Recovery of highly pure alpha-tocotrienol from crude palm oil extract

A continuous simulated moving bed separation process for the production of a high purity alpha-tocotrienol product stream from crude palm oil extract, said process comprising:

• a. diluting the crude palm oil extract comprising front end carotenoids, alpha-tocopherol, alpha-tocotrienol, gamma-tocopherol, gamma-tocotrienol, beta-tocopherol, delta-tocopherol, delta-tocotrienol, and back end carotenoids in a non-polar solvent to provide a feed stream comprising 20 to 25 wt-% of the crude palm oil extract,
• b. passing the feed stream to a first solid phase extraction zone and therein contacting a first solid phase adsorbent comprising silica for the adsorption of back end carotenoids to remove at least a portion of the back end carotenoids from the feed stream provide a first SMB feed stream;
• c. passing the first SMB feed stream to a first SMB zone comprising a plurality of adsorbent beds, each adsorbent bed containing a stationary phase agent comprising silica or alumina and passing a first mobile phase desorbent stream comprising non-polar solvent and a polar organic solvent in a first SMB zone ratio of from 80-99 parts non-polar solvent:
• 1-20 parts of said polar organic solvent to the first SMB zone to provide a first extract stream comprising non-polar solvent, polar organic solvent, back end carotenoids, gamma-tocotrienol, delta-tocotrienol, and gamma-tocopherol, and a first raffinate stream comprising non-polar solvent, organic polar solvent, front end carotenoids, alpha-tocopherol and alpha-tocotrienol;
• d. passing the first raffinate stream to a first evaporization zone to remove essentially all of the polar organic solvent from the first raffinate stream to provide a first solvent stream comprising the polar organic solvent and an evaporated first raffinate stream and diluting the evaporated first raffinate stream with non-polar solvent to provide a second SMB feed stream comprising 3 to 10 wt-% of the evaporated first raffinate stream in non-polar solvent;
• e. passing the second SMB feed stream to a second SMB zone comprising a plurality of adsorbent beds, each adsorbent bed containing a second stationary phase agent comprising silica or alumina and passing a second mobile phase desorbent stream comprising non-polar solvent and the polar organic solvent in a second SMB zone ratio of from 90-99 parts non-polar solvent:
• 1-10 parts of said polar organic solvent to the second SMB zone to provide a second raffinate stream comprising non-polar solvent, polar organic solvent, front end carotenoids, alpha-tocopherol, and to provide a second extract stream comprising non-polar solvent, polar organic solvent and alpha-tocotrienol;
• f. passing the second extract stream to a second evaporization zone to remove essentially all of the polar organic solvent from the second extract stream to provide a second solvent stream comprising the polar organic solvent and an evaporated second extract stream and diluting the evaporated second extract stream with non-polar solvent to provide a diluted evaporated second extract stream comprising 5 to 15 wt-% of the evaporated second extract stream in non-polar solvent;
• and,
• g. passing the diluted evaporated second extract stream to a second solid phase extraction zone and therein contacting a basic alumina adsorbent to provide a first high purity alpha-tocotrienol stream comprising the non-polar solvent and alpha-tocotrienol;
• h. terminating the passing of the diluted evaporated second extract stream to the second solid phase extraction zone and purging the second solid phase extraction zone in a first purging step with the non-polar solvent to provide a second high purity alpha-tocotrienol stream comprising the non-polar solvent and alpha-tocotrienol;
• i. terminating the first purging step and purging the second solid phase extraction zone in a second purging step with the polar solvent to provide a byproduct stream comprising beta-tocopherol;
• and,
• j. combining the first and second high purity alpha-tocotrienol streams and removing the non-polar solvent to provide the high purity alpha-tocotrienol product stream having an alpha-tocotrienol purity of greater than or equal to 95 wt-% on a solvent free basis,
• wherein the non-polar solvent is hexane or n-heptane, and the polar organic solvent is isopropanol, ethanol, or ethyl-acetate.