Method for preparation of 1,4-sorbitan
The invention discloses a method for preparation of 1,4-sorbitan by dehydration of D-sorbitol, wherein one equivalent of water is removed and a cyclization occurs, followed by a treatment with ethanol and isopropanol.
1. A method for preparation of 1,4-sorbitan with four consecutive steps STEP1, STEP2, STEP3 and STEP4, wherein
in STEP1 D-sorbitol is dehydrated in a dehydration reaction DEHYDREAC in the presence of p-toluenesulfonic acid and tetrabutylammonium bromide,
the reaction time TIME1-1 of DEHYDREAC is from 3 to 12 h;
DEHYDREAC is done at a temperature TEMP1, TEMP1 is from 95 to 130° C.,
DEHYDREAC is done at a pressure PRESS1 of 500 mbar or below,
STEP1 provides a mixture MIX1;
in STEP2 ethanol is mixed with MIX1, STEP2 provides a mixture MIX2;
in STEP3 isopropanol is mixed with MIX2, STEP3 provides a mixture MIX3;
in STEP4 1,4-sorbitan is isolated from MIX3.
2. The method according to claim 1 , wherein
the p-toluene sulfonic acid is used in form of p-toluenesulfonic acid monohydrate.
3. The method according to claim 1 , wherein
DEHYDREAC is done neat, wherein only the three components D-sorbitol, p-toluenesulfonic acid and tetrabutylammonium bromide are used for and are charged for DEHYDREAC.
4. The method according to claim 1 , wherein
DEHYDREAC is done at a temperature TEMP1, TEMP1 is from 95 to 120° C.
5. The method according to claim 1 , wherein
the reaction time TIME1-1 of DEHYDREAC is from 4 to 12 h.
6. The method according to claim 1 , wherein
DEHYDREAC is done at a pressure PRESS1 of 250 mbar or below.
7. The method according to claim 1 , wherein
water is removed during DEHYDREAC.
8. The method according to claim 1 , wherein
STEP2 is done at a temperature TEMP2 of from 60 to 90° C.
9. The method according to claim 1 , wherein
STEP3 is done at a temperature TEMP3-1 of from 10 to 30° C.
10. The method according to claim 1 , wherein
after the mixing of isopropanol, STEP3 comprises a cooling COOL3 of MIX3 to a temperature TEMP3-2 of from −5 to 5° C.
11. The method according to claim 1 , wherein
STEP3 comprises a stirring STIRR3 of MIX3, wherein STIRR3 is done for a time TIME3-2, wherein TIME3-2 is from 1 to 12 h.
12. The method according to claim 11 , wherein
STIRR3 is done after COOL3, wherein COOL3 comprises a cooling of MIX3 to a temperature TEMP3-2 of from −5 to 5° C.
13. The method according to claim 11 , wherein
STIRR3 is done at TEMP3-2, wherein TEMP3-2 is a temperature of from −5 to 5° C.
14. The method according to claim 1 , wherein
1,4-sorbitan is isolated in STEP4 from MIX3 by filtration.
15. The method according to claim 1 , wherein
STEP1, STEP2 and STEP3 are done consecutively in one and the same reactor.
16. A method for preparing prostaglandin analogues or Polysorbate comprising preparing 1,4-sorbitan according to claim 1 .