scholarly journals Chemical Composition of the Essential Oil from Corsican Mentha aquatica - Combined Analysis by GC(RI), GC-MS and 13C NMR Spectroscopy

2011 ◽  
Vol 6 (10) ◽  
pp. 1934578X1100601 ◽  
Author(s):  
Sylvain Sutour ◽  
Félix Tomi ◽  
Pascale Bradesi ◽  
Joseph Casanova
Keyword(s):  
Chemical Composition ◽  
Nmr Spectroscopy ◽  
Essential Oil ◽  
Silica Gel ◽  
Column Chromatography ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Combined Analysis ◽  
Mentha Aquatica ◽  
C Nmr

The essential oil (EO) of M. aquatica L. growing wild in Corsica was isolated by dry vapor distillation and submitted to combined analysis by column chromatography over silica gel, GC(RI), GC-MS and 13C NMR spectroscopy. The composition was dominated by oxygenated monoterpenes and characterized by the occurrence of menthofuran (50.7%) as the major component. In parallel, seven laboratory-distilled oil samples isolated from individual plants collected in Corsica were analyzed by GC(RI) and 13C NMR spectroscopy. Only quantitative differences were observed between the samples. Beside the usual terpenes, various p-menthane lactones (mintlactone, isomintlactone, hydroxymintlactone, menthofurolactone and epimenthofurolactone) have been identified in all the oil samples.

scholarly journals Combined Analysis by GC (RI), GC/MS and 13C NMR Spectroscopy of Elsholtzia blanda, E. penduliflora and E. winitiana Essential Oils

2007 ◽  
Vol 2 (8) ◽  
pp. 1934578X0700200 ◽  
Author(s):  
Dominique Lesueur ◽  
Ange Bighelli ◽  
Nguyen Thi Tam ◽  
Nguyen Viet Than ◽  
Pham thi Kim Dung ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Nmr Spectroscopy ◽  
Essential Oil ◽  
Essential Oils ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Retention Indices ◽  
Aerial Parts ◽  
Two Samples ◽  
C Nmr

The chemical composition of six oil samples, isolated from aerial parts of Elsholtzia blanda, E. penduliflora and E. winitiana, harvested in two provinces of Vietnam, was investigated by GC, in combination with retention indices (RI), GC/MS and 13C NMR spectroscopy. Linalool was the major component (75.2 and 56.8%) of the two samples of E. blanda essential oil, whereas the two oil samples from E. penduliflora were dominated by 1,8-cineole (62.7 and 65.5%). Conversely, the two oil samples of E. winitiana exhibited different compositions, rosefuran (56.0%) and dehydroelsholtzia ketone (22.8%) being the major components of one sample, whilst the second sample was dominated by elsholtzia ketone (87.5%).

A Novel Method for 13C-NMR Spectroscopy of Polymer in Emulsion: Quantitative Analysis of Microstructure of Crosslinked Polybutadiene in Latex

1999 ◽  
Vol 72 (5) ◽  
pp. 844-853 ◽  
Author(s):  
Seiichi Kawahara ◽  
Saori Bushimata ◽  
Takashi Sugiyama ◽  
Chihiro Hashimoto ◽  
Yasuyuki Tanaka
Keyword(s):  
Nmr Spectroscopy ◽  
High Resolution ◽  
13C Nmr ◽  
Lattice Relaxation ◽  
13C Nmr Spectroscopy ◽  
Lattice Relaxation Time ◽  
Solid Sample ◽  
Spin Lattice Relaxation ◽  
High Resolution Spectrum ◽  
C Nmr

Abstract A novel analytical method using high resolution 13C-NMR spectroscopy to study polymer latex, which is a heterogeneous system comprising polymer dispersoid and water, is described. The appropriate concentrations of surfactant and dried rubber content of a polybutadiene latex, which give the best spectrum, were found to be 1 w/v % and 10%, respectively. The half-widths of resonance peaks for the latex sample were almost identical to the half-widths obtained in solution, which were about one-third the width of those obtained using a solid sample of either a crosslinked or soluble polybutadiene. Nevertheless, the signal to noise ratio for the latex sample was slightly smaller than that for the solution sample. The values of spin-lattice relaxation time, T1, for the latex sample were similar to those for the solid sample. These demonstrate that the latex state C-NMR spectroscopy will be a powerful technique for structural characterization of crosslinked gels in the dispersoid because it gives a high resolution spectrum comparable to solution state spectroscopy, showing short T1 values corresponding to those for solid state C-NMR spectroscopy. High resolution latex state 13C-NMR spectroscopy was used to determine the concentrations of the various isomers of the polybutadiene in the dispersoid.

Extent of intramolecular cyclization in RAFT-synthesized methacrylic branched copolymers using 13C NMR spectroscopy

2015 ◽  
Vol 6 (7) ◽  
pp. 1143-1149 ◽  
Author(s):  
J. Rosselgong ◽  
S. P. Armes
Keyword(s):  
Nmr Spectroscopy ◽  
Intramolecular Cyclization ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Branched Copolymers ◽  
C Nmr

The extent of intramolecular cyclization for a series of soluble branched methacrylic copolymers is determined by 13C NMR spectroscopy via deconvolution of oxymethylene carbon signals.

Ethylene Insertion with Soluble Ziegler Catalysts: Direct Insight into the Reaction Using Enriched 13C2 H4 and 13C NMR Spectroscopy II. The System Cp2TiMeCl/AlMeCl2/13C2H4

1985 ◽  
Vol 40 (2) ◽  
pp. 158-166 ◽  
Author(s):  
Gerhard Fink ◽  
Wolfgang Fenzl ◽  
Richard Mynott
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Elementary Processes ◽  
Carbon Bond ◽  
Spectroscopic Evidence ◽  
Oligomer Distribution ◽  
Insight Into ◽  
C Nmr

Abstract The elementary processes involved in the polymerization of ethylene by soluble Ziegler catalysts of the type Cp2TiMeCl/AlMeCl2 have been studied by 13C NMR spectroscopy. Using 13C-enriched ethylene, detailed information was obtained directly on the system in the course of the polymerization. No spectroscopic evidence was found for precoordination of the monomer. The development of the oligomer distribution, which could be followed spectroscopically, proves that the mechanism proposed by Olivé cannot be correct. These experiments show conclusively that the ethylene is inserted into the titanium-carbon bond.

scholarly journals Chemical Composition of the Essential Oils from Two Vietnamese Asarum Species: A. glabrum and A. cordifolium

2013 ◽  
Vol 8 (2) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Tran Huy Thai ◽  
Ophélie Bazzali ◽  
Tran Minh Hoi ◽  
Nguyen Anh Tuan ◽  
Félix Tomi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Nmr Spectroscopy ◽  
Endangered Species ◽  
Essential Oil ◽  
Essential Oils ◽  
Spectroscopic Techniques ◽  
Red Data Book ◽  
Data Book ◽  
First Time ◽  
C Nmr

The essential oil isolated from Asarum cordifolium C. E. C. Fischer recently discovered in Vietnam, and A. glabrum Merr., an endangered species listed as vulnerable in the Red Data Book of Vietnam, have been analyzed by a combination of chromatographic and spectroscopic techniques including 13C NMR spectroscopy. The composition of A. cordifolium essential oil, investigated for the first time, was dominated by elemicin (82.5%). The essential oil isolated from A. glabrum contained safrole (41.9%) as its major component and was characterized by the diversity of phenylpropanoids contained in this oil (10 compounds).

Organoboranes and tetraorganoborates studied by 11B and 13C NMR spectroscopy and DFT calculations

2015 ◽  
Vol 70 (6) ◽  
pp. 421-424 ◽  
Author(s):  
Bernd Wrackmeyer
Keyword(s):  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
13C Nmr ◽  
Quantum Chemical ◽  
13C Nmr Spectroscopy ◽  
Coupling Constants ◽  
Line Widths ◽  
Nmr Signals ◽  
C Nmr ◽  
Extract Information

AbstractCare should be taken on recording the sometimes elusive 13C NMR signals for boron-bonded carbon atoms, since it is easy to extract information about coupling constants 1J(13C,11B) by measuring the respective line widths of 13C(B-C) and 11B NMR signals. This information can be confirmed by quantum-chemical calculations [B3LYP (6-311+G(d,p) level of theory] of nJ(13C,11B) in organoboranes and tetraorganoborates. For the latter, the signs for n = 2, 3, 4 were experimentally determined.

scholarly journals Composition of Seed Essential Oils of Rhododendron tomentosum

2012 ◽  
Vol 7 (2) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Asta Judzentiene ◽  
Rita Butkiene ◽  
Jurga Budiene ◽  
Félix Tomi ◽  
Joseph Casanova
Keyword(s):  
Quantitative Analysis ◽  
Chemical Composition ◽  
Nmr Spectroscopy ◽  
Essential Oil ◽  
Essential Oils ◽  
Thermal Isomerization ◽  
Total Oil ◽  
First Time ◽  
Rhododendron Tomentosum ◽  
C Nmr

For the first time, the chemical composition of the seed essential oil of Rhododendron tomentosum was determined. Forty-seven compounds were identified, comprising 91.7% of the total oil. Palustrol (38.3%) and ledol (27.0%) were the predominant constituents. Some constituents, such as β-pinene oxide, iso-menthyl acetate, nerolidyl acetate, cadalene and guaiazulene were characteristic only for the seeds and were identified for the first time in Rh. tomentosum oils. For comparison purposes, the essential oil isolated from the shoots of the same plant were analyzed [GC(FID) in combination with RIs, GC-MS and 13C NMR]. More than a half of the oil was comprised of ledol (36.5%) and palustrol (21.0%). Quantitative analysis of ascaridol, a heat-sensitive compound, was carried out by 13C NMR spectroscopy. Indeed, ascaridol undergoes partial thermal isomerization to iso-ascaridol during GC analyses.

Hochauflösungs-13C-NMR-Spektroskopie, VI [1]. Strukturabhängigkeit der 13C,H-Kopplungskonstanten in 6.6-disubstituierten Fulvenen / High Resolution 13C NMR Spectroscopy, VI [1]. Structure Dependence of the 13C,H Coupling Constants in 6,6-Disubstituted Fulvenes

1980 ◽  
Vol 35 (12) ◽  
pp. 1572-1574 ◽  
Author(s):  
Siegmar Braun ◽  
Ulrich Eiehenauer
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectroscopy ◽  
High Accuracy ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Structure Parameters ◽  
Structure Dependence ◽  
C Nmr

In order to study the structure dependence of the 13C,H couplings in the fulvene system the 1H-coupled 13C NMR spectra of 6,6-disubstituted fulvenes (R = R′ = C6H5, CH3, cyclopropyl and N(CH3)2) were recorded and the interesting couplings determined with high accuracy by complete analysis. They have values typical for unsaturated five membered rings with vastly localised double bonds like cyclopentadiene-1,3 and spiro[2.4]heptadiene- 4,6 and show characteristic correlations with structure parameters.

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