相转移催化合成甲基葡萄糖苷二油酸酯

以α-甲基葡萄糖苷和油酸甲酯为原料,在四丁基溴化铵(TBAB)和K_2CO_3的共同催化作用下,无溶剂法合成了甲基葡萄糖苷二油酸酯,并对产品进行了IR表征。探讨了相转移催化酯交换反应机理,考察了原料配比、催化剂种类及用量、反应温度、反应时间等因素对油酸甲酯转化率的影响。最佳工艺条件为:n(甲基葡萄糖苷):n(油酸甲酯)=1.1:2,w(TBAB):w(油酸甲酯)=3.5%,w(K_2CO_3):w(油酸甲酯)=2.5%,反应温度115～120℃,反应时间4.5h,反应压力～6kPa。上述条件下,产品收率可达92%,产品质量较好。

脂肪酶催化淀粉糖油酸酯的合成

研究了以淀粉糖(葡萄糖或麦芽糖)和油酸为原料,在固定化脂肪酶的催化下合成淀粉糖油酯的反应。通过对反应影响因素的考查,表明合成淀粉糖油酸酯的最适宜条件为:当淀粉糖:油酸为1∶1.5(物质的量比),脂肪酶Novozym435的用量为0.36 g/mol油酸,丙酮用量分别为20 mL/mol葡萄糖(10 mL/mol麦芽糖),加热回流反应分别为42 h(葡萄糖油酸酯)和72 h(麦芽糖油酸酯)时,油酸的转化率分别为93%和83%。表面张力测定显示,当葡萄糖油酸酯水溶液的浓度为7.0×10-4mol.L-1时,表面张力为32 mN.m-1;麦芽糖油酸酯水溶液浓度为5.0×10-5mol.L-1时,表面张力为31 mN.m-1。

Effects of Na2S2O3 and Glucose on the Compositions of Glycerolipids and Their Fatty Acids in Synechocystis sp. PCC 6803 Cells

Compositions of glycerolipids and fatty acid compositions of glycerolipids were compared among Synechocystis sp. PCC 6803 cells grown in the BG-11 medium containing different concentrations of glucose and Na2S2O3 in this study. It was found that Na2S2O3 can effectively increase the percentage of sulphoquinovosyl diacylglycerol (SQDG) and phosphatidylglycerol (PG) to total membrane lipids and the simultaneous application of glucose with Na2S2O3 can counteract the effect of Na2S2O3. In addition, Na2S2O3 can significantly increase the percentage of palmitic acid (C, 16:0) in fatty acid composition of monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG) and decrease the fatty acid unsaturation degree accordingly, and these effects can also be eliminated by glucose. These results indicate that Na2S2O3 can take as a reductant to make membrane lipids in a low unsaturated state, and the simultaneous application of glucose can decrease the reducing power of Na2S2O3. In addition, Na2S2O3 can take as a sulfur donor for the synthesis of SQDG.

化妆品用新原料介绍

PEG／PPG－25／25二甲基硅酮／丙烯酸酯共聚物。