scholarly journals Comparison of Pentaerythrotol and Its Derivatives as Intumescent Flame Retardants for Polypropylene

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Siwen Huang ◽  
Jiayou Xu ◽  
Haiming Deng ◽  
Jie Liu ◽  
Yuanfang Xiao
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Flame Retardant ◽  
Flame Retardants ◽  
High Carbon Content ◽  
H Nmr ◽  
Ft Ir ◽  
Intumescent Flame Retardants ◽  
Charring Layer ◽  
Nuclear Magnetic

Hydroquinol bis[di(2,6,7-trioxa-phosphabicyclo[2.2.2]-octane-1-oxo-4-hydroxylmethyl)]phosphate (PBPP), which contains caged phosphates and benzene groups, was synthesized. The caged phosphate structure of PBPP was characterized by Fourier transform infrared spectroscopy (FT-IR), hydrogen nuclear magnetic resonance (1H-NMR), and phosphorus nuclear magnetic resonance (31P-NMR). The experimental results showed that PBPP had better performance than 1-oxo-4-hydroxymethy1-2,6,7-trioxa-1-phosphabicyclo[2.2.2]-octane (PEPA) and pentaerythritol (PER) in water resistance, compatibility with polypropylene (PP), thermal stability, and flame retardancy of intumescent flame retardant PP (IFR-PP) systems. It was attributed to the symmetrical structure and stereohindrance effect of PBPP. The IFR-PP systems reached UL94 V-0 flammability rating when the minimal addition of IFR with PBPP, PEPA, or PER was 25%, 23%, and 28%, respectively. The flame retardant mechanisms of IFR containing PBPP, PEPA, and PER were investigated by FT-IR and scanning electron microscopy (SEM). PBPP formed a perfect charring layer, with the high carbon content of PBPP helping it form the charring layer more quickly.

Synthesis of Bis(p-aminophenoxy)Dimethylsilane(p-APDS) and its Process Optimization

2014 ◽  
Vol 936 ◽  
pp. 67-73
Author(s):  
Li Xin Chen ◽  
Fei Yang ◽  
Jin Yun
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Melting Point ◽  
Magnetic Resonance ◽  
Process Optimization ◽  
H Nmr ◽  
Ft Ir ◽  
Productivity Process ◽  
Nuclear Magnetic

Bis (p-aminophenoxy) dimethylsilane (p-APDS) was prepared by the reaction ofp-aminophenol or 4-acetamidophenol with dimethyldichlorosilane in the presence of triethylamine or pyridine through four different means. The structure of diamines was examined by melting point apparatus, FT-IR and nuclear magnetic resonance apparatus1H-NMR. The productivity, process and cost of four means were compared. The results showed that benzene as a solvent, triethylamine as acid,p-aminophenol and dimethyl dichlorosilane at 40°C for 4h is the most economical and reasonable process for synthesis of bis (p-aminophenoxy) dimethylsilane (p-APDS).

The regioselective catalyst-free synthesis of bis-quinoxalines and bis-pyrido[2,3-b]pyrazines by double condensation of 1,4-phenylene-bis-glyoxal with 1,2-diamines

2018 ◽  
Vol 24 (4) ◽  
pp. 193-196 ◽  
Author(s):  
Mehdi Ahmadi Sabegh ◽  
Jabbar Khalafy
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
New Products ◽  
Proton Nuclear Magnetic Resonance ◽  
Efficient Synthesis ◽  
H Nmr ◽  
Ft Ir ◽  
C Nmr ◽  
Nuclear Magnetic

AbstractThe oxidation of 1,4-diacetylbenzene using several oxidizing agents gave 1,4-phenylene-bis-glyoxal in 61–85% yields. A convenient and efficient synthesis of bis-quinoxaline and bis-pyrido[2,3-b]pyrazine derivatives involves the double condensation of 1,2-diamines with 1,4-phenylene-bis-glyoxal in ethanol under reflux conditions. The structures of the new products were defined by proton nuclear magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C NMR), Fourier-transform infrared spectroscopy (FT-IR) and mass spectrometry (MS).

Anesthetic-membrane interaction: A 2H nuclear magnetic resonance study of the binding of specifically deuterated tetracaine and procaine to phosphatidylcholine

1984 ◽  
Vol 62 (2-3) ◽  
pp. 178-184 ◽  
Author(s):  
Eric C. Kelusky ◽  
Ian C. P. Smith
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Local Anesthetics ◽  
Nuclear Magnetic Resonance Study ◽  
Weakly Bound ◽  
Slow Exchange ◽  
H Nmr ◽  
Line Shapes ◽  
Acyl Chains ◽  
Nuclear Magnetic

The binding of the local anesthetics tetracaine and procaine with multilamellar dispersions of egg phosphatidylcholine has been studied by 2H nuclear magnetic resonance (NMR). The 2H-NMR line shapes of specifically deuterated local anesthetics are found to be very dependent on the attainment of a true equilibrium. The equilibrium could be most properly reached by the use of repeated freeze–thaw–vortex cycles. The data for tetracaine are consistent with the three-site exchange model proposed earlier. Tetracaine is in slow exchange between a strongly bound site and a weakly bound site and in fast exchange between the weakly bound site and free in solution. The slow exchange rate is estimated, from temperature and dilution studies, to be approximately 1.5 × 103 s−1 at pH 5.5 and slightly faster at pH 9.5. Comparisons of the quadrupole splittings with those seen for our earlier work in egg phosphatidylethanolamine suggest that the location of the strongly bound site in phosphatidylcholine is dependent on the anesthetic charge. This is in contrast to egg phosphatidylethanolamine, where molecular shapes appear to be the determining factor for the location of the anesthetic. Procaine bound very weakly to the model membranes, to yield only a broad resonance and no quadrupole splitting. It appears that procaine, unlike tetracaine, is not bound by the ordered acyl chains.

scholarly journals Structural Characterization of Amadori Rearrangement Product of Glucosylated Nα-Acetyl-Lysine by Nuclear Magnetic Resonance Spectroscopy

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chuanjiang Li ◽  
Hui Wang ◽  
Manuel Juárez ◽  
Eric Dongliang Ruan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Maillard Reaction ◽  
Structural Characterization ◽  
Resonance Spectroscopy ◽  
H Nmr ◽  
Amadori Rearrangement ◽  
C Nmr ◽  
Nuclear Magnetic

Maillard reaction is a nonenzymatic reaction between reducing sugars and free amino acid moieties, which is known as one of the most important modifications in food science. It is essential to characterize the structure of Amadori rearrangement products (ARPs) formed in the early stage of Maillard reaction. In the present study, the Nα-acetyl-lysine-glucose model had been successfully set up to produce ARP, Nα-acetyl-lysine-glucose. After HPLC purification, ARP had been identified by ESI-MS with intense [M+H]+ ion at 351 m/z and the purity of ARP was confirmed to be over 90% by the relative intensity of [M+H]+ ion. Further structural characterization of the ARP was accomplished by using nuclear magnetic resonance (NMR) spectroscopy, including 1D 1H NMR and 13C NMR, the distortionless enhancement by polarization transfer (DEPT-135) and 2D 1H-1H and 13C-1H correlation spectroscopy (COSY) and 2D nuclear overhauser enhancement spectroscopy (NOESY). The complexity of 1D 1H NMR and 13C NMR was observed due to the presence of isomers in glucose moiety of ARP. However, DEPT-135 and 2D NMR techniques provided more structural information to assign the 1H and 13C resonances of ARP. 2D NOESY had successfully confirmed the glycosylated site between 10-N in Nα-acetyl-lysine and 7′-C in glucose.

Lactose quantification in bovine milk by nuclear magnetic resonance without deuterated solvent (No-D qNMR)

2020 ◽  
Vol 12 (40) ◽  
pp. 4892-4898
Author(s):  
Danyelle Alves da Cunha ◽  
Thays Cardoso Valim ◽  
Paulo Roberto Filgueiras ◽  
Valdemar Lacerda Junior ◽  
Alvaro Cunha Neto
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Bovine Milk ◽  
Nmr Analysis ◽  
H Nmr ◽  
Nuclear Magnetic

Validation of a method to quantify low lactose content in commercial lactose-free milk by 1H NMR analysis.

scholarly journals Correlations between Proton Nuclear Magnetic Resonance Imaging and Retrospective Histochemical Images in Experimental Cerebral Infarction

1985 ◽  
Vol 5 (2) ◽  
pp. 267-274 ◽  
Author(s):  
Hiroyuki Kato ◽  
Kyuya Kogure ◽  
Hitoshi Ohtomo ◽  
Muneshige Tobita ◽  
Shigeru Matsui ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Spin Echo ◽  
Proton Nuclear Magnetic Resonance ◽  
Nmr Imaging ◽  
Resonance Imaging ◽  
H Nmr ◽  
Experimental Cerebral Infarction ◽  
Nuclear Magnetic

Evaluation of ischemic brain injury in experimental cerebral infarction in gerbils and rats was performed by means of both proton nuclear magnetic resonance imaging ([1H]NMR-CT) and various histochemical analyses. In vivo nuclear magnetic resonance (NMR) imaging was carried out employing saturation recovery, inversion recovery, and spin echo pulse sequences. Spatial resolution of the images was excellent. The ischemic lesions were detected with a remarkable contrast in inversion recovery and spin echo images within a few hours after insult. Those changes in NMR images consistently corresponded with the various retrospective histochemical observations, especially with methods related to brain edema (K+ staining) rather than structural (enzymatic) studies. Calculated T1 and T2 relaxation times indicated the evolution of the edema state in the brain in situ. They correlated excellently with the retrospective water content measurement. As a result, detailed characterization of the edema state induced by cerebral ischemia was possible in vivo using [1H]NMR imaging.

Discrimination of hexabromocyclododecane from new polymeric brominated flame retardant in polystyrene foam by nuclear magnetic resonance

Chemosphere ◽  
2016 ◽  
Vol 144 ◽  
pp. 1391-1397 ◽  
Author(s):  
Damien Jeannerat ◽  
Marion Pupier ◽  
Sébastien Schweizer ◽  
Yavor Nikolaev Mitrev ◽  
Philippe Favreau ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Flame Retardant ◽  
Polystyrene Foam ◽  
Brominated Flame Retardant ◽  
Nuclear Magnetic

Analysis of 1H and 13C{1H} NMR Spectral Parameters of Diphenylchloroarsine, Diphenylcyanoarsine, and 10-Chloro- 5,10-Dihydrophenarsazine: Identification of the Compounds through Reference to Simulated Spectra

1997 ◽  
Vol 51 (5) ◽  
pp. 733-737 ◽  
Author(s):  
Markku Mesilaakso ◽  
Eeva-Liisa Tolppa ◽  
Paula Nousiainen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Spectral Parameters ◽  
H Nmr ◽  
Iterative Analysis ◽  
Simulation Of Spectra ◽  
Nuclear Magnetic

The 1H and 13C{1H} nuclear magnetic resonance (NMR) spectra of diphenylchloroarsine, diphenylcyanoarsine, and 10-chloro-5,10-dihydrophenarsazine were recorded from samples prepared in CDCl3, CD2Cl2, and (CD3)2CO. Spectra were analyzed, and detailed 1H NMR spectral parameters were determined by iterative analysis. Simulation of spectra and their use as reference spectra for identification of the compounds under different conditions are discussed.

scholarly journals 1H Nuclear Magnetic Resonance: A Future Approach to the Metabolic Profiling of Psychedelics in Human Biofluids?

2021 ◽  
Vol 12 ◽  
Author(s):  
Sylvana Vilca-Melendez ◽  
Malin V. Uthaug ◽  
Julian L. Griffin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Metabolic Profiling ◽  
Proton Nuclear Magnetic Resonance ◽  
Future Directions ◽  
H Nmr ◽  
Nuclear Magnetic ◽  
Psychedelic Research

While psychedelics may have therapeutic potential for treating mental health disorders such as depression, further research is needed to better understand their biological effects and mechanisms of action when considering the development of future novel therapy approaches. Psychedelic research could potentially benefit from the integration of metabonomics by proton nuclear magnetic resonance (1H NMR) spectroscopy which is an analytical chemistry-based approach that can measure the breakdown of drugs into their metabolites and their metabolic consequences from various biofluids. We have performed a systematic review with the primary aim of exploring published literature where 1H NMR analysed psychedelic substances including psilocin, lysergic acid diethylamide (LSD), LSD derivatives, N,N-dimethyltryptamine (DMT), 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and bufotenin. The second aim was to assess the benefits and limitations of 1H NMR spectroscopy-based metabolomics as a tool in psychedelic research and the final aim was to explore potential future directions. We found that the most current use of 1H NMR in psychedelic research has been for the structural elucidation and analytical characterisation of psychedelic molecules and that no papers used 1H NMR in the metabolic profiling of biofluids, thus exposing a current research gap and the underuse of 1H NMR. The efficacy of 1H NMR spectroscopy was also compared to mass spectrometry, where both metabonomics techniques have previously shown to be appropriate for biofluid analysis in other applications. Additionally, potential future directions for psychedelic research were identified as real-time NMR, in vivo1H nuclear magnetic resonance spectroscopy (MRS) and 1H NMR studies of the gut microbiome. Further psychedelic studies need to be conducted that incorporate the use of 1H NMR spectroscopy in the analysis of metabolites both in the peripheral biofluids and in vivo to determine whether it will be an effective future approach for clinical and naturalistic research.

Synthesis of new 3H-chromeno[2,3-d]pyrimidine-4,6(5H,7H)-diones via the tandem intramolecular Pinner/Dimroth rearrangement

2018 ◽  
Vol 24 (1) ◽  
pp. 31-35 ◽  
Author(s):  
Nasrin Karimi ◽  
Abolghasem Davoodnia ◽  
Mehdi Pordel
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Proton Nuclear Magnetic Resonance ◽  
Phosphoryl Chloride ◽  
Dimroth Rearrangement ◽  
H Nmr ◽  
High Yields ◽  
Aliphatic Carboxylic Acids ◽  
C Nmr ◽  
Nuclear Magnetic

Abstract The reaction of 2-amino-4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitriles with excess aliphatic carboxylic acids in the presence of phosphoryl chloride (POCl3) afforded new 2-alkyl-5-aryl-8,8-dimethyl-8,9-dihydro-3H-chromeno[2,3-d]pyrimidine-4,6(5H,7H)-diones in high yields. The suggested mechanism involves a tandem intramolecular Pinner/Dimroth rearrangement. The synthesized compounds were characterized by infrared (IR), proton nuclear magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C NMR) and elemental analysis.

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