Separation Of D-psicose,allitol And D-talitol Using Simulated Moving Bed Chromatography

D-psicose,allitol and D-talitol,three important members of rare sugers,scarcely occur in some fruit,vegetables,Itea virginica L and vegetative and reproductive tissues of brown algae Himanthalia elongate.They all have some important biological and physiological functions and some of them has been put into practical application to create enormous economic values.D-psicose can be used as a noncaloric sweetener,medicine for suppressing hyperglycemia and antioxidant.Allitol can work as medicine,low-calorie sweetener and raw material for producing other chemicals.It has demonstrated that D-talitol has the ability to inhibit cancer cell proliferation and can be used as antioxidant.So the techniques for production of rare sugars have always been the research focus in nearly two decades for which many advancements have been achieved.However,the problems of separation and purification of rare sugars in large scale has been the bottleneck of industrial production of rare sugars no matter what methods are used,e.g.chemical synthesis and biological transformation.The traditional methods of separation and purification such as crystallization,extraction,etc.have been unable to meet the requirements of modern industrial production.It has indeed been a critical issue for further research about how to innovate new technology to obtain large amounts of high-purity chemicals economically.This thesis,taking the problems of practical production into consideration,comprehensively utilizes multidisciplinary techniques of chromatography,theories of mathematical model,microbiology and chemistry etc.A set of methodological system consisting of screening of packing material,packing methods of preparative columns and establishing single-column models and multi-column models for preparative separation of rare sugars has been formed.A optimization process was then followed and the efficient separation and purification of target chemicals was eventually achieved.All the unsued D-fructose has been recovered under the prerequisite of ensuring the high purity of D-psicose.Meanwhile,the technique of preparative separation of allitol and D-talitol using SMBC was firstly established.All the work has laid a foundation for improvements in the future.1.Efficient production of allitol and D-talitol using chemical transformation.Systematically optimize the conditions of reduction of D-psicose with NaBH4.Achieve the results that the optimal reaction molar ratio and time of NaBH4 and D-psicose is 1:1 and 4 h,respectively.Reduction of D-psicose utilizing the optimal condition to get more allitol and D-talitol.2.Determination of the packing material for preparative separation of D-psicose,allitol and D-talitol through thoroughly consulting documents and single-column experiment.Systematically consulting and comparing documents on the separation of carbohydrates for the last 80 years.Measuring separation resolution of D-psicose,allitol and D-talitol in corresponding packing materials,respectively.Determining the packing materials for D-psicose,allitol and D-talitol and the result is ZG SPC 106(Ca2+)ion exchange resin for D-psicose and Dowex 50WX4(H+,200-400 mesh)ion exchange resin for allitol and D-talitol.3.Hydraulic slurry packing of preparative column for separation of rare sugars.Exploring the optimal conditions of hydraulic slurry packing method.The results are shown as below.The optimized conditions for Dowex 50WX4(H+,200-400 mesh)and Dowex 1X8(Cl-,200-400 mesh)ion exchange resin are 20 MPa,20 min and 100 ml slurry for a single time.The optimized conditions for ZG SPC 106(Ca2+)ion exchange resin are 20 MPa,10 min and 100 ml slurry for a single time.4.Preparative separation of D-psicose on the bases of TMB model,Equilibrium theory and Triangle method.Measuring and calculating the thermodynamic and dynamic parameters of preparative separation of D-psicose.Calculating the parameters of multi-column model for SMBC separation of D-psicose.SMBC separation of D-psicose is followed by conditions optimization.The results are that the purity of D-psicose is 99.30%,the recovery of D-psicose is 99.99%and the recover of D-fructose is 99.95%.5.Preparative separation of allitol and D-talitol on the bases of TMB model,equilibrium theory and triangle method.Measuring and calculating the thermodynamic and dynamic parameters of preparative separation of allitol and D-talitol,respectively.The isotherm is determined by frontal analysis.Calculating the parameters of multi-column model for SMBC separation of allitol and D-talitol.SMBC separation of allitol and D-talitol is followed by conditions optimization.The results are that the purity of allitol and D-talitol are 93.47%and 88.79%,the recovery of allitol and D-talitol is 96.31%and 67.33%,respectively.