US3363017A - Xylene isomerization - Google Patents
Xylene isomerization Download PDFInfo
- Publication number
- US3363017A US3363017A US421709A US42170964A US3363017A US 3363017 A US3363017 A US 3363017A US 421709 A US421709 A US 421709A US 42170964 A US42170964 A US 42170964A US 3363017 A US3363017 A US 3363017A
- Authority
- US
- United States
- Prior art keywords
- xylene
- para
- isomerization
- xylenes
- ortho
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000008096 xylene Substances 0.000 title description 32
- 238000006317 isomerization reaction Methods 0.000 title description 24
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 title description 17
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 description 28
- 150000003738 xylenes Chemical class 0.000 description 17
- IVSZLXZYQVIEFR-UHFFFAOYSA-N m-xylene Chemical group CC1=CC=CC(C)=C1 IVSZLXZYQVIEFR-UHFFFAOYSA-N 0.000 description 14
- 238000000034 method Methods 0.000 description 13
- 239000003054 catalyst Substances 0.000 description 11
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 9
- 238000001640 fractional crystallisation Methods 0.000 description 5
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 description 4
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 4
- 238000007323 disproportionation reaction Methods 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 229910011255 B2O3 Inorganic materials 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- 239000003208 petroleum Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- 229920002994 synthetic fiber Polymers 0.000 description 2
- 101100492805 Caenorhabditis elegans atm-1 gene Proteins 0.000 description 1
- 229920004934 Dacron® Polymers 0.000 description 1
- 238000005727 Friedel-Crafts reaction Methods 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- LGRFSURHDFAFJT-UHFFFAOYSA-N Phthalic anhydride Natural products C1=CC=C2C(=O)OC(=O)C2=C1 LGRFSURHDFAFJT-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- JHIWVOJDXOSYLW-UHFFFAOYSA-N butyl 2,2-difluorocyclopropane-1-carboxylate Chemical compound CCCCOC(=O)C1CC1(F)F JHIWVOJDXOSYLW-UHFFFAOYSA-N 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- -1 e.g. Substances 0.000 description 1
- 238000005194 fractionation Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000004758 synthetic textile Substances 0.000 description 1
- 150000005199 trimethylbenzenes Chemical class 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
- C07C5/22—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by isomerisation
- C07C5/27—Rearrangement of carbon atoms in the hydrocarbon skeleton
- C07C5/2729—Changing the branching point of an open chain or the point of substitution on a ring
- C07C5/2732—Catalytic processes
- C07C5/2735—Catalytic processes with metal oxides
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S585/00—Chemistry of hydrocarbon compounds
- Y10S585/949—Miscellaneous considerations
- Y10S585/954—Exploiting mass-action phenomenon
Definitions
- This invention relates to an improved process for isomerizing xylenes so as to produce maximum yields of ortho and para isomers.
- Para-xylene has for some time been an article of commerce. Hitherto, para-xylene was obtained from petroleum and coal tar xylene fractions, normally consisting essentially of ortho-, meta-, and para-xylenes and ethyl benzene, the content of the para-xylene varying between 10 and percent. More recently, the development of synthetic fabrics such as Dacron has increased the demand for para-xylene to such an extent that the supply of naturally occurring xylenes is insufiicient. Thus, considerable interest has been focused upon the preferential conversion of other hydrocarbons to para-xylene.
- catalysts of that type have been the acid treated clays or synthetic materials composed largely of silica in combination with alumina, magnesia, zirconia, or boric oxide. Such catalysts are described, for example, in US. Patents 2,741,646 and 2,818,451. However, even when equilibrium isomerization is achieved the percentage of the para isomer is relatively low at the operating pressures heretofore usedi.e., below about 150 atmospheres.
- This invention is concerned with isomerizing a mixed xylenes stream to produce maximum yields of the ortho and para isomers.
- an object of the invention to provide an improved process for isomerizing xylenes principally to paraand ortho-xylenes. Another object is to provide an improved process for isomerizing a mixed xylenes stream comprising principally meta-xylene, to paraand ortho-xylenes. A further object is to provide an improved xylene isomerization process which maximizes yields of ortho and para isomers and reduces disproportionation.
- the invention comprises isomerizing a mixed xylenes Patented Jan. 9, 1968 stream in intimate contact with a xylene isomerization catalyst at a pressure greater than 1000 atmospheres and, preferably, greater than 3000 atmospheres. It has been found that the yield of the para isomer when operating at these high pressures is about twice that obtained at conventional operating pressures. The yield of the ortho isomer is also almost doubled, and disproportionation reactions leading to the formation of toluene and the trimethyl benzenes are greatly reduced. Disproportionation is further reduced or eliminated by inclusion of about 110 volume percent of toluene in the feed to the isomerization zone.
- Other operation conditions for the process of the invention include a temperature of 200 to 800 F., preferably 350 to 650 F., and liquid hourly space velocity of 0.3 to 10, preferably 0.5 to 6.
- a stream of mixed xylenes produced by naphtha hydroforming for example, and optionally containing ethylbenzene, is fed to a highpressure, liquid-phase isomerization zone, the effiuent is fed to a fractional crystallization zone for removal of para-xylene, and the balance of the material-together with make-up fresh mixed xylenes feedis returned to the isomerization zone.
- the isomerization zone is followed by a fractionation zone to remove the ortho-xylene as a kettle product, the fractional crystallization zone is used to separate the para-xylene, and the meta-Xylene together with make-up fresh mixed xylenes feedis returned to the isomerization zone.
- Ortho-xylene can be used in the production of phthalic anhydride by oxidation and is thus at times a very desirable product.
- Meta 58 53 12 15 18 30 27 29 58 It is evident that little change in isomer content is effected by increasing operating pressure from 1 to 670 atm., but that a considerable change is effected by a further increase in operating pressure to 5400 atm.
- the essential feature of the invention is the pressure at which the isomerization is conducted, i.e., greater than 1000 atmospheres and, preferably, greater than 3000 atmospheres.
- a process comprising catalytically isomerizing a feed of mixed xylenes predominantly to the para isomer which comprises intimately contacting said xylenes at a pressure of at least 1000 atmospheres and a temperature in the range of 200 to 800 F. with a xylene isomerization catalyst comprising silica in combination with at least one of the group: alumina, magnesia, zirconia, and boric oxide.
- a process for iso-merizing a feed stream of mixed xylenes comprising orthoand meta-Xylenes predominantly to para-xylene which comprises intimately contacting said feed in an isomerization zone with an isomerization catalyst effective in isomerizing xylenes comprising silicaalumina, at a pressure of at least 1000 atmospheres, a temperature in the range of 200 to 800 F., and a liquid hourly space velocity in the range of about 0.3 to 10, so as to isomerize said xylene feed predominantly to paraxylene.
- step (b) subjecting the overhead stream of step (a) to fractional crystallization to recover para-Xylene as the solid phase and metaexylene as the liquid phase;
- step (c) passing the recovered meta-Xylene of step (b) and additional feed stream to said isomerization zone.
- step (b) recycling the liquid phase of step (a) to said isomerization zone.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
United States Patent O 3,363,017 XYLENE ISOMERIZATION Harold J. Hepp and Marvin M. Johnson, Bartlesville,
Okla, assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Dec. 28, 1964, Ser. No. 421,709 7 Claims. (Cl. 260668) ABSTRACT OF THE DISCLOSURE Xylenes are isomerized to produce maximum yields of ortho and para isomers using conventional Xylene isomerization catalysts, particularly those comprising silicaalumina, and at pressures of at least 1000 atmospheres.
This invention relates to an improved process for isomerizing xylenes so as to produce maximum yields of ortho and para isomers.
Para-xylene has for some time been an article of commerce. Hitherto, para-xylene was obtained from petroleum and coal tar xylene fractions, normally consisting essentially of ortho-, meta-, and para-xylenes and ethyl benzene, the content of the para-xylene varying between 10 and percent. More recently, the development of synthetic fabrics such as Dacron has increased the demand for para-xylene to such an extent that the supply of naturally occurring xylenes is insufiicient. Thus, considerable interest has been focused upon the preferential conversion of other hydrocarbons to para-xylene.
It has been known that the isomeric forms of xylene, namely the ortho-xylene, meta-xylene and para-xylene, can be converted one into the other by isomerization. However, that isomerization has been difficult to accomplish and when the isomerization has been carried out under conditions such as would give a relatively selective and clean cut isomerization, the reaction has taken place at such a slow rate as to make it impractical for commercial operation. When the isomerization was carried out under relatively drastic conditions leading to appreciable degradation of the product, the para-xylene yields were low. The xylenes have been isomerized by purely thermal means and by treatment under certain conditions with Friedel-Crafts type catalyst, e.g., aluminum chloride plus hydrogen chloride, but the required conditions were severe and the yields were poor.
Further development of the isomerization of xylenes resulted in the use of clay type cracking catalysts. Preferred catalysts of that type have been the acid treated clays or synthetic materials composed largely of silica in combination with alumina, magnesia, zirconia, or boric oxide. Such catalysts are described, for example, in US. Patents 2,741,646 and 2,818,451. However, even when equilibrium isomerization is achieved the percentage of the para isomer is relatively low at the operating pressures heretofore usedi.e., below about 150 atmospheres.
This invention is concerned with isomerizing a mixed xylenes stream to produce maximum yields of the ortho and para isomers.
Accordingly, it is an object of the invention to provide an improved process for isomerizing xylenes principally to paraand ortho-xylenes. Another object is to provide an improved process for isomerizing a mixed xylenes stream comprising principally meta-xylene, to paraand ortho-xylenes. A further object is to provide an improved xylene isomerization process which maximizes yields of ortho and para isomers and reduces disproportionation. Other objects of the invention will become apparent to one skilled in the art upon consideration of the accompanying disclosure.
The invention comprises isomerizing a mixed xylenes Patented Jan. 9, 1968 stream in intimate contact with a xylene isomerization catalyst at a pressure greater than 1000 atmospheres and, preferably, greater than 3000 atmospheres. It has been found that the yield of the para isomer when operating at these high pressures is about twice that obtained at conventional operating pressures. The yield of the ortho isomer is also almost doubled, and disproportionation reactions leading to the formation of toluene and the trimethyl benzenes are greatly reduced. Disproportionation is further reduced or eliminated by inclusion of about 110 volume percent of toluene in the feed to the isomerization zone.
Other operation conditions for the process of the invention include a temperature of 200 to 800 F., preferably 350 to 650 F., and liquid hourly space velocity of 0.3 to 10, preferably 0.5 to 6.
In the process of the invention, a stream of mixed xylenes, produced by naphtha hydroforming for example, and optionally containing ethylbenzene, is fed to a highpressure, liquid-phase isomerization zone, the effiuent is fed to a fractional crystallization zone for removal of para-xylene, and the balance of the material-together with make-up fresh mixed xylenes feedis returned to the isomerization zone. Optionally, if the ortho isomer is also desired as product, the isomerization zone is followed by a fractionation zone to remove the ortho-xylene as a kettle product, the fractional crystallization zone is used to separate the para-xylene, and the meta-Xylene together with make-up fresh mixed xylenes feedis returned to the isomerization zone. Ortho-xylene can be used in the production of phthalic anhydride by oxidation and is thus at times a very desirable product.
Pressure, atm 1 670 5,400
Xylene isomers, mol percent:
Meta 58 53 12 15 18 30 27 29 58 It is evident that little change in isomer content is effected by increasing operating pressure from 1 to 670 atm., but that a considerable change is effected by a further increase in operating pressure to 5400 atm.
While silica-alumina is the preferred catalyst, other isomerization catalysts such as those disclosed in US. Patents 2,741,646 and 2,818,451 are within the scope of the invention. The essential feature of the invention is the pressure at which the isomerization is conducted, i.e., greater than 1000 atmospheres and, preferably, greater than 3000 atmospheres.
Certain modifications of the invention will become apparent to those skilled in the art and the illustrative details disclosed are not to be construed as imposing unnecessary limitations on the invention.
We claim:
1. A process comprising catalytically isomerizing a feed of mixed xylenes predominantly to the para isomer which comprises intimately contacting said xylenes at a pressure of at least 1000 atmospheres and a temperature in the range of 200 to 800 F. with a xylene isomerization catalyst comprising silica in combination with at least one of the group: alumina, magnesia, zirconia, and boric oxide.
2. The process of claim 1 wherein the catalyst consists principally of silica-alumiua.
3. The process of claim 1 wherein the pressure is at least 3000 atmospheres.
4. The process of claim 1 wherein toluene in the range of 1 to 10 volume percent of the feed is incorporated therein to further reduce disproportionation.
5. A process for iso-merizing a feed stream of mixed xylenes comprising orthoand meta-Xylenes predominantly to para-xylene which comprises intimately contacting said feed in an isomerization zone with an isomerization catalyst effective in isomerizing xylenes comprising silicaalumina, at a pressure of at least 1000 atmospheres, a temperature in the range of 200 to 800 F., and a liquid hourly space velocity in the range of about 0.3 to 10, so as to isomerize said xylene feed predominantly to paraxylene.
6. The process of claim 5 wherein said feed is predominantly meta-xylene and the isomerized stream consists principally of orthoand para-xylenes, and including the steps of:
(a) fractionally distilling said isomerized stream to recover an ortho-xylene-rich bottoms stream and an overhead stream rich in para-xylene and containing a substantial concentration of meta-xylene;
(b) subjecting the overhead stream of step (a) to fractional crystallization to recover para-Xylene as the solid phase and metaexylene as the liquid phase;
(c) and passing the recovered meta-Xylene of step (b) and additional feed stream to said isomerization zone.
7. The process of claim 5 wherein said feed is predominantly meta-xylene and the isomerized stream consists principally of orthoand para-xylenes, and including the steps of:
(a) passing the isomerized stream into a fractional crystallization zone and subjecting same to fractional crystallization to recover para-xylene as a solid phase and metaand ortho-xylenes as a liquid phase; and
(b) recycling the liquid phase of step (a) to said isomerization zone.
References Cited UNITED STATES PATENTS 20 2,564,388 8/1951 Bennett et al. 260668 2,656,397 10/1953 Holzman et al. 260-668 2,775,628 12/1956 Nicholson Ct 211. 260-668 DELBERT E. GANTZ, Primary Examiner.
C. R. DAVIS, Assistant Examiner.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US421709A US3363017A (en) | 1964-12-28 | 1964-12-28 | Xylene isomerization |
| BE674353D BE674353A (en) | 1964-12-28 | 1965-12-27 | |
| NL6517020A NL6517020A (en) | 1964-12-28 | 1965-12-28 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US421709A US3363017A (en) | 1964-12-28 | 1964-12-28 | Xylene isomerization |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3363017A true US3363017A (en) | 1968-01-09 |
Family
ID=23671706
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US421709A Expired - Lifetime US3363017A (en) | 1964-12-28 | 1964-12-28 | Xylene isomerization |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US3363017A (en) |
| BE (1) | BE674353A (en) |
| NL (1) | NL6517020A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2564388A (en) * | 1950-01-09 | 1951-08-14 | Shell Dev | Isomerization of xylenes |
| US2656397A (en) * | 1952-03-08 | 1953-10-20 | Shell Dev | Isomerization and separation of xylenes |
| US2775628A (en) * | 1954-06-10 | 1956-12-25 | Exxon Research Engineering Co | Isomerization of xylenes |
-
1964
- 1964-12-28 US US421709A patent/US3363017A/en not_active Expired - Lifetime
-
1965
- 1965-12-27 BE BE674353D patent/BE674353A/xx unknown
- 1965-12-28 NL NL6517020A patent/NL6517020A/xx unknown
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2564388A (en) * | 1950-01-09 | 1951-08-14 | Shell Dev | Isomerization of xylenes |
| US2656397A (en) * | 1952-03-08 | 1953-10-20 | Shell Dev | Isomerization and separation of xylenes |
| US2775628A (en) * | 1954-06-10 | 1956-12-25 | Exxon Research Engineering Co | Isomerization of xylenes |
Also Published As
| Publication number | Publication date |
|---|---|
| BE674353A (en) | 1966-06-27 |
| NL6517020A (en) | 1966-06-29 |
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