Infrared spectroscopy functional groups containing

Infrared spectroscopy is most effective for functional groups containing heteroatoms such as oxygen or nitrogen. Infrared spectroscopy cannot effectively determine aromaticity, because CH bands do not respond well, partic-... 

Polymers containing pendant carbamate functional groups can be prepared by the reaction of phenyl isocyanate with poly(vinyl alcohol) in homogeneous dimethylsulfoxide solutions using a tri-ethylamine catalyst. These modified polymers are soluble in dimethyl sulfoxide, dimethylacetamide, dimethylformamide and formic acid but are insoluble in water, methanol and xylene. Above about 50% degree of substitution, the polymers are also soluble in acetic acid and butyrolactone. The modified polymers contain aromatic, C = 0, NH and CN bands in the infrared and show a diminished OH absorption. Similar results were noted in the NMR spectroscopy. These modified polymers show a lower specific and intrinsic viscosity in DMSO solutions than does the unmodified poly(vinyl alcohol) and this viscosity decreases as the degree of substitution increases. 

Now we move on to consider the analysis of copolymers. There are usually two things we would like to know. First, the composition of the copolymer and, second, some measure of sequence distributions. Again, in the early years, before the advent of commercial NMR instruments, infrared spectroscopy was the most widely used tool. The problem with the technique is that it requires that the spectrum contain bands that can be unambiguously assigned to specific functional groups, as in the (transmission) spectrum of an acrylonitrile/methyl methacrylate copolymer shown in Figure 7-43 (you can tell this is a really old spectrum, not only because it is plotted in transmission, but also because the frequency scale is in microns). 

Infrared spectroscopy is an extremely useful tool for detecting the presence and type of functional group. Strong absorption bands are characteristic of various classes of monosaccharides containing a carbonyl group. 

Look at the IR spectra of hexane, 1-hexene, and 1-hexyne in Figure 12.13 (p. 459) to see an example of how infrared spectroscopy can be used. Although all three IR spectra contain many peaks, there are characteristic absorptions of the C=C and CsC functional groups that allow the three... 

Additive Loss in Lubricants Additive loss is detrimental to the performance of lubricants. Some additive levels can be monitored by infrared spectroscopy. For instance, anti-wear additives, zinc dithio-dialkyl (diaryl) phosphate (ZDDP) and tri-cresyl phosphate (TCP) contain a common phosphate functional group that can be measured by infrared. The P-O-R (where R = alkyl/aryl) stretch shows a strong IR absorbance for all of these compounds and is used to trend the anti-wear level. The P-O-R stretch area is measured over the region of 1020-960 cm using the general baseline of 2000-600 cm. ... 

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