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Scissoring vibrations

EPDM backbone, together with the carbonyl and ether groups generated on the rubber itself causes the carbonyl and ether absorptions to increase. The absorption at 1630 cm of the fraw -vinylene bonds of TMPTA is mainly due to the grafting of TMPTA onto EPDM and partly due to the formation of vinylidene bonds at the chain ends on irradiation. The absorptions at 1460 and 1379 cm due to >CH2 scissoring vibration and —CH3 stretching vibration, respectively, result from the rubber and the grafted TMPTA. [Pg.885]

The asymmetrical vibration generally overlaps the scissoring vibration of the methylene groups (see below). Two distinct bands are observed, however, in compounds such as diethyl ketone, in which the methylene scissoring band has been shifted to a lower frequency, 1439-1399 cm-1, and increased in intensity because of its proximity to the carbonyl group. [Pg.82]

The absorption band near 1375 cm-1, arising from the symmetrical bending of the methyl C—H bonds, is very stable in position when the methyl group is attached to another carbon atom. The intensity of this band is greater for each methyl group in the compound than that for the asymmetrical methyl bending vibration or the methylene scissoring vibration. [Pg.82]

C—H Bending Vibrations Cyclization decreases the frequency of the CH2 scissoring vibration. Cyclohexane absorbs at 1452 cm-1, whereas n-hexane absorbs at 1468 cm-1. Cyclopentane absorbs at 1455 cm-1, cyclopropane absorbs at 1442 cm-1. This shift frequently makes it possible to observe distinct bands for methylene and methyl absorption in this region. Spectra of other saturated hydrocarbons appear in Appendix B hexane (No. 1), Nujol (No. 2), and cyclohexane (No. 3). [Pg.84]

Assignments have been made for a few of the more prominent and reliable in-plane bending vibrations. The vinyl group absorbs near 1416 cm-1 because of a scissoring vibration of the terminal methylene. The C—H rocking vibration of a cis-disubstituted alkene occurs in the same general region. [Pg.85]

An in-plane bending An out-of-plane bending vibration (scissoring) vibration (twisting)... [Pg.4]

Lipid A was investigated by FTIR, X-ray diffraction, and fluorescence techniques (Naumann et al., 1987). Analysis of the CH2 scissoring vibrations showed that lamellar structures exist at temperatures below 30 °C, but that no stable closed vesicles are formed. Orientation measurements of lipopolysaccharides prepared from E. coli and Salmonella minnesota by ATR-FTIR also showed a highly ordered gel phase. Besides, the transition from the gel pha.se a to the liquid crystalline phase was also studied (Brandenburg and Seydel, 1988). [Pg.371]

Furthermore, N-H scissor vibrations were absent from the EELS spectra. On the basis of these observations it was concluded that the dominant NH adsorption complex is NH ds and not NHj ads [Pg.293]


See other pages where Scissoring vibrations is mentioned: [Pg.138]    [Pg.202]    [Pg.102]    [Pg.109]    [Pg.190]    [Pg.248]    [Pg.138]    [Pg.96]    [Pg.102]    [Pg.138]    [Pg.25]    [Pg.275]    [Pg.293]    [Pg.65]    [Pg.11]    [Pg.96]    [Pg.101]    [Pg.312]    [Pg.312]    [Pg.859]    [Pg.275]    [Pg.293]    [Pg.521]    [Pg.112]    [Pg.33]    [Pg.101]    [Pg.105]    [Pg.138]    [Pg.88]    [Pg.330]    [Pg.191]    [Pg.171]    [Pg.158]    [Pg.406]    [Pg.859]    [Pg.476]   
See also in sourсe #XX -- [ Pg.157 ]

See also in sourсe #XX -- [ Pg.157 ]

See also in sourсe #XX -- [ Pg.33 ]

See also in sourсe #XX -- [ Pg.16 ]

See also in sourсe #XX -- [ Pg.18 ]




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