Process for making cyclohexanone

Patent metadata

Field	Value
Publication number	US-9868687-B2
Application number	US-201515504087-A
Country	US
Kind code	B2
Filing date	Sep 8, 2015
Priority date	Sep 30, 2014
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

Disclosed are processes and systems for making cyclohexanone from a mixture comprising phenol, cyclohexanone, and cyclohexylbenzene, comprising a step of or a device for subjecting at least a portion of the mixture to hydrogenation and a step of or a device for distilling a phenol/cyclohexanone/cyclohexylbenzene mixture to obtain an effluent rich in cyclohexanone.

First claim

The invention claimed is:

1. A process for making cyclohexanone, the process comprising the following steps:
(I) feeding a first mixture comprising cyclohexanone, phenol, and cyclohexylbenzene into a first distillation column;
(II) obtaining from the first distillation column:
a first upper effluent comprising cyclohexanone at a concentration higher than in the first mixture, phenol, and cyclohexylbenzene;
a first middle effluent comprising cyclohexanone, phenol at a concentration higher than in the first mixture, cyclohexylbenzene, and bicyclohexane; and
a first lower effluent comprising cyclohexylbenzene at a concentration higher than in the first mixture;
(III) feeding at least a portion of the first middle effluent and hydrogen into a hydrogenation reaction zone where phenol reacts with hydrogen in the presence of a hydrogenation catalyst under hydrogenation reaction conditions to obtain a hydrogenation reaction product comprising cyclohexanone at a concentration higher than in the first middle effluent, phenol at a concentration lower than the first middle effluent, cyclohexylbenzene, and bicyclohexane;
(IV) feeding at least a portion of the hydrogenation reaction product to the first distillation column;
(V) feeding at least a portion of the first upper effluent into a second distillation column; and
(VI) obtaining the following from the second distillation column:
a second upper effluent comprising cyclohexanone at a concentration higher than in the first upper effluent; and
a second lower effluent comprising cyclohexanone at a concentration lower than the first upper effluent, and cyclohexanol at a concentration higher than in the first upper effluent;
wherein at least a portion of the heat supplied to the second distillation column is provided by a liquid stream drawn from the first distillation column.

2. The process of claim 1 , wherein at least a portion of the heat supplied to the second distillation column is provided by a portion of the first middle effluent via a heat exchanger.

3. The process of claim 2 , wherein the portion of the first middle effluent providing heat to the second distillation column is recycled to the first distillation column at a location higher than in the location where the first middle effluent is drawn.

4. The process of claim 1 , wherein the first middle effluent has a temperature that is at least 20° C. higher than the bottom temperature of the second distillation column.

5. The process of claim 1 , wherein the liquid stream drawn from the first distillation column providing heat to the second distillation column is cooled by at least 10° C. as a result of providing heat to the second distillation column, and is subsequently recycled to the first distillation column.

6. The process of claim 1 , wherein the first distillation column has a bottom temperature that is at least 40° C. higher than the bottom temperature of the second distillation column.

7. The process of claim 1 , wherein at least a portion of the heat supplied to the second distillation column is provided by a portion of the hydrogenation reaction product.

8. The process of claim 7 , wherein the temperature of the hydrogenation reaction product is at least 40° C. higher than the bottom temperature of the second distillation column.

9. The process of claim 7 , wherein a portion of the hydrogenation reaction product is cooled by at least 20° C. as a result of supplying heat to the second distillation column and is subsequently recycled to the first distillation column.

10. The process of claim 1 , wherein the first distillation column has an absolute internal pressure of P 1 kPa at the location where the first upper effluent is drawn, and the second distillation column has an absolute internal pressure of P 2 kPa at the top of the second distillation column, P 1 is higher than P 2 , and the difference between P 1 and P 2 is in a range from 10 to 80.

11. The process of claim 10 , wherein both P 1 and P 2 are less than 100.

12. The process of claim 10 , wherein P 2 is in a range from 5 to 50.

13. The process of claim 10 , wherein P 1 is in a range from 15 to 80.

14. The process of claim 1 , wherein a vacuum source connected to the second distillation column generates the vacuum inside the second distillation column, and a connection pipe connecting the primary fractionation column and the second distillation column at least partially generates the vacuum inside the primary fractionation column.

15. The process of claim 14 , wherein the connection pipe also delivers at least a portion of the first upper effluent to the second distillation column.

16. The process of claim 1 , wherein in step (VI), a third upper effluent comprising components having normal boiling points lower than that of cyclohexanone is obtained at a location above the second upper effluent.

17. The process of claim 16 , further comprising condensing the third upper effluent to obtain a first liquid phase light fraction and a first vapor phase light fraction, and separating the first liquid phase light fraction from the first vapor phase light fraction in a first light fraction separation drum.

18. The process of claim 17 , further comprising recycling at least a portion of the first liquid phase light fraction to the second distillation column.

19. The process of claim 17 , further comprising condensing the first vapor phase light fraction to obtain a second liquid phase light fraction and a second vapor phase light fraction, and separating the second liquid phase light fraction from the second vapor phase light fraction in a second light fraction separation drum.

20. The process of claim 19 , further comprising recycling at least a portion of the second liquid phase light fraction to the first light fraction separation drum, and further wherein the second liquid phase light fraction comprises at least one of water and methylcyclopentanone.

21. The process of claim 19 , further comprising connecting the second light fraction separation drum with a vacuum source.

22. The process of claim 1 , wherein the second upper effluent comprises cyclohexanone at a concentration of at least 95 wt % based on the total weight of the second upper effluent.

23. The process of claim 1 , wherein the second lower effluent comprises a mixture of cyclohexanone and cyclohexanol.

24. The process of claim 1 , wherein step (IV) further comprises obtaining a third vapor stream comprising at least 50% by volume of hydrogen, and the process further comprises:
(VII) recycling at least a portion of the third vapor stream to the hydrogenation reaction zone.

25. The process of claim 1 , further comprising:
(VIII) feeding at least a portion of the first lower effluent to a third distillation column; and
(IX) obtaining the following from the third distillation column:
a third upper effluent comprising cyclohexylbenzene; and
a third lower effluent comprising components having boiling points higher than cyclohexylbenzene.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Becker Christopher L
• Davis Jason D
• Dakka Jihad M
• Nadler Kirk C

Classifications

• C07C2602/14

  All rings being cycloaliphatic · CPC title

• C07C45/006

  by hydrogenation of aromatic hydroxy compounds · CPC title

• C07C37/74

  by distillation · CPC title

• C07C45/82 Primary

  by distillation · CPC title