Trivinylcyclohexane stereoisomeric compositions and methods for preparing same
Disclosed herein is a process for making 1,2,4-trivinylcyclohexane that is enriched in a particular geometric isomer. The process involves the thermal isomerization of 1,5,9-cyclododecatriene at temperature between 400° C. and 600° C. followed by an equilibration of the resultant intermediate in either the gas phase or liquid phase at temperature between 180° C. and 375° C. and at pressures ranging from 0.101 kPa to 1,013 kPa. Also disclosed are 1,2,4-trivinylcyclohexane compositions that are enriched in a particular geometric isomer.
1. A process for preparing a 1,2,4-trivinylcyclohexane composition enriched in Isomer A—1,trans-2,trans-4-trivinyl-cyclohexane, the lowest boiling geometric isomer of 1,2,3-trivinylcyclohexane—having the three-dimensional structure of
comprising:
(i) heating 1,5,9-cyclododecatriene at a temperature of from about 400° C. to about 600° C. and at a pressure of from about 1 mbar to about 1.2 bar thereby forming a 1,2,4-trivinylcyclohexane composition containing low levels of Isomer A; and
(ii) subsequently equilibrating the composition from step (i) in a vapor phase or a liquid phase at a temperature ranging from about 180° C. to about 375° C. and at a pressure ranging from about 1 mbar to about 10 bar to produce a 1,2,4-trivinylcyclohexane composition enriched in Isomer A as compared to the composition of step (i).
2. The process of claim 1 wherein the 1,2,4-trivinylcyclohexane composition of step (ii) has a molar ratio of Isomer A, the lowest boiling isomer of 1,2,4-trivinylcyclohexane to isomer B, 1,trans-2,cis-4-trivinyl-cyclohexane having the three-dimensional structure of
the next higher boiling isomer of 1,2,4-trivinylcyclohexane, of between 2.4:1 and 3.5:1.
3. The process of claim 1 wherein step (i) is carried out at a temperature between about 507° C. and about 540° C., in the presence of an inert gas with a partial pressure of from about 30 mbar to about 256 mbar and a residence time of from about 6 seconds to about 11 seconds.
4. The process of claim 3 wherein step (i) is carried out in the presence of an inert gas at a partial pressure of from about 128 mbar to about 148 mbar.
5. The process of claim 1 wherein step (ii) is carried out at a temperature of from about 230° C. to about 350° C.
6. The process of claim 4 wherein step (ii) is carried out at a temperature of from about 230° C. to about 290° C.
7. The process of claim 1 wherein the composition of step (i) is equilibrated in a liquid phase.
8. The process of claim 1 wherein the composition of step (i) is equilibrated in a vapor phase.
9. The process of claim 7 wherein the composition of step (i) is equilibrated at a pressure of from 1 bar to 10 bar.
10. The process of claim 1 wherein the process for preparing 1,2,4-trivinylcyclohexane compositions enriched in Isomer A is carried out in a continuous, a semi-continuous, or a batch process.
11. The process of claim 10 , wherein the process for preparing 1,2,4-trivinylcyclohexane compositions enriched in Isomer A is carried out in a continuous process.
12. The process of claim 11 , wherein the process for preparing 1,2,4-trivinylcyclohexane compositions enriched in Isomer A is carried out in a semi-continuous process.
13. The process of claim 1 , wherein step (i) is carried out without the presence of any catalyst.
14. The process of claim 1 , wherein step (i) is carried out in the presence of a catalyst.
15. The process of claim 1 , wherein the composition of step (ii) is purified by distillation to provide a purified 1,2,4-trivinylcyclohexane composition.
16. The process of claim 15 , wherein the purified 1,2,4-trivinylcyclohexane composition has a molar ratio of Isomer A to Isomer B of from 4.0:1 to 99.9:1.
17. A process for preparing 1,2,4-trivinylcyclohexane compositions enriched in Isomer A, 1,trans-2,trans-4-trivinyl-cyclohexane having the three-dimensional structure of
comprising: equilibrating a 1,2,4-trivinylcyclohexane composition containing low levels of Isomer A in a vapor phase or a liquid phase at a temperature ranging from about 180° C. to about 375° C. and at a pressure ranging from about 1 mbar to about 10 bar to produce a 1,2,4-trivinylcyclohexane composition enriched in Isomer A.
18. The process of claim 17 , wherein the 1,2,4-trivinylcyclohexane composition having a molar ratio of Isomer A to Isomer B of less than 2.2 is equilibrated at a temperature of from 230° C. to 290° C. and at a pressure of from 1 bar to 10 bar.
19. The process of claim 17 wherein the equilibration is carried out for about one minute to about fifteen thousand minutes.
20. A composition containing 1,2,4-trivinylcyclohexane Isomer A and 1,2,4-trivinylcyclohexane isomer B wherein the molar ratio of isomer A to isomer B is from about 4:1 to 99.9:1.
21. The composition of claim 20 wherein the molar ratio of isomer A to isomer B is from about 4:1 to 10:1.