- 期刊
珈瑪線誘起蔗糖和脂肪酸之酯化研究
Gamma-Ray Induced Esterification of Sucrose and Fatty Acids
摘要
蔗糖和各種脂肪酸可在室溫空氣氣相及硫酸觸媒存在之下，由鈷六十珈瑪線誘起酯化反應。低級脂肪酸（如蟻酸或醋酸）之酯化反應容易進行而隨脂肪酸分子量之增加該反應進行漸趨困難，以至高級脂肪酸（如油酸或硬脂酸）之酯化已呈甚難或無法進行。在酷酸和蔗糖之酯化反應系統中發現所得之糖酯為單醋酸酯（monoacetic ester）及雙醋酸糖酯（diacetic ester），而三酷酸糖酯以上之酯化反應不易進行。所得之糖酯經過濾紙層次分析檢定後得知未因室溫照射而誘起分解產生其他較小分子量之分解化合物（如葡萄糖、果糖、葡萄糖酸等）。100公克薦糖和140公克氷醋酸在0.5 ml濃硫酸觸媒存在之下（室溫、空氣氣相）以總線量4.75×10^6侖琴之珈瑪線照射後可得86公克黃褐色水溶性液體糖酯（d_(20)^(20) 0.88～0.91）產率為98.1%（對反應蔗糖計算）。該糖酯之起泡力甚強，優於市販非肥皂類，但泡沫之保持不如非肥皂。該反應以反應速度之動力學觀點考察後得知酯化反應速度應對蔗糖分子中之醇基或當量羧基濃度之平方成正比例，卽該酯化反應屬於二次反應式。關於蔗糖之G-值由實驗結果計算得為390～594。其他珈瑪線誘起之蔗糖酯化反應之見識及反應機構之推想等在本研究中已提出並討論之。
關鍵字
無資料並列摘要
Gamma-ray induced esterification of sucrose with equimolar amounts of various fatty acids has been investigated at the room temperature. The fundamental fact for the reaction was found that the esterification of sucrose was easily carried out with fatty acids of lower molecular weight and the reaction was retarded severely as the molecular weight of fatty acid becomes larger. When a mixture of 100g sucrose and 140g glacial acetic acid was irradiated with the total gamma-ray dose of 4.75×10^6 rontgen with 0.5ml 98% H_2SO_4 catalyst, the yellowish brown water-soluble viscous liquid (86g) was produced, giving a high yield of 98.1% (based on reacted sucrose). The product has a superior property of foaming effect toward its water solution, inspite of its easy-fading of foams. The observation and discussion have also been performed on the kinetic mechanisms of esterification of sucrose with glacial acetic acid. The rate of reaction was found to follow the 2nd-order equation. The assuming reaction mechanism and the calculated G-value for esterification of sucrose have been proposed in detail.