1964 年 13 巻 7 号 p. 365-369
Study was made on selectiveness of reaction of hydrogenation and stability to oxidation of the resultant oil referred to in the previous report with IR and UV absorption spectra with the following result.
1. Catalyst consisting of reduced nickel and MPS produced less trans acid than the catalyst of reduced nickel alone. The effect of MPS is affected by its viscosity and the higher viscosity shows the higher effect than the low viscosity.
2. When the resultant oil is hydrogenated with catalyst of nickel alone until its iodine value reaches 86, conjugated diene acid disappeares. But with catalyst having MPS added, it disappeares at iodine value 81. On the other hand formation of trans acid has a tendency to increase sharply at about the iodine value at which conjugated diene acid disappeares.
3. Disappearance of triene acid occures at iodine value 90 or so with catalyst of nickel alone against 88 in the case of catalyst having an addition of MPS.
4. There is no difference in stability to oxidation between catalyst of nickel and that of nickel and MPS in the AOM and oven tests. And it has a tendency to rise sharply at about the iodine value at which triene acid disappeares. In hydrogenation for iodine value more than 90, reversion of fish flavor is recognized before rancid flavor is produced.