Applications of Computerized Nuclear Magnetic Resonance and Infrared Spectroscopic Techniques to Rubber Analyses

1982 ◽  
Vol 55 (3) ◽  
pp. 913-930 ◽  
Author(s):  
Robert C. Hirst
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Small Computer ◽  
Spectroscopic Techniques ◽  
Special Effect ◽  
Ir Instrumentation ◽  
Nuclear Magnetic

Abstract Fourier transform spectroscopy is without doubt one of the most important developments in spectroscopy in the last few years. Although the basic principle had been known for many years, its applications in spectroscopy became practical only because of advances in small computer technology. In the case of nuclear magnetic resonance and infrared spectroscopy, the digital computer has had a special effect, in that it has caused, or at least made possible, the total redesign of NMR and IR instrumentation based on the Fourier transform (FT) concept. Because of its advantages over conventional methods, the FT method has caused great changes in NMR and IR spectroscopy, and FT instruments have made possible the solutions to many problems which previously were technically too difficult. NMR spectroscopy was reviewed in this Journal in 1976 and infrared spectroscopy was reviewed in 1972. Developments since those reviews will be emphasized here. In a short, selective review of this type, it is necessary to omit references to many excellent contributions in the literature. For very comprehensive listings of literature references, the reader may wish to consult the biennial reviews in “Analytical Chemistry” on NMR spectroscopy, infrared spectroscopy, rubber, analysis of high polymers, and coatings.

Uses of Nuclear Magnetic Resonance Spectroscopy Technique in Pharmaceutical Analysis: A Review

2017 ◽  
Vol 8 (02) ◽  
Author(s):  
Imad Hadi Zohra ◽  
Abeer Fauzi Al-Rubaye ◽  
Mohanad Jawad Kadhim
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Ratio Method ◽  
Resonance Spectroscopy ◽  
Spectroscopic Techniques ◽  
Nuclear Magnetic

Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a magnetic field absorb and re-emit electromagnetic radiation. Many scientific techniques exploit NMR phenomena to study molecular physics, crystals, and non-crystalline materials through nuclear magnetic resonance spectroscopy. NMR phenomena are also utilized in low-field NMR, NMR spectroscopy and MRI in the Earth's magnetic field (referred to as Earth's field NMR), and in several types of magnetometers. Modern NMR spectroscopy has been emphasizing the application in biomolecular systems and plays an important role in structural biology. NMR spectroscopy is very important to identify a drug or an excipient, evaluate the level of impurities (and to elucidate the structure), observe the course of a decomposition, to evaluate residual solvents, determine the isomeric composition, i.e. the ratio of diastereomers and the enantiomeric excess by means of chiral additive, assess a single drug or drug composition, characterize a polymer mostly being a mixture and used as excipients, identify counter ions (if of organic origin and having protons), characterize an entire formulation, e.g. a tablet. Fundamentals of quantitative NMR spectroscopy NMR spectroscopy can be considered as a primary ratio method of measurement being characterized by the fact that the ratio of substances can be determined directly from the physical context of the measurement without referencing to another substance. NMR has become one of the most powerful and versatile spectroscopic techniques for the analysis of biomacromolecules, allowing characterization of biomacromolecules and their complexes up to 100 kDa. Together with X-ray crystallography.

Simultaneous In Situ Monitoring of Trimethoxysilane Hydrolysis Reactions Using Raman, Infrared, and Nuclear Magnetic Resonance (NMR) Spectroscopy Aided by Chemometrics and Ab Initio Calculations

2018 ◽  
Vol 72 (9) ◽  
pp. 1404-1415
Author(s):  
Xiaoyun Chen ◽  
Donald Eldred ◽  
Jing Liu ◽  
Hsu Chiang ◽  
Xianghuai Wang ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Reaction Rates ◽  
In Situ Monitoring ◽  
Spectroscopic Techniques ◽  
Wide Range ◽  
Nuclear Magnetic ◽  
Hydrolysis Reactions

Sol-gels are found in many different scientific fields and have very broad applications. They are often prepared by the hydrolysis and condensation of alkoxysilanes such as trimethoxysilanes, which are commonly used as precursors in the preparation of silsequioxanes via the sol-gel process. The reaction rates of such reactions are influenced by a wide range of experimental factors such as temperature, pH, catalyst, etc. In this study, we combined multiple in situ spectroscopic techniques to monitor the hydrolysis and partial condensation reactions of methyltrimethoxysilane and phenyltrimethoxysilane. A rich set of kinetics information on intermediate species of the hydrolysis reactions were obtained and used for kinetics modeling. Raman and nuclear magnetic resonance (NMR) spectroscopy provided the most information about hydrolysis and NMR provided the most information about condensation. A quantitative method based on Raman spectra to quantify the various transient intermediate hydrolysis products was developed using NMR as the primary method, which can be deployed in the field where it is impractical to carry out NMR measurements.

Synthesis and studies of electrochemical properties of lophine derivatives

RSC Advances ◽  
2014 ◽  
Vol 4 (97) ◽  
pp. 54740-54746 ◽  
Author(s):  
A. Hariharasubramanian ◽  
Y. Dominic Ravichandran
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Liquid Chromatography ◽  
Infrared Spectroscopy ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Electrochemical Properties ◽  
Fourier Transform Infrared Spectroscopy ◽  
Liquid Chromatography Mass Spectrometry

A versatile series of lophine derivatives (1–13) were synthesized and characterized, Fourier transform infrared spectroscopy (FTIR), Liquid Chromatography-Mass Spectrometry (LC-MS), and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy.

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