Process for the mild distillative separation of mixtures

Abstract

The invention relates to a semibatchwise process for the mild distillative separation of mixtures, in a first stage a column being supplied continuously with a feed and the feed being separated at least into different fractions, one of the fractions being removed continuously into a container, and, in a second step, the fraction removed into the container being recycled to the column and being separated again batchwise into different fractions.

1 . A process for the distillative separation of mixtures, comprising:
 a) continuously supplying a column having a stripping section and a rectification section with a feed, separating the feed into fractions containing at least a low boiler fraction and a high boiler fraction, removing the high boiler fraction continuously into a container; and   b) stopping the feed, recycling the high boiler fraction, removed in step a) into the container, to the column, separating the high boiler fraction batchwise by an ascending procedure into at least a further low boiler fraction and a further high boiler fraction.   
   
   
       2 . The process according to  claim 1 , wherein the fractions separated in step a) further comprise a medium boiler fraction, and the fraction being separated in step b) further comprise a medium boiler fraction. 
   
   
       3 . The process according  claim 1 , wherein the step a) or step b) or the step a) and step b), independently of one another, is or are repeated once or several times. 
   
   
       4 . The process according to  claim 1 , wherein at least one packed column selected from the group consisting of dumped packings, stacked packings, tray columns, dividing wall columns, and thermally coupled columns, is used as the column. 
   
   
       5 . The process according to  claim 1 , wherein the removal and the residence of the removed fraction in the container are effected without additional heat supply or with cooling. 
   
   
       6 . The process according to  claim 1 , wherein the residence of the removed fraction in the container is affected with cooling. 
   
   
       7 . The process according to  claim 1 , wherein step a) is automated. 
   
   
       8 . The process according to  claim 1 , wherein in step b) the feeding of the column is effected from the container via an evaporator. 
   
   
       9 . The process according to  claim 8  wherein the evaporator used is a falling-film evaporator or thin-film evaporator. 
   
   
       10 . The process according to  claim 8 , wherein at least one preheater is connected upstream of the evaporator. 
   
   
       11 . The process according to  claim 8 , wherein the bottom of the column is filled with sufficient liquid to enable the evaporator to be put into operation, thereby starting up the column. 
   
   
       12 . The process according to  claim 1 , wherein the continuously supplying a column with a feed is by an intermittent feed or a predetermined ramp feed. 
   
   
       13 . The process according to  claim 1 , wherein reaction mixtures or solvent mixtures are used as the feed.