Dehydrogenation process

• US 9,249,077 B2
• Filed: 04/04/2011
• Issued: 02/02/2016
• Est. Priority Date: 07/14/2009
• Status: Expired due to Fees

• Current Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Dakka, Jihad M., DeCaul, Lorenzo C.
• Primary Examiner(s): Zucker, Paul A
• Assistant Examiner(s): LUDERER, MARK R
• Application Number:
  US13/698,830
• Publication Number:
  US 20130204048A1
• Time in Patent Office: 1,765 Days
• Field of Search: 568/799
• US Class Current: 1/1
• CPC Class Codes: B01J 23/42 Platinum
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/647 2-50 nm
• CPC Class Codes: B01J 37/0009 Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
• CPC Class Codes: B01J 37/0201 Impregnation
• CPC Class Codes: C07C 37/07 with simultaneous reduction of C=O group in that ring
• CPC Class Codes: C07C 39/04 Phenol
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

Abstract

In a process for the dehydrogenation of at least one dehydrogenatable hydrocarbon, at least one dehydrogenatable hydrocarbon selected from an oxygen-containing six-membered carbon ring compound is supplied to a first dehydrogenation reaction zone together with at least one stabilizing compound selected from a non-oxygen-containing six membered carbon ring compound to the first dehydrogenation reaction zone, such that the weight ratio of the stabilizing compound to the dehydrogenatable hydrocarbon supplied to the first dehydrogenation reaction zone is in the range of from 1:200 to 200:1. The dehydrogenation feed stream and the at least one stabilizing compound are contacted with a first dehydrogenation catalyst in the first dehydrogenation reaction zone under dehydrogenation conditions to convert at least a portion of the dehydrogenatable hydrocarbon into an unsaturated six-membered carbon ring compound and hydrogen.

Claims

1. A process for the dehydrogenation of at least one dehydrogenatable hydrocarbon, the process comprising:

(a) supplying a dehydrogenation feed stream comprising at least one dehydrogenatable hydrocarbon to a first dehydrogenation reaction zone wherein the at least one dehydrogenatable hydrocarbon is an oxygen-containing six-membered carbon ring compound;

(b) supplying at least one stabilizing compound to the first dehydrogenation reaction zone, such that the weight ratio of the stabilizing compound to the dehydrogenatable hydrocarbon supplied to the first dehydrogenation reaction zone is in the range of from 1;

200 to 200;

1 wherein the stabilizing compound is a non-oxygen-containing six membered carbon ring compound;

(c) contacting the at least one dehydrogenatable hydrocarbon and the at least one stabilizing compound with a first dehydrogenation catalyst in the first dehydrogenation reaction zone under dehydrogenation conditions to convert at least a portion of the dehydrogenatable hydrocarbon into an unsaturated six-membered carbon ring compound and hydrogen;

(d) contacting benzene and hydrogen with a hydroalkylation catalyst under hydroalkylation conditions to produce a hydroalkylation reaction product stream comprising cyclohexylbenzene, cyclohexane, and benzene;

(e) oxidizing at least a portion of the cyclohexylbenzene from the hydroalkylation reaction product stream to produce cyclohexylbenzene hydroperoxide;

(f) cleaving at least a portion of the cyclohexylbenzene hydroperoxide from the oxidizing step (e) to produce a cleavage reaction product stream comprising phenol and cyclohexanone;

(g) employing at least a portion of the cleavage reaction product stream as the dehydrogenation feed stream in step (a);

(h) dividing at least a portion of the hydroalkylation reaction product stream into (i) a C₆ stream comprising cyclohexane and benzene; and

(ii) a cyclohexylbenzene stream; and

(i) supplying at least a portion of the C₆ stream to the first dehydrogenation reaction zone as the at least one stabilizing compound.

2. The process of claim 1, wherein the weight ratio of the stabilizing compound to the dehydrogenatable hydrocarbon supplied to the first dehydrogenation reaction zone is in the range of from 1:

100 to 10;

1.

3. The process of claim 1, wherein the weight ratio of the stabilizing compound to the dehydrogenatable hydrocarbon supplied to the first dehydrogenation reaction zone in the range of from 1:

200 to 1;

1.

4. The process of claim 1, wherein the at least one stabilizing compound is selected from cyclohexane, benzene and mixture thereof.

5. The process of claim 1, wherein the at least on stabilizing compound is cyclohexane.

6. The process of claim 1, wherein the at least one stabilizing compound is benzene.

7. The process of claim 1, wherein the at least one dehydrogenatable hydrocarbon is cyclohexanone and the unsaturated six-membered carbon ring compound is phenol.

8. The process of claim 1, wherein at least a portion of the cyclohexane in the C₆ stream is converted to benzene by the contacting step (c) and at least a portion of the benzene is recycled to the contacting step (d).

9. The process of claim 1, and further comprising supplying a further portion of the C₆ stream to a second dehydrogenation reaction zone and contacting the further portion of the C₆ stream with a second dehydrogenation catalyst in the second dehydrogenation reaction zone under dehydrogenation conditions to convert at least a portion of the cyclohexane into benzene and produce a second dehydrogenation product stream.

10. The process of claim 1, and further comprising recycling at least a portion of the second dehydrogenation product stream back to the contacting step (d).

11. The process of claim 1, wherein at least a portion of the cleavage reaction product stream is supplied without fractionation to the first dehydrogenation reaction zone as the dehydrogenation feed stream.

12. The process of claim 1, and further comprising distilling at least a portion of the cleavage reaction product stream into (i) a first fraction comprising an azeotropic mixture of phenol and cyclohexanone;

and (ii) a second cyclohexanone fraction.

13. The process of claim 12, wherein at least a portion of the first fraction is supplied to the first dehydrogenation reaction zone as the dehydrogenation feed stream.

14. The process of claim 12, wherein at least a portion of the second fraction is supplied to the first dehydrogenation reaction zone as the dehydrogenation feed stream.

15. The process of claim 1, wherein the hydroalkylation reaction product stream further comprises dicyclohexylbenzene and the dicyclohexylbenzene is converted to additional cyclohexylbenzene either by dealkylation or by transalkylation with benzene.