US3856871A - Xylene isomerization - Google Patents

Xylene isomerization Download PDF

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Publication number
US3856871A
US3856871A US00397038A US39703873A US3856871A US 3856871 A US3856871 A US 3856871A US 00397038 A US00397038 A US 00397038A US 39703873 A US39703873 A US 39703873A US 3856871 A US3856871 A US 3856871A
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Prior art keywords
xylene
ethyl benzene
xylenes
zsm
catalyst
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US00397038A
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English (en)
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W Haag
D Olson
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ExxonMobil Oil Corp
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Mobil Oil Corp
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Publication date
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Priority to US00397038A priority Critical patent/US3856871A/en
Priority to CA200,640A priority patent/CA1026384A/en
Priority to IN1261/CAL/74A priority patent/IN142292B/en
Priority to ZA00743917A priority patent/ZA743917B/xx
Priority to FR7421256A priority patent/FR2243919B1/fr
Priority to JP6972974A priority patent/JPS5341657B2/ja
Priority to ES428167A priority patent/ES428167A1/es
Priority to GB3166374A priority patent/GB1444702A/en
Priority to SU742049507A priority patent/SU890971A3/ru
Priority to RO7479759A priority patent/RO71348A/ro
Priority to DE2441516A priority patent/DE2441516C3/de
Priority to NLAANVRAGE7412093,A priority patent/NL173846C/xx
Priority to BE148467A priority patent/BE819848A/xx
Priority to CS746283A priority patent/CS189668B2/cs
Priority to IT27243/74A priority patent/IT1021337B/it
Priority to DD74181056A priority patent/DD113741B3/de
Priority to PL1974174095A priority patent/PL94144B1/pl
Priority to AR255604A priority patent/AR224491A1/es
Application granted granted Critical
Publication of US3856871A publication Critical patent/US3856871A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B01J29/7034—MTW-type, e.g. ZSM-12, NU-13, TPZ-12 or Theta-3
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • 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
    • C07C5/2702—Catalytic processes not covered by C07C5/2732 - C07C5/31; Catalytic processes covered by both C07C5/2732 and C07C5/277 simultaneously
    • C07C5/2708—Catalytic processes not covered by C07C5/2732 - C07C5/31; Catalytic processes covered by both C07C5/2732 and C07C5/277 simultaneously with crystalline alumino-silicates, e.g. molecular sieves
    • 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
    • C07C5/2737—Catalytic processes with crystalline alumino-silicates, e.g. molecular sieves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/10—After treatment, characterised by the effect to be obtained
    • B01J2229/26—After treatment, characterised by the effect to be obtained to stabilize the total catalyst structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/30—After treatment, characterised by the means used
    • B01J2229/42—Addition of matrix or binder particles
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

  • Distillation provides a fraction consisting essentially of C aromatics.
  • o-xylene is separable from other Cg aromatics by fractional distillation
  • p-xylene is separable by fractional crystallization.
  • Present demand is largely for p-xylene and it has become desirable to convert m-xylene, the principal xylene present in the feed stream, to the more desired p-xylene.
  • Isomerization of xylenes can be accomplished by the action of any one of a number of known catalysts. It is therefore possible to treat C aromatic fractions in a loop including means to separate desired xylene or xylenes and subject the residue to isomerization with recycle of isomerizate in admixture-with fresh charge. Unless the ethyl benzene be separated from the mixture, it will build up in the loop, reducing capacity of the equipment. Because its boiling point is very close to that of some of the xylenes, separation by distillation is extremely expensive.
  • p-xylene is derived from mixtures of C aromatics separated from such raw materials as petroleum naphthas, particularly reformates, usually by selective solvent extraction.
  • the C aromatics in such mixtures and their properties are:
  • Ethyl benzene may be separated by fractional distillation although this is a costly operation.
  • Ortho xylene may be separated by fractional distillation and is so produced commercially. Para xylene is separated from the mixed isomers by fractional crystallization.
  • Octafining process operates in conjunction with the product xylene or xylenes separation processes.
  • a virgin C aromatics mixture is fed to such a processing combination in'which the residual isomers emerging from the product separation steps are then charged to the isomerizer unit and the effluent isomerizate C aromatics are recycled to the product separation steps.
  • the composition of isomerizer feed is then a function of the virgin Cg aromatic feed, the product separation unit performance, and the isomerizer performance.
  • the isomerizer unit itself is most simply described as a single reactor catalytic reformer. As in reforming, the catalyst contains a small amount of platinum and the reaction is carried out in a hydrogen atmosphere.
  • Octafiner unit designs recommended by licensors of Octafining usually lie within these specification ranges:
  • Octafining can accept a charge stream which contains that component. Normally, a portion of the ethyl benzene is removed by fractional distillation before the charge is processed. If no attempt is made to reduce ethyl benzene below a few percent by weight, this can be accomplished relatively inexpensively and the ethyl benzene recovered is in usable form as a relatively pure chemical, e.g., for dehydrogenation to styrene.
  • the Octafiner is in a loop which includes means for separation of desired xylenes; p-xylene by crystallization and, possible, o-xylene by distillation.
  • the C stream stripped of desired xylenes returns to the Octafiner where more of the desired xylenes are generated, for example by isomerization of m-xylene. It will be apparent that ethyl benzene will tend to build up in the loop as other components are removed.
  • the Octafining catalyst has capability for converting ethyl benzene, thus counteracting that tendency.
  • the Octafining catalyst has the disadvantage that it is a hydrocracking catalyst due to the acid function of its silica/alumina base and its content of hydrogenation/dehydrogenation metal of the platinum group. In addition to converting ethyl benzene, this catalyst also causes net loss of xylenes.
  • Zeolite ZSM-l2 is described in German Offenlegungsschrift 2213109. The activity of these catalysts for the stated purpose and ofZSM-2l is described and claimed in copending application of R. A. Morrison, Ser. No. 397,039, filed Sept. 13, 1973, the disclosure of which is hereby incorporated by reference.
  • Octafining catalyst and the zeolite catalysts referred to above behave in about the same manner, except for their aging characteristics; decline of activity with time on stream.
  • a typical charge to the isomerizing reactor (effluent of crystallizer for separation of p-xylene) may contain 17 wt.% ethyl benzene, 65 wt.% m-xylene, 11 wt.% pxylene and 7 wt.% o-xylene
  • the thermodynamic equilibrium varies slightly with temperature in a system in which o-xylene is separated in the loop by fractional distillation prior to the crystallizer.
  • the objective in the isomerization reactor is to bring the charge as near to theoretical equilibrium concentrations as may be feasible consistent with reaction times which do not give extensive cracking and disproportionation.
  • ethyl benzene reacts through ethyl cyclohexane to dimethyl cyclohexanes which in turn equilibrate to xylenes. Competing reactions are disproportionation of ethyl benzene to benzene and diethyl benzene, hydrocracking of ethyl benzene to ethane and benzene and hydrocracking of the alkyl cyclohexanes.
  • the rate of ethyl benzene approach to equilibrium concentration in a C aromatic mixture is related to effective contact time.
  • Hydrogen partial pressure has a very significant effect onethyl benzene approach to equilibrium,
  • Temperature change within the range of Octafining conditions (830 to 900F.) has but a very small effect on ethyl benzene approach to equilibrium.
  • Concurrent loss of ethyl benzene to other molecular weight products relates to approach to equilibrium.
  • Products formed from ethyl benzene include C naphthenes, benzene from cracking, benzene and C aromatics from disproportionation, and total loss to other than C molecular weight.
  • C and lighter hydrocarbon by-products are also formed.
  • Loss of xylenes to other molecular weight products varies with contact time.
  • By-products include naphthenes, toluene, C aromatics and C and lighter hydrocracking products.
  • Ethyl benzene has been found responsible for a relatively rapid decline in catalyst activity of Octafining catalyst and this effect is proportional to its concentration in a C aromatic feed mixture. It has been possible then to relate catalyst stability (or loss in activity) to feed composition (ethyl benzene content and hydrogen recycle ratio) so that for any C aromatic feed, desired xylene products can be made with a selected suitably long catalyst use cycle.
  • LTI Low Temperature lsomerization
  • LTl has one disadvantage. It leaves ethyl benzene unchanged.
  • catalysts which are the acid forms of zeolite ZSM-S type, zeolite ZSM-l2 or zeolite ZSM-Zl provide C aromatic isomerization catalysts which not only are very active and selective for shifting methyl groups on xylenes, but also convert ethyl benzene in a manner not previously described as effective for feeds of this type.
  • the process is conducted in liquid phase at the upper part of the ranges described in the cited patents for practice of LTI. At these conditions, the catalyst of this invention induce extensive disproportionation of ethyl benzene with little disproportionation of xylenes.
  • a mixture of C aromatics is supplied to the system by line I, as from solvent extraction of a narrow cut taken by distillation of product of reforming a petroleum naphtha over platinum on alumina catalyst in the presence of hydrogen.
  • the feed passes to distillation in ethyl benzene tower 2, from which a portion of the ethyl benzene content is taken overhead by line 3. It is impracticably expensive to attempt removal of substantially all of the ethyl benzene by tower 2.
  • the amount removed as essentially pure ethyl benzene, suitable for charge to such operations as dehydrogenation to styrene, will depend on exact nature of the charge and demand for different products.
  • the ethyl benzene tower 2 can be omitted with further reduction in investment and operating costs.
  • Bottoms from tower 2 are constituted by the xylenes present in the charge and a reduced content of ethyl benzene.
  • This mixture passes by line 4i and is blended with recycle xylenes, derived in a manner presently to be described, from line 5.
  • the blended stream is admitted to splitter tower 6 from which a heavy end is withdrawn by line 7.
  • that heavy end ' is constituted by C aromatics derived from disproportion of ethyl benzene and from the minor side reaction of transalkylation of xylenes in the isomerizer.
  • splitter tower 6 may be operated to include o-xylene in the bottoms which are then passed to distillation for separation of o-xylene from (3 aromatics (not shown).
  • the overhead of splitter tower 6 passes by line 8 to means for separation of p-xylene.
  • p-xylene is separated by fractional crystallization in crystallizer 9, involving chilling and filtration of p-xylene crystals from the liquid phase, for example. in the manner described by Machell et al. U.S. Pat. No. 3,622,0l3, dated May 9, 1972. It will be understood that other systems for p-xylene separation may be used in a plant for practice of this invention, e.g., selective sorption as described in Cattanach US. Pat. No. 3,699,182 dated Oct. 17, 1972. By whatever means separated, high purity p-xylene is withdrawn as product by line It).
  • the stream of C aromatics of reduced p-xylene content is withdrawn from crystallizer 9 by line 11, passed through heater l2 and admitted to catalytic isomerizer 13 where it is contacted at reaction conditions with the acid form of ZSM-5 type zeolite or zeolite Z SM-l2 or zeolite ZSM-2l.
  • the principal reaction in isomerizer I3 is shifting of methyl groups in xylene molecules toward the equilibruim concentrations of the three xylens.
  • the isomerizate produced in isomerizer 13 is transferred by line 14 through heat exchanger 15 to stripper 16.
  • the light ends of the isomerizate (benzene, toluene and normally gaseous hydrocarbons) are taken overhead byline 117 from stripper l6 and the balance passes by line 5 to be blended with fresh feed and recycled in the process.
  • the catalyst is prepared by converting the zeolite to ,acid form" by calcination which converts tetraalkylammonium cations characteristic of these zeolites to protons by decomposition of the substituted ammonium cations. Additional protons and various metal cations may be substituted for the sodium cations present in the zeolites as formed by base exchange in conventional manner. It is csential to success in the present process that the zeolite catalyst be at least partially in the acid form, that is, that at least a portion of the cation positions be occupied by protons. Metal cations of various types may occupy the other sites if desired.
  • the zeolite crystals are preferably embedded in a bonding material to provide pellets of desired size and resistance to attrition.
  • a suitable binder is alumina. In 1 order to provide a preponderance of the active zeolite, the binder is a minor constituent of the composite.
  • a particularly preferred catalyst is constituted by pellets of 35 wt.% alumina and wt.% of the acid form of type ZSM-5 zeolite ZSM-l2 or zeolite ZSM-Zl.
  • the isomerization process of this invention is operated in the liquid phase at temperatures of 500F. to 660F. under pressure sufficient to liquefy the charge.
  • pressure does not seem to be a critical parameter and will be dictated in the usual case by economic and engineering considerations. Excessively high pressures, above about 1000 p.s.i.g. will be generally undesirable.
  • Space velocities will vary in the range of 0.5 to volumes of charge per volume of catalyst per hour (liquid hourly space velocity, LHSV).
  • temperature and LHSV will be coordinated to provide a desired severity which will provide an adequate degree of xylene isomerization and ethyl benzene conversion without excessive losses to by-products.
  • temperatures in the lower part ofthe temperature range will normally call for low space velocities.
  • the process of the invention is essentially an improvement on the low temperature process (LTI) which itself has several advantages over Octafining: e.g.
  • Ethyl benzene is not converted and is essentially an inert diluent. With feeds containing ethyl benzene, means have to be provided for its removal, otherwise it would build up in the recycle stream. For example, ethyl benzene is removed by distillation in a special ethyl benzene column.
  • the proposal is based on the surprising finding that with ZSM-S type, with ZSM-l2 and with ZSM-2l as catalysts, disproportionation and transalkylation occur very selectively to convert ethyl benzene relative to xylenes.
  • transalkylation i.e. transfer of alkyl groups between aromatic hydrocarbons can be used to include disproportionation (transalkylation between like molecules).
  • the severity of the process conditions should be optimally chosen such that sufficient ethyl benzene is converted to prevent its buildup in the recycle stream (see FIGURE 1 attached). This optimum amount of conversion depends on the feed composition, on the particular method to remove p-xylene (e.g. crystallization or extraction via sorption) and whether o-xylene is also recovered for sales. In general, the following equation describes the degree of ethyl benzene conversion:
  • the necessary degree of ethyl benzene conversion is controlled by the severity of the process conditions, in particular by temperature and space velocity that can be traded off within relatively wide limits. Typical conditions are 500660F., suffient pressure to establish liquid phase conditions, i.e., -520 p.s.i.g. respectively, or higher, a LHSV 0.5-10, preferably 1-5, catalysts are HZSM-S type, HZSM-l2 and HZSM-Zl.
  • the ratio of ethyl benzene to xylene (R) in the recycle stream can be the same as that in the fresh feed. However, it has been found that the small loss of xylenes due to transalkylation can be further minimized and a higher ultimate yield of p-xylene can be obtained 0 by having a higher ratio R in the recycle stream than in the fresh feed. This can be achieved during plant startup by adding some ethyl benzene to the feed for an initial period of several hours; alternatively, start-up conditions of lower severity can be chosen that lead to the build-up of ethyl benzene in the recycle stream to the desired level. This modified procedure is particularly preferred with a feed that is low in ethyl benzene.
  • EXAMPLE 1 This example concerns isomerization of a mixed C,,- 10 EXAMPLE 2 aromatics feed that closely resembles a commercial HZSM-ZI is also an excellent Xylene isomerization isomerization f ed stock, whi h i ll i h i catalyst with activity, selectivity and aging characterisxylene and contains ethyl benzene (EB).
  • EB ethyl benzene
  • HZSM-Zl having a siO /Al O ratio of 29 was used as the catalyst. Before use, the material was calcined in air 1C/min. from room temperature to 1000F. and held at l()F. for hours.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
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US00397038A 1973-09-13 1973-09-13 Xylene isomerization Expired - Lifetime US3856871A (en)

Priority Applications (18)

Application Number Priority Date Filing Date Title
US00397038A US3856871A (en) 1973-09-13 1973-09-13 Xylene isomerization
CA200,640A CA1026384A (en) 1973-09-13 1974-05-23 Xylene isomerization
IN1261/CAL/74A IN142292B (it) 1973-09-13 1974-06-10
ZA00743917A ZA743917B (en) 1973-09-13 1974-06-18 Xylene isomerization
FR7421256A FR2243919B1 (it) 1973-09-13 1974-06-19
JP6972974A JPS5341657B2 (it) 1973-09-13 1974-06-20
ES428167A ES428167A1 (es) 1973-09-13 1974-07-11 Un procedimiento mejorado de conversion de una mezcla de compuestos aromaticos.
GB3166374A GB1444702A (en) 1973-09-13 1974-07-17 Xylene isomerization
SU742049507A SU890971A3 (ru) 1973-09-13 1974-07-24 Способ получени изомеров ксилола
RO7479759A RO71348A (ro) 1973-09-13 1974-08-13 Procedeu pentru izomerizarea xilenilor
DE2441516A DE2441516C3 (de) 1973-09-13 1974-08-30 Verwendung von wenigstens teilweise durch Wasserstoffionen ausgetauschten Zeolithen zum Isomerisieren von Xylolen
NLAANVRAGE7412093,A NL173846C (nl) 1973-09-13 1974-09-11 Werkwijze voor het omzetten van een mengsel van aromatische verbindingen met 8 koolstofatomen.
CS746283A CS189668B2 (en) 1973-09-13 1974-09-12 Process for the isomerisation of xylenes
IT27243/74A IT1021337B (it) 1973-09-13 1974-09-12 Procedimento migliorato per l iso merizzazione di frazioni aromati che c 8
BE148467A BE819848A (fr) 1973-09-13 1974-09-12 Isomerisation des xylenes
DD74181056A DD113741B3 (de) 1973-09-13 1974-09-12 Xyld-isomerisation
PL1974174095A PL94144B1 (it) 1973-09-13 1974-09-13
AR255604A AR224491A1 (es) 1973-09-13 1974-09-13 Un procedimiento para la conversion de una mezcla de compuestos aromaticos

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US00397038A US3856871A (en) 1973-09-13 1973-09-13 Xylene isomerization

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US (1) US3856871A (it)
JP (1) JPS5341657B2 (it)
AR (1) AR224491A1 (it)
BE (1) BE819848A (it)
CA (1) CA1026384A (it)
CS (1) CS189668B2 (it)
DD (1) DD113741B3 (it)
DE (1) DE2441516C3 (it)
ES (1) ES428167A1 (it)
FR (1) FR2243919B1 (it)
GB (1) GB1444702A (it)
IN (1) IN142292B (it)
IT (1) IT1021337B (it)
NL (1) NL173846C (it)
PL (1) PL94144B1 (it)
RO (1) RO71348A (it)
SU (1) SU890971A3 (it)
ZA (1) ZA743917B (it)

Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2376835A1 (fr) * 1977-01-10 1978-08-04 Mobil Oil Isomerisation du xylene a basse pression
US4159283A (en) * 1978-04-07 1979-06-26 Mobil Oil Corporation Isomerization process
US4159282A (en) * 1978-06-09 1979-06-26 Mobil Oil Corporation Xylene isomerization
US4163028A (en) * 1977-07-22 1979-07-31 Mobil Oil Corporation Xylene isomerization
EP0005909A1 (en) * 1978-06-02 1979-12-12 The British Petroleum Company p.l.c. Isomerisation of alkyl aromatics using a gallium containing aluminosilicate catalyst
US4188282A (en) * 1978-06-12 1980-02-12 Mobile Oil Corporation Manufacture of benzene, toluene and xylene
US4218573A (en) * 1978-06-12 1980-08-19 Mobil Oil Corporation Xylene isomerization
US4224141A (en) * 1979-05-21 1980-09-23 Mobil Oil Corporation Manufacture of aromatic compounds
US4236996A (en) * 1979-05-25 1980-12-02 Mobil Oil Corporation Xylene isomerization
US4283584A (en) * 1980-04-14 1981-08-11 Mobil Oil Corporation Manufacture of aromatic compounds
EP0042754A1 (en) * 1980-06-23 1981-12-30 Toray Industries, Inc. Conversion of xylenes containing ethyl benzene
EP0065364A1 (en) * 1981-05-20 1982-11-24 Imperial Chemical Industries Plc Process for the isomerization of alkylbenzenes
US4435608A (en) 1980-12-12 1984-03-06 Exxon Research & Engineering Co. Xylene isomerization
US4450312A (en) * 1980-12-17 1984-05-22 Imperial Chemical Industries Plc Hydrocarbon conversion
US4482774A (en) * 1980-12-12 1984-11-13 Exxon Research & Engineering Co. Hydrocarbon conversion process with a composite zeolite
USRE31782E (en) * 1978-06-09 1984-12-25 Mobil Oil Corporation Xylene isomerization
US5043512A (en) * 1988-10-06 1991-08-27 Mobil Oil Corp. Alkylaromatic isomerization process
US5763714A (en) * 1997-01-08 1998-06-09 Catalytic Distillation Technologies Process and apparatus for the production and recovery of p-xylene
US5866736A (en) * 1997-10-14 1999-02-02 Catalytic Distillation Technologies Process for the production of alkyl benzene
US6518472B1 (en) 1996-08-05 2003-02-11 Bp Corporation North America Inc. Stabilized dual bed xylene isomerization catalyst system
US20050010074A1 (en) * 2003-07-08 2005-01-13 Kazuyoshi Iwayama Conversion catalyst for ethylbenzene containing xylenes and process for converting ethylbenzene containing xylenes by using catalyst
US6872866B1 (en) 2003-12-15 2005-03-29 Uop Llc Liquid phase process for C8 alkylaromatic isomerization
US20050143614A1 (en) * 2003-12-30 2005-06-30 Leon-Escamilla E. A. Process and catalyst for C8 alkylaromatic isomerization
US20050143615A1 (en) * 2003-12-30 2005-06-30 Bogdan Paula L. Process and bimetallic catalyst for C8 alkylaromatic isomerization
US20050277796A1 (en) * 2003-12-30 2005-12-15 Bogdan Paula L Process for C8 alkylaromatic isomerization
WO2013159081A2 (en) 2012-04-20 2013-10-24 The Coca-Cola Company Methods of preparing para-xylene from biomass
US20140023563A1 (en) * 2010-06-25 2014-01-23 Exxonmobil Chemical Patents Inc. Paraxylene Production Process And Apparatus
US8697929B2 (en) 2010-04-21 2014-04-15 Exxonmobil Chemical Patents Inc. Xylene isomerization process and catalyst therefor
US10384989B2 (en) 2016-12-21 2019-08-20 Uop Llc Composition of matter and structure of zeolite UZM-55 and use in isomerization of aromatic molecules
US10647641B2 (en) 2018-07-20 2020-05-12 Scg Chemicals Co., Ltd. Process for the separation of ethylbenzene from other C8 aromatic compounds
US10975006B2 (en) 2018-07-20 2021-04-13 Scg Chemicals Co., Ltd. Integrated processes for para-xylene production
US10987662B2 (en) 2015-08-18 2021-04-27 Ineos Us Chemicals Company Desilicated ZSM-5 catalysts for xylene isomerization

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EP0006700A1 (en) * 1978-06-09 1980-01-09 Mobil Oil Corporation Isomerization of a mixture of ethyl benzene and xylene
US4188282A (en) * 1978-06-12 1980-02-12 Mobile Oil Corporation Manufacture of benzene, toluene and xylene
US4218573A (en) * 1978-06-12 1980-08-19 Mobil Oil Corporation Xylene isomerization
US4224141A (en) * 1979-05-21 1980-09-23 Mobil Oil Corporation Manufacture of aromatic compounds
US4236996A (en) * 1979-05-25 1980-12-02 Mobil Oil Corporation Xylene isomerization
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US6518472B1 (en) 1996-08-05 2003-02-11 Bp Corporation North America Inc. Stabilized dual bed xylene isomerization catalyst system
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US20050010074A1 (en) * 2003-07-08 2005-01-13 Kazuyoshi Iwayama Conversion catalyst for ethylbenzene containing xylenes and process for converting ethylbenzene containing xylenes by using catalyst
US7199070B2 (en) 2003-07-08 2007-04-03 Toray Industries, Inc. Conversion catalyst for ethylbenzene containing xylenes and process for converting ethylbenzene containing xylenes by using catalyst
US20050153829A1 (en) * 2003-12-15 2005-07-14 Nemeth Laszlo T. Catalysts for C8 alkylaromatic isomerization process
US6872866B1 (en) 2003-12-15 2005-03-29 Uop Llc Liquid phase process for C8 alkylaromatic isomerization
US20050131261A1 (en) * 2003-12-15 2005-06-16 Nemeth Laszlo T. Process and catalysts for C8 alkylaromatic isomerization
WO2005058778A1 (en) * 2003-12-15 2005-06-30 Uop Llc Liquid phase process for c8 alkylaromatic isomerization
US20050277796A1 (en) * 2003-12-30 2005-12-15 Bogdan Paula L Process for C8 alkylaromatic isomerization
US20050143615A1 (en) * 2003-12-30 2005-06-30 Bogdan Paula L. Process and bimetallic catalyst for C8 alkylaromatic isomerization
US20050143614A1 (en) * 2003-12-30 2005-06-30 Leon-Escamilla E. A. Process and catalyst for C8 alkylaromatic isomerization
US7525008B2 (en) 2003-12-30 2009-04-28 Uop Llc Process for C8 alkylaromatic isomerization
US8697929B2 (en) 2010-04-21 2014-04-15 Exxonmobil Chemical Patents Inc. Xylene isomerization process and catalyst therefor
US20140023563A1 (en) * 2010-06-25 2014-01-23 Exxonmobil Chemical Patents Inc. Paraxylene Production Process And Apparatus
US9457292B2 (en) * 2010-06-25 2016-10-04 Exxonmobil Chemical Patents Inc. Paraxylene production process and apparatus
WO2013159081A2 (en) 2012-04-20 2013-10-24 The Coca-Cola Company Methods of preparing para-xylene from biomass
US10987662B2 (en) 2015-08-18 2021-04-27 Ineos Us Chemicals Company Desilicated ZSM-5 catalysts for xylene isomerization
US10384989B2 (en) 2016-12-21 2019-08-20 Uop Llc Composition of matter and structure of zeolite UZM-55 and use in isomerization of aromatic molecules
US10647641B2 (en) 2018-07-20 2020-05-12 Scg Chemicals Co., Ltd. Process for the separation of ethylbenzene from other C8 aromatic compounds
US10975006B2 (en) 2018-07-20 2021-04-13 Scg Chemicals Co., Ltd. Integrated processes for para-xylene production

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SU890971A3 (ru) 1981-12-15
DD113741A5 (de) 1975-06-20
PL94144B1 (it) 1977-07-30
AR224491A1 (es) 1981-12-15
DE2441516B2 (de) 1979-04-26
IT1021337B (it) 1978-01-30
BE819848A (fr) 1975-03-12
NL7412093A (nl) 1975-03-17
NL173846B (nl) 1983-10-17
CS189668B2 (en) 1979-04-30
FR2243919B1 (it) 1979-08-03
DE2441516C3 (de) 1979-12-13
DE2441516A1 (de) 1975-03-20
DD113741B3 (de) 1986-06-11
RO71348A (ro) 1982-02-01
JPS5053335A (it) 1975-05-12
CA1026384A (en) 1978-02-14
IN142292B (it) 1977-06-18
ES428167A1 (es) 1976-07-16
GB1444702A (en) 1976-08-04
ZA743917B (en) 1976-01-28
NL173846C (nl) 1984-03-16
JPS5341657B2 (it) 1978-11-06
FR2243919A1 (it) 1975-04-11

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