Fatty acids, part X. Raman spectra of all dimethylene interrupted methyl cis, cis-octadecadienoates and octadecadiynoates

Abstract

The Raman spectra of all the dimethylene interrupted methyl cis, cis-octadecadienoates and octadecadiynoates have been studied. The Raman band positions and their relative intensities for the ν(CC), ν(CC), ν(CO), ν(CH) and δ(CH 2) modes are recorded. The height intensity of the bands arising from ν(CC) relative to ν(CO) provides a means of determining the number of cis-ethylenic bonds in a mono-ester. In the acetylenic series, the intensity of the bands arising from ν(CC) relative to ν(CO) failed to indicate with certainty the number of acetylenic bonds in the mono-esters studied, due to the weak intensity of the band due to ν(CO). However a better correlation between the relative intensities of the ν(CC) and δ(CH 2) bands is established instead. An attempt to correlate the areas under the bands due to ν(CC), (CC), (CO) and δ(CH 2) failed to produce any significant results. The Raman spectra of the methyl octadec- cis-10-en-5-ynoate and methyl octadeca-5, 10-diynoate are also recorded.