Abstract
The photochemical reactions of conjugated fatty acid methyl esters, that is, methyl α-eleostearate, methyl cis-9, trans-11-and trans-9, trans-11-octadecadienoates, under various conditions were studied. The formation of dimers was rapid from these conjugated fatty esters in either CCl4 or CHCl3. However, the dimers produced were found to be chlorinated. Accordingly, the photo-dimerization in halomethanes was recognized to be a kind of telomerization, where the halomethane itself took part in the reaction.
In the greater part of the photochemical reactions in organic solvents other than halomethanes, the cis-trans isomerization reaction was observed. Especially, the cis, trans-conjugated fatty ester was converted into only trans, trans-conjugated isomer in heptane without forming the dimer. Then, both the photo-dimerization and the isomerization of the conjugated fatty esters in heptane were suggested to be carried out by the conversion of the conjugated fatty esters into their electronically excited molecules by irradiation.
Futhermore, the effective wave length of light on the photochemical reactions of the conjugated esters was also examined by monochromatic radiation.
