COMPARISON OF METHOXYMERCURIALS DERIVED FROM CYCLOPENTENE AND CYCLOHEXENE

1953 ◽  
Vol 31 (6) ◽  
pp. 536-542 ◽  
Author(s):  
A. G. Brook ◽  
R. Donovan ◽  
George F Wright
Keyword(s):  
Melting Point ◽  
Dipole Moments ◽  
Thermal Analyses ◽  
X Ray ◽  
Point Composition

The α- and β-2-methoxycyclopentylmercuric chlorides, bromides, and iodides have been prepared. The X-ray powder patterns, dipole moments, and thermal analyses among each series have been compared with the homologous methoxycyclohexyl derivatives. In both of the series the dipole moments of the β-diastereomers are greater than those of the corresponding α -isomers. In both series the α- and β-diastereomers seem to comprise isostructural series among the three halides. This isostructural relationship seems to be reflected in the melting point composition diagrams.

A Study of the Liquid Structure of Dimethyl Sulfoxide by the X-Ray Diffraction

1987 ◽  
Vol 42 (8) ◽  
pp. 858-862 ◽  
Author(s):  
Sumiko Itoh ◽  
Hitoshi Ohtaki
Keyword(s):  
Solid State ◽  
Melting Point ◽  
Dimethyl Sulfoxide ◽  
Liquid State ◽  
Dipole Moments ◽  
Liquid Structure ◽  
Structure Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Arrangement

The liquid structure of dimethyl sulfoxide (DMSO) was investigated by X-ray diffraction. The intramolecular structure parameters were obtained as follows: S = 0 150(1) pm, C - S 180(1) pm, nonbonding C · · · O 267(4) pm and C · · · C 271 (7) pm. It is suggested that the molecular arrangement in the liquid state is similar to that in the solid state. It is pointed out that not only the value but also the position of the dipole mom ent vector in the molecule is essential for dipoledipole intermolecular interactions and that the latter factor results in a higher melting point of DMSO than of N ,N -dimethylformamide in spite of their similar dipole moments.

Melting and Crystallization of Poly(oxyethylene) Mixtures

1995 ◽  
Vol 60 (11) ◽  
pp. 1855-1868 ◽  
Author(s):  
Ivo Lapeš ◽  
Josef Baldrian ◽  
Ján Biroš ◽  
Julius Pouchlý ◽  
Hanes Mio
Keyword(s):  
Melting Point ◽  
Lamellar Structure ◽  
Composition Dependence ◽  
Eutectic Phase ◽  
Eutectic Melting ◽  
Pure Polymer ◽  
X Ray ◽  
Long Period ◽  
Solid Liquid ◽  
Melting And Crystallization

Solid-liquid eutectic phase diagrams of mixtures of poly(oxyethylene) (M.w. 2 000) with hydroxy and methoxy endgroups, crystallizing in extended-chain macroconformation only, with glutaric acid, benzoic acid or 1,2-diphenylethane are given. The composition dependence of the melting temperature can be fitted by the Flory-Huggins equation. Interaction parameters X and interaction energy densities B evaluated from the diluent branch of the phase diagram are consistent with those obtained from the polymer branch provided the calorimetric value of enthalpy of polymer fusion is used in the latter computation. Measurements of small- and wide-angle X-ray scatterings showed a stacked lamellar structure of POE. Below the eutectic melting point, the long period of the polymer is almost independent of the diluent concentration. On raising temperature gradually from this melting point to the melting point of pure polymer, the increasing long period indicates the penetration of the diluent between the lamellae. As follows from SAXS measurements, the crystallinity of poly(oxyethylene) in the mixtures remains unchanged compared to that of the pure polymer.

scholarly journals Structure of the amorphous titania precursor phase of N-doped photocatalysts

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8619-8627
Author(s):  
I. E. Grey ◽  
P. Bordet ◽  
N. C. Wilson
Keyword(s):  
Thermal Analyses ◽  
Real Space ◽  
Ammonia Solution ◽  
Scattering Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Amorphous Titania ◽  
Precursor Phase ◽  
Titania Precursor ◽  
Titanyl Sulphate

Amorphous titania samples prepared by ammonia solution neutralization of titanyl sulphate have been characterized by chemical and thermal analyses, and with reciprocal-space and real-space fitting of wide-angle synchrotron X-ray scattering data.

Structural and thermodynamic properties of nanocrystalline fcc metals prepared by mechanical attrition

1992 ◽  
Vol 7 (7) ◽  
pp. 1751-1761 ◽  
Author(s):  
J. Eckert ◽  
J.C. Holzer ◽  
C.E. Krill ◽  
W.L. Johnson
Keyword(s):  
Thermal Analysis ◽  
Grain Size ◽  
Melting Point ◽  
Grain Boundary ◽  
Bulk Modulus ◽  
Atomic Level ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fcc Metals ◽  
Mechanical Attrition

Nanocrystalline fcc metals have been synthesized by mechanical attrition. The crystal refinement and the development of the microstructure have been investigated in detail by x-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The deformation process causes a decrease of the grain size of the fcc metals to 6–22 nm for the different elements. The final grain size scales with the melting point and the bulk modulus of the respective metal: the higher the melting point and the bulk modulus, the smaller the final grain size of the powder. Thus, the ultimate grain size achievable by this technique is determined by the competition between the heavy mechanical deformation introduced during milling and the recovery behavior of the metal. X-ray diffraction and thermal analysis of the nanocrystalline powders reveal that the crystal size refinement is accompanied by an increase in atomic-level strain and in the mechanically stored enthalpy in comparison to the undeformed state. The excess stored enthalpies of 10–40% of the heat of fusion exceed by far the values known for conventional deformation processes. The contributions of the atomic-level strain and the excess enthalpy of the grain boundaries to the stored enthalpies are critically assessed. The kinetics of grain growth in the nanocrystalline fcc metals are investigated by thermal analysis. The activation energy for grain boundary migration is derived from a modified Kissinger analysis, and estimates of the grain boundary enthalpy are given.

Synthesis, X-ray structure determination, and formation of 3,4,5-trichloroguaiacol occurring in kraft pulp spent bleach liquors

1980 ◽  
Vol 58 (8) ◽  
pp. 815-822 ◽  
Author(s):  
K. Lindström ◽  
F. Österberg
Keyword(s):  
Reaction Mechanism ◽  
Melting Point ◽  
Structure Determination ◽  
Kraft Pulp ◽  
Chemical Shifts ◽  
X Ray ◽  
Nmr Chemical Shifts ◽  
Chemical Pulp ◽  
C Nmr

3,4,5-Trichloroguaiacol, which is formed during bleaching of chemical pulp and shown to bioaccumulate in fish, has been synthesized. The structure of the compound has been determined by means of X-ray analysis. The values of the 13C nmr chemical shifts and melting point differ from those previously reported. A reaction mechanism is suggested for the formation of 3,4,5- and 4,5,6-trichloroguaiacol.

Novel tetrazole PtII and PdII complexes with enhanced water solubility: synthesis, structural characterization and evaluation of antiproliferative activity

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Tatiyana V. Serebryanskaya ◽  
Alexander S. Lyakhov ◽  
Ludmila S. Ivashkevich ◽  
Yuri V. Grigoriev ◽  
Andreii S. Kritchenkov ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Performance ◽  
Water Solubility ◽  
Thermal Analyses ◽  
High Water ◽  
Acetonitrile Solution ◽  
X Ray ◽  
Molecular And Crystal Structures ◽  
Tetrazole Derivatives ◽  
High Water Solubility

AbstractNovel platinum(II) and palladium(II) chlorido complexes with tetrazole derivatives 1-(2-hydroxyethyl)tetrazole (het) and 1-[tris(hydroxymethyl)methyl]tetrazole (thm), viz. cis-[Pt(het)2Cl2], trans-[Pt(het)2Cl2], trans-[Pt(thm)2Cl2], trans-[Pd(het)2Cl2], and trans-[Pd(thm)2Cl2], were synthesized. The compounds were characterized by elemental and high-resolution electrospray ionization (HRESI) mass spectrometry, high-performance liquid chromatography (HPLC), 1H, 13C and 195Pt nuclear magnetic resonance (NMR) spectroscopy, thermal analyses, and Infrared (IR) spectroscopy. Molecular and crystal structures of trans-[PdL2Cl2] and trans-[PtL2Cl2] (L = het, thm) were established by single-crystal X-ray analysis. The complex cis-[Pt(het)2Cl2] was found to undergo cis–to–trans isomerization upon heating in acetonitrile solution and in the solid state. The synthesized complexes show rather high water solubility lying in the range of 2–10 mg/L.

Copper-containing nanocomposites on the basis of isotactic polypropylene and butadiene-nitrile rubber

2021 ◽  
Vol 5 ◽  
pp. 76-81
Author(s):  
N.I. Kurbanova ◽  
◽  
S. K. Ragimova ◽  
N. A. Alimirzoeva ◽  
N. Ya. Ishenko ◽  
...  
Keyword(s):  
Isotactic Polypropylene ◽  
Thermal Analyses ◽  
Nitrile Rubber ◽  
Polymer Composition ◽  
Rheological Parameters ◽  
Structure And Properties ◽  
Pressing Method ◽  
X Ray ◽  
High Pressure Polyethylene ◽  
Butadiene Nitrile Rubber

The influence of additives of nanofillers (NF) containing nanoparticles of copper oxides stabilized by a polymer matrix of high-pressure polyethylene (PE) obtained by the mechanochemical method on the structure and properties features of metal-containing nanocomposites based on isotactic polypropylene (PP) and butadiene-nitrile rubber (BNK) is studied by X-ray phase (XRD) and differential thermal analyses(DTA). The improvement of strength, deformation and rheological parameters, as well as thermal-oxidative stability of the obtained nanocomposites was revealed, which, apparently, is associated with the synergistic effect of interfacial interaction of copper-containing nanoparticles in the PE matrix with the components of the PP/BNK polymer composition. It is shown that nanocomposites based on PP/BNK/NF can be processed both by pressing method and by injection molding and extrusion methods, which expands the scope of its application.

Are mesoionic compounds aromatic?

1998 ◽  
Vol 76 (6) ◽  
pp. 869-872 ◽  
Author(s):  
Alfredo Mayall Simas ◽  
Joseph Miller ◽  
Petrônio Filgueiras de Athayade Filho
Keyword(s):  
Experimental Evidence ◽  
Key Words ◽  
Dipole Moments ◽  
The Other ◽  
Side Chain ◽  
Theoretical Studies ◽  
X Ray Diffraction ◽  
Ring Plane ◽  
X Ray ◽  
Single Bonds

We have evaluated the experimental evidence relevant to the structure and character of mesoionic compounds, accumulated for more than 100 years and including X-ray diffraction studies. We have also evaluated relevant theoretical studies. All these, including our own extensive work, lead us to conclude that mesoionic compounds are not aromatic. According to our recent definition “mesoionic compounds are planar five-membered heterocyclic betaines with at least one side chain whose α-atom is also in the ring plane and with dipole moments of the order of 5 D. Electrons are delocalized over two regions separated by what are essentially single bonds. One region, which includes the a-atom of the side chain is associated with the HOMO and negative π-charge whereas the other is associated with the LUMO and positive π-charge.” Key words: mesoionic compounds, betaines, aromaticity.

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