The Synthesis And On-line Monitoring Of Sucrose-6-acetate

Sucrose-6-acetate is the key intermediates for the synthesis of green sweetener sucralose.The concentration and purity of Sucrose-6-acetate can significantly influence the quality and yield of sucralose.Due to the increasing market demand of sucralose,the demand of a relatively high concentration and purity sucrose-6-acetate is increasing gradually.So it calls for a rapid,convenient and efficient analysis method to sucrose-6-acetate.Through mix-uniform design experiment to the synthesis process of sucrose-6-acetate,and monitoring the synthesis process by TLC,the optimal synthesis process of sucrose 6-acetate is obtained in this article.It facilitates the preparation of high purity sucralose.Furthermore,a rapid analysis method based on The Space Vector Angle combined with the infrared spectra is established for the synthesis process of sucrose-6-acetate.The specific contents of the study include the following:?1?The TLC monitoring and technical study of the synthesis of S-6-A:An in-depth introduction to the synthesis methods,synthesis techniques,crystallization purification and analysis methods of S-6-A has been made.The optimal synthesis process of S-6-A has been found through mix-uniform design experiment.Thin layer chromatography?TLC?analysis methods of S-4,6-E and S-6-A are explored,and different suitable TLC test conditions for the acetal reaction,the ring-opening reaction and acyl transfer reaction are obtained.Process conditions of these three reactions are respectively optimized based on the semi-quantitative analysis of TLC.?2?The optimization for the crystallization process of S-6-A:Glacial acetic acid is used as crystal solvent by means of solvent-out crystallization method.Influence factors like crystallization temperature,concentration degree of synthetic,crystallization solvent dosage and crystallization time which affects The crystallization yield were investigated.Under the optimal concentration degree,to optimize the crystallization process By mixing uniform design experiment,the best process conditions for S-6-A crystallization is:The concentration degree of synthetic is V_{concentrated solution}:V_{synthetic liquid}=1.3:1,V_{glacial acetic acid}:V_{concentrated solution}=3.7:1,Crystallization temperature is 15?,Crystallization time is one time,average purity of the product is 89.95%.?3?The quantitative analysis based on mid-infrared spectrum:Standard addition method is used to gradually increase the content of S-6-A in the sucrose—S-6-A DMF?dimethylformamide?mixed solution.to determine the mid-infrared spectrum of mixed samples with different amount of S-6-A and the S-6-A reference substance,to establish the approximate linear relationship between the spectral vector Angle and the S-6-A contents,the linear correlation coefficient reaches 99.57%.To predict the content of S-6-A in unknown mixed solution by the approximate linear relationship,the relative error range of the predicted values and the the real value range from-2.15%to 5.75%.The results Show that this method is suit for the rapid analysis of S-6-A content in the Simple mixed system.?4?The Online monitoring of sucrose-6-acetate synthesis process:By infrared spectroscopy combined with Space Vector Angle to establish approximate linear relationship between the content of S-6-A in the mixture samples of ring opening reaction and acyl transfer reaction and the space vector Angle,their linear correlation coefficient are both greater than 99.5%.Using this method respectively to predict the content of S-6-A in the ring opening reaction and acyl transfer reaction,and comparing the Predicted results with the determination results by the HPLC method,the relative deviation is less than 6%.It indicates this method can be used in the process analysis of the synthesis of S-6-A.