scholarly journals Application of 13C-NMR Coal Structure Analysis for the Formation of Volatile from High-volatile Coals under High-temperature Pressurized Gasifier Conditions

2021 ◽  
Vol 100 (9) ◽  
pp. 177-185
Author(s):  
Katsuhiko YOKOHAMA ◽  
Hiroaki WATANABE
Keyword(s):  
High Temperature ◽  
Structure Analysis ◽  
Coal Structure ◽  
C Nmr

scholarly journals NMR, X-Ray and MS Investigations of Ethyl 2-Aroyl-and Ethyl 2-Arylcarbamoyl-4,5- dimethyl-1,2,3,6-tetrahydropyridazine-1- carboxylates: Flexible Multidentate Ligands

1999 ◽  
Vol 23 (3) ◽  
pp. 186-187
Author(s):  
Erkki Kolehmainen ◽  
Katri Laihia ◽  
Maija Nissinen ◽  
Kalevi Pihlaja ◽  
Alexander Perjéssy ◽  
...  
Keyword(s):  
Structure Analysis ◽  
Multidentate Ligands ◽  
X Ray ◽  
C Nmr

The 1H and 13C NMR spectral assignments of ethyl 2-aroyl-4,5-dimethyl-1,2,3,6-tetrahydropyridazine-1-carboxylates (1a-1h) and ethyl 2-arylcarbamoyl-4,5-dimethyl-1,2,3,6-tetrahydropyridazine-1-carboxylates (2a-2k) are given based on DQF COSY, 1H,13C HMQC and 1H,13C HMBC-measurements; the dynamics of the tetrahydropyridazine ring has been studied by 1H, 1H EXSY-technique and the structure of one congener (4′-methylphenyl-derivative, 2a) has been confirmed by X-ray structure analysis.

Über Antimon-haltige Heterocyclen, V Antimon(III)-dithiolate mit verbrückten 5-und 8-Ringen/On Heterocyclic Systems Containing Antimony, V Antimony(III) Dithiolates with Bridged 5-and 8 -Membered Rings

1986 ◽  
Vol 41 (11) ◽  
pp. 1455-1460 ◽  
Author(s):  
Harald M. Hoffmann ◽  
Martin Dräger
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Nmr Spectra ◽  
Crystal Structure Analysis ◽  
Coordination Polyhedra ◽  
Starting Point ◽  
C Nmr

Abstract For diamony(III)-trisdithiolates two constitutions (bicyclic B or two bridged monocycles C) are possible. Two synthetical paths to three examples Sb2(XS2)3 with X = CH2CH2 (1), CH2CH2- O - CH2CH2 (2), CH2CH2- S - CH2CH2 (3) are reported. 13C NMR spectra in CDCl3 solution show the constitution C for 2 and 3, and a possible equilibrium C ⇌ 4:1) for 1. This corresponds to the result of a crystal structure analysis (R = 0.027). The constitution C found in solid 1 exhibits expanded coordination polyhedra around the two antimony atoms which indicate a starting point for rearrangement into the constitution B. The two bridged 5-membered rings have different conformations: envelope and half-chair.

Zur Darstellung und Struktur des 1.3-Dichloro-5-N.N-dimethylamino-1.3-dithia-2.4.6-triazins / Synthesis and Structure of 1,3-Dichloro-5-N,N-dimethylamino-1,3-dithia-2,4,6-triazine

1983 ◽  
Vol 38 (3) ◽  
pp. 347-349 ◽  
Author(s):  
Herbert W. Roesky ◽  
Pierre Schäfer ◽  
Mathias Noltemeyer ◽  
George M. Sheldrick
Keyword(s):  
Structure Analysis ◽  
Nmr Spectra ◽  
Membered Ring ◽  
Monoclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Cl Atoms ◽  
C Nmr

Abstract The six membered ring of composition (CH3)2NCN3S2Cl2 3 a was prepared from N,N-dimethylguanidinhydrochloride and trithiadiazindichloride. 3 a was characterized on the basis of mass, 1H, 13C NMR spectra and X-ray structure analysis. Crystals of 3 a are monoclinic, space group P21/c, with a = 660.3(6), b = 834.5(7), c = 1774.7(15) pm, β = 112.83(6)° and Z = 4. The C2N unit lies approximately in the plane of the [-CNSNSN-] ring, with both Cl atoms on the same side of the ring.

Exploring the reaction of formaldehyde with α-N-protected amino acid hydrazides

2008 ◽  
Vol 86 (7) ◽  
pp. 714-719
Author(s):  
Giancarlo Verardo ◽  
Paola Geatti ◽  
Marta Mancuso ◽  
Paolo Strazzolini
Keyword(s):  
High Temperature ◽  
Amino Acid ◽  
Monomeric Form ◽  
Enantiomerically Pure ◽  
Final Reaction ◽  
Protected Amino Acid ◽  
Condensation Reactions ◽  
C Nmr ◽  
Aqueous Formaldehyde

The reaction of formaldehyde with enantiomerically pure α-N-protected amino acid hydrazides is described. The system has been investigated in different solvents, including both aqueous formaldehyde and paraformaldehyde, with the aim of simplifying the final reaction mixture. Aqueous formaldehyde in refluxing THF proved to be the best combination, affording mainly the corresponding monomeric N-methylene and 1,3,5-trisubstituted-1,3,5-hexahydrotriazine derivatives. The monomeric form was the only one present at high temperature, as evidenced by 1H and 13C NMR spectroscopy.Key words: amino acid hydrazides, formaldehyde, condensation reactions, monomeric N-methylene derivatives, oligomers.

scholarly journals Quasicrystals: What do we know? What do we want to know? What can we know?

2018 ◽  
Vol 74 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Walter Steurer
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Structure Analysis ◽  
Self Assembly ◽  
State Of The Art ◽  
The State ◽  
Growth Mechanisms ◽  
Dan Shechtman ◽  
Big Picture ◽  
Quasicrystal Structure

More than 35 years and 11 000 publications after the discovery of quasicrystals by Dan Shechtman, quite a bit is known about their occurrence, formation, stability, structures and physical properties. It has also been discovered that quasiperiodic self-assembly is not restricted to intermetallics, but can take place in systems on the meso- and macroscales. However, there are some blank areas, even in the centre of the big picture. For instance, it has still not been fully clarified whether quasicrystals are just entropy-stabilized high-temperature phases or whether they can be thermodynamically stable at 0 K as well. More studies are needed for developing a generally accepted model of quasicrystal growth. The state of the art of quasicrystal research is briefly reviewed and the main as-yet unanswered questions are addressed, as well as the experimental limitations to finding answers to them. The focus of this discussion is on quasicrystal structure analysis as well as on quasicrystal stability and growth mechanisms.

Calibration of solid state NMR carbon structural parameters and application in coal structure analysis

2017 ◽  
Vol 45 (10) ◽  
pp. 1153-1163 ◽  
Author(s):  
Li-shi CHEN ◽  
Lan-lan WANG ◽  
Tie-ying PAN ◽  
Yang ZHOU ◽  
Yuan-yuan ZHANG ◽  
...  
Keyword(s):  
Solid State ◽  
Structure Analysis ◽  
Solid State Nmr ◽  
Structural Parameters ◽  
Coal Structure

Cesium State, Thermal Evolution In Csc24

1982 ◽  
Vol 20 ◽  
Author(s):  
H. Estrade-Szwarckopf ◽  
J. Conard ◽  
P. Lauginie ◽  
J. Van Der Klink ◽  
P. Lagrange ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Evolution ◽  
Smooth Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature State ◽  
C Nmr

ABSTRACTBy 133Cs and 13C NMR, EPR, susceptibility anisotropy and X-Ray diffraction,we studied the thermal evolution of Cs24 from 100 to 500 K. A smooth transition is observed near 300 K which can be interpreted in structural and electronic terms: at lower temperatures, the Cs atoms are located in a disordered manner on graphitic hexagonal sites and are almost completely ionized; in the high temperature state, the Cs atoms are completely disordered relatively to the graphitic lattice and their electrons are at least partly relocalized on the metallic s-function.

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