Solid-state NMR studies of methyl celluloses. Part 2: Determination of degree of substitution and O-6 vs. O-2/O-3 substituent distribution in commercial methyl cellulose samples

Karrasch, Andrea; Jäger, Christian; Saake, Bodo; Potthast, Antje; Rosenau, Thomas

doi:10.1007/s10570-009-9304-2

Cited by 14 publications

(2 citation statements)

References 6 publications

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“…According to Figure 9 the non-doped MC revealed an absorption band at 3446 cm −1 , related to the stretching vibration ν of the hydroxyl group (O-H). The bands at 2900 were assigned to C-H stretching of the methyl groups of the MC [ 23 ]. The peaks at 1374 and 1452 cm −1 represented the vibration of deformation in the plane of δ (C-H).…”

Section: Resultsmentioning

confidence: 99%

The Influence of UV Radiation on the Degradation of Pharmaceutical Formulations Containing Quercetin

2020

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The aim of this study was to assess the photostability of quercetin in the presence of anionic and nonionic polymeric gels with varied compositions of an added component—glycerol. The samples were irradiated continuously at constant temperature. The stability of quercetin in solution and incorporated into the gels was evaluated by an UV-Vis spectrophotometer. FTIR spectroscopy (Fourier-transform infrared spectroscopy) was used to detect the changes in the structure of quercetin depending on the polymer used in the gel, and on the exposure time. Photostabilization is an important aspect of quality assurance in photosensitive compounds. The decomposition rate of quercetin in the ionic preparation of polyacrylic acid (PAA) with glycerol was 1.952·10−3 min−1, whereas the absence of glycerol resulted in a decay rate of 5.032·10−4 min−1. The formulation containing non-ionic methylcellulose resulted in a decomposition rate of quercetin in the range of 1.679·10−3 min−1. The decay rate of quercetin under light influence depended on the composition of the gel. It was found that the cross-linked PAA stabilized quercetin and the addition of glycerol accelerated the photodegradation.

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Section: Resultsmentioning

confidence: 99%

The Influence of UV Radiation on the Degradation of Pharmaceutical Formulations Containing Quercetin

2020

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“…Cellulose acetate is an ester of cellulose and finds various applications in films, membranes, and fibers, depending on the way it is processed [17]. Ethyl cellulose [25,26] has also found applications in drug delivery systems [19]. Furthermore, hydroxypropyl cellulose, which is soluble in water, has been used as a lubricant [27,28].…”

Section: Introductionmentioning

confidence: 99%

Solid State NMR a Powerful Technique for Investigating Sustainable/Renewable Cellulose-Based Materials

et al. 2022

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Solid state nuclear magnetic resonance (ssNMR) is a powerful and attractive characterization method for obtaining insights into the chemical structure and dynamics of a wide range of materials. Current interest in cellulose-based materials, as sustainable and renewable natural polymer products, requires deep investigation and analysis of the chemical structure, molecular packing, end chain motion, functional modification, and solvent–matrix interactions, which strongly dictate the final product properties and tailor their end applications. In comparison to other spectroscopic techniques, on an atomic level, ssNMR is considered more advanced, especially in the structural analysis of cellulose-based materials; however, due to a dearth in the availability of a broad range of pulse sequences, and time consuming experiments, its capabilities are underestimated. This critical review article presents the comprehensive and up-to-date work done using ssNMR, including the most advanced NMR strategies used to overcome and resolve the structural difficulties present in different types of cellulose-based materials.

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Solid-state 13C NMR, X-ray diffraction and structural study of methyl 4-O-methyl β-D-glucopyranosides with all eight possible methyl-substitution patterns

et al. 2023

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Cellulose model compounds that mimic the building blocks of modified cellulose and cellulose derivatives are widely used in cellulose research to infer the properties of the polymer from the monomer. Based on the well-established model compound methyl 4-O-methyl β-d-glucopyranoside, in which the methyl groups represent the truncated side chains of the cellulose, the corresponding O-methyl-substituted derivatives with all eight different substitution patterns (mono-, di- and trisubstituted at O-2, O-3, O-6) were synthesized. Crystallization of the products in sufficient quality for solid-state structure determination by single-crystal X-ray diffraction succeeded in all cases, and the results are reported. Two of the compounds showed more than one independent molecule per unit cell. Solid-state 13C NMR showed a significant down-field shift (5–10 ppm) of the OMe-substituted carbons relative to the OH-substituted counterparts and generally confirmed the important influence of solid-state packing on the chemical shifts as seen by comparison to the solution NMR data. Graphical abstract

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Solid-state NMR studies of methyl celluloses. Part 2: Determination of degree of substitution and O-6 vs. O-2/O-3 substituent distribution in commercial methyl cellulose samples

Cited by 14 publications

References 6 publications

The Influence of UV Radiation on the Degradation of Pharmaceutical Formulations Containing Quercetin

The Influence of UV Radiation on the Degradation of Pharmaceutical Formulations Containing Quercetin

Solid State NMR a Powerful Technique for Investigating Sustainable/Renewable Cellulose-Based Materials

Solid-state 13C NMR, X-ray diffraction and structural study of methyl 4-O-methyl β-D-glucopyranosides with all eight possible methyl-substitution patterns

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