Dsm IP Assets B.v.

Werner Pietzonka

Angela Wildermann

Juan Ramon Herguijuela

Thomas Wolf

Peter Ruckstuhl

A process for the rectification of mixtures of high-boiling air- and/or temperature-sensitive substances which require a high separation efficiency is proposed, in particular a process for the working-up of a VE- or VEA-containing product stream. The process includes a first purification stage to separate low-boiling products and unspecified isomers of the useful product from the product stream virtually without loss of useful product and a second purification stage for removing the useful product in a stream having a purity of &#x3e;97% by weight and a further stream having a purity of &#x3e;92% by weight.

Process for the rectification of mixtures of high-boiling air- and/or temperature-sensitive useful products

According to the invention, a process for the rectification of mixtures of high-boiling air- and/or temperature-sensitive substances which require a high separation efficiency is proposed, in particular a process for the working-up of a VE- or VEA-containing product stream. The process is characterized in particular in that, in a first purification stage, low-boiling products and unspecified isomers of the useful product are separated from the product stream virtually without loss of useful product and that, in a second purification stage, the useful product is removed in a stream having a purity of &#x3e;97% by weight and a further stream having a purity of &#x3e;92% by weight. A preferred embodiment of the process serves for working up VEA, in which the loss of useful product in the first purification stage is less than 5%, based on that amount of VEA in the feed which is added to the purification stage per unit time. Furthermore, the first purification stage may comprise a rectification column (), from the top () of which the low-boiling products and the unspecified isomers of VEA are taken off, a stream containing the useful product in purified form being taken off at the side () and/or at the bottom () of the column ().

A rectification column and system for the working-up of a vitamin E (VE)- and/or vitamin E acetate (VEA)-containing product stream includes purification of a vitamin E-containing product stream, acetylation of at least a part of the purified vitamin E and purification of at least a part of the acetylated vitamin E, the purification of vitamin E and vitamin E acetate preferably being effected by distillation, for example rectification.

Process for the working-up of a vitamin E- and vitamin E-acetate-containing mixture or product stream

The invention relates to a process for the working-up of a vitamin E (VE)- and/or vitamin E acetate (VEA)-containing product stream, which is substantially characterized by purification of a vitamin E-containing product stream, acetylation of at least a part of the purified vitamin E and purification of at least a part of the acetylated vitamin E, the purification of vitamin E and vitamin E acetate preferably being effected by distillation, for example rectification. A preferred process according to the invention is characterized in that a vitamin E-containing product stream is fed to a first rectification column (), low-boiling products and unspecified isomers of vitamin E being taken off at the top () of this first rectification column virtually without loss of useful substance, and a purified, vitamin E-containing stream being taken off at the side () and/or at the bottom () of the rectification column (), at least a part of the side take-off or of the bottom take-off or at least a part of the side and bottom take-off is passed, for acetylation of vitamin E, into an acetylation stage (), at least a part of the product stream emerging from the acetylation stage is passed into a second rectification column () or is taken off as useful product having a purity of &#x2267;92% by weight, and in a second rectification column, the VEA useful product is obtained as a side take-off having a purity of &#x2267;97% by weight.

Process for the working-up of a vitamin E- and vitamin E-acetate- containing mixture or products stream

According to the invention, a process for the rectification of mixtures of high-boiling air- and/or temperature-sensitive substances which require a high separation efficiency is proposed, in particular a process for the working-up of a VE- or VEA-containing product stream. The process is characterized in particular in that, in a first purification stage, low-boiling products and unspecified isomers of the useful product are separated from the product stream virtually without loss of useful product and that, in a second purification stage, the useful product is removed in a stream having a purity of &#x3e;97% by weight and a further stream having a purity of &#x3e;92% by weight. A preferred embodiment of the process serves for working up VEA, in which the loss of useful product in the first purification stage is less than 5%, based on that amount of VEA in the feed which is added to the purification stage per unit time. Furthermore, the first purification stage may comprise a rectification column (), from the top (Ia) of which the low-boiling products and the unspecified isomers of VEA are taken off, a stream containing the useful product in purified form being taken off at the side () and/or at the bottom (Ib) of the column ().

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Therwil, Switzerland

Werner Pietzonka