不飽和脂肪酸の異性化に関する研究 (第5報)
リノール酸メチル純粋異性体の熱変化について
1961 年 10 巻 3 号 p. 146-150
詳細
1961 年 10 巻 3 号 p. 146-150
In the previous report, the thermal change of methyl cis-linoleate and methyl cis-linolenate were investigated, and it was found that trans-trans conjugated isomer and cis-trans conjugated isomer were obtained respectively in the first stage and that the product accumulated in the final stage was trans non-conjugated isomer in both cases.
In this report, the process of isomerization was investigated quantitatively by the ultraviolet and infrared absorption spectrometric methods. The thermal change of four pure isomers of methyl linoleate, -cis non-conjugated, cis-trans conjugated, trans-trans conjugated and trans non-conjugated isomers-, was carried out.
The obtained results are summarized as follows :
1) From cis non-conjugated isomer, little amount of trans-trans conjugated isomer and finally trans non-conjugated one was resulted.
2) Cis-trans conjugated one rapidly isomerizes to trans-trans conjugated one until it accumulates about 57%, and the latter isomerizes to trans non-conjugated one gradually.
3) Trans-trans conjugated one slowly isomerizes to trans non-conjugated one.
4) Trans non-conjugated one does not change to any other isomers.
In all cases, it was proved that trans non-conjugated isomer was accumulated in the thermal change. However, in the thermal change, the dimerization was also found simultaneously. In case of change of trans non-conjugated one at 300°C for 5hr, the amount of dimer was about 25%.
