Alkylaromatics Production Herstellung Von Alkylaromaten Production De Composes Alkylaromatiques - DocsLib

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(11) EP 1 542 947 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention (51) Int Cl.: of the grant of the patent: C07C 2/66 (2006.01) 13.01.2010 Bulletin 2010/02 (86) International application number: (21) Application number: 03754437.6 PCT/US2003/027581

(22) Date of filing: 04.09.2003 (87) International publication number: WO 2004/026797 (01.04.2004 Gazette 2004/14)

(54) ALKYLAROMATICS PRODUCTION HERSTELLUNG VON ALKYLAROMATEN PRODUCTION DE COMPOSES ALKYLAROMATIQUES

(84) Designated Contracting States: • SMITH, Charles, M. AT BE BG CH CY CZ DE DK EE ES FI FR GB GR Houston, TX 77005 (US) HU IE IT LI LU MC NL PT RO SE SI SK TR • CIMINI, Ronald, J. Friendswood, TX 77546 (US) (30) Priority: 23.09.2002 US 252767 • MAERZ, Brian Chelmsford, MA (US) (43) Date of publication of application: 22.06.2005 Bulletin 2005/25 (74) Representative: Dew, Melvyn John et al ExxonMobil Chemical Patents Inc., (73) Proprietors: P.O. Box 105 • ExxonMobil Chemical Patents Inc. 1830 Machelen (BE) Bayton, TX 77520 (US) • Washington Group International, Inc. (56) References cited: Boise, FR-A- 2 706 888 US-A- 4 107 224 Idaho 83712 (US) US-A- 5 430 211 US-A- 5 600 048

(72) Inventors: • DATABASE EPODOC [Online] EUROPEAN • CLARK, Michael, C. PATENT OFFICE, THE HAGUE, NL; XP002275731 Pasadena, 77505 Texas (US) & CN 1 051 166 A (CHINA PETROCHEM COR) 8 May 1991 (1991-05-08)

Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 1 542 947 B1

Printed by Jouve, 75001 PARIS (FR) 1 EP 1 542 947 B1 2

Description a yield loss, the PEBs are converted back to ethylbenzene by transalkylation with additional benzene, normally Field of the Invention in a separate transalkylation reactor. [0007] By way of example, vapor phase ethylation of [0001] The present invention relates to a process for 5 benzene over the crystalline aluminosilicate zeolite ZSM- producing alkylaromatic compounds, particularly ethyl- 5 is disclosed in U.S. Patent Nos: 4,107,224 (Dwyer), benzene. 3,751,504 (Keown et al.), 3,751,506 (Burress), and 3,755,483 (Burress). Background of the Invention [0008] In most cases, vapor phase ethylation systems 10 use polymer grade ethylene feeds. Moreover, although [0002] Ethylbenzene is a key raw material in the pro- commercial vapor phase processes employing dilute eth- duction of styrene and is produced by the reaction of ylene feeds have been built and are currently in opera- ethylene and benzene in the presence of an acid catalyst. tion, the investment costs associated with these proc- Old ethylbenzene production plants, typically built before esses is high and the products contain high concentra- 15 1980, used AlCl3 or BF3 as the acidic catalyst. Newer tions of xylene impurities. plants have in general been switching to zeolite-based [0009] In recent years the trend in industry has been acidic catalysts. to shift away from vapor phase reactors to liquid phase [0003] Commercial ethylbenzene manufacturing proc- reactors. Liquid phase reactors operate at a temperature esses typically require the use of polymer grade ethylene, of about 220-270°C, which is under the critical tempera- which has a purity exceeding 99.9 mol %. However, the 20 ture of benzene (290°C). One advantage of the liquid purification of ethylene streams to polymer grade is a phase reactor is the very low formation of xylenes and costly process and hence there is considerable interest oligomers. The rate of the ethylation reaction is lower in developing processes that can operate with lower compared with the vapor phase, but the lower design grade ethylene streams. One such ethylene source is temperature of the liquid phase reaction usually econom- the dilute ethylene obtained as an off gas from the fluid 25 ically compensates for the negatives associated with the catalytic cracking or steam cracking unit of a petroleum higher catalyst volume. Thus, due to the kinetics of the refinery which, after removal of reactive impurities, such lower ethylation temperatures, resulting from the liquid as propylene, typically contains about 20-80 wt% ethyl- phase catalyst, the rate of the chain reactions forming ene, with the remainder being ethane together with minor PEBs is considerably lower; about 5-8% of the ethylben- amounts of hydrogen, methane and benzene. 30 zene is converted to PEBs in liquid phase reactions ver- [0004] Three types of ethylation reactor systems are sus the 15-20% converted in vapor phase reactions. used for producing ethylbenzene, namely, vapor phase Hence the stoichiometric excess of benzene in liquid reactor systems, liquid phase reactor systems, and phase systems is typically 150-400%, compared with mixed phase reactor systems. 400-800% in vapor phase systems. [0005] In vapor-phase reactor systems, the ethylation 35 [0010] Liquid phase ethylation of benzene using zeo- reaction of benzene and ethylene is carried out at a tem- lite beta as the catalyst is disclosed in U.S. Patent No. perature of about 380-420°C and a pressure of 9-15 4,891,458 and European Patent Publication Nos. kg/cm2-g in multiple fixed beds of zeolite catalyst. Ethyl- 0432814 and 0629549. More recently it has been dis- ene exothermally reacts with benzene to form ethylben- closed that MCM-22 and its structural analogues have zene, although undesirable chain and side reactions also 40 utility in these alkylation/transalkylation reactions; see, occur. About 15% of the ethylbenzene formed further re- for example, U.S. Patent No. 4,992,606 (MCM-22), U.S. acts with ethylene to form di-ethylbenzene isomers Patent No. 5,258,565 (MCM-36), U.S. Patent No. (DEB), tri-ethylbenzene isomers (TEB) and heavier aro- 5,371,310 (MCM-49), U.S. Patent No. 5,453,554 (MCM- matic products. All these chain reaction products are 56), U.S. Patent No. 5,149,894 (SSZ-25); U.S. Patent commonly referred as polyethylated benzenes (PEBs). 45 No. 6,077,498 (ITQ-1); International Patent Publication In addition to the ethylation reactions, the formation of Nos. WO97/17290 and WO01/21562 (ITQ-2). xylene isomers as trace products occurs by side reac- [0011] Commercial liquid phase ethylbenzene plants tions. This xylene formation in vapor phase processes normally employ polymer grade ethylene. Moreover, al- can yield an ethylbenzene product with about 0.05-0.20 though plants can be designed to accept ethylene wt % of xylenes. The xylenes show up as an impurity in 50 streams containing up to 30 mol% ethane by increasing the subsequent styrene product and are generally con- the operating pressure, the costs associated with the de- sidered undesirable. sign and operation of these plants are significant. [0006] In order to minimize the formation of PEBs, a [0012] Technology has also been developed for the stoichiometric excess of benzene, about 400-900% per production of ethylbenzene in a mixed phase using re- pass, is applied, depending on process optimization. The 55 active distillation. Such a process is described in U.S. effluent from the ethylation reactor contains about 70-85 Patent No. 5,476,978. Mixed phase processes can be wt % of unreacted benzene, about 12-20 wt % of ethyl- used with dilute ethylene streams since the reaction tem- benzene product and about 3-4 wt % of PEBs. To avoid perature of the ethylation reactor is below the dew point

2 3 EP 1 542 947 B1 4 of the dilute ethylene/benzene mixture but well above the [0017] In said one embodiment, said conditions in step bubble point. The diluents of the ethylene feed, ethane, (a) include a temperature of 150 to 270°C and a pressure methane and hydrogen, remain essentially in the vapor of 675 to 8300 kPa. phase. The benzene in the reactor is split between vapor [0018] Conveniently, said alkylation catalyst is select- phase and liquid phase, and the ethylbenzene and PEB 5 ed from MCM-22, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ- reaction products remain essentially in the liquid phase. 2, MCM-36, MCM-49, MCM-56, faujasite, mordenite and However, reactive distillation units are complex and ex- zeolite beta. pensive and the catalyst is prone to deactivation as a result of the production of ethylene oligomers. Description of the Drawings [0013] U.S. Patent No. 6,252,126 discloses a mixed 10 phase process for producing ethylbenzene by reaction [0019] The accompanying drawing is a flow diagram of a dilute ethylene stream containing 3 to 50 mol% eth- of a process for producing ethylbenzene in accordance ylene with a benzene stream containing 75 to 100 wt% with one example of the invention. benzene. The reaction is conducted in an isothermal ethylation section of a reactor vessel which also includes 15 Detailed Description of the Embodiments a benzene stripping section, where the unreacted benzene is thermally stripped from the ethylation products. [0020] The present invention provides a mixed phase Integrated, countercurrent vapor and liquid traffic is main- process for producing alkylaromatic compounds from a tained between the ethylation section and the benzene dilute alkene feedstock, in which the feedstock also in- stripping section. 20 cludes an alkane and typically other impurities. Although the process is particularly directed to the production of Summary of the Invention ethylbenzene from dilute ethylene, it is equally applicable to the production of other C2-C6 alkylaromatic com- [0014] The present invention resides in a process for pounds, such as cumene, as well as C6+ alkylaromatics, 25 producing an alkylaromatic compound by reacting an such as C8-C16 linear alkylbenzenes. Where the feed- alkylatable aromatic compound with a feed comprising stock is dilute ethylene, the impurities present will nor- an alkene and an alkane in a multistage reaction system mally include ethane, methane and/or hydrogen. comprising a plurality of series-connected alkylation re- [0021] The process involves reacting an alkylatable ar- action zones each containing an alkylation catalyst, the omatic compound with the dilute alkene feedstock in a process comprising the steps of: 30 multistage alkylation reaction system comprising at least first and second, and normally at least three, series-con- (a) operating at least one of said alkylation reaction nected alkylation reaction zones, which each contain an zones under conditions of temperature and pressure alkylation catalyst and which are typically located in a effective to cause alkylation of said aromatic com- single reaction vessel. At least the first alkylation reaction pound with said alkene in the presence of said alkyla- 35 zone, and normally each alkylation reaction zone, is op- tion catalyst, said temperature and pressure being erated under conditions of temperature and pressure ef- such that part of said aromatic compound is in the fective to cause alkylation of the aromatic compound with vapor phase and part is in the liquid phase; the alkene in the presence of the alkylation catalyst, the temperature and pressure being such that the aromatic (b) withdrawing from said one alkylation reaction 40 compound is partly in the vapor phase and partly in the zone an effluent comprising said alkylaromatic com- liquid phase. pound, unreacted alkylatable aromatic compound, [0022] The effluent from the first alkylation reaction any unreacted alkene and said alkane; zone comprises the desired alkylaromatic compound, unreacted alkylatable aromatic compound, any unreact- (c) removing at least part of said alkane from said 45 ed alkene (alkene conversion is expected to be one alkylation reaction zone effluent to produce an 98-99.99%) and the alkane impurity. Before being fed to alkane-depleted effluent; and the second alkylation reaction zone, the first alkylation reaction zone effluent is passed to a separation system (d) supplying said alkane-depleted effluent to anoth- including, for example, a flash drum where at least part er of said alkylation reaction zones. 50 of the alkane impurity is removed. The alkane-depleted effluent is then fed to the second alkylation reaction zone [0015] Typically, the feed comprises at least 20 wt% where additional dilute alkene feedstock is added for re- of said alkene, such as from 20 to 80 wt% of said alkene. action with the unreacted aromatic compound. Removing Typically, said alkane has the same number of carbon the alkane impurity between the first and second alkyla- atoms as said alkene. 55 tion reaction zones increases the liquid to vapor ratio and [0016] In one embodiment, said alkylatable aromatic hence the alkene conversion in the second alkylation re- compound includes benzene, said alkene includes eth- action zone. Where the process employs more than two ylene and said alkane includes ethane. alkylation reaction zones, the effluent from each zone is

3 5 EP 1 542 947 B1 6 fed to the separation system prior to passage to the next tion include an alkylatable aromatic compound and a di- zone or to the transalkylation unit. Alternatively, the ef- lute alkene alkylating agent. fluent from every second bed or every third bed, etc., can [0027] The term "aromatic" in reference to the alkylat- be fed to the separation system depending on the eco- able compounds which are useful herein is to be under- nomics and optimization of a specific plant. 5 stood in accordance with its art-recognized scope which [0023] In addition to, and upstream of, the series-con- includes alkyl substituted and unsubstituted mono- and nected alkylation reaction zones, the alkylation reaction polynuclear compounds. Compounds of an aromatic system may also include a by passable reactive guard character which possess a heteroatom are also useful bed that may be bypassed, which is normally located in provided they do not act as catalyst poisons under the a prereactor separate from the remainder of the alkylation 10 reaction conditions selected. system. The reactive guard bed is also loaded with alkyla- [0028] Substituted aromatic compounds which can be tion catalyst, which may be the same of different from alkylated herein must possess at least one hydrogen at- the catalyst used in the multi-stage alkylation reaction om directly bonded to the aromatic nucleus. The aromatic system, and is maintained under ambient or up to alkyla- rings can be substituted with one or more alkyl, aryl, alkar- tion conditions. The alkylatable aromatic compound and 15 yl, alkoxy, aryloxy, cycloalkyl, halide, and/or other groups the dilute alkene feedstock are passed through the reac- which do not interfere with the alkylation reaction. tive guard bed prior to entry into the first zone of the se- [0029] Suitable aromatic hydrocarbons include ben- ries-connected alkylation reaction zones. The reactive zene, naphthalene, anthracene, naphthacene, perylene, guard bed not only serves to effect the desired alkylation coronene, and phenanthrene, with benzene being pre- reaction but is also used to remove any reactive impuri- 20 ferred. ties in the feeds, such as nitrogen compounds, which [0030] Generally the alkyl groups which can be present could otherwise poison the remainder of the alkylation as substituents on the aromatic compound contain from catalyst. The catalyst in the guard bed is therefore subject about 1 to 22 carbon atoms and usually from about 1 to to more frequent regeneration and/or replacement than 8 carbon atoms, and most usually from about 1 to 4 car- the remainder of the alkylation catalyst and hence the 25 bon atoms. guard bed is normally provided with a by-pass circuit so [0031] Suitable alkyl substituted aromatic compounds that the alkylation feedstocks can be fed directly to the include toluene, xylene, isopropylbenzene, normal pro- series-connected alkylation reaction zones when the pylbenzene, alpha-methylnaphthalene, ethylbenzene, guard bed is out of service. The reactive guard bed may mesitylene, durene, cymenes, butylbenzene, pseu- operate in all liquid phase or mixed phase in co-current 30 documene, o-diethylbenzene, m-diethylbenzene, p-di- upflow or downflow operation. ethylbenzene, isoamylbenzene, isohexylbenzene, pen- [0024] The multi-stage alkylation reaction system used taethylbenzene, pentamethylbenzene; 1,2,3,4-tetrae- in the process of the invention is normally operated so thylbenzene; 1,2,3,5-tetramethylbenzene; 1,2,4-triethyl- as to achieve essentially complete conversion of the benzene; 1,2,3-trimethylbenzene, m-butyltoluene; alkene in the dilute alkene feedstock. However, for some 35 p-butyltoluene; 3,5-diethyltoluene; o-ethyltoluene; applications, it may be desirable to operate at below p-ethyltoluene; m-propyltoluene; 4-ethyl-m-xylene; 100% alkene conversion and employ a separate finishing dimethylnaphthalenes; ethylnaphthalene; 2,3-dimethyl- reactor downstream of the multi-stage alkylation reaction anthracene; 9-ethylanthracene; 2-methylanthracene; o- system (not shown). The finishing reactor would also con- methylanthracene; 9,10-dimethylphenanthrene; and 3- tain alkylation catalyst, which could be the same of dif- 40 methyl-phenanthrene. Higher molecular weight alkylar- ferent from the catalyst used in the multi-stage alkylation omatic hydrocarbons can also be used as starting mate- reaction system and could be operated under, vapor rials and include aromatic hydrocarbons such as are pro- phase, liquid phase or mixed phase alkylation conditions. duced by the alkylation of aromatic hydrocarbons with [0025] The multi-stage alkylation reaction system used olefin oligomers. Such products are frequently referred in the process of the invention is highly selective to the 45 to in the art as alkylate and include hexylbenzene, non- desired monoalkylated product, such as ethylbenzene, ylbenzene, dodecylbenzene, pentadecylbenzene, hexy- but normally produces at least some polyalkylated spe- ltoluene, nonyltoluene, dodecyltoluene, pentadecytolu- cies. Thus the effluent from the final alkylation stage, after ene, etc. Very often alkylate is obtained as a high boiling passage through the alkane separation system and re- fraction in which the alkyl group attached to the aromatic 50 covery of the monoalkylated product, is fed to a nucleus varies in size from about C6 to about C12. transalkylation reactor, which is normally separate from [0032] Reformate containing substantial quantities of the alkylation reactor, where additional monoalkylated benzene, toluene and/or xylene constitutes a particularly product is produced by reacting the polyalkylated species useful feed for the alkylation process of this invention. with additional aromatic compound. [0033] The alkylating agent useful in the process of 55 this invention includes a dilute alkene feed which con- Reactants tains at least one alkane and typically at least one alkane having the same number of carbon atoms as the alkene. [0026] The reactants used in the process of the inven- For example, where the alkene is ethylene, the alkane

4 7 EP 1 542 947 B1 8 may be ethane. Typically, the dilute alkene feed compris- 3,308,069, and Re. No. 28,341. Low sodium Ultrastable es at least 20 wt% of the alkene, such as from 20 to 80 Y molecular sieve (USY) is described in U.S. Patent Nos. wt% of the alkene. One particularly useful feed is the 3,293,192 and 3,449,070. Dealuminized Y zeolite (Deal dilute ethylene stream obtained as an off gas from the Y) may be prepared by the method found in U.S. Patent fluid catalytic cracking unit of a petroleum refinery. 5 No. 3,442,795. Zeolite UHP-Y is described in U.S. Patent [0034] Preferably, the reactants in the process of the No. 4,401,556. Mordenite is a naturally occurring material invention are benzene and dilute ethylene and the de- but is also available in synthetic forms, such as TEA- sired reaction product is ethylbenzene. mordenite (i.e., synthetic mordenite prepared from a reaction mixture comprising a tetraethylammonium direct- Alkylation and Transalkylation Catalysts 10 ing agent). TEA-mordenite is disclosed in U.S. Patent Nos. 3,766,093 and 3,894,104. [0035] The alkylation and transalkylation catalyst used [0039] The above molecular sieves may be used as in the process of the invention is not critical but normally the alkylation or transalkylation catalyst in the process of comprises a molecular sieve selected from MCM-22, the invention without any binder or matrix, i.e., in so- PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, MCM-36, MCM- 15 called self-bound form. Alternatively, the molecular sieve 49 and MCM-56. may be composited with another material which is resist- [0036] MCM-22 and its use to catalyze the synthesis ant to the temperatures and other conditions employed of alkylaromatic, including ethylbenzene, is described in in the alkylation reaction. Such materials include active U.S. Patent Nos. 4,992,606; 5,077,445; and 5,334,795. and inactive materials and synthetic or naturally occur- PSH-3 is described in U.S Patent No. 4,439,409. SSZ- 20 ring zeolites as well as inorganic materials such as clays 25 and its use in aromatics alkylation are described in and/or oxides such as alumina, silica, silica-alumina, zir- U.S. Patent No. 5,149,894. ERB-1 is described in Euro- conia, titania, magnesia or mixtures of these and other pean Patent No. 0293032. ITQ-1 is described in U.S. oxides. The latter may be either naturally occurring or in Patent No 6,077,498. ITQ-2 is described in International the form of gelatinous precipitates or gels including mix- Patent Publication No. WO97/17290 and WO01/21562. 25 tures of silica and metal oxides. Clays may also be in- MCM-36 is described in U.S. Patent Nos. 5,250,277 and cluded with the oxide type binders to modify the mechan- 5,292,698. U.S. Patent No. 5,258,565 describes the syn- ical properties of the catalyst or to assist in its manufac- thesis of alkylaromatics, including ethylbenzene, using a ture. Use of a material in conjunction with the molecular catalyst comprising MCM-36. MCM-49 is described in sieve, i.e., combined therewith or present during its syn- U.S Patent No. 5,236,575. The use of MCM-49 to cata- 30 thesis, which itself is catalytically active may change the lyze the synthesis of alkylaromatics, including ethylben- conversion and/or selectivity of the catalyst. Inactive ma- zene, is described in U.S. Patent Nos. 5,493,065 and terials suitably serve as diluents to control the amount of 5,371,310. MCM-56 is described in U.S. Patent No. conversion so that products can be obtained economi- 5,362,697. The use of MCM-56 to catalyze the synthesis cally and orderly without employing other means for con- of alkylaromatics including ethylbenzene is described in 35 trolling the rate of reaction. These materials may be in- U.S. Patent Nos. 5,557,024 and 5,453,554. corporated into naturally occurring clays, e.g., bentonite [0037] Alternatively, the alkylation and transalkylation and kaolin, to improve the crush strength of the catalyst catalyst can comprise a medium pore molecular sieve under commercial operating conditions and function as having a Constraint Index of 2-12 (as defined in U.S. binders or matrices for the catalyst. The relative propor- Patent No. 4,016,218), including ZSM-5, ZSM-11, ZSM- 40 tions of molecular sieve and inorganic oxide matrix vary 12, ZSM-22, ZSM-23, ZSM-35, and ZSM-48. ZSM-5 is widely, with the sieve content ranging from about 1 to described in detail in U.S. Patent Nos. 3,702,886 and Re. about 90 percent by weight and more usually, particular- 29,948. ZSM-11 is described in detail in U.S. Patent No. ly, when the composite is prepared in the form of beads, 3,709,979. ZSM-12 is described in U.S. Patent No. in the range of about 2 to about 80 weight percent of the 3,832,449. ZSM-22 is described in U.S. Patent No. 45 composite. 4,556,477. ZSM-23 is described in U.S. Patent No. [0040] The same catalyst may be used in both the 4,076,842. ZSM-35 is described in U.S. Patent No. transalkylation zone and the alkylation zones of the 4,016,245. ZSM-48 is more particularly described in U.S. present process. Preferably, however, different catalysts Patent No. 4,234,231. are chosen for the two zones, so as to be tailored for the [0038] As a further alternative, the alkylation and 50 particular reactions catalyzed therein. For example, in transalkylation catalyst can comprise a large pore mo- one embodiment, MCM-22, either in bound or unbound lecular sieve having a Constraint Index less than 2. Suit- form, is used in the reactive guard bed and the series- able large pore molecular sieves include zeolite beta, connected alkylation reaction zones and a suitable zeolite Y, Ultrastable Y (USY), Dealuminized Y (Deal Y), transalkylation catalyst is used in the transalkylation mordenite, ZSM-3, ZSM-4, ZSM-18, and ZSM-20. Zeo- 55 zone. In such an embodiment, any finishing reactor could lite ZSM-14 is described in U.S. Patent No. 3,923,636. include MCM-22 for liquid phase operation or ZSM-5 for Zeolite ZSM-20 is described in U.S. Patent No. vapor phase operation. 3,972,983. Zeolite Beta is described in U.S. Patent Nos.

5 9 EP 1 542 947 B1 10

Reaction Conditions the guard bed is composed of ethylbenzenes, unreacted benzene and unreactive light impurites (mainly ethane) [0041] In the process of the invention, the alkylation from the dilute ethylene feed. The guard bed effluent 18 reaction in at least the first, and normally in each, of the is then passed to the top bed in a main alkylation reactor series-connected alkylation reaction zones takes place 5 19, which includes a plurality of vertically spaced, series- under mixed liquid/vapor phase conditions, such that the connected catalyst beds 21. Each bed 21 also receives alkylatable aromatic compound is partly in the vapor the dilute ethylene feed 17 such that the ethylene and phase and partly in the liquid phase. the benzene-containing effluent from the guard bed 16 [0042] Particular conditions for carrying out the mixed or the previous bed 21 pass cocurrently down through phase alkylation of benzene with ethylene may include 10 the bed. Again each bed 21 of the reactor 19 is typically a temperature of from about 150 to 270°C, a pressure of operated at or near to 100% ethylene conversion. about 675 to about 8300 kPa; such as a temperature [0048] The effluent from each bed 21, except for the from about 170 to 220°C and pressure of about 1500 to bottom bed, of the reactor 19 is passed to a heat ex- 4000 kPa, a WHSV based on ethylene of from about 0.1 changer and flash drum, indicated collectively as 22, to about 10 hr-1, and a mole ratio of benzene to ethylene 15 where the effluent is cooled and separated into a liquid from about 1 to about 10. stream 23 and a vapor stream 24. The liquid stream 23, [0043] Where the alkylation system includes a reactive which contains mostly benzene and ethylbenzene, is guard bed, this may be operated under liquid phase con- sent to the next catalyst bed in the reactor 19. The vapor ditions or vapor phase conditions or mixed liquid/vapor stream 24 normally contains mostly ethane but, in view phase conditions, but is preferably operated under liquid 20 of its volatility, can contain from about 10 to about 90% phase conditions. The guard bed will preferably operate benzene which must be removed before the ethane can at a temperature between 20 and 270°C and a pressure be used as, for example, a fuel source. The stream 24 between about 675 to about 8300 kPa. is therefore passed to a prefractionator 25, where most [0044] The transalkylation reaction may also take of the benzene condenses, and then to a scrubber 26, place under liquid phase conditions or vapor phase con- 25 where the remainder of the benzene is adsorbed by ditions or mixed liquid/vapor phase conditions, but pref- streams heavier than ethylbenzene, for example, the pol- erably takes place under liquid phase conditions. Partic- yethylated benzenes or residue produced in the process. ular conditions for carrying out the liquid phase [0049] The effluent 20 from the bottom bed of the re- transalkylation of benzene with polyethylbenzenes may actor 19, which contains the desired ethylbenzene prod- include a temperature of from about 150°C to about 30 uct as well as unreacted benzene and small quantities 260°C, a pressure of 7000 kPa or less, a WHSV based of polyethylated benzenes and ethane, is fed initially to on the weight of the total liquid feed to the reaction zone the prefractionator 25 where the ethane is removed as of from about 0.5 to about 100 hr-1 and a mole ratio of overhead and passed to the scrubber 26. The bottoms benzene to polyethylbenzene of from 1:1 to 30:1. fraction from the prefractionator 25 is passed to a ben- [0045] One embodiment of the process of the inven- 35 zene column 27 where the unreacted benzene is re- tion, in which the alkylatable aromatic compound is ben- moved as overhead and recycled to the reservoir 14. The zene and the alkylating agent is a dilute ethylene stream, bottoms fraction from the benzene tower is passed to an is shown in the accompanying drawing. ethylbenzene column 28 where the desired ethylben- [0046] Referring to the drawing, in the embodiment zene is recovered as overhead and the bottoms fraction shown a benzene feed 11 is passed to a drying column 40 is passed to a PEB column 29. The polyethylated ben- 12, where the water content of the benzene is preferably zenes, mostly diethylbenzene, are removed as an over- reduced to below 20ppm. From the column 11, the ben- heads fraction from the PEB column 29. The bottoms zene is passed to a reservoir 14 by way of treaters 13 fraction from PEB column 29 is removed as residue. Pref- which serve to remove catalyst poisons, particularly ni- erably, at least a portion of the polyethylated benzenes trogen and sulfur containing organic species from the 45 or residue may be passed through the scrubber 26 before benzene. From the reservoir 14, the benzene is pumped being fed to a transalkylator 31. The transalkylator 31 to a heat exchanger 15, where the benzene is indirectly also receives a supply of benzene from the reservoir 14 heated by high pressure steam, before being fed to a and is operated under conditions such that 20-80% of reactive guard bed 16. the polyethylated benzenes are converted to ethylben- [0047] The reactive guard bed 16 also receives a dilute 50 zene. The effluent 32 from the transalkylator is combined ethylene feed 17 from a compressor 18 (which may or with the effluent 20 from the reactor 19 as it passes to may not be present) such that the benzene and dilute the prefractionator 25 and then the columns 27, 28 and ethylene pass cocurrently down through a bed of alkyla- 29. tion catalyst in the guard bed. Alternately, the flow can [0050] The invention will now be more particularly de- be co-current upflow. The guard bed 16 typically operates 55 scribed with reference to the following Example. at or near to 100% ethylene conversion but may operate at lower conversions (alternately, no ethylene can be in- troduced to the guard bed) so that the effluent 18 leaving

6 11 EP 1 542 947 B1 12

Example compound, any unreacted alkene and said alkane; [0051] The first and fourth beds of a four-bed ethylben- (c) removing at least part of said alkane from zene reactor were simulated in an adiabatic fixed-bed said one alkylation reaction zone effluent to pro- laboratory flow reactor with a four-gram catalyst loading 5 duce an alkane-depleted effluent; and of an appropriate zeolite to facilitate the alkylation of ben- (d) supplying said alkane-depleted effluent to zene with ethylene. another of said alkylation reaction zones. [0052] The first bed liquid feed was pure benzene, whereas the simulated fourth bed liquid feed had the fol- 2. The process of claim 1 wherein said feed comprises lowing composition: 10 at least 20 wt% of said alkene

Benzene 77.80% 3. The process of claim 1 or 2 wherein said feed com- Ethylbenzene 20.86% prises about 20 to about 80 wt% of said alkene. Diethylbenzene 1.18% Triethylbenzene 0.04% 15 4. The process of claim 1, 2, or 3 wherein said alkane has the same number of carbon atoms as said alkene. [0053] The simulated first bed gas feed was a mixture of ethylene and ethane at a molar ratio 65:35. Simulated 5. The process of any preceding claim wherein said operation of the first bed was at a temperature of 200°C, 20 alkylatable aromatic compound includes benzene. a pressure of 350 psig (2514 kPa), a WHSV of 0.68 (ethylene basis) and an aromatic:ethylene ratio of 57:1 6. The process of any preceding claim wherein said weight basis). The ethylene conversion was 98.0%. alkene includes ethylene and said alkane includes [0054] In one simulation, without interstage ethane re- ethane. moval, the simulated fourth bed gas feed was a mixture 25 of ethylene and ethane at a molar ratio 33:67. Simulated 7. The process of claim 5 or 6 wherein said alkene in- operation of the fourth bed was under the same condi- cludes ethylene and said alkylaromatic compound tions as the first bed and the ethylene conversion was includes ethylbenzene. only 88.0%. [0055] In another simulation, with interstage ethane re- 30 8. The process of claim 7 wherein said conditions in moval, the simulated fourth bed gas feed was a mixture step (a) include a temperature of 150 to 270°C and of ethylene and ethane at a molar ratio 67:33. Simulated a pressure of 675 to 8300 kPa. operation of the fourth bed was again under the same conditions as the first bed but now the ethylene conver- 9. The process of claim 7 or 8 wherein said conditions sion had increased to 99.5%. 35 in step (a) include a temperature of 170 to 220°C and a pressure of 1500 to 4000 kPa.

Claims 10. The process of any preceding claim wherein the alkylation catalyst includes a molecular sieve select- 1. A process for producing an alkylaromatic compound 40 ed from MCM-22, PSH-3, SSZ-25, ERB-1, ITQ-1, by reacting an alkylatable aromatic compound with ITQ-2, MCM-36, MCM-49 and MCM-56. a feed comprising an alkene and an alkane in a multistage reaction system comprising a plurality of se- 11. The process of any of claims 1 through 9 wherein ries-connected alkylation reaction zones each con- the alkylation catalyst includes a molecular sieve taining an alkylation catalyst, the process comprising 45 having a Constraint Index of about 2 to about 12. the steps of: 12. The process of claim 11 wherein alkylation catalyst (a) operating at least one of said alkylation re- includes a molecular sieve selected from ZSM-5, action zones under conditions of temperature ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, and and pressure effective to cause alkylation of said 50 ZSM-48. aromatic compound with said alkene in the presence of said alkylation catalyst, said tempera- 13. The process of any of claims 1 through 9 wherein ture and pressure being such that part of said alkylation catalyst includes a molecular sieve having aromatic compound is in the vapor phase and a Constraint Index of less than 2. part is in the liquid phase; 55 (b) withdrawing from said one alkylation reaction 14. The process of claim 13 wherein alkylation catalyst zone an effluent comprising said alkylaromatic includes a molecular sieve selected from zeolite be- compound, unreacted alkylatable aromatic ta, zeolite Y, Ultrastable Y (USY), Dealuminized Y

7 13 EP 1 542 947 B1 14

(Deal Y), mordenite, ZSM-3, ZSM-4, ZSM-18, and schen Verbindung in der Dampfphase vorliegt ZSM-20. und ein Teil in der flüssigen Phase vorliegt, (b) aus dieser einen Alkylierungsreaktionszone 15. The process of any preceding claim wherein said ein Ausfluss abgezogen wird, der die alkylaro- removing step (c) includes passing said one alkyla- 5 matische Verbindung, nicht-umgesetzte alky- tion reaction zone effluent through a flash drum. lierbare, aromatische Verbindung, irgendwel- ches unumgesetztes Alken und das Alkan ent- 16. The process of any preceding claim comprising the hält, additional steps of: (c) mindestens ein Teil des Alkans aus diesem 10 einen Alkylierungsreaktionszonenausfluss ent- (i) separating a polyalkylated aromatic fraction fernt wird, um einen alkanarmen Ausfluss her- from an effluent of a final alkylation reaction zustellen, und zone, and (d) der alkanarme Ausfluss einer anderen der (ii) contacting at least part of said polyalkylated Alkylierungsreaktionszonen zugeführt wird. aromatic fraction with a transalkylatable aromat- 15 ic compound in the presence of a transalkylation 2. Verfahren nach Anspruch 1, bei dem das Einsatz- catalyst under transalkylating conditions. material mindestens 20 Gew.-% des Alkens enthält.

17. The process of claim 16 including the further step of 3. Verfahren nach Anspruch 1 oder 2, bei dem das Ein- contacting said alkane removed in step (c) with at 20 satzmaterial etwa 20 bis etwa 80 Gew.-% des Alkens least part of said polyalkylated aromatic fraction such enthält. that said polyalkylated aromatic fraction adsorbs unreacted aromatic compound contained by said al- 4. Verfahren nach Anspruch 1, 2 oder 3, bei dem das kane. Alkan die gleiche Anzahl an Kohlenstoffatomen auf- 25 weist wie das Alken. 18. The process of any preceding claim comprising the further step of contacting said alkylatable aromatic 5. Verfahren nach einem der vorhergehenden Ansprü- compound and said feed with an alkylation catalyst che, bei dem die alkylierbare aromatische Verbin- in a by-passable prereactor separate from and up- dung Benzol einschließt. stream of said multistage reaction system. 30 6. Verfahren nach einem der vorhergehenden Ansprü- 19. The process of any preceding claim comprising the che, bei dem das Alken Ethylen einschließt und das further step of contacting unreacted alkylatable aro- Alkan Ethan einschließt. matic compound and unreacted alkene from said multistage reaction system under alkylation condi- 35 7. Verfahren nach Anspruch 5 oder 6, bei dem das Al- tions with an alkylation catalyst in a finishing reactor ken Ethylen einschließt und die alkylaromatische separate from and downstream of said multistage Verbindung Ethylbenzol einschließt. reaction system. 8. Verfahren nach Anspruch 7, bei dem die Bedingun- 40 gen in Schritt (a) eine Temperatur von 150 bis 270°C Patentansprüche und einen Druck von 675 bis 8300 kPa einschließen.

1. Verfahren zum Herstellen von alkylaromatischer 9. Verfahren nach Anspruch 7 oder 8, bei dem die Be- Verbindung durch Umsetzen von alkylierbarer, aro- dingungen in Schritt (a) eine Temperatur von 170 matischer Verbindung mit einem Einsatzmaterial, 45 bis 220°C und einen Druck von 1500 bis 4000 kPa das Alken und Alkan enthält, in einem mehrstufigen einschließen. Reaktionssystem, das eine Vielzahl von nacheinan- der angeordneten Alkylierungsreaktionszonen um- 10. Verfahren nach einem der vorhergehenden Ansprü- fasst, von denen jede Alkylierungskatalysator ent- che, bei dem der Alkylierungskatalysator Molekular- hält, wobei bei dem Verfahren 50 sieb einschließt, das aus MCM-22, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, MCM-36, MCM-49 und MCM- (a) mindestens eine der Alkylierungsreaktions- 56 ausgewählt ist. zonen unter Temperatur- und Druckbedingun- gen betrieben wird, die wirksam sind, Alkylie- 11. Verfahren nach einem der Ansprüche 1 bis 9, bei rung der aromatischen Verbindung mit dem Al- 55 dem der Alkylierungskatalysator Molekularsieb ein- ken in Gegenwart des Alkylierungskatalysators schließt, das einen Beschränkungsindex von etwa hervorzurufen, wobei die Temperatur und der 2 bis etwa 12 aufweist. Druck derart sind, dass ein Teil der aromati-

8 15 EP 1 542 947 B1 16

12. Verfahren nach Anspruch 11, bei dem der Alkylie- Revendications rungskatalysator Molekularsieb einschließt, das aus ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM- 1. Procédé de production d’un composé alkylaromati- 35 und ZSM-48 ausgewählt ist. que consistant à faire réagir un composé aromatique 5 susceptible d’être alkylé avec une charge compre- 13. Verfahren nach einem der Ansprüche 1 bis 9, bei nant un alcène et un alcane dans un système réac- dem der Alkylierungskatalysator Molekularsieb ein- tionnel à plusieurs étages comprenant une pluralité schließt, das einen Beschränkungsindex von weni- de zones réactionnelles d’alkylation reliées en série ger als 2 aufweist. contenant chacune un catalyseur d’alkylation, le pro- 10 cédé comprenant les étapes consistant à : 14. Verfahren nach Anspruch 13, bei dem der Alkylie- rungskatalysator Molekularsieb einschließt, das aus (a) mettre en service au moins une desdites zo- Zeolith Beta, Zeolith Y, ultrastabilem Y (USY), dealu- nes réactionnelles d’alkylation dans des condi- minisiertem Y (Deal Y), Mordenit, ZSM-3, ZSM-4, tions de température et de pression efficaces ZSM-18 und ZSM-20 ausgewählt ist. 15 pour provoquer l’alkylation dudit composé aromatique avec ledit alcène en présence dudit ca- 15. Verfahren nach einem der vorhergehenden Ansprü- talyseur d’alkylation, ladite température et ladite che, bei dem im entfernenden Schritt (c) der eine pression étant telles qu’une partie dudit compo- Alkylierungsreaktionszonenausfluss durch eine Ab- sé aromatique soit en phase vapeur et qu’une dampftrommel geleitet wird. 20 partie soit en phase liquide ; (b) soutirer de ladite zone réactionnelle d’alky- 16. Verfahren nach einem der vorhergehenden Ansprü- lation un effluent comprenant ledit composé alk- che, bei dem außerdem ylaromatique, le composé aromatique susceptible d’être alkylé n’ayant pas réagi, l’alcène (i) eine polyalkylierte, aromatische Fraktion von 25 n’ayant pas réagi éventuel et ledit alcane ; einem Ausfluss einer letzten Alkylierungsreak- (c) éliminer au moins une partie dudit alcane de tionszone abgetrennt wird und l’effluent de ladite zone réactionnelle d’alkyla- (ii) mindestens ein Teil der polyalkylierten, aro- tion pour produire un effluent appauvri en matischen Fraktion mit transalkylierbarer, aro- alcane ; et matischer Verbindung in Gegenwart von Tran- 30 (d) envoyer ledit effluent appauvri en alcane vers salkylierungskatalysator unter Transalkylie- une autre desdites zones réactionnelles d’alky- rungsbedingungen in Kontakt gebracht wird. lation.

17. Verfahren nach Anspruch 16, bei dem ferner das in 2. Procédé selon la revendication 1, dans lequel ladite Schritt (c) entfernte Alkan derart mit mindestens ei- 35 charge comprend au moins 20% en poids dudit al- nem Teil der polyalkylierten, aromatischen Fraktion cène. in Kontakt gebracht wird, dass die polyalkylierte, aromatische Fraktion nicht-umgesetzte aromatische 3. Procédé selon la revendication 1 ou 2, dans lequel Verbindung adsorbiert, die in dem Alkan enthalten ladite charge comprend environ 20 à environ 80% ist. 40 en poids dudit alcène.

18. Verfahren nach einem der vorhergehenden Ansprü- 4. Procédé selon la revendication 1, 2 ou 3, dans lequel che, bei dem ferner die alkylierbare aromatische Ver- ledit alcane possède le même nombre d’atomes de bindung und das Einsatzmaterial in einem umgeh- carbone que ledit alcène. baren Vorreaktor, der vom mehrstufigen Reaktions- 45 system getrennt und diesem vorgeschaltet ist, mit 5. Procédé selon l’une quelconque des revendications Alkylierungskatalysator in Kontakt gebracht werden. précédentes, dans lequel ledit composé aromatique susceptible d’être alkylé comprend le benzène. 19. Verfahren nach einem der vorhergehenden Ansprü- che, bei dem ferner nicht-umgesetzte alkylierbare 50 6. Procédé selon l’une quelconque des revendications aromatische Verbindung und nicht-umgesetztes Al- précédentes, dans lequel ledit alcène comprend ken aus dem mehrstufigen Reaktionssystem in ei- l’éthylène et ledit alcane comprend l’éthane. nem Endreaktor, der vom mehrstufigen Reaktions- system getrennt und diesem nachgeschaltet ist, un- 7. Procédé selon la revendication 5 ou 6, dans lequel ter Alkylierungsbedingungen mit Alkylierungskataly- 55 ledit alcène comprend l’éthylène et ledit composé sator in Kontakt gebracht werden. alkylaromatique comprend l’éthylbenzène.

8. Procédé selon la revendication 7, dans lequel lesdi-

9 17 EP 1 542 947 B1 18

tes conditions dans l’étape (a) comprennent une ledit alcane éliminé dans l’étape (c) avec au moins température de 150 à 270°C et une pression de 675 une partie de ladite fraction aromatique polyalkylée à 8300 kPa. de telle sorte que ladite fraction aromatique polyalk- ylée adsorbe le composé aromatique n’ayant pas 9. Procédé selon la revendication 7 ou 8, dans lequel 5 réagi contenu dans ledit alcane. lesdites conditions dans l’étape (a) comprennent une température de 170 à 220°C et une pression de 18. Procédé selon l’une quelconque des revendications 1500 à 4000 kPa. précédentes comprenant l’étape supplémentaire consistant à mettre en contact ledit composé aroma- 10. Procédé selon l’une quelconque des revendications 10 tique susceptible d’être alkylé et ladite charge avec précédentes, dans lequel le catalyseur d’alkylation un catalyseur d’alkylation dans un préréacteur pou- comprend un tamis moléculaire choisi parmi MCM- vant être mis hors circuit, séparé et en amont dudit 22, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, MCM-36, système réactionnel à plusieurs étages. MCM-49 et MCM-56. 15 19. Procédé selon l’une quelconque des revendications 11. Procédé selon l’une quelconque des revendications précédentes comprenant l’étape supplémentaire 1 à 9, dans lequel le catalyseur d’alkylation com- consistant à mettre en contact le composé aromati- prend un tamis moléculaire ayant un indice de con- que susceptible d’être alkylé n’ayant pas réagi et l’al- trainte d’environ 2 à environ 12. cène n’ayant pas réagi provenant dudit système 20 réactionnel à plusieurs étages, dans des conditions 12. Procédé selon la revendication 11, dans lequel le d’alkylation, avec un catalyseur d’alkylation dans un catalyseur d’alkylation comprend un tamis molécu- réacteur de finition séparé et en aval dudit système laire choisi parmi ZSM-5, ZSM-11, ZSM-12, ZSM- réactionnel à plusieurs étages. 22, ZSM-23, ZSM-35 et ZSM-48. 25 13. Procédé selon l’une quelconque des revendications 1 à 9, dans lequel le catalyseur d’alkylation comprend un tamis moléculaire ayant un indice de con- trainte inférieur à 2. 30 14. Procédé selon la revendication 13, dans lequel le catalyseur d’alkylation comprend un tamis molécu- laire choisi parmi la zéolithe bêta, la zéolithe Y, la zéolithe Y ultrastable (USY), la zéolithe Y désalumi- née (Deal Y), la mordénite, ZSM-3, ZSM-4, ZSM-18 35 et ZSM-20.

15. Procédé selon l’une quelconque des revendications précédentes, dans lequel ladite étape d’élimination (c) comprend le fait de faire passer l’effluent de ladite 40 zone réactionnelle d’alkylation à travers un ballon de détente.

16. Procédé selon l’une quelconque des revendications précédentes comprenant les étapes supplémentai- 45 res consistant à :

(i) séparer une fraction aromatique polyalkylée d’un effluent d’une zone réactionnelle d’alkylation finale, et 50 (ii) mettre en contact au moins une partie de ladite fraction aromatique polyalkylée avec un composé aromatique susceptible d’être tran- salkylé en présence d’un catalyseur de transalkylation dans des conditions de transalkylation. 55

17. Procédé selon la revendication 16 comprenant l’éta- pe supplémentaire consistant à mettre en contact

10 EP 1 542 947 B1

11 EP 1 542 947 B1

REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

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