Determination of m-Cresol and p-Cresol in Industrial Cresols by Raman Spectrometer

Adopting raman spectrometer to conduct qualitative and quantitative analysis of m-cresol and p-cresol, selecting the respective character peak of bencycloquidium after deformation vibration (m-cresol at 732 cm-1 and p-cresol at 841 cm-1), via experiment and calculations, the relative raman cross section of m-cresol and p-cresol can be concluded:(∂σ/∂Ω)732cm-1/(∂σ/∂Ω)1000cm-1 is 0.74 (height-fitting of the peak), and 0.61 (area-fitting of the peak). This method samples simply and rapidly, and has a short testing time, whose quantitative analysis result of m-/p-cresol is consistent with that of GC analysis.

Deformation, Vibration, Buckling of Continuum Nanotorus

A nanotorus is theoretically described as carbon nanotube bent into a torus (doughnut shape). Nanotori are predicted to have many unique properties, such as magnetic moments 1000 times larger than previously expected for certain specific radii. Its properties vary widely depending on radius of the torus and radius of the tube. Here, we developed a continuum model of nanotorus and obtained a closed form solutions for nanotorus deformation, vibration, and buckling and embedded in an elastic medium. The nanotorus is considered as a continuum model.

Molecular Orbitals and CH3, CH2, and CH Deformation Group Frequencies

A linear relationship has been found between the wavenumber of the CH3 symmetrical deformation vibration and the electron density on the CH3 carbon as calculated from CNDO/2 molecular orbital theory. Other CH deformation vibrations are also related to the electron density on the carbon and, as a result, can be correlated with the CH3 symmetrical deformation wavenumber. These include ν̄(CH2 def), ν̄(CH2 wag) and both components of ν̄(CH wag). The splitting of ν̄(CH3 sym def) in isopropyl and t-butyl groups has long been known. It is shown here that the effect is due to an interaction force constant relating to the CH3 symmetrical deformation vibrations of two or three different neighboring CH3 groups. The origin of the interaction is thought to be an H,H′ repulsion between hydrogens on the different CH3 groups.

Infrared spectroscopy of ferrihydrite: evidence for the presence of structural hydroxyl groups

IR spectroscopy has shown that adsorbed water is almost completely removed from ferrihydrite by evacuation at room temperature. Absorption bands at 3615 and 3430 cm−1 appearing thereafter are interpreted as arising from OH groups located respectively at the surface and deeper in the structure. These groups are readily converted to OD on treatment with D2O vapour and this has allowed the OH deformation vibration to be identified at 800 cm−1. It is proposed that OH groups in ferrihydrite are about half as numerous as those in akaganéite (β-FeOOH) and that they may occur in environments similar to those in this mineral. The formula for ferrihydrite proposed by earlier workers, 5 Fe2O3.9H2O, should thus be amended to Fe2O3. 2 FeOOH.2·6H2O in order to indicate the presence of structural OH groups. A re-appraisal of the ferrihydrite structure appears desirable.