Studies On The Process Control And Analysis Methods About The Synthesis Of Sucralose

Sucralose is a high intensity sweetener with significant characteristics. In this research, sucralose was synthesized through a three-step process, which comprised using organictin as regioselectivity reagent, acylating sucrose to produce sucrose-6-ester, selectively chlorinating the sucrose-6-ester to produce sucralose-6-ester and deacylating the sucralose-6-ester to produce sucralose. On the base of this process, the terms of every step were improved, and the methods of react process control in the industrialization synthesis and product analysis were established.1, Sucrose-6-ester was synthesized by using dibutyltin oxide as the high regioselsctivity reagent. Sucrose and dibutyltin oxide were mixed in DMF and heated to reflux and remove the water with cyclohexane. Then, acetic anhydride was dropped to the reaction solution and sucrose-6-ester could be obtained in high yield. The influences of the reaction time, the reaction temperature, the solvents, the ratio of the materials and so on have been researched systematically and optimized. The obtained DMF solution of sucrose-6-ester could be used in the next step directly.2, The Vilsimier reagent, which is combined of POC13 and DMF, was used as chlorination reagent to chlorinate sucrose-6-ester selectively, and so to prepare sucralose-6-ester. In this step, the usage quantities of POC13 and the solvents have been studied.The results indicated that when the molar ratio of sucrose: POC13 was 10:1, the outcome of chlorination is best and when the sucrose: DMF: toluene was Imol: 1.401: 2.801, it was most rational.3, The processes of the selective chlorination have been researched in detail, several role by-products-4, 6, 1', 6'-tetrachlorosucrose, 4, 6,1', 6'-tetrachlorosucrose-3-ester,4, 6, 1', 6'-tetrachlorosucrose-2-ester, sucralose-3, 6-diester, 4, 6'-bichlorosucrose-6-ester, and so on- have been isolated and their structure have been studied and elucidated based on 1H NMR, 13C NMR, 2D NMR and MS in the first time. The determination of the by-products' structure has great effects on the optimizing of the synthesis technologies and the controlling of the reaction processes.4, A new method that sucralose-6-ester was deprotected and the solvent was removed directly to prepare sucralose has been probed, by which the purity of sucralose was obtained conforming with the international standard ( ≥ 98%), and the process of recrystallization was not in need any more.5 , On the ground of comprehensive research to the above mentioned reaction steps, the methods of reaction process control were probed. Using TLC (CHC13-CH3OH system and CeHg-CHaCOOEt-EtOH system) could follow the reaction process conveniently. By using HPLC, the best condition for every step was determined and the purity of last-product sucralose was tested.