scholarly journals Melt Crystallization of Ammonium Dinitramide (ADN) Investigated by Means of X‐ray Diffraction

2021 ◽  
Author(s):  
Michael Herrmann ◽  
Ulrich Förter‐Barth ◽  
Thomas Heintz
Keyword(s):  
Melt Crystallization ◽  
Ammonium Dinitramide ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Acemetacin cocrystal structures by powder X-ray diffraction

IUCrJ ◽  
2017 ◽  
Vol 4 (3) ◽  
pp. 206-214 ◽  
Author(s):  
Geetha Bolla ◽  
Vladimir Chernyshev ◽  
Ashwini Nangia
Keyword(s):  
Crystal Structures ◽  
Molecular Electrostatic Potential ◽  
Acid Group ◽  
Mutual Orientation ◽  
Type I ◽  
Type Ii ◽  
Melt Crystallization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrogen Bond Interactions

Cocrystals of acemetacin drug (ACM) with nicotinamide (NAM),p-aminobenzoic acid (PABA), valerolactam (VLM) and 2-pyridone (2HP) were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD) provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM–NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid–amide dimer three-point synthonR32(9)R22(8)R32(9) with three differentsynamides (VLM, 2HP and caprolactam). The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, beinganti(type I) orsyn(type II). ACM hydrate, ACM—NAM, ACM–NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP) surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O...H, N...H, Cl...H and C...H interactions. The physicochemical properties of these cocrystals are under study.

Pressure/Temperature/Reaction Phase Diagrams for Several Nitramine Compounds

1992 ◽  
Vol 296 ◽  
Author(s):  
T. P. Russell ◽  
P. J. Miller ◽  
G. J. Piermarini ◽  
S. Block
Keyword(s):  
Phase Diagrams ◽  
Diamond Anvil Cell ◽  
Temperature Reaction ◽  
Ammonium Dinitramide ◽  
X Ray Diffraction ◽  
Reaction Phase ◽  
X Ray ◽  
Ft Raman Spectroscopy ◽  
Diamond Anvil ◽  
Ft Raman

AbstractPressure/temperature/reaction phase diagrams for several nitramine compounds, including hexanitrohexaazaisowurtzitane (HNIW), 1,3,5-trinitrohexahydro-l,3,5-triazine (RDX), ammonium dinitramide (ADN), and p-nitroaniline (PNA) are presented. A diamond anvil cell was used in conjunction with optical polarizing light microscopy (OPLM), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray diffraction (EDXD), and micro FT-Raman spectroscopy to determine these diagrams. A description is given of the diamond anvil cell and the associated techniques employed.

scholarly journals Phase Transition and Melt-Recrystallization Behavior of Poly(Butylene Adipate) Investigated by Simultaneous Measurements of Wide-Angle X-Ray Diffraction (WAXD) and Differential Scanning Calorimetry (DSC)

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 75
Author(s):  
Mengfan Wang ◽  
Weiyu Cao
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Heating Process ◽  
Wide Angle ◽  
Melt Crystallization ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Β Phase ◽  
Simultaneous Measurements

Simultaneous measurements of wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) were carried out to investigate the phase transition and melting behaviors of poly(butylene adipate) (PBA). Thermal expansion changes along the a and b axes of the β form unit cell are different from each other during the heating process. At the beginning of the β to αH (high-temperature α phase) phase transition, the β phase melts very fast, while the recrystallization of the αH phase is delayed and slowed. With the further increment of the temperature, the melting rate of the β phase slows down, while the recrystallization of the αH phase accelerates. The diffraction peak intensity ratios of the β(020):β(110) and αH(020):αH(110) diffraction peaks during the first heating process have similar value. However, the above value is different from the value of α(020):α(110) during the following melt-crystallization process. This difference comes from the different orientations of the crystal lattices of the α and αH(β) crystals to the substrate plane, which indicates that the αH phase inherits the orientation of the β phase during phase transition and the orientation of αH form crystals is different from the α form crystals that crystallized from the melt.

Effect of Sodium Benzoate on the Crystallization Behavior of Poly (3-Hydroxybutyrate-Co-4-Hydroxybutyrate)

2014 ◽  
Vol 665 ◽  
pp. 375-378 ◽  
Author(s):  
Xiao Ping Wang ◽  
Wen Feng Li ◽  
Hao Zhang ◽  
De Ming Jia
Keyword(s):  
Activation Energy ◽  
Sodium Benzoate ◽  
Mechanical Performance ◽  
Crystallization Rate ◽  
Melt Crystallization ◽  
Crystalline Morphology ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Biodegradable Poly

Poly (3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB), as the latest generation of biosynthesis and biodegradable Poly (β-hydroxyalkanoate) material, its mechanical performance is greatly improved while its application in industry is confined for the inadequate crystallization properties. The effect of sodium benzoate on P34HB’s crystallization behaviors and nucleation mechanism were investigated through differential scanning calorimetry (DSC) and Angle X-ray diffraction (WAXD). WAXD analysis indicated that the adding of sodium benzoate did not chang the crystalline morphology of P34HB. The analysis of the kinetic parameters including the activation energy (ΔEc) of the non-isothermal melt-crystallization were carried out, which demonstrated that both of the Mo crystallization rate parameter and the Kissinger activation energy value are found to be sharply dropped with the addition of sodium benzoate. Compared to pure P34HB, F(T) on 80 % crystallinity of P34HB with 0.25 phr sodium benzoate fell from 38.79 to 17.89, and ΔEc decreased from-63.1 KJ·mol-1 to-108.8 KJ·mol-1, which indicated that the application of sodium benzoate can obviously improve the crystallization rate of P34HB.

New Insight of Isothermal Melt Crystallization in Poly(aryl ether ether ketone) via Time-Resolved Simultaneous Small-Angle X-ray Scattering/Wide-Angle X-ray Diffraction Measurements

1995 ◽  
Vol 28 (20) ◽  
pp. 6931-6936 ◽  
Author(s):  
Benjamin S. Hsiao ◽  
Bryan B. Sauer ◽  
Ravi K. Verma ◽  
H. Gerhard Zachmann ◽  
Soenke Seifert ◽  
...  
Keyword(s):  
Small Angle ◽  
Wide Angle ◽  
Melt Crystallization ◽  
Aryl Ether ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Ether Ether Ketone ◽  
Ether Ketone

scholarly journals Studies of preparation, characterization, and solubility of mefenamic acid-nicotinamide co-crystal synthesized by using melt crystallization method

2017 ◽  
Vol 10 (5) ◽  
pp. 135 ◽  
Author(s):  
Dwi Utami Purwantoro ◽  
Ilma Nugrahani ◽  
Slamet Ibrahim Surantaatmadja
Keyword(s):  
Mefenamic Acid ◽  
Crystal Formation ◽  
Melt Crystallization ◽  
Infrared Spectrophotometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystallization Method ◽  
Solid Crystal ◽  
Layer Chromatography ◽  
Scanning Electron

Objective : The objective of this study is to develop the formation mefenamic acid (MFA) – nicotinamide (NCT) co-crystal by using melt crystallization method and investigate its solubility.Method : Co-crystal was prepared by using melt crystallization method of MFA-NCT (1:2)  at (220±3) ° C. The initial co-crystal formation was performed by powder x-ray diffraction (PXRD). The thin layer chromatography (TLC) method was done to confirm the chemical stability of MFA and NCT due to synthesized process. The melt crystallization of MFA-NCT (1:2) was characterized by DSC/TG, Infrared spectrophotometry, and scanning electron microscopy. The solubility of the melt crystallization of MFA-NCT (1:2) was evaluated by incubated the samples in water at 25 °C and shaken for 24 h. The solubility of MFA was measured by UV-Vis spectrophotometer.Result : Characterizations of a co-crystal MFA-NCT (1:2) including PXRD, FTIR, DSC and SEM have indicated the formation of new solid crystal phase that differ from MFA, NCT and its physical mixture. The chromatogram of the TLC study exhibited two spot that corresponds to MFA and NCT. The solubility of the melt crystallization of MFA-NCT (1:2) was 57.97 %  higher than MFA solubility.Conclusion : These results suggest that MFA-NCT co-crystal can be synthesized by using melt crystallization method without decomposition of its component and provides an opportunity for the development of MFA solid form.Keywords: co-crystal, mefenamic acid, nicotinamide, melt crystallization, solubility

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

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