Separation of α-Tocopherol with a Two-Feed Simulated Moving Bed

A two-feed simulated moving bed (SMB) was proposed to utilize the stationary phase more effectively. Zone I is disconnected with zone II and zone III is disconnected with zone IV. Two feeds are added to zones I and III, while two desorbents are added to zones II and IV separately. The investigation on the movement of concentration bands indicated that the tail of the strong retained solute and the front of the weak retained solute were eluted from zones I and III orderly, so the streams from zones I and III could be cut into different fractions to give the products with high purity. The two-feed SMB was used to separate α-tocopherol from its homologue mixture successfully, and could double the productivity if both feeds were identical to the feed in the conventional four-zone SMB. The solvent consumption could be reduced by reusing the middle fraction without solutes.