Determination of the degree of branching in alkanes by infrared spectroscopy. I. Resolution of overlapping absorption bands in the 3000-2900 cm-1 region

1967 ◽  
Vol 32 (3) ◽  
pp. 1125-1136 ◽  
Author(s):  
R. Řeřicha ◽  
M. Horák
Keyword(s):  
Infrared Spectroscopy ◽  
Absorption Bands ◽  
Degree Of Branching

The Temperature Dependence of Band Maxima Molar Absorptivities of the Carbon-Bromine Stretching Modes in n-Butyl Bromide in the Liquid Phase

1987 ◽  
Vol 41 (5) ◽  
pp. 807-809 ◽  
Author(s):  
J. E. Katon ◽  
Stanislaus R. Lobo ◽  
J. C. Simpson
Keyword(s):  
Mathematical Model ◽  
Infrared Spectroscopy ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Energy Difference ◽  
Temperature Dependent ◽  
Butyl Bromide ◽  
Absorption Bands ◽  
A Value

In the determination of energy differences of conformers in the fluid states by infrared spectroscopy it is nearly always assumed that the ratio of the molar absorptivities at the band maxima of two separate absorption bands is independent of temperature. This assumption has been tested by fitting the data obtained from n-butyl bromide to a mathematical model which can be iterated to convergence on a value of the energy difference between the trans and gauche isomers. The data utilized are the C-Br stretching modes of the two conformers at about 655 and 567 cm−1, respectively. It is shown that the assumption of temperature independence of the ratios of the molar absorptivities at the peak maxima is a good one, although both values are individually temperature dependent.

Infrared Spectra of Cured and Uncured Rubbers

1959 ◽  
Vol 32 (2) ◽  
pp. 628-638
Author(s):  
G. A. Blokh ◽  
A. F. Mal'nev
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared ◽  
Infrared Absorption Spectrum ◽  
Infrared Region ◽  
Absorption Bands ◽  
Linear Absorption ◽  
Infrared Rays ◽  
Other Substances ◽  
The Individual

Abstract The newest physical-chemical methods of research enlarge the scope of study of the vulcanization process. There is a possibility of studying the structure changes during vulcanization of rubber by the application of infrared spectroscopy. Infrared rays are selectively absorbed. Therefore the infrared absorption spectrum can be used as a characteristic property of a substance and could be used for analytical purposes. The large spectral range of the infrared rays indicates their importance for the study of the properties and structure of substances; this makes possible the determination of the moments of inertia of atomic nuclei and molecules, isotopic mass, arrangement and strength of atomic bonds in the molecule and the frequencies of their vibrations. By knowing the frequencies for pure substances, molecular analyses of complicated mixtures of various organic rubbers, accelerators and other substances could be performed. The study of linear absorption spectra is the basis of the spectrographic method in the infrared region. Since the frequencies of near infrared radiation correspond to the characteristic frequencies of the atoms in the molecules, this method could be used to obtain interesting information concerning the structure of organic molecules, the chemical structure of high molecular weight compounds, the determination of the presence of specific groups or atoms in the rubber molecule, the character of the bonds between these groups and the order of arrangement of the individual chain links. This is true because the position of the absorption bands, which are specific for a given group of atoms, is practically the same for the different combinations in which the group occurs. The complicated process of polymerization of diene and vinyl compounds and the structure of different types of rubbers can be investigated with the aid of infrared spectroscopy. For example, Table I lists the characteristic absorption frequencies in the infrared region for some important chemical combinations.

First Nano-Infrared Spectroscopy and Imaging Measurements of Single Phospholipid Bilayers

2018 ◽  
Author(s):  
Adrian Cernescu ◽  
Michał Szuwarzyński ◽  
Urszula Kwolek ◽  
Karol Wolski ◽  
Paweł Wydro ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Ir Spectroscopy ◽  
Absorption Band ◽  
Spectral Region ◽  
Near Field ◽  
Phospholipid Bilayers ◽  
Model Systems ◽  
Absorption Bands ◽  
Protein Complement ◽  
20 Nm

<div><div>Scattering-mode Scanning Near-Field Optical Microscopy (sSNOM) allows one to obtain absorption spectra in the mid-IR region for samples as small as 20 nm in size. This configuration has made it possible to measure FTIR spectra of the protein complement of membranes. (Amenabar 2013) We now show that mid-IR sSNOM has the sensitivity required to measure spectra of phospholipids in individual bilayers in the spectral range 800 cm<sup>-1</sup>–1400 cm<sup>-1</sup>. We have observed the main absorption bands of the dipalmitoylphosphatidylcholine headgroups in this spectral region above noise level. We have also mapped the phosphate absorption band at 1070 cm<sup>-1</sup> simultaneously with the AFM topography. We have shown that we could achieve sufficient contrast to discriminate between single and multiple phospholipid bilayers and other structures, such as liposomes. This work opens the way to further research that uses nano-IR spectroscopy to describe the biochemistry of cell membranes and model systems.</div></div><div></div>

Near Infrared Spectroscopy Used in Purification and Determination of Pharmaceutical Cocrystal

2013 ◽  
Vol 41 (12) ◽  
pp. 1928
Author(s):  
Zong-Liang CHI ◽  
Miao-Miao WANG ◽  
Xiao-Dong CONG ◽  
Shao-Guang LIU ◽  
Bao-Chang CAI
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Pharmaceutical Cocrystal
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