Process for converting syngas to aromatics and catalyst system suitable therefor

Patent metadata

Field	Value
Publication number	US-10196325-B2
Application number	US-201514965099-A
Country	US
Kind code	B2
Filing date	Dec 10, 2015
Priority date	Jan 15, 2015
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

The present invention relates to a multistage process and catalyst system therefor to convert syngas to aromatics. In a first stage, syngas is converted to a C 1 -C 4 alcohol mixture by contacting syngas with a first catalyst comprising rhodium or copper at moderate temperature. In a second stage, the C 1 -C 4 alcohol mixture is converted into an aromatic product by contact with a second catalyst comprising a molecular sieve and at least one Group 8-14 element, the molecular sieve having a Constraint Index about 1 to 12 and a silica to alumina ratio of about 10 to 100 at effective conversion conditions. The final aromatic product is rich in benzene, toluene, and xylenes (e.g. greater than 50% aromatics on a hydrocarbon basis).

First claim

What is claimed is:

1. A multistage process for converting syngas to aromatics comprising:
(a) contacting syngas in a first reactor with a first catalyst comprising rhodium or copper to produce a C1-C4 alcohol mixture at a gas hourly space velocity (GHSV) of at least 500 hr 1 , wherein the GHSV is the liters of syngas per hour flowing through the first reactor divided by the liters of the first catalyst within the first reactor; and
(b) contacting said C1-C4 alcohol mixture in a second reactor with a second catalyst comprising a molecular sieve to produce an aromatic product, wherein said molecular sieve is a ZSM-5 zeolite having a silica to alumina ratio of about 10 to 100, and wherein the second catalyst comprises said ZSM-5 zeolite physically mixed with gallium and zinc substantially in the form of mixed oxides thereof.

2. The process of claim 1 , wherein the reaction of syngas with the first catalyst in step (a) to produce said C 1 -C 4 alcohol mixture has a yield of at least 50%.

3. The process of claim 1 , wherein said C 1 -C 4 alcohol mixture contains at least 10% by weight of a methanol, ethanol and propanol mixture.

4. The process of claim 3 , wherein said methanol, ethanol and propanol mixture contains at least 50% by weight of ethanol and propanol.

5. The process of claim 1 , wherein said syngas has a volume ratio of hydrogen to carbon monoxide of 20:1 to 0.1:1.

6. The process of claim 1 , wherein said first catalyst comprises Rh—Mn/SiO 2 .

7. The process of claim 1 , wherein step (a) is carried out at a reaction temperature of 260 to 300° C.

8. The process of claim 1 , wherein said aromatic product contains at least 50% by weight of a benzene, toluene and xylene mixture on a hydrocarbon basis.

9. The process of claim 8 , wherein said benzene, toluene and xylene mixture contains at least 20% by weight of xylenes on a hydrocarbon basis.

10. The process of claim 1 , wherein step (b) is carried out at a reaction temperature of 350 to 450° C.

11. The process of claim 1 , wherein step (b) is carried out at a reaction pressure of 0.1 to 2.8 MPaa.

12. The process of claim 1 , wherein step (b) is carried out at a weight hourly space velocity of 0.1 to 20.

13. The process of claim 1 , further comprising separating at least a portion of said aromatic product to form a C 8 product stream and at least one of a C 7− stream and a C 9+ stream.

14. The process of claim 1 , wherein the first catalyst comprises Rhodium (Rh), Manganese (Mn), Iron (Fe), M 1 , and M 2 , wherein M 1 comprises one or both of Lithium (Li) and Sodium (Na), and wherein M 2 comprises one or both of Ruthenium (Ru) and Iridium (Ir).

15. The process of claim 14 , wherein the first catalyst comprises 0.1 to 3 wt. % Rh, and wherein:
the weight ratio of Mn/Rh in the first catalyst is 0.5-12;
the weight ratio of Fe/Rh in the first catalyst is 0.01-0.5;
the weight ratio of M 1 /Rh in the first catalyst is 0.04-0.2; and
the weight ratio of M 2 /Rh in the first catalyst is 0.1-1.0.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Soultanidis Nikolaos
• Shekhar Mayank
• Coleman John S

Classifications

• C07C15/04

  Benzene · CPC title

• B01J29/405

  containing rare earth elements, titanium, zirconium, hafnium, zinc, cadmium, mercury, gallium, indium, thallium, tin or lead · CPC title

• C07C1/20 Primary

  starting from organic compounds containing only oxygen atoms as heteroatoms · CPC title

• C07C15/08

  Xylenes · CPC title

• C07C15/06

  Toluene · CPC title