Influence of Substituting Al by Mg-Co and Mn-Co on the Properties of AlPO4-5

1992 ◽  
Vol 57 (4) ◽  
pp. 750-755 ◽  
Author(s):  
Liao Changsheng
Keyword(s):  
Catalytic Activity ◽  
Infrared Spectra ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Surface Acidity ◽  
Chemical Compositions ◽  
Hydrothermal Crystallization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystallization Method

Two kinds of crystalline microporous metal aluminophosphate molecular sieves, magnesium cobalt aluminophosphate (MgCoAPO-5) and manganese cobalt aluminophosphate (MnCoAPO-5), were synthesized by hydrothermal crystallization method in order to improve the surface acidity and catalytic activity of AlPO4-5. The results of X-ray diffraction, infrared spectra and chemical compositions of MgCoAPO-5 and MnCoAPO-5 indicate that Mg-Co or Mn-Co enter the framework of AlPO4-5 molecular sieve without disrupting the microporous framework. However, the results of catalytic studies show that MgCoAPO-5 and MnCoAPO-5 possess much higher surface acidity and catalytic activity than the unmodified AlPO4-5.

Investigating the properties and performance of 3A molecular sieves as an adsorbent to prevent coke formation in olefin dehydration process

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zoya Moslempour ◽  
Sepehr Sadighi ◽  
Ali Dashti ◽  
Ali Ahmadpour
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
Coke Formation ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Na Ions ◽  
Temperature Programmed ◽  
And Performance ◽  
Physical And Chemical

Abstract To study the affinity of 3A aluminosilicate adsorbents to prevent oligomerization of olefin molecules and forming green oil, physical and chemical properties of 3A molecular sieves are measured by using characterization techniques such as temperature-programmed desorption (TPD), nitrogen (N2) and water adsorptions, X-ray diffraction (XRD), X-ray fluorescence (XRF), crushing strength, and carbon dioxide (CO2) adsorption. Moreover, coke formation affinities of the understudy adsorbents are evaluated in a bench-scale system using 1-butene and 1,3-butadiene at temperatures of 220 and 260 °C, and outcomes are validated against the actual data gathered from an industrial scale olefin dehydration plant. Results confirm that the type of binder and the amount of ion exchange affect the performance of a 3A molecular sieve nominated for dehydrating olefinic streams. The binder with the least amount of acidity is preferred, and at least 35% of Na ions of the 4A zeolite should be exchanged with K ions to make it applicable for synthesizing an appropriate 3A molecular sieve. Furthermore, to control the oligomerization and inhibit green oil formation, the CO2 adsorption and acidity of Trisiv shape molecular sieves with the sizes of 1/4 inch should be less than 0.5 wt % and 1.7 mmol NH3/g, respectively. For extrudate shape with the sizes of 1/16 inch CO2 adsorption and acidity should be less than 0.2 wt % and 2.2 mmol NH3/g, respectively.

scholarly journals Effect of Sulfation on Zirconia-Pillared Montmorillonite to the Catalytic Activity in Microwave-Assisted Citronellal Conversion

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Is Fatimah ◽  
Dwiarso Rubiyanto ◽  
Thorikul Huda
Keyword(s):  
Catalytic Activity ◽  
Surface Acidity ◽  
Total Pore Volume ◽  
High Catalytic Activity ◽  
X Ray Diffraction ◽  
Adsorption Method ◽  
X Ray ◽  
Pillared Montmorillonite ◽  
Microwave Assisted ◽  
Tandem Cyclization

Preparation of sulfated zirconia-pillared montmorillonite was carried out in two steps; zirconia pillarization and sulfation to zirconia-pillared montmorillonite. The prepared materials were characterized by using X-ray diffraction (XRD), measurement of the specific surface area, total pore volume and pore size distribution by the N2adsorption method, scanning electron microscopy-energy dispersive X-ray (SEM-EDX), and surface acidity determination by using pyridine adsorption-FTIR analysis. The activity of the materials as catalysts was evaluated for a microwave-assisted conversion of citronellal. The results showed that the prepared materials had a physicochemical character that promoted high catalytic activity to convert citronellal. From varied Zr content and study of the effect of sulfation on the activity, it was found that Zr content and sulfation increase the surface acidity of the material as shown by the higher total conversion and tendency to produce menthol as a product of the tandem cyclization-hydrogenation mechanism.

scholarly journals Effect of Calcination Temperature on the Synthesis of ZrO2-Pillared Saponite to Catalytic Activity in Menthol Esterification

2018 ◽  
Vol 16 (1) ◽  
pp. 8 ◽  
Author(s):  
Is Fatimah ◽  
Dwiarso Rubiyanto ◽  
Nanda Candra Kartika
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Calcination Temperature ◽  
Surface Acidity ◽  
Physicochemical Characteristics ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcination Temperatures ◽  
Solid Acidity

The influence of calcination temperature on the synthesis of zirconia-pillared saponite (PILS) and on its catalytic activity in menthol esterification has been studied. Zirconia pillarization was conducted using zirconium tetraisopropoxide as a precursor and with calcination temperatures of 450, 600 and 700 °C. Evaluation of physicochemical characteristics at these varied temperatures was carried out by X-Ray Diffraction (XRD), surface area analysis, Scanning Electron Eicroscope (SEM) analysis, Differential Thermal Analysis (DTA) and total acidity. The obtained results indicate that the structure and surface acidity of saponite were strongly influenced by calcination temperature. The solid acidity and surface parameters such as specific surface area, pore volume, and pore radius play an important role in the total conversion and selectivity in menthol esterification.

Low Temperature Studies Of Rare Gases Adsorbed On Molecular Sieve Materials

1991 ◽  
Vol 233 ◽  
Author(s):  
Graham F. Mccann ◽  
I. Gameson ◽  
W.J. Steado ◽  
T. Rayment ◽  
P.J. Barrie ◽  
...  
Keyword(s):  
Low Temperature ◽  
Phase Transformations ◽  
Adsorption Isotherms ◽  
Low Temperatures ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Variable Temperature ◽  
Rare Gases ◽  
X Ray Diffraction ◽  
X Ray

ABSTRACTX-ray diffraction (XRD) and adsorption isotherms have long been traditional methods of characterising molecular sieves. By combining these techniques at low temperatures with variable temperature 129-Xe N.M.R. we now have a fuller understanding of the behaviour of sorbed layers inside these materials. In particular we have observed phase transformations of Xe in a polyhydroxyaluminium-pillared montmorillonite molecular sieve and have developed a model consistent with the data. In addition, using XRD, an interpillar distance of ca. 30Å was calculated. We present the first detailed low temperature studies of 129-Xe N.M.R. on these systems.

scholarly journals Separation of Ethanol-Water MixtureUsing Type-A Zeolite Molecular Sieve

2010 ◽  
Vol 7 (2) ◽  
pp. 483-495 ◽  
Author(s):  
Juan Camilo Díaz ◽  
Iván Darío Gil-Chávez ◽  
Liliana Giraldo ◽  
Juan Carlos Moreno-Piraján
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
Type A ◽  
Water Mixture ◽  
X Ray Diffraction ◽  
Experimental Procedure ◽  
X Ray ◽  
Promoter Characterization ◽  
Reactive Mixture

This paper presents an experimental procedure for the synthesis of a type-A zeolite molecular sieve, usable in the separation of an ethanol-water mixture. The type-A zeolite molecular sieve is obtained from a reactive mixture formed by a source of alumina, a source of silica and a promoter. Characterization of the molecular sieves obtained in this work was undertaken using X-ray diffraction (XRD), adsorption isotherms and scanning electron microscopy (SEM). The results from the characterization procedures showed that part of the product presented a pore diameter suitable for the separation of an ethanol-water mixture.

Environmentally Friendly Catalyst of Zirconium Pillared Saponite for Solvent Free Esterification of Menthol

2015 ◽  
Vol 1101 ◽  
pp. 272-275
Author(s):  
Is Fatimah
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Pore Volume ◽  
Surface Acidity ◽  
Sol Gel ◽  
Measurement Techniques ◽  
Pyridine Adsorption ◽  
X Ray Diffraction ◽  
X Ray

In this research zirconium pillared saponite clay (Zr-PILS) was prepared for catalysis application. Pillarization was conducted by zirconium isopropoxide via using sol-gel mechanism and the characterization was performed by X-ray diffraction, gas sorption analysis and surface acidity measurement by pyridine adsorption-FTIR measurement techniques. Result showed that pillaring process to saponite produced pillared saponite with increasing specific surface area, pore volume as well as surface acidity that contributed to enhance catalytic activity in menthol esterification. Reusability test was also showed that Zr-PILS activity is relatively stable.

Infrared spectroscopic study of the YPO4-YCrO4 system

1985 ◽  
Vol 50 (10) ◽  
pp. 2139-2145
Author(s):  
Alexander Muck ◽  
Eva Šantavá ◽  
Bohumil Hájek
Keyword(s):  
Spectroscopic Study ◽  
Infrared Spectra ◽  
Point Of View ◽  
Mixed Crystals ◽  
Crystal Symmetry ◽  
Infrared Spectroscopic Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Spectroscopic ◽  
Diffraction Patterns

The infrared spectra and powder X-ray diffraction patterns of polycrystalline YPO4-YCrO4 samples are studied from the point of view of their crystal symmetry. Mixed crystals of the D4h19 symmetry are formed over the region of 0-30 mol.% YPO4 in YCrO4. The Td → D2d → D2 or C2v(GS eff) correlation is appropriate for both PO43- and CrO43- anions.

Bis(μ-carboxylato)dienerhodium(I) Complexes - Synthesis, Characterization and Catalytic Activity

2008 ◽  
Vol 73 (8-9) ◽  
pp. 1205-1221 ◽  
Author(s):  
Jiří Zedník ◽  
Jan Sedláček ◽  
Jan Svoboda ◽  
Jiří Vohlídal ◽  
Dmitrij Bondarev ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Diffraction Analysis ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
X Ray

Dinuclear rhodium(I) η2:η2-cycloocta-1,5-diene (series a) and η2:η2-norborna-2,5-diene (series b) complexes with μ-RCOO- ligands, where R is linear C21H43 (complexes 1a, 1b), CH2CMe3 (2a, 2b), 1-adamantyl (3a, 3b) and benzyl (4a, 4b), have been prepared and characterized by spectroscopic methods. Structures of complexes 2b, 3a and 4a were determined by X-ray diffraction analysis. Complexes prepared show low to moderate catalytic activity in polymerization of phenylacetylene in THF giving high-cis-transoid polymers, but they show only oligomerization activity in dichloromethane.

scholarly journals New Insights into the Crystal Chemistry of Elpidite, Na2Zr[Si6O15]·3H2O and (Na1+YCax□1−X−Y)Σ=2Zr[Si6O15]·(3−X)H2O, and Ab Initio Modeling of IR Spectra

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2160
Author(s):  
Alexander Bogdanov ◽  
Ekaterina Kaneva ◽  
Roman Shendrik
Keyword(s):  
Ir Spectra ◽  
Structural Models ◽  
Chemical Characterization ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Special Group ◽  
X Ray ◽  
Influence Of Water ◽  
Radioactive Species

Elpidite belongs to a special group of microporous zirconosilicates, which are of great interest due to their capability to uptake various molecules and ions, e.g., some radioactive species, in their structural voids. The results of a combined electron probe microanalysis and single-crystal X-ray diffraction study of the crystals of elpidite from Burpala (Russia) and Khan-Bogdo (Mongolia) deposits are reported. Some differences in the chemical compositions are observed and substitution at several structural positions within the structure of the compounds are noted. Based on the obtained results, a detailed crystal–chemical characterization of the elpidites under study was carried out. Three different structure models of elpidite were simulated: Na2ZrSi6O15·3H2O (related to the structure of Russian elpidite), partly Ca-replaced Na1.5Ca0.25ZrSi6O15·2.75H2O (close to elpidite from Mongolia), and a hypothetical CaZrSi6O15·2H2O. The vibration spectra of the models were obtained and compared with the experimental one, taken from the literature. The strong influence of water molecule vibrations on the shape of IR spectra of studied structural models of elpidite is discussed in the paper.

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