Exxonmobil Chemical Patents Inc.

Exxonmobil Research and Engineering Company

Catherine M Dorsi

Michael P Lanci

Changyub Paek

Gaurav Agrawal

Dana Lynn Pilliod

Michael W Weber

Todd E Detjen

Scott Jeffrey Weigel

Tan-Jen Chen

John Roger Porter

Michael Salciccioli

Mayank Shekhar

Javier Guzman

Seth McConkie Washburn

Monica D Lotz

Anthony Go

Hsu Chiang

Constantinos P Bokis

John S Kennedy

This disclosure provides an improved process for converting benzene/toluene via methylation with methanol/dimethyl ether for producing, e.g., p-xylene, comprising separating and recycling dimethyl ether from the methylation reaction product mixture effluent to the methylation reactor. High selectivity toward p-xylene, among others, can be achieved.

Processes and systems for converting benzene and/or toluene via methylation

Systems and methods are provided for integration of an aromatic formation process for converting non-aromatic hydrocarbon to an aromatic product and subsequent methylating of a portion of the aromatic product to produce a methylated product, with improvements in the aromatic formation process and/or the methylation process based on integrating portions of the secondary processing trains associated with the aromatic formation process and the methylation process. The aromatic formation process and methylation process can be used, for example, for integrated production of specialty aromatics or gasoline blending components.

Integrated aromatics formation and methylation

Processes are described for separating 3,4'- and 4,4&#x2032;-dimethylbiphenyl from a mixture comprising at least 3,3&#x2032;-, 3,4&#x2032;- and 4,4&#x2032;-dimethylbiphenyl. In the processes, the mixture is cooled to produce a crystallization product comprising at least of the 4,4&#x2032;-dimethylbiphenyl from the feed mixture and a first mother liquor product. The first mother liquor product is distilled to produce a bottoms stream enriched in 4,4&#x2032;-dimethylbiphenyl as compared with the first mother liquor product and an overhead stream deficient in 4,4&#x2032;-dimethylbiphenyl as compared with the first mother liquor product. The overhead stream is then cooled to produce a second crystallization product comprising at least part of the 3,4&#x2032;-dimethylbiphenyl from the overhead stream and a second mother liquor product.

Production and use of 3,4' and 4,4&#x2032;-dimethylbiphenyl isomers

In a process for separating dimethyl biphenyl isomers a mixture comprising one or more 3,3', 3,4&#x2032;- or 4,4&#x2032;-dimethyl biphenyl isomers, one or more 2,X&#x2032;-dimethyl biphenyl isomers (where X=2, 3, or 4) and one or more further hydrocarbon components is contacted with a first adsorbent, thereby selectively adsorbing one or more of the dimethyl biphenyl isomers within the first adsorbent. A first raffinate stream containing less selectively adsorbed components is withdrawn from the first adsorbent and a first extract stream containing selectively adsorbed dimethyl biphenyl isomers is withdraw. The selectively adsorbed dimethyl biphenyl isomers comprise one or more of 3,3&#x2032;-, 3,4&#x2032;- or 4,4&#x2032;-dimethyl biphenyl isomers and one or more of 2,X&#x2032;-dimethyl biphenyl isomers (where X&#x2032;=2, 3, or 4).

Production and separation of dimethyl biphenyl isomers

In a process for producing one or more 2,X'-dimethyl biphenyl isomers (where X=2, 3 or 4), a feed comprising toluene is contacted with hydrogen in the presence of a hydroalkylation catalyst under conditions effective to produce a hydroalkylation reaction product comprising (methylcyclohexyl)toluene. At least part of the hydroalkylation reaction product is dehydrogenated in the presence of a dehydrogenation catalyst under conditions effective to produce a dehydrogenation reaction product comprising dimethyl biphenyl isomers. The dehydrogenation reaction product is then separated into at least a first stream comprising one or more 3,3&#x2032;-, 3,4&#x2032;- and 4,4&#x2032;-dimethyl biphenyl isomers and at least one second stream comprising one or more 2,X&#x2032;-dimethyl biphenyl isomers (where X=2, 3 or 4). The at least one second stream is then contacted with a first adsorbent thereby selectively adsorbing one or more 2,X&#x2032;-dimethyl biphenyl isomers (where X=2, 3 or 4) within said first adsorbent and then withdrawing from said first adsorbent a first extract stream comprising one or more selectively adsorbed 2,X&#x2032;-dimethyl biphenyl isomers (where X=2, 3 or 4) and a first raffinate stream comprising one or more less selectively adsorbed components.

Methods and related systems are disclosed for condensing a minor portion of an effluent stream from an alkylation reactor by contacting the effluent stream with a first liquid hydrocarbon quench stream and a second liquid hydrocarbon quench stream. The effluent stream includes catalyst fines from the reactor, and at least a portion of the catalyst fines are carried with the condensed minor portion of the effluent stream.

Systems and methods for aromatic alkylation

Disclosed is a process for recovering paraxylene in which a first simulated moving bed adsorption unit is used to produce two extract streams&#x2014;one rich in paraxylene and a paraxylene-rich extract stream that is lean in ethylbenzene and an ethylbenzene-rich extract stream that is lean in paraxylene- and a paraxylene-depleted raffinate stream. A significant amount of the ethylbenzene is removed in the ethylbenzene-rich extract stream (at least enough to limit buildup in the isomerization loop), so the paraxylene-depleted raffinate stream may be isomerized in the liquid phase. Avoiding vapor phase isomerization saves energy and capital, as liquid phase isomerization requires less energy and capital than the vapor phase isomerization process due to the requirement of vaporizing the paraxylene-depleted stream and the use of hydrogen, which requires an energy and capital intensive hydrogen recycle loop.

Processes for recovering paraxylene

Disclosed herein are processes for recovering paraxylene in which a first simulated moving bed adsorption unit is used to produce a paraxylene-rich extract stream that also contains a significant amount of the ethylbenzene and a paraxylene-depleted raffinate stream. Because a significant amount of the ethylbenzene is removed in the paraxylene-rich extract stream (at least enough to limit buildup in the isomerization loop), the paraxylene-depleted raffinate stream may be isomerized in the liquid phase. Avoiding vapor phase isomerization saves energy and capital, as liquid phase isomerization requires less energy and capital than the vapor phase isomerization process due to the requirement of vaporizing the paraxylene-depleted stream and the use of hydrogen, which requires an energy- and capital-intensive hydrogen recycle loop.

Process for the recovering of paraxylene

In a process for producing one or more 3,3'-, 3,4&#x2032;- and 4,4&#x2032;-dimethyl biphenyl isomers, a feed comprising toluene is contacted with hydrogen in the presence of a hydroalkylation catalyst under conditions effective to produce a hydroalkylation reaction product comprising (methylcyclohexyl)toluenes. At least part of the hydroalkylation reaction product is dehydrogenated in the presence of a dehydrogenation catalyst under conditions effective to produce a dehydrogenation reaction product comprising a mixture of dimethyl biphenyl isomers. The dehydrogenation reaction product is then separated into at least a first stream containing one or more 3,3&#x2032;-, 3,4&#x2032;- and 4,4&#x2032;-dimethyl biphenyl isomers and at least one second stream comprising one or more 2,X&#x2032;-dimethyl biphenyl isomers (where X is 2, 3, or 4). The 3,3&#x2032;-, 3,4&#x2032;- and 4,4&#x2032;-dimethyl biphenyl isomers are then separated utilizing selective adsorption.

Growing community of inventors

Houston, TX, United States of America

Catherine M Dorsi