13C-NMR quantification of proton exchange at LewisX hydroxyl groups in water

2011 ◽  
Vol 47 (38) ◽  
pp. 10800 ◽  
Author(s):  
Shinya Hanashima ◽  
Koichi Kato ◽  
Yoshiki Yamaguchi
Keyword(s):  
13C Nmr ◽  
Proton Exchange ◽  
Hydroxyl Groups

Bleaching ability of pre-hydrolyzed pulps in the context of a biorefinery mill

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 49-53 ◽  
Author(s):  
CHRISTINE CHIRAT ◽  
LUCIE BOIRON ◽  
DOMINIQUE LACHENAL
Keyword(s):  
Carbon Content ◽  
Acid Hydrolysis ◽  
13C Nmr ◽  
Kraft Lignin ◽  
Kappa Number ◽  
Hydroxyl Groups ◽  
Kraft Pulps ◽  
Quaternary Carbon ◽  
Oxygen Delignification

Autohydrolysis and acid hydrolysis treatments were applied on mixed softwood chips. The cooking ability was studied by varying the alkali and duration of the cook. Pulps with kappa numbers varying from 30 to 70 were obtained. The bleaching ability of these pulps was studied and compared to control kraft pulps. The prehydrolyzed pulps were shown to be more efficiently delignified by oxygen than the control kraft pulps starting from the same kappa number. Furthermore, the final bleaching was also easier for these pulps. It was also shown that extensive oxygen delignification applied on high-kappa pre-hydrolyzed pulps could be a way to improve the overall yield, which is a prerequisite for the development of such biorefinery concepts. Lignin was isolated from the control kraft and the two pre-hydrolyzed kraft pulps and analyzed by 13C NMR. Lignins from pre-hydrolyzed kraft pulps had similar free phenolic groups content to the control kraft lignin, but their aliphatic hydroxyl groups and β-O-4 content were lower than for the control lignin. The quaternary carbon content was the same for all the samples.

scholarly journals The Synthesis of Poly(Vinyl Alcohol) Grafted with Fluorinated Protic Ionic Liquids Containing Sulfo Functional Groups

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4158
Author(s):  
Patrycja Glińska ◽  
Andrzej Wolan ◽  
Wojciech Kujawski ◽  
Edyta Rynkowska ◽  
Joanna Kujawa
Keyword(s):  
Ionic Liquids ◽  
Vinyl Alcohol ◽  
Proton Exchange ◽  
Polymer Materials ◽  
Polymerization Reaction ◽  
Poly Vinyl Alcohol ◽  
Hydroxyl Groups ◽  
Protic Ionic Liquids ◽  
Synthesis Route ◽  
Sulfo Groups

There has been an ongoing need to develop polymer materials with increased performance as proton exchange membranes (PEMs) for middle- and high-temperature fuel cells. Poly(vinyl alcohol) (PVA) is a highly hydrophilic and chemically stable polymer bearing hydroxyl groups, which can be further altered. Protic ionic liquids (proticILs) have been found to be an effective modifying polymer agent used as a proton carrier providing PEMs’ desirable proton conductivity at high temperatures and under anhydrous conditions. In this study, the novel synthesis route of PVA grafted with fluorinated protic ionic liquids bearing sulfo groups (–SO3H) was elaborated. The polymer functionalization with fluorinated proticILs was achieved by the following approaches: (i) the PVA acylation and subsequent reaction with fluorinated sultones and (ii) free-radical polymerization reaction of vinyl acetate derivatives modified with 1-methylimidazole and sultones. These modifications resulted in the PVA being chemically modified with ionic liquids of protic character. The successfully grafted PVA has been characterized using 1H, 19F, and 13C-NMR and FTIR-ATR. The presented synthesis route is a novel approach to PVA functionalization with imidazole-based fluorinated ionic liquids with sulfo groups.

scholarly journals Identification of the Crystalline Product of Liquid-Phase Oxidation of α-Pinene with Atmospheric Oxygen in the Presence of Cobalt (II) Stearate

2021 ◽  
pp. 173-180
Author(s):  
Alexandra Sosnovskaya ◽  
◽  
Viachaslau Fleisher ◽  
Keyword(s):  
Liquid Phase ◽  
13C Nmr ◽  
Standard Sample ◽  
Atmospheric Oxygen ◽  
Liquid Phase Oxidation ◽  
Wave Number ◽  
Hydroxyl Groups ◽  
Nmr Spectrum ◽  
Crystalline Product ◽  
Phase Oxidation

One of the possible directions of liquid-phase oxidation of α-pinene by atmospheric oxygen leads to the formation of a mixture of terpene oxygen-containing compounds (epoxides, alcohols, ketones, etc.). The problem of this direction is the formation of a large amount of 2,3-epoxypinane which over time turns into trans-sobrerol, campholene aldehyde, trans-pinocarveol, trans-carveol, and trans-3-pinen-2-ol as a result of hydrolysis. One of the abovementioned substances with a solid crystalline structure is trans-sobrerol. Sobrerol is widely used in perfumery for synthesis of synthetically fragrant substances and pharmaceutical industry, in particular, it is a part of medicines with mucolytic action, as well as in the treatment of headaches and diseases such as rhinorrhea and chronic bronchitis. The aim of this work is to identify a crystalline product produced by liquid-phase oxidation of α-pinene with atmospheric oxygen in the presence of cobalt (II) stearate. The process of liquid-phase oxidation was carried out in the following conditions: temperature – 70 °С, air consumption – 16.67 cm3/s, duration – 5 h, amount of catalyst – 0.2–0.5 wt.%. Then the mixture was exposed to steam distillation in order to separate monomers (they contain terpene oxygen-containing compounds and hydrocarbons) from polymers. As a result of settling and storage of the mixture, crystals were found and isolated from the mother liquor solution. Their identification was carried out using IR and 13C NMR spectroscopy as well as scanning electron microscopy. It was found that the spatial organization of the isolated crystals and the standard sample (Sigma Aldrich) is represented by multilayer rectangular plates. Analysis of the IR spectra of the crystals showed that the absorption band at a wave number of 3318 cm–1 corresponds to intramolecular and intermolecular hydrogen bonds in hydroxyl groups, at wave numbers of 2887, 2935, 2975 cm–1 it corresponds to methyl groups. The results obtained are comparable with the results of the IR-spectrum of the standard sample. Given the results of previous studies of 1H NMR spectrum [15] and 13C NMR spectrum, it was determined that the resulting crystalline product of liquid-phase oxidation of α-pinene is trans-sobrerol.

13C NMR spectra of hydroxy adamantanes additivity in 13C NMR spectra of dihydroxyadamantanes

1979 ◽  
Vol 44 (7) ◽  
pp. 2230-2237 ◽  
Author(s):  
Jan Schraml ◽  
Harald Jancke ◽  
Günter Engelhardt ◽  
Luděk Vodička ◽  
Josef Hlavatý
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Hydroxyl Groups ◽  
13C Nmr Spectra ◽  
Limited Information ◽  
Adamantane Skeleton ◽  
Cyclic Compounds ◽  
Intramolecular Hydrogen ◽  
C Nmr

The 13C NMR spectra of all monohydroxy and ditopic dihydroxy adamantane isomers were measured and the lines assigned. The numbers of the isomers and of the non-equivalent carbon atoms permitted a verification of the simple additivity of the shielding contributions of two hydroxyl groups on the rigid adamantane skeleton in the isomers without a possibility of a direct OH-OH interaction. If such interactions occur, deviations are found. The direction and magnitude of the deviations is in agreement with the current interpretation of 13C chemical shifts in other classes of cyclic compounds. It is concluded that the deviations are not caused by intramolecular hydrogen bonds. The deviations and the values of substituent chemical shifts offer some limited information about the origin of the shielding effects, especially of those dependent on stereochemistry and degree of substitution (γanti effect).

Chemistry of chromotropic acid. 1H and 13C NMR spectroscopy of chromotropic acid and its derivatives

1991 ◽  
Vol 69 (8) ◽  
pp. 1207-1211 ◽  
Author(s):  
Paris E. Georghiou ◽  
Chi Keung (Jimmy) Ho ◽  
Chester R. Jablonski
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Deuterium Oxide ◽  
13C Nmr Spectroscopy ◽  
Chromotropic Acid ◽  
Hydroxyl Groups ◽  
Two Dimensional ◽  
1H And 13C Nmr ◽  
C Nmr

The 1H and 13C NMR spectra of chromotropic acid (CTA) (4,5-dihydroxy-2,7-naphthalenedisulphonic acid) have been unambiguously assigned. Proton NOED spectra were used to show the proximity of both H-3 and H-6 and the hydroxyl groups. Two-dimensional 1H–13C NMR correlation spectra of CTA, of its corresponding diacetoxy derivative, and of 3-bromo- and 3,6-dibromo-CTA support the assignments. A regioselective deuterium exchange reaction of the C-3 and C-6 protons of CTA with deuterium oxide was observed during the NMR experiments. This latter finding is strongly indicative of the mode of formation, and of the nature of the chromogen formed in the reaction of CTA with formaldehyde in the well-known CTA-formaldehyde analytical reaction. Key words: chromotropic acid, 3-bromochromotropic acid, 3,6-dibromochromotropic acid.

Analysis of oligosaccharides. 29Si and 13C NMR spectra of pertrimethylsilylated oligosaccharides derived from xylopyranose

1987 ◽  
Vol 52 (6) ◽  
pp. 1501-1513 ◽  
Author(s):  
Eva Petráková ◽  
Jan Schraml ◽  
Ján Hirsch ◽  
Magdalena Kvíčalová ◽  
Jan Zelený ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Parent Compound ◽  
Hydroxyl Groups ◽  
13C Nmr Spectra ◽  
Polyfunctional Compounds

29Si and 13C chemical shifts are reported for a series of 30 pertrimethylsilylated oligosaccharides containing xylopyranosyl unit. The number of lines in 29Si NMR spectra is in all cases in agreement with the number of hydroxyl groups present in the parent compound prior to trimethylsilylation. The results demonstrate the usefulness of 29Si NMR spectroscopy for the analysis of oligosaccharides and other polyfunctional compounds. The validity of direct additivity of 13C chemical shifts is tested on some model trisaccharides.

13C-NMR spectra of aldoses in molybdate complexes

1980 ◽  
Vol 45 (1) ◽  
pp. 123-126 ◽  
Author(s):  
Juraj Alföldi ◽  
Vojtech Bílik ◽  
Ladislav Petruš
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Hydroxyl Groups ◽  
13C Nmr Spectra ◽  
C Nmr

Analysis of 13C-NMR spectra has shown that ribose, talose and allose behave as trident donors in their molybdate complexes using hydroxyl groups at C(2), C(3) and C(4), whereas lyxose and mannose use hydroxyl groups at C(1), C(2) and C(3).

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