| 6-O-L-ascorbyl stearate(L-AS), one of the derivatives of L-ascorbic acid(AsA), is a significant ingredient in the food, cosmetic, pharmaceutical, as well as other industries. Compared with the rampant mortality caused by single usage of acetaminophen, it has been established that L-AS can reduce about 35% of the mortality. The synthesis of L-AS has been studied thoroughly. But, the downstream process existing the defects which the raw materials cannot be recycled and the properties of L-AS have not been reported at home and abroad. Then, we need to improve and perfect the downstream, and study the properties of L-AS.In this paper, the method of recrystallization of L-AS by ethyl acetate(EA) is based on the method of destroying the solid mixtures consisting of methyl stearate(SAME), As A and L-AS, togethering with the solubility difference of AsA, SAME and L-AS in the EA. Then, we choose SAME and AsA as raw materials, lipases as catalyst, tert-butyl alcohol as solvents, building a benign environmentally downstream to recrystall the product by EA. Throughout all of the process, there will be no generation of the waste water, neither synthesis, nor downstream process. The single recovery rate of L-AS is 50.5%, the purity of it is 99% which detected by LC/MS. The mother liquor formed during this step can be recycling.This paper measure the critical micelle concentration(CMC) and Krafft Point by the method of surface tension, and the CMC of L-AS is 3×10-4 mol?L-1,the Krafft Point is 58 ℃.Besides, the paper study the hydrogel of L-AS which formed by heating-cooling. The minimum gel concentration(MGC) is 2%, X-ray diffraction(XRD) has also been used to gain insight about the molecular arrangement which is amorphous. From the rheological properties of L-AS hydrogel, we can draw the conclusion that it is solid-fiber structure. L-AS and 6-O-L-ascorbyl palmitate(L-AP) can form organogel in the organic solvents of Hydrocarbon/water mixed solvents by the method of heating-cooling. The organogels of L-AP and L-AS is liquid-fiber structure which is different from L-AS hydrogel. |
