抄録
In the alcoholysis reaction of fatty oils with pentaerythritol, the effects of reaction conditions on the reaction rate and the composition of reaction products were investigated and the reaction mechanism was discussed.
Reaction products consist of glycerol, pentaerythritol, and their esters as shown Fig.-1 These compounds were clearly separated by means of the thin layer chromatography, using silica gel as absorbent and diethylether as solvent. The composition of reaction products was determined by the measurement of the concentration of spots using densitometer.
The effects of reaction conditions on the reaction rate were investigated and the following results were obtained.
1) In the system of soybean oil-pentaerythritol, the apparent activation energy of this reaction was about 27 kcal/mole.
2) Reaction rate constants in various fatty oils were in the order of linseed oil > olive oil _??_ coconut oil _??_ dehydrated castor oil > soybean oil, and the apparent activation energies were opposite to this order.
3) Lead oleate was most active among the various catalysts tested and litharge (PbO) was the second.
The order of catalytic activity in metal oleates was as follows.
Pb >> Ca > Zn _??_ Mn > Li _??_ K > Fe
Reaction was obviously the second-order reaction and it was supposed that alkoxy anion which was formed by the reaction of pentaerythritol with catalyst attacked carbonyl group of fatty oils.
Furthermore, it was found that the composition of reaction products was almost independent of various reaction conditions and was consistent with the calculated values assuming the random distribution of fatty acid groups.
