Studies on the reesterification of rice bran oil was performed to find out optimum condition of the reaction. Reesterification of crude rice bran oil (A.V. 119.7) was attempted with addition of theoretical equivalent of glycerol.
Tin chloride ($SnCl_2·2H_2O$) was used as a catalyst at 0.2% concentration. In the preliminary analysis of the reactant, the crude rice bran oil contained 92.9% of neutral lipid. Triglyceride content of the reactant was 10.4 %. Oleic acid (42.5%), linoleic acid (29.0%), and palmitic acid (20.3%) were the major components of fatty acids from HPLC analysis of fatty acid composition. According to the analysis of product, catalyzed reaction at 250℃ decreased the acid value to 2.7 in six hours, while uncatalyzed reaction decreased the acid value only to 12.1 under the same condition.
The rate of reaction was increased as the temperature was elevated. In case of catalyzed reaction, A.V. of each reesterified oil was decreased to 16.1, 5.4, and 2.7 in six hours, when the reaction temperature were 170℃, 210℃, and 250℃ respectively.
Iodine value (I.V.) was decreased considerably when the reesterification temperature was elevated regardless of the presence of catalyst. The decrease in I.V. of reesterified oil at 250℃ for 6 hours was about 2.0, but the decrease was less than 0.5 when reesterified at 170℃ respectively. Reesterified oil of A.V. 12.1, and A.V. 2.7 contained 61.1%, and 72.9% of triglyceride respectively.
미강유의 에스터화 반응에서, 그 반응의 최적조건을 구하기 위해서 본 연구를 수행하였다. 산가 119.7인 미강유에 이에 상당하는 양의 글리세린을 첨가하고 전체무게의 0.2%되는 $SnCl_2 · 2H_2O$를 촉매로 사용했다.
반응물질, 즉 미강유의 예비분석에서 중성지질이 전체 미강유의 92.9%를 차지했고, 중성지질의 10.4%가 Triglyceride 형태로 존재했으며, HPLC 에 의한 지방산 조성 분석결과 Oleic acid가 42.5%, Linoleic acid 가 29.0%, Palmitic acid 가 20.3%로서 그 주성분임을 알수 있었다. 생성물의 분석결과 촉매를 사용하고 250℃ 에서 6시간 반응한 경우에는 산가가 2.7까지 내려 갔으나, 촉매를 사용하지 않은 반응은 산가 16.1에 그쳤다.
반응속도는 온도가 상승할수록 증가했는데, 촉매를 사용하고 반응온도가 170℃, 210℃, 250℃ 에서 각각 6시간 반응시키면 산가가 각각 16.1, 5.4, 2.7로 되었다.
요오드 값은 촉매에 관계없이 반응온도가 상승할때에만 현저히 감소하였다. 반응온도를 170℃ 또는 210℃ 로 했을 경우 6시간 반응후의 요오드 값의 감소정도는 0.5이내 이지만 250℃ 에서 같은 시간동안 반응시킨후에는 약 2.0 정도의 감소를 보였다.
