Method for separating a mixture comprising three components by simulated moving bed chromatography

A method for separating a mixture comprising three components by simulated moving bed chromatography, characterized in that, using a simulated moving bed device comprising a first, a second, and a third zone, each of the three zones comprising one or more chromatographic columns connected in series with each other, wherein the first zone is located between the eluent-inlet and the extract-outlet, the second zone is located between the extract-outlet and the feeding port, and the third zone is located between the feeding port and the raffinate-outlet, the method comprising:

• (1) the step of feeding:
• firstly, a solution 1 and a solution 2 are prepared, wherein the volume percentage of the solvent having strong eluting power in the solution 2 is higher than that of the solvent having strong eluting power in the solution 1;
• secondly, the mixture to be purified comprising three components is dissolved in the solution 1 to prepare a feeding solution;
• thirdly, the feeding solution flows into the simulated moving bed through the feeding port, and the solution 2 flows into the simulated moving bed through the eluent-inlet port, and thus, the eluting power of the liquid phase within the second zone is stronger than that of the liquid phase within the third zone, such that in the second zone, the target component moves forward to the third zone along with the liquid phase while in the third zone, the target component moves backward to the second zone with the switch of the columns;
• thereby the target component is trapped in the second and the third zone, and gradually accumulates;
• at the same time, the pre-impurity in the second and the third zone moves together with the liquid phase and flows out of the raffinate-outlet together with the raffinate, while the post-impurity in the second and the third zone moves with the switch of the columns and flows out of the extract-outlet together with the extract;
• (2) the step of purification:
• the solution 1, replacing the feeding solution, is fed into the simulated moving bed through the feeding port, and at the same time, the pre-impurity is collected from the raffinate-outlet and the post-impurity is collected from the extract-outlet;
• thereby the target component trapped in the second and the third zone is further purified;
• and
• (3) the step of recovery:
• the target component trapped in the simulated moving bed is eluted out of the simulated moving bed.