# US 2006/0149105 A1 · Low space-velocity transalkylation process for ethylbenzene

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- Number: US 2006/0149105 A1
- Document ID: US20060149105A1
- Status: Published application
- Kind: A1
- Application number: 10/461,076
- Filed: 2003-06-13
- Published: 2006-07-06
- Earliest claimed: 2003-06-13
- Inventors: Mark Krawczyk
- Web page: https://patentgrep.com/patent/US20060149105A1

## CPC

- C07C 6/126: {of more than one hydrocarbon}
- C07C 2529/08: of the faujasite type, e.g. type X or Y
- C07C 2529/18: of the mordenite type
- C07C 2529/70: of types characterised by their specific structure not provided for in groups C07C2529/08 - C07C2529/65
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

The use of a low space-velocity reactor containing transalkylation catalysts to react heavy aromatic compounds of carbon number nine (and heavier carbon numbers) with benzene to form carbon number eight aromatics is disclosed. Conditions of low space-velocity promote approach to equilibrium at temperatures favoring carbon number eight aromatics. The catalyst system preserves ethyl-group species on the heavier aromatics that would otherwise be de-ethylated over most gas-phase transalkylation catalysts to form undesired ethane gas with benzene or toluene. The catalyst system also promotes methyl-group species transalkylation at selected conditions. Thus, by using a transalkylation step to save ethylbenzene, a greater yield of para-xylene or other carbon number eight aromatics may be achieved within an integrated aromatics complex.

## Claims

### Claim 1

A process for transalkylation of a benzene stream with C9+ alkylaromatics comprising contacting the stream within a low space-velocity reactor containing a transalkylation catalyst under at least partial liquid-phase transalkylation conditions to produce a product stream comprising ethylbenzene and at least 1 wt-% xylenes, the transalkylation conditions comprising a molar ratio of benzene to C9+ alkylaromatics from about 0.1 to about 10, a temperature less than about 300° C. and a space-velocity ranging from about 0.1 to about 0.3 hr−1 and wherein the C9+ alkylaromatics contain at least one component selected from the group consisting of alkylaromatic hydrocarbons of the formula C6H(6-n)Rn, where n is an integer from 1 to 5 and each R is independently selected from the group consisting of CH3, C3H7, and C4H9.

### Claim 2 (depends on 1)

The process of claim 1 wherein the transalkylation catalyst comprises a zeolitic aluminosilicate component selected from the group consisting of MTW, MFI, type Y, beta, and mordenite.

### Claim 3 (depends on 2)

The process of claim 2 wherein the component is type Y or beta.

### Claim 4

(canceled)

### Claim 5 (depends on 1)

The process of claim 1 wherein the molar ratio of benzene to C9+ alkylaromatics is less than about 6.0.

### Claim 6 (depends on 5)

The process of claim 5 wherein the molar ratio is less than about 3.0.

### Claim 7 (depends on 1)

The process of claim 1 wherein the temperature is less than about 250° C.

### Claim 8 (depends on 7)

The process of claim 7 wherein the reactor produces greater than 4 wt-% xylenes on a net effluent basis with benzene normalized out.

### Claim 9 (depends on 8)

The process of claim 8 where in the reactor produces greater than 6 wt-% xylenes on a net effluent basis with benzene normalized out.

### Claim 10 (depends on 1)

The process of claim 1 wherein the transalkylation conditions are liquid-phase and hydrogen is substantially absent.

### Claim 11

A process for conversion of aromatic hydrocarbons into para-xylene using a low space-velocity reactor integrated into an aromatics complex comprising:
a) providing a stream containing benzene and C9+ alkylaromatics, wherein the molar ratio of benzene to C9+ alkylaromatic is from about 0.1 to about 10 and wherein the C9+ alkylaromatics contain at least one component selected from the group consisting of alkylaromatic hydrocarbons of the formula C6H(6-n)Rn, where n is an integer from 1 to 5 and each R is independently selected from the group consisting of CH3, C3H7, and C4H9;
b) passing the stream of step (a) to an at least partial liquid-phase transalkylation unit, wherein the stream is contacted under transalkylation conditions including a space velocity from about 0.1 to about 0.3 hr−1, within a low space-velocity reactor containing transalkylation catalyst comprising a zeolitic aluminosilicate component selected from the group consisting of MTW, MFI, type Y, beta, and mordenite, and an inorganic oxide binder component, to produce a transalkylation product stream comprising ethylbenzene and at least 4 wt-% xylene calculated on a net effluent basis;
c) separating the product streams of step (b) in a fractionation zone comprising at least one column to produce a fractionated-benzene stream, and a xylene-plus stream;
d) separating the xylene-plus stream in a xylene column to produce a xylene enriched stream and a C9+ alkylaromatic-enriched stream;
e) passing the xylene enriched stream to a para-xylene production unit, wherein para-xylene is recovered as a product.

### Claim 12 (depends on 11)

The process of claim 11 wherein at least part of the fractionated-benzene stream is recycled back to the benzene stream of step (a).

### Claim 13 (depends on 11)

The process of claim 11 wherein at least part the C9+ alkylaromatic-enriched stream is recycled back to the C9+ alkylaromatic stream of step (a).

### Claim 14 (depends on 11)

The process of claim 11 wherein the molar ratio of benzene to C9+ alkylaromatics is less than about 6.0.

### Claim 15 (depends on 14)

The process of claim 14 wherein the molar ratio is less than about 3.0.

### Claim 16

(canceled)

### Claim 17 (depends on 16)

The process of claim 16 where in the reactor produces greater than 6 wt-% xylenes on a net effluent basis with benzene normalized out.

### Claim 18

A process for transalkylation of a benzene stream with C9+ alkylaromatics comprising contacting the stream within a low space-velocity reactor containing a transalkylation catalyst comprising a zeolitic aluminosilicate component selected from the group consisting of MTW, MFI, type Y, beta, and mordenite under at least partial liquid-phase transalkylation conditions to produce a product stream comprising ethylbenzene and at least 1 wt-% xylenes, the transalkylation conditions comprising a molar ratio of benzene to C9+ alkylaromatics from about 0.1 to about 6 a space velocity from about 0.1 to about 0.3 hr−1, and a temperature less than about 300° C.; wherein the C9+ alkylaromatics contain at least one component selected from the group consisting of alkylaromatic hydrocarbons of the formula C6H6-n)Rn, where n is an integer from 1 to 5 and each R is independently selected from the group consisting of CH3, C3H7, and C4H9.

### Claim 19 (depends on 18)

The process of claim 18 wherein the reactor produces greater than 4 wt-% xylenes on a net effluent basis with benzene normalized out.

### Claim 20 (depends on 19)

The process of claim 19 where in the reactor produces greater than 6 wt-% xylenes on a net effluent basis with benzene normalized out.