ◽  
Adsorption Desorption ◽  
Ionic Copolymer

Hexagonally ordered mesoporous AlSBA-15 with different nSi/nAl ratios have been hydrothermally synthesized using the non-ionic copolymer Pluronic P123 surfactant as the structure directing agent and characterized by XRD, N2 adsorption-desorption, and ammonia-temperature programmed desorption (pyridine-TPD). Acetal and acylal formation reactions of organic carbonyl compounds were efficiently catalyzed by AlSBA-15 under liquid-phase reaction conditions and the results were compared with the MFI, BEA and AlMCM-41(23). Of the catalysts studied, AlSBA-15(45) showed the highest activity in both the acetalization and acylal reactions of the carbonyl compounds under the optimized reaction conditions, and could be recycled several times without loss in activity. AlSBA-15(45) catalyst is highly stable, efficient, chemoselective, and environmental friendly, which could open the possibility for environment benign approach for the synthesis of acetals, acylals and its derivatives under mild reaction conditions.

scholarly journals Mesoporous Silica as a Drug Delivery System for Naproxen: Influence of Surface Functionalization

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4722
Author(s):  
Lukáš Žid ◽  
Vladimír Zeleňák ◽  
Miroslav Almáši ◽  
Adriana Zeleňáková ◽  
Jaroslava Szücsová ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Surface Functionalization ◽  
High Performance ◽  
Nitrogen Adsorption ◽  
Ethanol Solution ◽  
Physiological Solution ◽  
Ordered Mesoporous ◽  
Ft Ir ◽  
Hexagonally Ordered ◽  
Adsorption Desorption

In this work we describe the relationship between surface modification of hexagonally ordered mesoporous silica SBA-15 and loading/release characteristics of nonsteroidal anti-inflammatory drug (NSAID) naproxen. Mesoporous silica (MPS) was modified with 3-aminopropyl, phenyl and cyclohexyl groups by grafting method. Naproxen was adsorbed into pores of the prepared MPS from ethanol solution using a solvent evaporation method. The release of the drug was performed in buffer medium at pH 2 and physiological solution at pH 7.4. Parent MPSs as well as naproxen loaded MPSs were characterized using physicochemical techniques such as nitrogen adsorption/desorption, thermogravimetric analysis (TG), Zeta potential analysis, Fourier transform infrared spectroscopy (FT-IR), and elemental analysis. The amount of naproxen released from the MPSs into the medium was determined by high-performance liquid chromatography (HPLC). It was shown that the adsorption and desorption characteristics of naproxen are dependent on the pH of the solution and the surface functionalization of the host.

scholarly journals Ni-containing catalysts based on ordered mesoporous MgO–Al2O3for methane dry reforming

2018 ◽  
Vol 5 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Svetlana Pavlova ◽  
Yuliya Fedorova ◽  
Arkadii Ishchenko ◽  
Maxim Melgunov ◽  
Elena Melgunova ◽  
...  
Keyword(s):  
Self Assembly ◽  
Mesoporous Structure ◽  
Dry Reforming ◽  
One Pot ◽  
Methane Dry Reforming ◽  
Pluronic P123 ◽  
Ordered Mesoporous ◽  
Evaporation Induced Self Assembly ◽  
The One ◽  
Adsorption Desorption

Abstract The ordered mesoporous Mg- and Ni-Mg-alumina samples of general formula xwt%Mg-Al2O3 and ywt%Nixwt% Mg-Al2O3(x, y = 5, 10 % wt) have been prepared by the one-pot evaporation induced self-assembly (EISA) method using Pluronic P123 as a template. The textural and structural properties of the prepared samples have been characterized by N2adsorption-desorption analysis, BET, XRD, TEM with EDX, HAADF-STEM, and H2-TPR. The samples calcined at 700°C had an ordered mesoporous structure with a SSA of 170-250 m2/g, a pore volume of 0.5-0.64 cm3/g and a narrow distribution of the pore size (mean 12-16 nm). For the catalysts prepared by the one-pot EISA method, the size of the metal Ni particles was in the range of 3-12 nm and was conditioned by their confinement in the mesopores and the interaction with MgO and Al2O3. Testing in methane dry reforming in the 15v.% CH4+ 15v.%CO2feed, with He balance, at 650-750°C and the contact time of 0.015 s has shown the higher activity and stability of the ordered mesoporous 10w%Ni- 10w%Mg-Al2O3catalysts prepared by the one-pot method as compared with the catalyst of the same composition obtained by impregnation.

scholarly journals Single-Pot Synthesis of Biodiesel using Efficient Sulfonated-Derived Tea Waste-Heterogeneous Catalyst

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2293 ◽  
Author(s):  
Umer Rashid ◽  
Junaid Ahmad ◽  
Mohd Lokman Ibrahim ◽  
Jan Nisar ◽  
Muhammad Asif Hanif ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Nitrogen Adsorption ◽  
Biodiesel Production ◽  
Catalyst Loading ◽  
Reaction Conditions ◽  
Tea Waste ◽  
Before And After ◽  
Optimum Reaction ◽  
Temperature Programmed ◽  
Adsorption Desorption

The main purpose of this manuscript is to report the new usage of tea waste (TW) as a catalyst for efficient conversion of palm fatty acid distillate (PFAD) to biodiesel. In this work, we investigate the potential of tea waste char as a catalyst for biodiesel production before and after sulfonation. The activated sulfonated tea waste char catalyst was characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), elemental composition (CHNS), nitrogen adsorption-desorption using Brunauer-Emmett-Teller (BET) and ammonia-temperature-programmed desorption (NH3-TPD). The activated tea waste char catalyst shows higher acid density of 31 μmol g−1 as compared to tea waste char of 16 μmol g−1 and higher surface area of 122 m2/g. The optimum fatty acid conversion conditions were found that 4 wt % of catalyst loading with 9:1 of methanol:PFAD for 90 min of reaction time at 65 °C gives 97% free fatty acid (FFA) conversion. In conclusion, the sulfonated tea waste (STW) catalyst showed an impressive catalytic activity towards the esterification of PFAD at optimum reaction conditions with significant recyclability in five successive cycles without any reactivation step.

Efficient Synthesis of Diethyl Carbonate by Mg, Zn Promoted Hydroxyapatite via Transesterification Reaction

2020 ◽  
Vol 18 (4) ◽  
Author(s):  
Kartikeya Shukla ◽  
Vimal Chandra Srivastava
Keyword(s):  
Thermal Analysis ◽  
Active Sites ◽  
Molar Ratio ◽  
Diethyl Carbonate ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
High Basicity ◽  
Temperature Programmed ◽  
Adsorption Desorption

AbstractTransesterification of propylene carbonate (PC) and ethanol is a potent non-phosgene route for the synthesis of diethyl carbonate (DEC). In the present study, hydroxyapatite was synthesized and modified using Zn and Mg (Zn/HAP and Mg/HAP). Modified hydroxyapatite was used as catalyst for the synthesis of DEC. The thermal analysis of the catalytic precursor was studied using thermogravimetric-differential thermal analysis. The structural analysis, surface morphology, and nature of active sites over the catalyst surface were studied using techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and CO2 temperature-programmed desorption. Effects of reaction conditions like reaction temperature, reaction time and ethanol/PC molar ratio on DEC yield were also studied. The effects of Mg and Zn on HAP were found to be promotional for the synthesis of DEC using PC and ethanol. Mg/HAP was found to be the best among the three catalysts studied owing to its high basicity. Maximum DEC yield of 52.1 % was obtained in 5 h at 433 K using Mg/HAP catalyst.

scholarly journals Relevance of the Physicochemical Properties of Calcined Quail Eggshell (CaO) as a Catalyst for Biodiesel Production

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Leandro Marques Correia ◽  
Juan Antonio Cecilia ◽  
Enrique Rodríguez-Castellón ◽  
Célio Loureiro Cavalcante ◽  
Rodrigo Silveira Vieira
Keyword(s):  
Sunflower Oil ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Activity Phase ◽  
Temperature Programmed ◽  
Adsorption Desorption

The CaO solid derived from natural quail eggshell was calcined and employed as catalyst to produce biodiesel via transesterification of sunflower oil. The natural quail eggshell was calcined at 900°C for 3 h, in order to modify the calcium carbonate present in its structure in CaO, the activity phase of the catalyst. Both precursor and catalyst were characterized using Hammett indicators method, X-ray fluorescence (XRF), X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), CO2temperature-programmed desorption (CO2-TPD), X-ray photoelectronic spectroscopy (XPS), Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2adsorption-desorption at −196°C, and distribution particle size. The maximum biodiesel production was of 99.00 ± 0.02 wt.% obtained in the following transesterification reaction conditions:XMR(sunflower oil/methanol molar ratio of 1 : 10.5 mol : mol),XCAT(catalyst loading of 2 wt.%),XTIME(reaction time of 2 h), stirring rate of 1000 rpm, and temperature of 60°C.

Preparation, Characterization and Catalytic Performance of ZnO-SBA-15 Catalysts

2016 ◽  
Vol 690 ◽  
pp. 212-217 ◽  
Author(s):  
Supranee Lao-Ubol ◽  
Rungsinee Khunlad ◽  
Siriporn Larpkiattaworn ◽  
Shih Yuan Chen
Keyword(s):  
Pore Size ◽  
Mesoporous Structure ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Total Acid ◽  
Narrow Pore Size Distribution ◽  
Surface Areas ◽  
Ordered Mesoporous ◽  
Temperature Programmed ◽  
Adsorption Desorption

The series of ZnO-SBA-15 catalysts with 0.9wt% to 8.5wt% ZnO content have been synthesized by solvothermal impregnated of Zn acetate in ethanol on mesoporous silica SBA-15 platelets in order to maximize the methyl ester selectivity in transesterification reaction. The properties of these catalyst were characterized by N2 adsorption-desorption isotherm, NH3 temperature-programmed desorption, SEM, and XRD. The results showed that the ordered mesoporous structure of SBA-15 was remained with specific surface areas above 500 m2/g and a narrow pore size distribution observed with the mean pore size around 60 Å after ZnO modification. The strength of the acid sites and total acid amount of ZnO-SBA-15 catalysts is varied with number of ZnO loadings. The synthesized ZnO-SBA-15 catalyst was tested for catalytic activity in transesterification of crude Jatropha oil. It was found that at 200 °C for 2 h reaction of the ZnO-SBA-15 catalysts with acid capacities of 0.36-1.29 mmol H+/g-catal gave 68-98wt% of FAME yields and 0.4-1.4wt% of FFA yields which are comparable to the pure ZnO.

Cleavage of C=N derivatives and Oxidation of Thiols in Water under Neutral Conditions with 1,4-dichloro-1,4-diazoniabicyclo[2,2,2]octane bischloride

2007 ◽  
Vol 2007 (8) ◽  
pp. 486-489 ◽  
Author(s):  
Mahmood Tajbakhsh ◽  
Setareh Habibzadeh
Keyword(s):  
Carbonyl Compounds ◽  
High Yield ◽  
Reaction Conditions ◽  
Neutral Conditions

1,4-Diazabicyclo[2,2,2]octane (DABCO) is easily chlorinated and gives a complex which efficiently converts aliphatic and aromatic oximes, phenylhydrazones and semicarbazones to their corresponding carbonyl compounds in water at 50°C in high yield. This reagent can also be used for conversion of thiols to their compounding disulfide under the same reaction conditions. DABCO is quantitatively recovered which can be rechlorinated and reused several times.

A Rational Repeating Template Method for Synthesis of 2 D Hexagonally Ordered Mesoporous Precious Metals

2010 ◽  
Vol 6 (3) ◽  
pp. 881-887 ◽  
Author(s):  
Azusa Takai ◽  
Yoji Doi ◽  
Yusuke Yamauchi ◽  
Kazuyuki Kuroda
Keyword(s):  
Precious Metals ◽  
Template Method ◽  
Ordered Mesoporous ◽  
Hexagonally Ordered

Behaviours of direct yellow 12 adsorption on mesoporous carbons with different pore geometries

2018 ◽  
Vol 2017 (1) ◽  
pp. 219-228
Author(s):  
Fengling Liu ◽  
Ziyan Guo ◽  
Hui Qiu ◽  
Xia Lu ◽  
Hua Fang ◽  
...  
Keyword(s):  
Mesoporous Carbons ◽  
X Ray Diffraction ◽  
Pore Characteristics ◽  
X Ray ◽  
Transmission Electron ◽  
Cylindrical Pores ◽  
Pseudo Second Order ◽  
Hexagonally Ordered ◽  
Adsorption Desorption ◽  
Interconnected Pore

Abstract Four kinds of mesoporous carbons, C1-h-w, C2-h-h, C3-s-w, and C4-s-h, with different pore geometries were prepared and characterised, and their adsorption behaviours with aqueous direct yellow 12 (DY-12) were investigated. The results of X-ray diffraction and transmission electron microscopy show that C1-h-w and C3-s-w have wormlike pore characteristics, whereas C2-h-h and C4-s-h have 2-D hexagonally arranged pores. According to the N2 adsorption/desorption results, the specific surface area of C1-h-w (1,378 m2/g) is the largest among the four carbons. The adsorption isotherms could be effectively fitted using the Langmuir model. The maximum adsorption amounts of C1-h-w, C2-h-h, C3-s-w and C4-s-h are 0.968 mmol/g, 0.726 mmol/g, 0.161 mmol/g and 0.156 mmol/g, respectively. The pseudo-second-order rate constants of C1-h-w (39.8 g/(mmol·min)) and C2-h-h (7.28 g/(mmol·min)) are substantially larger than those of C3-s-w (0.0046 g/(mmol·min)) and C4-s-h (0.014 g/(mmol·min)), indicating that an open and interconnected pore geometry is favourable for DY-12 adsorption. Furthermore, DY-12 diffusion in 2-D hexagonally ordered cylindrical pores is superior to that in wormlike pores due to the smoothness of the channels in the former. External mass transfer and intraparticle diffusion both play roles in the adsorption process.

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