scholarly journals Application of nuclear magnetic resonance (NMR) in biooil characterization and authentication of chemical structures

2021 ◽  
Author(s):  
Fanxin Liu ◽  
Wujun Zeng ◽  
Yinglei Wei ◽  
Ben Hao ◽  
Han-Quing Jiang
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Structures ◽  
Nuclear Magnetic

This article discusses the application of nuclear magnetic resonance (NMR) in biooil characterization and authentication of chemical structures.

Novel amino-containing fluorene-based bisphthalonitrile compounds with flexible group

2017 ◽  
Vol 30 (7) ◽  
pp. 767-775 ◽  
Author(s):  
An-ran Wang ◽  
Abdul Qadeer Dayo ◽  
Dan Lv ◽  
Yi-le Xu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Mechanical Analysis ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Rheological Analysis ◽  
Chemical Structures ◽  
The Fourier Transform ◽  
Alkoxy Groups ◽  
Nuclear Magnetic

A series of amino-containing fluorene-based bisphthalonitrile (AFPN) monomers with alkyl or alkoxy groups were successfully produced by the reaction of 4-nitrophthalonitrile with 9, 9-bis (3-alkyl (or alkoxy)-4-aminophenyl)-2, 7-dihydroxylfluorene in the presence of potassium carbonate by a nucleophilic substitution reaction. The chemical structures of the synthesized monomers were confirmed by the Fourier transform infrared (FTIR), proton nuclear magnetic resonance, and carbon-13 nuclear magnetic resonance analyses. The synthesized monomers’ curing behaviors were evaluated by FTIR and differential scanning calorimetry, and a rheological analysis was performed to evaluate their respective processabilities. Moreover, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were performed for the thermomechanical, thermal, and thermo-oxidative analyses of the polymers. The results confirmed that the newly prepared phthalonitrile (PN) monomers with alkyl or alkoxy groups exhibited a self-promoted curing behavior. The rheological analysis suggested that the processing windows of the synthesized monomers were wider than that of APFN monomer bearing no flexible group. DMA and TGA revealed that the cured polymers exhibited high glass transition temperature (358–416°C) and the char yields at 800°C under nitrogen were between 70% and 77%. Moreover, the introduction of alkyl or alkoxy groups into the PN monomers’ backbones slightly reduced the thermal stability of the resulting polymers.

scholarly journals Nuclear magnetic resonance in chemical structures authentication and pyrolysis oil characterization

2022 ◽  
Author(s):  
Fanxin Liu ◽  
Wujun Zeng ◽  
Yinglei Wei
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Compositions ◽  
Pyrolysis Oil ◽  
Chemical Structures ◽  
Bio Oil ◽  
Dry Heating ◽  
Oil Characterization ◽  
Spin Properties ◽  
Nuclear Magnetic

Abstract Nuclear Magnetic Resonance (NMR) involves the study of nuclei immersed in a static magnetic field and exposed to a second oscillating field. Nuclei have two properties; spin properties and charge properties. Pyrolysis oil is created by dry heating biomass in a reactor without oxygen to around 500 degrees Celsius and then cooling it. Pyrolysis oil is a type of tar that includes too much oxygen to be classified as a pure hydrocarbon. One of the most fundamental methods in synthetic chemistry is using NMR to verify chemical structure. In the literature, little attention has been paid to the application of NMR in the authentication of chemical structures. In this study, we present a use case of NMR to characterize pyrolysis oil and authenticate chemical structures. Results show that the elucidation of chemical compositions of bio-oil is essential for the optimization of its processing technology and exploration of its potential application.

Nuclear Magnetic Resonance Spectroscopic Analysis of Gossypol and Its Analogs in Cotton Flower Buds (Gossypium)

1978 ◽  
Vol 61 (1) ◽  
pp. 146-149
Author(s):  
Anthony C Waiss ◽  
Bock G Chan ◽  
Mabry Benson ◽  
Maurice J Lukefahr
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Spectroscopic Analysis ◽  
Internal Standard ◽  
Aromatic Proton ◽  
Flower Bud ◽  
Chemical Structures ◽  
Magnetic Resonance Spectroscopic Analysis ◽  
Proton Peak ◽  
Nuclear Magnetic

Abstract A specific nuclear magnetic resonance (NMR) method has been developed for determining gossypol and its analogs in the cotton flower bud. Gossypol and its related analogs, some of whose chemical structures have not yet been determined, can be identified by the distinctive NMR absorption of the aldehydic protons between 10.0 and 11.3 ppm. These compounds are quantitatively estimated by comparing the areas of the aldehydic proton absorptions with the aromatic proton peak (6.82 ppm) from p-dimethoxybenzene internal standard.

scholarly journals Novel 6a,12b-Dihydro-6H,7H-chromeno[3,4-c] chromen-6-ones: Synthesis, Structure and Antifungal Activity

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1745 ◽  
Author(s):  
Jin-ping Bao ◽  
Cui-lian Xu ◽  
Guo-yu Yang ◽  
Cai-xia Wang ◽  
Xin Zheng ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Chemical Structures ◽  
Rate Method ◽  
High Resolution Mass Spectrometer ◽  
Nuclear Magnetic

A new series of coumarin derivatives, 7-hydroxy-7-(trifluoromethyl)-6a,12b-dihydro-6H,7H-chromeno[3,4-c]chromen-6-ones 3a–p, were synthesized via Michael addition, transesterification and nucleophilic addition from the reaction of 3-trifluoroacetyl coumarins and phenols in the presence of an organic base. The products were characterized by infrared spectroscopy (IR), hydrogen nuclear magnetic resonance spectroscopy (1H-NMR), carbon nuclear magnetic resonance spectroscopy (13C-NMR) and high-resolution mass spectrometer (HRMS). Single crystal X-ray analysis of compounds 3a and 3n clearly confirmed their assigned chemical structures and their twisted conformations. Compound 3a crystallized in the orthorhombic system, Pbca, in which a = 8.6244(2) Å, b = 17.4245(4) Å, c = 22.5188(6) Å, α = 90°, β = 90°, γ = 90°, v = 3384.02(14) Å3, and z = 8. In addition, the mycelial growth rate method was used to examine the in vitro antifungal activities of the title compounds 3a–p against Fusarium graminearum and Fusarium monitiforme at 500 µg/mL. The results showed that compound 3l exhibited significant anti-Fusarium monitiforme activity with inhibitory index of 84.6%.

An emerging technology: Nuclear magnetic resonance microscopy

1988 ◽  
Vol 46 ◽  
pp. 1000-1001
Author(s):  
M.J. Hennessy ◽  
E. Kwok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Basic Research ◽  
Local Environment ◽  
Magnetic Resonance Images ◽  
Nmr Microscopy ◽  
Mri Scans ◽  
Temperature Relaxation ◽  
Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

Nuclear magnetic resonance microscopy

1989 ◽  
Vol 47 ◽  
pp. 828-829
Author(s):  
Paul C. Lauterbur
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Fields ◽  
Signal To Noise ◽  
Field Gradients ◽  
Useful Signal ◽  
Magnetic Field Gradients ◽  
Observation Times ◽  
Nuclear Magnetic

Nuclear magnetic resonance imaging can reach microscopic resolution, as was noted many years ago, but the first serious attempt to explore the limits of the possibilities was made by Hedges. Resolution is ultimately limited under most circumstances by the signal-to-noise ratio, which is greater for small radio receiver coils, high magnetic fields and long observation times. The strongest signals in biological applications are obtained from water protons; for the usual magnetic fields used in NMR experiments (2-14 tesla), receiver coils of one to several millimeters in diameter, and observation times of a number of minutes, the volume resolution will be limited to a few hundred or thousand cubic micrometers. The proportions of voxels may be freely chosen within wide limits by varying the details of the imaging procedure. For isotropic resolution, therefore, objects of the order of (10μm) may be distinguished.Because the spatial coordinates are encoded by magnetic field gradients, the NMR resonance frequency differences, which determine the potential spatial resolution, may be made very large. As noted above, however, the corresponding volumes may become too small to give useful signal-to-noise ratios. In the presence of magnetic field gradients there will also be a loss of signal strength and resolution because molecular diffusion causes the coherence of the NMR signal to decay more rapidly than it otherwise would. This phenomenon is especially important in microscopic imaging.

Sign in / Sign up

Export Citation Format

Share Document