CH167166A - Process for obtaining a starting material intended for the production of pure vitamin A. - Google Patents

Description

  

  Process for obtaining a starting material intended for the production of pure vitamin A. To obtain pure vitamin A, the starting materials have been freed from the contaminating constituents as far as possible by distillation or adsorption.

   It has now been found that largely pre-purified vitamin A preparations, which are intended for the production of pure vitamin A, can also be obtained by dissolving a raw preparation containing vitamin A in a water-miscible solvent, separates the impurities by freezing, removes them, repeatedly adding water in increasing amounts after the solvent,

   refrigerated after each addition of water and the respective vitamin A-rich deposits formed, expediently with the exclusion of atmospheric oxygen, separated and finally the mother liquor extracted with an organic solvent.



  In this way it is possible to largely separate off contaminating admixtures and to obtain products with an increased C.L. 0 number, which are intended as starting material for the production of pure vitamin A.



  The following examples explain the process.



       Example <I> 1: </I> The unsaponifiable portion of Hippoglossus hippoglossus Tran with the CL 0. number (Cod Liver Oil number) 5000 is dissolved in 100% methanol and this solution in a cold mixture of solid carbonic acid and Brought acetone. A precipitate I precipitates out, which is separated off at a low temperature (-50 to -60).

   This separation is expediently carried out in the absence of air in such a way that 'one uses a layer of solid carbonic acid as a filter; the developing gaseous carbonic acid excludes oxygen from the air. So much water is then added to the filtrate that a 96% methanol solution is formed, and this liquid is cooled again in the carbonic acid-acetone mixture. A second precipitate II is thus obtained, which in turn is separated off at low temperature, as described in more detail above.

   A third precipitate III falls out after diluting the methanol with water to 90 in the freezing mixture. On cooling, a fourth precipitate IV separates from the filtrate to which a further 15% water has been added.



  The individual precipitates are dissolved in low-boiling petroleum ether and these solutions evaporated in vacuo.



  A fifth preparation is made from the final methyl alcohol filtrate from which the others. Precipitates have formed by adding more water to the dilute methanol solution and extracting it with petroleum ether.



  Preparations I and II (from the precipitates I and II) are dark brown in color. The C.L. 0 number of I is the lowest (3000). Preparations III, IV and V are light yellow. The highest C.

   L. 0. number is found in preparation III. The following list provides information about the effectiveness of the individual preparations:
EMI0002.0028
  
    Preparation <SEP> I <SEP> C. <SEP> L. <SEP> 0.-number <SEP> 3000
<tb> "<SEP> 1I <SEP> <B> 11 </B> <SEP> 7000
<tb> "<SEP> III <SEP> <B> 10000 </B>
<tb> "<SEP> IV <SEP> 8500
<tb> "<SEP> V <SEP> <B> 9000 </B> Example <I> 2: </I> The unsaponifiable part of Scombresox saurus-Tran with the C.L. 0. number 4800 is dissolved in acetone.

   By increasing the addition of water and cooling with a carbonic acid / acetone cold mixture, precipitates are produced in a manner analogous to that described in Example 1. The first precipitate I is deposited from 99% acetone, the second precipitate II from 93% acetone, and the third precipitate III from 80% acetone. After diluting with water and soaking in petroleum ether, the filtrate gives preparation IV.



  In this case too, the preparation obtained from Precipitation I has the darkest color. The later factions look bright yellow. The C.L. 0 number was found to be highest with preparation IV.
EMI0002.0044
  
    Preparation <SEP> I <SEP> C. <SEP> L. <SEP> 0.-number <SEP> 3200
<tb> "<SEP> II <SEP> 7500
<tb> "<SEP> III <SEP> 8000
<tb> "<SEP> IV <SEP> 9600

 

Claims (1)

PATENT CLAIM: Process for obtaining a starting material intended for the production of pure vitamin A, characterized in that a raw preparation containing vitamin A is dissolved in a water-miscible solvent, the impurities are separated by freezing and the solution is repeatedly watered to set in increasing quantities, after each addition of water cools deeply and separates the vitamin A-rich deposits that form on cooling and finally extracts the mother liquor with an organic solvent. SUBSTANTIAL CLAIM: Process according to patent claim, characterized in that a layer of solid carbonic acid is used as a filter to separate the deposits obtained from the mother liquor.