The Synthesis And Separation Of Sucrose Laurate Under Ultrasound

Sucrose fatty acid esters is a good surfactant. At present,the synthetic method of sucrose ester also exists some drawbacks such as long reaction time,high reaction temperature,poor selectivity,the price of catalyst is expensive and so on.This do not fit in with conception of Green Chemistry. Ultrasound has been shown to have desirable effects on organic reactions, such as increasing the conversion, enhancing the selectivity, improving the yield, even novel chemistries. The ultrasonic was introduced to the preparation of sucrose ester, which not only contributes to explore a new method for synthesis of sucrose ester, but expand and enrich the connotation of sonochemistry.In this paper, the sucrose and methyl laurate was used as the raw material to synthesis of sucrose laurates under ultrasonic irradiation. The main contents and results are as following.1. Compared with the traditional method, The synthetic method under ultrasonic irradiation shorten the reaction time and raised the Sucrose monolaurate yields. Effects of the molar ratio of sucrose to methyl laurate, DMSO amount and the amount of catalyst on the monoesters yield were investigated under ultrasonic irradiation,The result showed that the molar ratio of sucrose to methyl laurate is the most significant influence factor, DMSO amount takes the second place, and the amount of catalyst is the least significant influence factor.According to the Box-Benhnken design principle, the response surface methodology with3factors and3levels was used to set up a quadratic polynomial regression equation for the monoesters yield as function of above three factors: R=69.78-9.71A+2.35B+4.92C+0.31AB-2.08AC+2.13BC-14.00A2-2.78B2-12.08C2.The optimum conditions were obtained as follows: the molar ratio of sucrose to methyl laurate6.7:1, DMSO amount7.9mL and the amount of catalyst13.1%. Under these conditions, sucrose monoesters yield was71.96%.2. To develop a accurate,rapid and sensitive high performance liquid chromatographic (HPLC) method with evaporative light scattering detection (ELSD) for the determination of utrasonic synthesized sucrose laurate. The results of Electrospray ionization mass spectrometry confirms that the isomers of sucrose monolaurate have at least six kinds, most of whom are the three isomers of1’-O-lauroylsucrose、6’-O-lauroylsucrose、6-O-lauroylsucrose,and the isomers of sucrose dilaurate have at least six kinds in Ultrasonic Synthesized Sucrose Laurate.3. The influence of ultrasonic parameters on the synthesis of Sucrose Laurate were investigated based on Multifrequency Ultrasonic Reactor. The study found are as following.In the four frequency of20kHz、33kHz、53kHz and80kHz, the lower the ultrasonic frequency, the higher the Sucrose monolaurate yield, and the higher the ultrasonic frequency, the higher Sucrose dilaurate yield, The proportion of Sucrose monolaurate rises as ultrasonic frequency decreases.In the0.55to1.04W·cm-2range, the higher ultrasonic intensity, the more beneficial to the The Synthesis of sucrose laurate; Rising the sound intensity, not only increase the sucrose laurate yield,but also can shorten the reaction time.In the scope of40%～100%pulsed ultrasound, The shorter the pulse width, the lower the Sucrose laurate yield and the longer the reaction time in the range60～90℃, When the temperature increased, the initial reaction rate of Sucrose monolaurate yield increased and sucrose dilaurate yield increased,But the higher reaction temperature did not significantly increase the sucrose monolaurate yield and shorten the reaction time.