scholarly journals Liquid-Phase Catalytic Oxidation of Limonene to Carvone over ZIF-67(Co)

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 374 ◽  
Author(s):  
Yizhou Li ◽  
Yepeng Yang ◽  
Daomei Chen ◽  
Zhifang Luo ◽  
Wei Wang ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Catalytic Oxidation ◽  
Heterogeneous Catalyst ◽  
Product Selectivity ◽  
X Ray Diffraction ◽  
Zeolitic Imidazolate Framework ◽  
X Ray ◽  
Mild Conditions ◽  
Before And After ◽  
Diffraction Patterns

Liquid-phase catalytic oxidation of limonene was carried out under mild conditions, and carvone was produced in the presence of ZIF-67(Co), cobalt based zeolitic imidazolate framework, as catalyst, using t-butyl hydroperoxide (t-BHP) as oxidant and benzene as solvent. As a heterogeneous catalyst, the zeolitic imidazolate framework ZIF-67(Co) exhibited reasonable substrate–product selectivity (55.4%) and conversion (29.8%). Finally, the X-ray diffraction patterns of the catalyst before and after proved that ZIF-67(Co) acted as a heterogeneous catalyst, and can be reused without losing its activity to a great extent.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Carbonization Effect on Phase Structures of Zirconium Oxides with 2-3 Percent Yttrium

2014 ◽  
Vol 936 ◽  
pp. 181-186
Author(s):  
Zhi Qin Xue ◽  
Yong Quan Guo
Keyword(s):  
Tetragonal Phase ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconium Oxides ◽  
Percent Yttrium ◽  
Before And After ◽  
Cubic Structure ◽  
Diffraction Patterns ◽  
Rietveld Structural Refinement

Phase evolutions and structures of zirconium oxides with 2 percent yttrium before and after carbonization have been systemically studied with X-ray diffraction and Rietveld structural refinement. The carbonization decreases the structural stability of original ZrO2. According to the X-ray diffraction patterns, three phases with monoclinic, tetragonal and cubic structure coexist after carbonization. With increasing carbonizing temperature, the content of tetragonal phase in ZrO2with 2% mol Y2O3 doped increases，however, the phase content of monoclinic phase decreases. The content of tetragonal phase in ZrO2with 3% mol Y2O3doped increases greatly after carbonization. It implies that carbonization is beneficial for the formation of ZrO2tetragonal phase.

High Tc Superconductor Films Grown by the Liquid Phase Epitaxial Technique

1989 ◽  
Vol 169 ◽  
Author(s):  
C. S. Yang ◽  
A. S. Yue
Keyword(s):  
Liquid Phase ◽  
Cross Sections ◽  
X Ray Diffraction ◽  
High Tc ◽  
Liquid Phase Epitaxial ◽  
X Ray ◽  
Diffraction Patterns ◽  
High Degree ◽  
Superconductor Films

AbstractHigh Tc superconducting YBa2Cu3O7 films have been prepared by the Liquid Phase Epitaxial (LPE) technique. The x‐ray diffraction patterns displayed a high degree of (00l) preferred orientations with c‐axes perpendicular to the film surfaces. The in‐situ grown YBa2Cu3O7 films showed zero‐resistivity at 76*K. Examination of the film cross sections by SEM revealed a growth mechanism.

Reactive Adsorption of Sulfur Compounds from FCC Gasoline on NiO/γ-Al2O3

2009 ◽  
Vol 79-82 ◽  
pp. 2219-2222 ◽  
Author(s):  
Hai Yan Yin ◽  
Chun Hu Li ◽  
Lin Xue Wang ◽  
Ying Min Yu
Keyword(s):  
Nitrogen Adsorption ◽  
Sulfur Compounds ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fcc Gasoline ◽  
Reactive Adsorption ◽  
Before And After ◽  
Desulfurization Efficiency ◽  
Diffraction Patterns ◽  
Sulfur Adsorption

NiO/γ-Al2O3 adsorbent was prepared by wet impregnated method. XRD, SEM-EDS, nitrogen adsorption techniques were used to characterize the adsorbents and GC-FPD was utilized to analyze the composition of gasoline before and after reaction. X-ray diffraction patterns indicate that noncrystal NiO particles are supported on the surface of γ-Al2O3. The results show that NiO/γ-Al2O3 adsorbent could be used to remove sulfur compounds and is effective on removing benzothiophene (BT). The maximum desulfurization efficiency appears when NiO content reaches 16%, and the total sulfur adsorption capacity is 1.84mg/g, however for 16%Ni/γ-Al2O3 the value reaches 3.495mg/g.

scholarly journals Zinc containing borate glasses and glass-ceramics: Search for biomedical applications

2014 ◽  
Vol 8 (4) ◽  
pp. 185-193 ◽  
Author(s):  
Amr Abdelghany ◽  
Fatema Elbatal ◽  
Hatem Elbatal
Keyword(s):  
Glass Ceramic ◽  
Corrosion Behaviour ◽  
Glass Ceramics ◽  
Soda Lime ◽  
Dissolution Mechanism ◽  
Borate Glasses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Diffraction Patterns

Ternary soda lime borate glass and samples with ZnO replacing CaO up to 10mol%were prepared and studied for their bone bonding ability. Fourier transform infrared (FTIR) absorption spectra of the prepared glasses before and after immersion in simulated body fluid (SBF), for one or two weeks, showed the appearance of calcium phosphate (hydroxyapatite (HA)) which is an indication of bone bonding ability. X-ray diffraction patterns were measured for the glasses and indicated the presence of small peaks related to hydroxyapatite in the samples immersed in SBF. The glasses were heat treated with controlled two-step regime to convert them to their corresponding glass-ceramic derivatives. FTIR and X-ray diffraction measurements of the glass-ceramic samples (before and after immersion in SBF) confirmed the appearance of HA which is influenced by ZnO content. The overall data are explained on the basis of current views about the corrosion behaviour of borate glasses including hydrolysis and direct dissolution mechanism.

X-Ray Diffraction Patterns of Oil Palm Empty Fruit Bunch Fibers with Varying Crystallinity

2015 ◽  
Vol 1087 ◽  
pp. 321-328 ◽  
Author(s):  
Fatin Afifah Ahmad Kuthi ◽  
Khairiah Haji Badri ◽  
Azlin Mohmad Azman
Keyword(s):  
Acid Hydrolysis ◽  
Oil Palm ◽  
Empty Fruit Bunch ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Before And After ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Xrd Patterns

Crystallinity of oil palm fiber from empty fruit bunch (EFB) with and without tretaments was studied by analyzing the X-ray diffraction (XRD) pattern. In this paper, we focused on the effect of acid hydrolysis onto EFB on the crystallinity of the extracted cellulose. The reaction was carried out by soaking EFB in 1% (v/v) aqueous sulfuric acid (H2SO4) at different temperatures of 120, 130 and 140°C for 1 h. The XRD patterns significantly showed changes in the 2θ peaks before and after the treatment. These changes were described in term of polymorphs type present, reflection and allomorphs of the samples. XRD peak high and XRD deconvolution methods were used to calculate and compare the percentage of crystallinity of untreated EFB (UT-EFB) and acid hydrolyzed samples (AH-EFB). Based on the calculation, increment of about 1.3 times and 1.5 times were achieved by using WAXS and XRD deconvolution methods respectively. This is due to the removal of amorphous part contributed by lignin, hemicellulose and cellulose. Fourier Transform infrared (FTIR) spectra showed the presence of similar peaks in AH-EFB and commercial microcrystalline cellulose (C-MCC) at 1427, 1315, 895 and 1022 cm-1. The micrographic features showed the acid hydrolysis had successfully took place and separated the EFB microfibrils bundles.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

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.

An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride

1991 ◽  
Vol 56 (12) ◽  
pp. 2917-2935 ◽  
Author(s):  
Eva Klinotová ◽  
Václav Křeček ◽  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Acetic Anhydride ◽  
Spectral Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mild Conditions ◽  
Condensation Products ◽  
Unsaturated Lactones ◽  
C Nmr

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

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