(19)
(11)EP 1 866 267 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
05.11.2014 Bulletin 2014/45

(21)Application number: 06736556.9

(22)Date of filing:  01.03.2006
(51)International Patent Classification (IPC): 
C07C 2/66(2006.01)
(86)International application number:
PCT/US2006/007262
(87)International publication number:
WO 2006/107471 (12.10.2006 Gazette  2006/41)

(54)

ALKYLAROMATICS PRODUCTION USING DILUTE ALKENE

HERSTELLUNG VON ALKYLAROMATISCHEN VERBINDUNGEN UNTER VERWENDUNG VON VERDÜNNTEM ALKEN

PRODUCTION D'ALKYLAROMATIQUES UTILISANT UN ALCENE DILUE


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

(30)Priority: 31.03.2005 US 666809 P

(43)Date of publication of application:
19.12.2007 Bulletin 2007/51

(73)Proprietor: Badger Licensing LLC
Boston, MA 02111 (US)

(72)Inventors:
  • CLARK, Michael, C.
    Pasadena, Texas 77505 (US)
  • MAERZ, Brian
    Chelmsford, Massachusetts 01824 (US)

(74)Representative: Denness, James Edward et al
Abel & Imray 20 Red Lion Street
London WC1R 4PQ
London WC1R 4PQ (GB)


(56)References cited: : 
WO-A-2004/026797
US-A- 5 998 687
US-A- 5 105 041
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD



    [0001] The present invention relates to a process for producing alkylated aromatic products, particularly ethylbenzene and cumene.

    BACKGROUND



    [0002] Ethylbenzene is a key raw material in the production of styrene and is produced by the reaction of ethylene and benzene in the presence of an acid alkylation catalyst. Older ethylbenzene production plants, those typically built before 1980, used AlCl3 or BF3 as the acidic alkylation catalyst. Plants built after 1980 have in general used zeolite-based acidic catalysts as the alkylation catalyst.

    [0003] Commercial ethylbenzene manufacturing processes typically require the use of concentrate ethylene that has a purity exceeding 80 mol.%. For example, a polymer grade ethylene has a purity exceeding 99 mol.% ethylene. However, the purification of ethylene streams to attain chemical or polymer grade is a costly process and hence there is considerable interest in developing processes that can operate with lower grade or dilute ethylene streams. One source of a dilute ethylene stream is the off gas from the fluid catalytic cracking or steam-cracking unit of a petroleum refinery. The dilute ethylene stream, after removal of reactive impurities, such as propylene, typically contains about 10-80 mol.% ethylene, with the remainder being ethane, hydrogen, methane, and/or benzene.

    [0004] Three types of ethylation reactor systems are used for producing ethylbenzene, namely, vapor phase reactor systems, liquid phase reactor systems, and mixed phase reactor systems.

    [0005] In vapor-phase reactor systems, the ethylation reaction of benzene and ethylene is carried out at a temperature of about 350 to 450°C and a pressure of 690-3534 KPa-a (6-35 kg/cm2-g) in multiple fixed beds of zeolite catalyst. Ethylene exothermicly reacts with benzene to form ethylbenzene, although undesirable reactions also occur. About 15 mol.% of the ethylbenzene formed further reacts with ethylene to form di-ethylbenzene isomers (DEB), triethylbenzene isomers (TEB) and heavier aromatic products. All these undesirable reaction products are commonly referred as polyethylated benzenes (PEBs).

    [0006] By way of example, vapor phase ethylation of benzene over the crystalline aluminosilicate zeolite ZSM-5 is disclosed in U.S. Patent Nos. 3,751,504 (Keown et al.), 3,751,506 (Burress), and 3,755,483 (Burress).

    [0007] In most cases, vapor phase ethylation systems use polymer grade ethylene feeds. Moreover, although commercial vapor phase processes employing dilute ethylene feeds have been built and are currently in operation, the investment costs associated with these processes is high.

    [0008] In recent years the trend in industry has been to shift away from vapor phase reactors to liquid phase reactors. Liquid phase reactors operate at a temperature of about 150-280°C, which is below the critical temperature of benzene (290°C). The rate of the ethylation reaction is lower compared with the vapor phase, but the lower design temperature of the liquid phase reaction usually economically compensates for the negatives associated with the higher catalyst volume.

    [0009] Liquid phase ethylation of benzene using zeolite beta as the catalyst is disclosed in U.S. Patent No. 4,891,458 and European Patent Publication Nos. 0432814 and 0629549. More recently it has been disclosed that MCM-22 and its structural analogues have utility in these alkylation/transalkylation reactions, for example, U.S. Patent No. 4,992,606 (MCM-22), U.S. Patent No. 5,258,565 (MCM-36), U.S. Patent No. 5,371,310 (MCM-49), U.S. Patent No. 5,453,554 (MCM-56), U.S. Patent No. 5,149,894 (SSZ-25); U.S. Patent No. 6,077,498 (ITQ-1); International Patent Publication Nos. WO97/17290 and WO01/21562 (ITQ-2).

    [0010] Commercial liquid phase ethylbenzene plants normally employ polymer grade ethylene. Moreover, although plants can be designed to accept ethylene streams containing up to 30 mol.% ethane by increasing the operating pressure, the costs associated with the design and operation of these plants have proven to be significant.

    [0011] Technology has also been developed for the production of ethylbenzene in a mixed phase using reactive distillation. Such a process is described in U.S. Patent No. 5,476,978. Mixed phase processes can be used with dilute ethylene streams since the reaction temperature of the ethylation reactor is below the dew point of the dilute ethylene/benzene mixture, but above the bubble point. The diluents of the ethylene feed, ethane, methane and hydrogen, remain essentially in the vapor phase. The benzene in the reactor is split between vapor phase and liquid phase, and the ethylbenzene and PEB reaction products remain essentially in the liquid phase.

    [0012] U.S. Patent No. 6,252,126 discloses a mixed phase process for producing ethylbenzene by reaction of a dilute ethylene stream containing 3 to 50 mol.% ethylene with a benzene stream containing 75 to 100 wt.% benzene. The reaction is conducted in an isothermal ethylation section of a reactor, which also includes a benzene stripping section, where the unreacted benzene is thermally stripped from the ethylation products. Integrated, countercurrent vapor and liquid traffic is maintained between the ethylation section and the benzene stripping section.

    [0013] U.S. Patent Application Serial No. 10/252,767 and the related publication WO2004/026797 disclose a process for the production of ethylbenzene by reacting benzene with a dilute ethylene stream containing 20 to 80 wt.% ethylene and ethane. The reaction takes place in one of a series of series-connected reaction zones in the presence of an alkylation catalyst including a molecular sieve such as MCM-22. The temperature and pressure of the reaction zone being such that the benzene and dilute ethylene feedstock are under liquid phase conditions. The intermediate products between reaction zones are cooled and a portion of alkane, e.g., ethane, in the intermediate products is removed to maintain liquid phase by avoiding accumulation of ethane from zone to zone. A comparative example is given of a simulated process carried out in an adiabatic fixed bed reactor and having no inter-stage ethane removal. The ethylene conversion in the fourth bed was only 88.0 %.

    [0014] This invention relates a process for producing an alkylated aromatic compound in predominantly liquid phase alkylation reactor with an alkene feedstock containing alkene and at least 1 mol.% alkane without inter-zone alkane removal.

    SUMMARY OF THE INVENTION



    [0015] In one embodiment, this invention relates to a process for producing an alkylated aromatic compound in a reactor having a plurality of reaction zones including a first reaction zone and a second reaction zone, the process comprises the steps of:
    1. (a) introducing a first feedstock and a second feedstock to the first reaction zone, wherein the first feedstock comprises an alkylatable aromatic compound(s), wherein the second feedstock comprises an alkene and at least 1 mol.% alkane;
    2. (b) contacting the first feedstock and the second feedstock with a first catalyst in the first reaction zone to produce a first effluent, the first reaction zone being maintained under conditions such that the first reaction zone is predominately liquid phase, wherein the first effluent comprises an alkylated aromatic compound and alkane;
    3. (c) cooling the first effluent without separation of the alkane from the first effluent;
    4. (d) supplying at least a portion of the cooled first effluent and a third feedstock to the second reaction zone, wherein the third feedstock comprises an alkene; and
    5. (e) contacting the at least a portion of the cooled first effluent and the third feedstock with a second catalyst in the second reaction zone to produce a second effluent, the second reaction zone being maintained under conditions such that the second reaction zone is predominately liquid phase.


    [0016] In another embodiment, the process comprises another step of separating the first and second effluents to recover the alkylated aromatic compound. In yet another embodiment, the process comprises another step of separating at least a portion of liquid at the bottom of a reaction zone prior to the liquid exiting for cooling. In yet another embodiment, the process comprises another step of feeding at least a portion of vapor and/or liquid effluent at the bottom of a reaction zone prior to the liquid exiting for cooling to a downstream reaction zone.

    [0017] In yet another embodiment, the process comprises a further step of contacting the first feedstock and the fourth feedstock with an alkylation catalyst in a by-passable pre-reactor upstream of the reactor, wherein the fourth feedstock comprises an alkene. In another embodiment, the process comprises a further step of contacting the second feedstock from the reactor under alkylation conditions with an alkylation catalyst in a finishing-reactor downstream of the reactor.

    [0018] In one aspect of the above embodiment, the first and second catalysts is a molecular sieve selected from the group consisting of MCM-22, MCM-36, MCM-49, MCM-56, beta zeolite, faujasite, mordenite, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, zeolite Y, Ultrastable Y (USY), Dealuminized Y, rare earth exchanged Y (REY), ZSM-3, ZSM-4, ZSM-18, ZSM-20, or any combination thereof. In a preferred embodiment, the first and second catalysts have at least one catalyst composition. In an alternative embodiment, at least one reaction zone has a first catalyst composition and at least another reaction zone has a second catalyst composition.

    [0019] In yet another aspect of any one of the above embodiments, the conditions in steps (b) and (e) include a temperature of 100 to 285°C (212 to 500°F) and a pressure of 689 to 4601 kPa-a (100 to 667 psia).

    [0020] In another embodiment of this invention, the second, the third, and the fourth feedstocks comprise a mixture of first alkene component and a second alkene component. The first alkene component comprises 80 mol.% to 100 mol.% of the alkenes. The second alkene component comprises at least 10 mol.% alkene. Preferably, the second alkene component comprises from 20 to 80 mol.% alkene.

    [0021] In one aspect of any one of the above embodiments, the second, the third, and the fourth feedstocks are made by 1) mixing the first alkene component and the second alkene component; and 2) adjusting the mixed component to the conditions of steps (b) and/or (e). In another aspect of any one of the above embodiments, the second feedstock is made by 1) adjusting the first alkene component and the second alkene component separately to the conditions of steps (b) or (e); and 2) mixing the conditioned first alkene component and the conditioned second alkene component.

    [0022] In an alternative embodiment of this invention, the above mentioned processes are suitable for retrofitting an existing ethylbenzene or cumene plant with a vapor, liquid, or mixed phase alkylation reactor. In yet another embodiment of this invention, the above mentioned processes are suitable for retrofitting an existing AlCl3 or BF3 ethylbenzene or cumene plant.

    [0023] In a preferred embodiment, the alkylated aromatic compound comprises ethylbenzene, the first feedstock comprises benzene, and the second, the third and the fourth feedstocks comprise a mixture of ethylene, methane, and ethane.

    [0024] In another preferred embodiment, the alkylated aromatic compound comprises cumene, the first feedstock comprises benzene, and the second, the third and the fourth feedstocks comprise a mixture of propylene, propane, methane, and ethane.

    [0025] In yet another preferred embodiment, said second effluent comprises said alkylated aromatic compound and polyalkylated aromatic compound(s) and the process further comprises;
    1. (a) separating at least a portion the first and/or second effluents to recover the polyalkylated aromatic compound(s) to form a transalkylation feed stream; and
    2. (b) contacting at least a portion of the transalkylation feed stream with a fourth feedstock in the presence of a transalkylation catalyst to produce a transalkylation effluent under transalkylation conditions, wherein the fourth feedstock comprises an alkylatable aromatic compound(s), the transalkylation effluent which comprises the alkylated aromatic compound.


    [0026] The above embodiment may further comprise the step of separating the transalkylation effluent to recover the alkylated aromatic compound.

    [0027] In one aspect of the above embodiments, the transalkylation catalyst is a molecular sieve selected from the group consisting of MCM-22, MCM-36, MCM-49 and MCM-56, beta zeolite, faujasite, mordenite, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, zeolite Y, Ultrastable Y (USY), Dealuminized Y, rare earth exchanged Y (REY), ZSM-3, ZSM-4, ZSM-18, ZSM-20, or any combination thereof. In another aspect of the above embodiments, the transalkylation conditions of the transalkylation zone include temperature of 100 to 450°C (212 to 842°F) and a pressure of 689 to 4601 kPa-a (100 to 667 psia).

    [0028] In one preferred embodiment, the alkylated aromatic compound comprises ethylbenzene. In another preferred embodiment, the alkylated aromatic compound comprises cumene.

    DESCRIPTION OF THE DRAWINGS



    [0029] Figures 1 and 2 are flow diagrams of a process for producing ethylbenzene in accordance with the examples of the invention.

    DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS


    Detail Description of the Process



    [0030] Referring to one embodiment of this invention as illustrated in Figure 1, a reactor 20 has three reaction zones, a first reaction zone 35, a second reaction zone 47, and a third reaction zone 59. A first feedstock comprising an alkylatable aromatic compound, is fed to a by-passable reactive guard bed 25 via line 7 and further via line 9. A first alkene component comprising a concentrate alkene via line 1 is premixed with a second alkene component comprising dilute alkene via line 3 to form a second feedstock comprising an alkene and at least 1 mol.% alkane. The second feedstock is fed to the by-passable reactive guard bed 25 via line 13. A portion of both the first feedstock and the second feedstock may by-pass the reactive guard bed 25 via line 19. The reactive guard bed 25 may contain alkylation catalyst, e.g., MCM-22. The reactive guard bed 25 typically operates at or near 100% alkene conversion, but may operate at lower conversion so that the effluent of the reactive guard bed 25 leaving via line 27 is composed of alkylated aromatic compound (e.g., ethylbenzene or cumene), any unreacted alkene (e.g., ethylene), unreacted alkylatable aromatic compound (e.g., benzene), and unreacted light impurities (e.g., hydrogen, nitrogen, methane, and ethane). The reactive guard bed effluent in line 27 is further combined with the stream in line 19 and then passed to a heat exchanger 21 via line 23. An effluent of the heat exchanger 21 is fed to the reaction zone 35 via line 33. Additional second feedstock is fed to the reaction zone 35 via line 31. The conditions (temperature and pressure) of the reaction zone 35 is such that the mixed feedstocks is in predominantly liquid phase. The reaction zone 35 is packed with an alkylation catalyst, e.g., MCM-22. The unreacted alkylatable aromatic compound in the stream of line 33 is alkylated with the alkene in the additional second feedstock in line 31. An effluent from the reaction zone 35 is withdrawn from the reaction zone 35 via line 37. The conditions of the reaction zone 35 are such that the reaction zone 35 is maintained in predominantly liquid phase. The alkylation catalyst of the reaction zone 35 is typically operated at or near to 100% ethylene conversion.

    [0031] An effluent from the reaction zone 35 is withdrawn from the reaction zone 35 via line 37, passed to a heat exchanger 39 prior to injection into the reaction zone 47 via line 41. A portion of the effluent from the reaction zone 35 may by-pass the heat exchanger 39 via line 45. Additional second feedstock is fed to the reaction zone 47 via line 43. The conditions of the reaction zone 47 are such that the reaction zone 47 is maintained in predominantly liquid phase. The alkylation catalyst of the reaction zone 47 is typically operated at or near to 100% ethylene conversion. An effluent from the reaction zone 47 is withdrawn from reaction zone 47 via line 49, passed to the heat exchanger 51 prior to injection in the reaction zone 59 via line 53. Again, a portion of the effluent from the reaction zone 47 may by-pass the heat exchanger 51 via line 57 and additional second feedstock is fed to reaction zone 59 via line 55. The conditions of the reaction zone 59 are such that the reaction zone 59 is maintained in predominantly liquid phase. The alkylation catalyst of the reaction zone 59 is typically operated at or near to 100% ethylene conversion. An effluent from the reaction zone 59 is withdrawn from reaction zone 59 via line 61, passed to the heat exchanger 62 prior to injection into a by-passable finishing-reactor 67 via line 64. Again, a portion of the effluent from the reaction zone 59 may by-pass the heat exchanger 62 via line 66 and additional second feedstock is fed to the by-passable finishing-reactor 67 via line 63. The conditions of the by-passable finishing-reactor 67 are such that the by-passable finishing-reactor 67 is maintained in predominantly liquid phase. A portion of the feed to the by-passable finishing-reactor 67 may by-pass the by-passable finishing-reactor 67 via line 71. The alkylation catalyst of the by-passable finishing-reactor 67 is typically operated at or near to 100% ethylene conversion.

    [0032] The effluent of line 69 from the reaction zone 67 combining with the by-pass stream via line 71 leaves by-passable finishing-reactor 67 via line 73. The stream in line 73 containing the desired alkylated aromatic effluent as well as any unreacted alkene, unreacted alkylatable aromatic compound, polyalkylated aromatic compounds, methane, and ethane further via line 75 is fed to a separation block 77. The unreacted benzene is separated and withdrawn via line 97 recycling to the reaction zones. An overhead effluent of the separation block 77 containing benzene and lights (e.g., ethane, and methane), is withdrawn from separation block 77 via line 79 to a striper 81 where benzene is striped and withdrawn via line 87. The lights are removed via line 83. Heavies comprising the polyalkylated aromatic compounds separated from the separation block 77 are withdrawn from the separation block 77 via line 89 to a further separation block 91 where the polyalkylated aromatic compounds are separated and withdrawn via line 85 to the striper 81, optionally combined with additional polyalkylated aromatic compounds via line 82. The combined polyalkylated aromatic compounds strips the benzene component in the striper 81. A bottom stream of the striper 81 is withdrawn via line 87 further combines with additional first feedstock via line 99. The combined stream is fed to a transalkylation reactor 103 via line 101. The transalkylation reactors 103 is operated under conditions such that 20-100 wt.%, preferably 40 to 80 wt.%, of the polyalkylated aromatic compounds in the stream of line 101 are converted to alkylated aromatic compound. An effluent in line 105 from the transalkylation reactors is combined with the effluent of line 73 from the by-passable finishing reactor 67 as it passes to the separation block 77. The alkylated aromatic compound is separated as a effluent stream withdrawn via line 93.

    [0033] Referring to another embodiment of this invention as illustrated in Figure 2, a reactor 221 has three reaction zones, a reaction zone 235 , a reaction zone 247, and a reaction zone 259. A first feedstock comprising alkylatable aromatic compound is fed to a by-passable reactive guard bed 225 via line 207 and further via line 209. A second feedstock comprising alkene and at least 1 mol.% of alkane is fed to a reactive guard bed 225 via line 213. The second feedstock is a mixture of a first alkene component comprising a concentrate alkene and/or a second alkene component comprising dilute alkene. A portion of both the first feedstock and the second feedstock may by-pass the reactive guard bed 225 via line 219. The reactive guard bed 225 may contain alkylation catalyst, e.g., MCM-22. The reactive guard bed 225 typically operates at or near 100% alkene conversion, but may operate at lower conversion so that an effluent of line 227 leaving the reactive guard bed 225 is composed of alkylated aromatic compound (e.g., ethylbenzene or cumene), any unreacted alkene (e.g., ethylene), unreacted alkylatable aromatic compound (e.g., benzene), and unreacted light impurities (e.g., hydrogen, nitrogen, methane, and ethane). The reactive guard bed effluent in line 227 is further combined with the stream of line 219 and then passed to a heat exchanger 221 via line 223 before passing to the reaction zone 235 via line 233. Additional second feedstock is fed to the reaction zone 235 via line 231. The addition second feedstock is a mixture of a first alkene component comprising a concentrate ethylene and/or a second alkene component comprising dilute alkene, which may be different in composition from the second feedstock feeding through line 213. The conditions (temperature and pressure) of the reaction zone 235 is such that the mixed feedstocks is in predominantly liquid phase. The reaction zone 235 is packed with an alkylation catalyst, e.g., MCM-22. The unreacted alkylatable aromatic compound in feed of line 233 is alkylated with the alkene in the additional second feedstock via line 231. An effluent from the reaction zone 235 is withdrawn from the reaction zone 235 via line 237. The alkylation catalyst of the reaction zone 235 is typically operated at or near to 100% ethylene conversion.

    [0034] The effluent from the reaction zone 235 is withdrawn from the reaction zone 235 via line 237, passed to a heat exchanger 239 prior to injection in the reaction zone 247 via line 241. A portion of the effluent from the reaction zone 235 may by-pass the heat exchanger 239 via line 245. Another additional second feedstock is fed to the reaction zone 247 via line 243. The conditions of the reaction zone 247 are such that the reaction zone 247 is maintained in predominantly liquid phase. The alkylation catalyst of the reaction zone 247 is typically operated at or near to 100% ethylene conversion. An effluent from the reaction zone 247 is withdrawn from reaction zone 247 via line 249, passed to a heat exchanger 251 prior to injection in the reaction zone 259 via line 253. Again, a portion of the effluent from the reaction zone 247 may by-pass the heat exchanger 251 via line 257 and additional second feedstock is fed to reaction zone 259 via line 255. The conditions of the reaction zone 259 are such that the reaction zone 259 is maintained in predominantly liquid phase. The alkylation catalyst of the reaction zone 259 is typically operated at or near to 100% ethylene conversion. An effluent from the reaction zone 259 is withdrawn from reaction zone 259 via line 261, passed to the heat exchanger 262 prior to injection in a by-passable finishing-reactor 267 via line 264. Again, a portion of the effluent from the reaction zone 259 may by-pass the heat exchanger 262 via line 266 and additional second feedstock is fed to the by-passable finishing-reactor 267 via line 263. The conditions of the by-passable finishing-reactor 267 are such that the by-passable finishing-reactor 267 is maintained in predominantly liquid phase. A portion of the feed to the by-passable finishing-reactor 267 may by-pass the by-passable finishing-reactor 267 via line 271. The alkylation catalyst of the by-passable fmishing-reactor 267 is typically operated at or near to 100% ethylene conversion.

    [0035] An effluent in line 269 from the reaction zone 269 combining with the by-pass stream via line 271 which contains the desired alkylated aromatic product as well as any unreacted alkene, unreacted alkylatable aromatic compound, polyalkylated aromatic compounds, methane, ethane. The combined stream is withdrawn via line 273 and further via line 290 feeding to a separation block 277. An overhead effluent of the separation block 277 containing benzene and lights (e.g., ethane, and methane), is withdrawn from separation block 277 via line 279 to a striper 281 where benzene is striped and withdrawn via line 287. The lights are removed via line 283. Heavies comprising the unreacted benzene and the polyalkylated aromatic compounds separated from the separation block 277 are withdrawn from the separation block 277 via line 289 to a separation block 296 where the unreacted benzene is separated as an overhead effluent and recycled via line 297. A bottom stream comprising polyalkylated aromatic compounds is withdrawn via line 298 to a further separation block 291. The polyalkylated aromatic compounds are separated and withdrawn via line 285 to a striper 281, optionally combined with additional polyalkylated aromatic compounds via line 282. The combined polyalkylated aromatic compounds strip the benzene component in the striper 281 and withdrawn via line 287 further combines with additional first feedstock via line 299. The combined stream is fed to a transalkylation reactor 303 via line 301. The transalkylation reactors 303 is operated under conditions such that 20-100 wt.%, preferably 40 to 80 wt.%, of the polyalkylated aromatic compounds are converted to alkylated aromatic compound. The effluent of line 305 from the transalkylation reactors is combined with the effluent of line 273 from the reactor 267 as it passes to the separation block 277. The alkylated aromatic compound is separated as a effluent stream withdrawn via line 293.

    Feedstocks



    [0036] The first feedstock comprises an alkylatable aromatic compound. The term "aromatic" in reference to the alkylatable compounds which are useful herein is to be understood in accordance with its art-recognized scope which includes alkyl substituted and unsubstituted mono- and polynuclear compounds. Compounds of an aromatic character, which possess a heteroatom are also useful provided they do not act as catalyst poisons under the reaction conditions selected.

    [0037] Substituted aromatic compounds which can be alkylated herein must possess at least one hydrogen atom directly bonded to the aromatic nucleus. The aromatic rings can be substituted with one or more alkyl, aryl, alkaryl, alkoxy, aryloxy, cycloalkyl, halide, and/or other groups which do not interfere with the alkylation reaction.

    [0038] Suitable aromatic hydrocarbons include benzene, naphthalene, anthracene, naphthacene, perylene, coronene, and phenanthrene, with benzene being preferred.

    [0039] Suitable alkyl substituted aromatic compounds include toluene, xylene, isopropylbenzene, normal propylbenzene, alpha-methylnaphthalene, ethylbenzene, mesitylene, durene, cymenes, butylbenzene, pseudocumene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, isoamylbenzene, isohexylbenzene, pentaethylbenzene, pentamethylbenzene; 1,2,3,4-tetraethylbenzene; 1,2,3,5-tetramethylbenzene; 1,2,4-triethylbenzene; 1,2,3-trimethylbenzene, m-butyltoluene; p-butyltoluene; 3,5-diethyltoluene; o-ethyltoluene; p-ethyltoluene; m-propyltoluene; 4-ethyl-m-xylene; dimethylnaphthalenes; ethylnaphthalene; 2,3-dimethylanthracene; 9-ethylanthracene; 2-methylanthracene; o-methylanthracene; 9,10-dimethylphenanthrene; and 3-methyl-phenanthrene. Higher molecular weight alkylaromatic hydrocarbons can also be used as starting materials and include aromatic hydrocarbons such as are produced by the alkylation of aromatic hydrocarbons with olefin oligomers. Such products are frequently referred to in the art as alkylate and include hexylbenzene, nonylbenzene, dodecylbenzene, pentadecylbenzene, hexyltoluene, nonyltoluene, dodecyltoluene, pentadecytoluene, etc. Very often alkylate is obtained as a high boiling fraction in which the alkyl group attached to the aromatic nucleus varies in size from about C6 to about C12.

    [0040] Reformate containing substantial quantities of benzene, toluene and/or xylene constitutes a particularly useful feed for the alkylation process of this invention. Although the process is particularly directed to the production of ethylbenzene from polymer grade and dilute ethylene, it is equally applicable to the production of other C7-C20 alkylaromatic compounds, such as cumene, as well as C6+ alkylaromatics, such as C8-C16 linear and near linear alkylbenzenes.

    [0041] The second feedstock comprises an alkene compound. Typically, the second feedstock includes a concentrated alkene feedstock (e.g., grade alkene) and a dilute alkene feedstock (e.g., catalytic cracking off-gas).

    [0042] The concentrated alkene alkylating agent of the feedstock useful in the process of this invention includes an alkene feed comprised of at least 80 mol.% of the alkene and preferably at least 99 mol.% to 100 mol.%.

    [0043] The dilute alkylating agent of the feedstock useful in the process of this invention includes a dilute alkene feed which contains at least one alkene and optionally at least one alkane. For example, where the alkene is ethylene, the alkane may be ethane and/or methane. Typically, the dilute alkene feed comprises at least 10 mol.% of the alkene, preferably from 20 to 80 mol.% of the alkene. One particularly useful feed is the dilute ethylene stream obtained as an off gas from the fluid catalytic cracking unit of a petroleum refinery.

    [0044] In one embodiment of the invention, the second feedstock includes a concentrated alkene feedstock only. In another embodiment of the invention, the second feedstock includes a dilute alkene feedstock only. In yet another embodiment of the invention, the second feedstock is a mixture of a plurality of feedstocks having alkene and alkane e.g., at least one concentrated alkene feedstock having at least 80 mol.% alkene and at least one dilute alkene feedstock having 10-80 mol.% alkene.

    [0045] In one embodiment, a plurality of feedstocks having alkene may be pre-mixed before being brought to the suitable conditions for alkylation reaction. In another embodiment of the invention, a plurality of feedstocks having alkene may be separately conditioned to the suitable conditions before feeding to the reaction zone(s). The relative amount of each separately conditioned alkene feedstock to be mixed and fed to the reaction zone(s) is varied based on the reaction conditions, catalyst (activity and amount), and space hour velocity. In one embodiment, the first few reaction zones of the reactor are fed with a second feedstock having higher alkene content than that of the second feedstock for the second few reaction zones.

    Alkylation and Transalkylation Reactions



    [0046] The alkylation reaction zone is operated in a predominantly liquid phase. In one embodiment, the inlet conditions of the inlet portion of the reaction zone include a temperature of 100 to 260°C (212 to 500°F) and a pressure of 689 to 4601 kPa-a (100 to 667 psia), preferably, a pressure of 1500 to 3500 kPa-a (218 to 508 psia).The conditions of the downstream reaction zone include a temperature of 150 to 285°C (302 to 545°F) and a pressure of 689 to 4601 kPa-a (100 to 667 psia), preferably, a pressure of 1500 to 3000 kPa-a (218 to 435 psia), a WHSV based on alkene for overall reactor of 0.1 to 10 h-1, preferably, 0.2 to 2 h-1, more preferably, 0.5 to 1 h-1, or a WHSV based on both alkene and benzene for overall reactor of 10 to 100 h-1, preferably, 20 to 50 h-1. Typically temperature is higher in the downstream portion of the reaction zone than the inlet portion of the reaction zone due to the exothermic nature of the alkylation reaction. The alkylatable aromatic compound is alkylated with the alkene in the second feedstock in the presence of an alkylation catalyst in a reactor having at least two reaction zones. The reaction zones are typically located in a single reactor vessel, but may include a reaction zone including an alkylation catalyst bed, located in separate vessel which may be a by-passable and which may operate as a reactive guard bed. The catalyst composition used in the reactive guard bed may be different from the catalyst composition used in the alkylation reactor. The catalyst composition used in the reactive guard bed may have multiple catalyst compositions. At least the first alkylation reaction zone, and normally each alkylation reaction zone, is operated under conditions effective to cause alkylation of the alkylatable aromatic compound with the alkene component of the second feedstock in the presence of a alkylation catalyst.

    [0047] The effluent from the first alkylation reaction zone (first product) comprises the desired alkylated aromatic product, unreacted alkylatable aromatic compound, any unreacted alkene (alkene conversion is expected to be at least 90 mol.%, preferably, about 98-99.9999 mol.%) and the alkane component and the other impurities. The temperature, pressure, and composition of the effluent is such that the effluent is maintained in predominantly liquid phase when the effluent exits the reaction zone. The temperature of the effluent is typically higher than the temperature of the feed because the alkylation reaction is generally exothermic. To maintain the next reaction zone in liquid-phase, the effluent is typically removed from the first reaction zone and cooled. The effluent can also be cooled by internal cooling system between reaction zones. The cooling step does not remove any unreacted alkane except to the extent of leak or loss due to equipment and operation. At least a portion of the effluent is fed to the second alkylation reaction zone where additional second feedstock is added for reaction with the unreacted alkylatable aromatic compound with a second catalyst. Where the process employs more than two alkylation reaction zones, the effluent from each zone is fed to the next zone with additional second feedstock. The effluent from the second reaction zone contains more unreacted alkane and more alkylated aromatic compound. Furthermore, at least a portion the effluent from the second alkylation reaction zone and/or other zones can be fed directly or indirectly to a transalkylation unit.

    [0048] The term "predominately liquid phase" used herein is understood as having at least 95 wt.% liquid phase, preferably, 98 wt.%, more preferably, 99 wt.%, and most preferably, 99.5 wt.%.

    [0049] In addition to, and upstream of, the alkylation zones, the alkylation reaction system may also include a by-passable reactive guard bed normally located in a pre-reactor separate from the remainder of the alkylation reactor. The reactive guard bed may also loaded with alkylation catalyst, which may be the same or different from the catalyst used in the multi-stage alkylation reaction system. The reactive guard bed is maintained from under ambient or up to alkylation conditions. At least a portion of alkylatable aromatic compound and typically at least a portion of the second feedstock are passed through the reactive guard bed prior to entry into the first reaction zone of the alkylation reaction zones in the reactor. The reactive guard bed not only serves to affect the desired alkylation reaction but is also used to remove any reactive impurities in the feeds, such as nitrogen compounds, which could otherwise poison the remainder of the alkylation catalyst. The catalyst in the reactive guard bed is therefore subject to more frequent regeneration and/or replacement than the remainder of the alkylation catalyst and hence the guard bed is normally provided with a by-pass circuit so that the alkylation feedstock can be fed directly to the series connected alkylation reaction zones in the reactor when the guard bed is out of service. The reactive guard bed operates in predominantly liquid phase and in co-current upflow or downflow operation.

    [0050] The alkylation reactor used in the process of the present invention is normally operated so as to achieve essentially complete conversion of the alkene in the second feedstock. However, for some applications, it may be desirable to operate at below 100% alkene conversion. The employment a separate finishing reactor downstream of the multi-zones alkylation reactor may be desirable under certain conditions. The finishing reactor would also contain alkylation catalyst, which could be the same or different from the catalyst used in the alkylation reactor and could be operated under predominantly liquid phase alkylation conditions.

    [0051] The alkylation reactor used in the process of the present invention is highly selective to the desired alkylated product, such as ethylbenzene, but normally produces at least some polyalkylated species. Thus the effluent from the final alkylation reaction zone is supplied to a transalkylation reactor which is normally separate from the alkylation reactor. The transalkylation reactor produces additional alkylated product by reacting the polyalkylated species with aromatic compound.

    [0052] Particular conditions for carrying out the liquid phase alkylation of benzene with ethylene may a temperature of from about 120 to 285°C, preferably, a temperature of from about 150 to 260°C, a pressure of 689 to 4601 kPa-a (100 to 667 psia), preferably, a pressure of 1500 to 3000 kPa-a (218 to 435 psia), a WHSV based on ethylene for overall reactor of 0.1 to 10 h-1, preferably, 0.2 to 2 h-1, more preferably, 0.5 to 1 h-1, or a WHSV based on both ethylene and benzene for overall reactor of 10 to 100 h-1, preferably, 20 to 50 h-1, and a mole ratio of benzene to ethylene from about 1 to about 10.

    [0053] Particular conditions for carrying out the predominantly liquid phase alkylation of benzene with propylene may include a temperature of from about 80 to 160°C, a pressure of about 680 to about 4800 kPa-a; preferably from about 100 to 140°C and pressure of about 2000 to 3000 kPa-a, a WHSV based on propylene of from about 0.1 about 10 hr-1, and a mole ratio of benzene to ethylene from about 1 to about 10.

    [0054] Where the alkylation system includes a reactive guard bed, it is operated under at least partial liquid phase conditions. The guard bed will preferably operate at a temperature of from about 120 to 285°C, preferably, a temperature of from about 150 to 260°C, a pressure of 689 to 4601 kPa-a (100 to 667 psia), preferably, a pressure of 1500 to 3000 kPa-a (218 to 435 psia), a WHSV based on ethylene for overall reactor of 0.1 to 10 h-1, preferably, 0.2 to 2 h-1, more preferably, 0.5 to 1 h-1, or a WHSV based on both ethylene and benzene for overall reactor of 10 to 100 h-1, preferably, 20 to 50 h-1, and a mole ratio of benzene to ethylene from about 1 to about 10.

    [0055] The polyalkylated aromatic compounds in the effluents may be separated for transalkylation with alkylatable aromatic compound(s). The alkylated aromatic compound is made by transalkylation between polyalkylated aromatic compounds and the alkylatable aromatic compound.

    [0056] The transalkylation reaction takes place under predominantly liquid phase conditions. Particular conditions for carrying out the predominantly liquid phase transalkylation of polyethylbenzene(s) with benzene may include a temperature of from about 150° to about 260°C, a pressure of 696 to 4137 kPa-a (101 to 600 psia), a WHSV based on the weight of the polyethylbenzene(s) feed to the reaction zone of from about 0.5 to about 100 hr-1 and a mole ratio of benzene to polyethylbenzene(s) of from 1:1 to 30:1, preferably, 1:1 to 10:1, more preferably, 1:1 to 5:1.

    [0057] In another embodiment, the transalkylation reaction takes place under vapor phase conditions. Particular conditions for carrying out the vapor phase transalkylation of polyethylbenzenes with benzene may include a temperature of from about 350 to about 450°C, a pressure of 696 to 1601 kPa-a (101 to 232 psia), a WHSV based on the weight of the polyethylbenzene(s) feed to the reaction zone of from about 0.5 to about 20 hr-1, preferably, from about 1 to about 10 hr-1, and a mole ratio of benzene to polyethylbenzene(s) of from 1:1 to 5: 1, preferably, 2:1 to 3:1.

    [0058] In an alternative embodiment of this invention, the above mentioned processes are suitable for retrofitting an existing ethylbenzene or cumene plant with a vapor, liquid, or mixed phase alkylation reactor. In particular, the process of this invention may be used to retrofit an existing ethylbenzene or cumene plant using polymer grade or chemical grade ethylene or propylene with minimum amount of new equipments, such as, extra compressors for the second feedstock, extra-separation column for light gas and aromatics, and other equipment.

    Catalysts



    [0059] The alkylation and transalkylation catalyst used in the process of the invention is not critical but normally comprises at least one of MCM-22, MCM-49, MCM-36, MCM-56, beta zeolite, faujasite, mordenite, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2 and optionally SAPO molecular sieves (e.g., SAPO-34 and SAPO-41).

    [0060] MCM-22 and its use to catalyze the synthesis of alkylaromatics, including ethylbenzene, is described in U.S. Patent Nos. 4,992,606; 5,077,445; and 5,334,795. PSH-3 is described in U.S Patent No. 4,439,409. SSZ-25 and its use in aromatics alkylation are described in U.S. Patent No. 5,149,894. ERB-1 is described in European Patent No.0293032. ITQ-1 is described in U.S. Patent No 6,077,498. ITQ-2 is described in International Patent Publication No. WO97/17290 and WO01/21562. MCM-36 is described in U.S. Patent Nos. 5,250,277 and 5,292,698. U.S. Patent No. 5,258,565 describes the synthesis of alkylaromatics, including ethylbenzene, using a catalyst comprising MCM-36. MCM-49 is described in U.S Patent No. 5,236,575. The use of MCM-49 to catalyze the synthesis of alkylaromatics, including ethylbenzene, is described in U.S. Patent Nos. 5,508,065 and 5,371,310. MCM-56 is described in U.S. Patent No. 5,362,697. The use of MCM-56 to catalyze the synthesis of alkylaromatics including ethylbenzene is described in U.S. Patent Nos. 5,557,024 and 5,453,554.

    [0061] Alternatively, the alkylation and transalkylation catalyst can comprise a medium pore molecular sieve having a Constraint Index of 2-12 (as defined in U.S. Patent No. 4,016,218), including ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, and ZSM-48. ZSM-5 is described in detail in U.S. Patent Nos. 3,702,886 and Re. 29,948. ZSM-11 is described in detail in U.S. Patent No. 3,709,979. ZSM-12 is described in U.S. Patent No. 3,832,449. ZSM-22 is described in U.S. Patent No. 4,556,477. ZSM-23 is described in U.S. Patent No. 4,076,842. ZSM-35 is described in U.S. Patent No. 4,016,245. ZSM-48 is more particularly described in U.S. Patent No. 4,234,231.

    [0062] As a further alternative, the alkylation and transalkylation catalyst can comprise a large pore molecular sieve having a Constraint Index less than 2. Suitable large pore molecular sieves include zeolite beta, zeolite Y, Ultrastable Y (USY), Dealuminized Y (Deal Y), mordenite, ZSM-3, ZSM-4, ZSM-18, and ZSM-20. Zeolite ZSM-14 is described in U.S. Patent No. 3,923,636. Zeolite ZSM-20 is described in U.S. Patent No. 3,972,983. Zeolite Beta is described in U.S. Patent Nos. 3,308,069, and Re. No. 28,341. Low sodium Ultrastable Y molecular sieve (USY) is described in U.S. Patent Nos. 3,293,192 and 3,449,070. Dealuminized Y zeolite (Deal Y) may be prepared by the method found in U.S. Patent No. 3,442,795. Zeolite UHP-Y is described in U.S. Patent No. 4,401,556. Rare earth exchanged Y (REY) is described in U.S. Patent No. 3,524,820. Mordenite is a naturally occurring material but is also available in synthetic forms, such as TEA-mordenite (i.e., synthetic mordenite prepared from a reaction mixture comprising a tetraethylammonium directing agent). TEA-mordenite is disclosed in U.S. Patent Nos. 3,766,093 and 3,894,104.

    [0063] The same catalyst may be used in both the transalkylation zone and the alkylation zones of the present invention. Preferably, however, catalysts are chosen for the different alkylation zones and the transalkylation zone, so as to be tailored for the particular reactions catalyzed therein. In one embodiment of the present invention, a standard activity catalyst for example, 50% zeolite and 50% binder is used in the higher temperature alkylation catalyst beds and a higher activity catalyst for example, 75% zeolite and 25% binder is used in the lower temperature alkylation catalyst beds, while suitable transalkylation catalyst is used in the transalkylation zone. In such an embodiment, any finishing reactor zone could include a MCM-22 catalyst bed for predominantly liquid phase operation.

    [0064] In the process of the invention, the alkylation reaction in at least the first, and normally in each, of the alkylation reaction zones takes place under predominantly liquid phase conditions, such that the alkylatable aromatic compound is in the predominantly liquid phase.

    [0065] The invention will be more particularly described with reference to the following Examples.

    Examples


    Example 1: Liquid Phase Alkylation



    [0066] The following example is a computer simulation of benzene ethylation with ethylene in liquid phase. Simulation results were obtained using a proprietary numerical software package. Vapor-liquid equilibrium was calculated, the Soave-Redlich-Kwong Equation-of-State (with optimized interaction coefficients).

    [0067] The feed to each catalyst bed is characterized by a B/E ratio (Benzene to Ethylene molar ratio) and an E/E ratio (Ethylene to Ethane molar ratio). The very high E/E ratio is an indication of an ethylene feedstock with a polymer grade ethylene purity. This case is configured to operate in the liquid phase with high E/E ratio. The temperatures and pressures of the feed and effluent streams to each bed are sufficient to allow all liquid phase operation in the catalyst bed. The results of the simulation are shown in Table 1.
    Table 1
      Ethylene conversion (%)EB cumulative yield (mol. %)B/E ratioE/E ratioFraction LiquidT (°C)P (kPa-a)
    Bed 1 Feed -   21.0 261 1 222.2 4270
    Effluent 100 4.8 - - 1 246.3 4220
    Bed 2 Feed -   20.0 229 1 242.6 4210
    Effluent 100 9.0 - - 1 265 4165
    Bed 3 Feed -   19.1 218 1 222.9 4035
    Effluent 100 13.0 - - 1 246.4 3980
    Bed 4 Feed -   18.1 183 1 242.9 3980
    Effluent 100 16.9 - - 1 264.9 3915
    Bed 5 Feed -   17.2 166 1 223.5 3715
    Effluent 100 20.6 - - 1 246.4 3660
    Bed 6 Feed -   16.3 152 1 243.1 3660
      Effluent 100 24.1 - - 1 264.7 3590

    Example 2: Liquid Phase Alkylation with mixed ethylene feedstocks



    [0068] The following example is a computer simulation of mixed-phase/liquid-phase benzene ethylation with mixed ethylene feedstocks by the process of the present invention. The case is configured to operate in liquid-phase. The temperatures and pressures of the feed and effluent streams to each bed are sufficient to allow liquid-phase operation in the catalyst bed.. The results of the simulation are shown in Table 2.

    [0069] Option 1 for modification of the plant after addition of dilute ethylene has the characteristics shown in Table 2. The feed to each catalyst bed is characterized by a B/E ratio (Benzene to Ethylene molar ratio) and an E/E ratio (Ethylene to Ethane molar ratio). The E/E ratio is significantly lower than in the base-case (example 1) indicating a greater concentration of ethane and representative of dilute ethylene streams and/or mixed chemical/polymer grade and dilute ethylene streams. The entire contents of this dilute ethylene configuration operates in the liquid phase (after sufficient residence time is allowed downstream of the ethylene/ethane injectors to allow the ethylene/ethane to completely dissolve in the liquid. The Temperatures and Pressures of the feed and effluent streams to each bed are sufficient to allow all liquid phase operation in the catalyst bed.

    [0070] The E/E ratio decreases from bed to bed in the reactor because while the ethylene is consumed, the ethane builds up in the reactor. In addition, the average temperature of each pair of catalyst beds decreases down the length of the reactor to compensate for the ethane build-up and reduced pressure, due to pressure drop across the catalyst beds. In this way, a total liquid phase is maintained even in the presence of significant amounts of ethane, which, if maintained at base-case conditions, would cause the reaction mixture to be in a mixed-phase (liquid/vapor) state.
    Table 2
      Ethylene conversion (%)EB cumulative yield (%)B/E ratioE/E ratioFraction LiquidT (°C)P (kPa-a)
    Bed 1 Feed     15.9 4.5 1 225.7 4270
    Effluent 100 6     1 256.3 4220
    Bed 2 Feed     36.5 3.2 1 253.2 4210
    Effluent 100 8.2     1 264.8 4165
    Bed 3 Feed     13.6 2.1 1 179.9 3925
    Effluent 100 13.5     1 214.9 3870
    Bed 4 Feed     17.0 1.2 1 211.8 3870
    Effluent 100 17.2     1 235.8 3805
    Bed 5 Feed     14.5 1.0 1 180.4 3635
    Effluent 100 21     1 208.1 100
    Bed 6 Feed     31.2 0.42 1 206.9 3580
    Effluent 100 22.5     1 218.5 3510

    Example 3: Liquid Phase Alkylation with mixed ethylene feedstocks



    [0071] Option 2 for modification of the plant after addition of dilute ethylene has the characteristics shown in Table 3. The feed to each catalyst bed is characterized by a B/E ratio (Benzene to Ethylene molar ratio) and an E/E ratio (Ethylene to Ethane molar ratio). The E/E ratio is significantly lower than in the base-case (example 1) indicating a greater concentration of ethane and representative of dilute ethylene streams and/or mixed chemical/polymer grade and dilute ethylene streams. The entire contents of this dilute ethylene configuration operates in the liquid phase (after sufficient residence time is allowed downstream of the ethylene/ethane injectors to allow the ethylene/ethane to completely dissolve in the liquid. The Temperatures and Pressures of the feed and effluent streams to each bed are sufficient to allow all liquid phase operation in the catalyst bed.

    [0072] Similarly to example 2, the E/E ratio decreases from bed to bed in the reactor because while the ethylene is consumed, the ethane builds up in the reactor. In addition, the average temperature of each pair of catalyst beds decreases down the length of the reactor to compensate for the ethane build-up and reduced pressure, due to pressure drop across the catalyst beds. In this way, a total liquid phase is maintained even in the presence of significant amounts of ethane, which, if maintained at base-case conditions, would cause the reaction mixture to be in a mixed-phase (liquid/vapor) state.

    [0073] Dissimilar to example 2, the E/E ratio of the beds nearest the inlet is significantly larger than the E/E ratio of those same beds in example 2. This indicates that more chemical/polymer grade ethylene is introduced in the inlet beds and more dilute ethylene feed is introduced in the outlet beds. Consistent with this, the temperature of beds 2 & 4 in particular are much higher than the temperature of these same beds in example 2. Catalyst beds 1 & 2 tend to be close in temperature in both example 2 and example 3 because the total amount of C2 (ethylene and ethane).
    Table 3
      Ethylene conversion ( %)EB cumulative yield (%)B/E ratioE/E ratioFraction LiquidT (°C)P (kPa-a)
    Bed 1 Feed     15.1 15.0 1 214.2 4320
    Effluent 100 6.4     1 247.7 4270
    Bed 2 Feed     20.9 6.7 1 243.8 4210
    Effluent 100 10.2     1 264.7 4165
    Bed 3 Feed     14.6 6.4 1 222 4035
    Effluent 100 15.2     1 251.6 3980
    Bed 4 Feed     21.0 3.5 1 248.3 3980
    Effluent 100 18.3     1 266.3 3915
    Bed 5 Feed     14.4 1.2 1 179.6 3685
    Effluent 100 21.5     1 207.3 3630
    Bed 6 Feed     41.9 0.31 1 206 3630
    Effluent 100 22.5     1 214.5 3560


    [0074] When numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated.


    Claims

    1. A process for producing an alkylated aromatic compound in a reactor having a plurality of reaction zones including a first reaction zone and a second reaction zone, said process comprising the steps of:

    (a) introducing a first feedstock and a second feedstock to said first reaction zone, wherein said first feedstock comprises an alkylatable aromatic compound(s), wherein said second feedstock comprises an alkene and at least 1 wt.% alkane;

    (b) contacting said first feedstock and said second feedstock with a first catalyst in said first reaction zone to produce a first effluent, said first reaction zone being maintained under conditions such that said first reaction zone is predominately liquid phase, wherein said first effluent comprises an alkylated aromatic compound and alkane;

    (c) cooling said first effluent without separation of said alkane from said first effluent;

    (d) supplying at least a portion of said cooled first effluent and a third feedstock to said second reaction zone, wherein said third feedstock comprises an alkene; and

    (e) contacting said at least a portion of said cooled first effluent and said third feedstock with a second catalyst in said second reaction zone to produce a second effluent, said second reaction zone being maintained under conditions such that said second reaction zone is predominately liquid phase.


     
    2. The process of claim 1, wherein said first and second catalysts are a molecular sieve selected from the group consisting of MCM-22, MCM-36, MCM-49 and MCM-56, beta zeolite, faujasite, mordenite, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, zeolite Y, Ultrastable Y (USY), Dealuminized Y, rare earth exchanged Y (REY), ZSM-3, ZSM-4, ZSM-18, ZSM-20, or any combination thereof.
     
    3. The process of claim 1 wherein said conditions in steps (b) and (c) include a temperature of 120 to 285°C and a pressure of 689 to 4601 kPa-a (100 to 667 psia), a WHSV based on the weight of alkene of 0.1 to 10 h-1.
     
    4. The process of claim 1 wherein said second and third feedstocks comprise a first alkene component and a second alkene component.
     
    5. The process of claim 4 wherein said first alkene component comprises 99 mol.% to 100 mol.% of said alkenes.
     
    6. The process of claim 4 wherein said second alkene component comprises at least 20 mol.% alkene.
     
    7. The process of claim 4 wherein said second alkene component comprises from 20 to 80 mol.% alkene.
     
    8. The process of claim 1 wherein said second feedstock has the same composition as said third feedstock.
     
    9. The process of claim 1, further comprising the step of:

    (f) separating said second effluent to recover said alkylated aromatic compound.


     
    10. The process of claim 1 wherein said alkylated aromatic compound comprises ethylbenzene, said first feedstock comprises benzene, and said second feedstock and said third feedstock comprise a mixture of ethylene and ethane.
     
    11. The process of any preceding claim wherein said alkylated aromatic compound comprises cumene, said first feedstock comprises benzene, and said second feedstock and said third feedstock comprise a mixture of propylene and propane.
     
    12. The process of any preceding claim comprising the further step of contacting said first feedstock and a fourth feedstock with an alkylation catalyst in a by-passable pre-reactor upstream of said reactor, wherein said fourth feedstock comprises an alkene.
     
    13. The process of any preceding claim comprising the further step of contacting said second effluent under alkylation conditions with an alkylation catalyst in a finishing-reactor downstream of said reactor.
     
    14. A process as claimed in claims 1 to 8, wherein said second effluent comprises said alkylated aromatic compound and polyalkylated aromatic compounds and said process further comprises;

    (a) separating at least a portion said first and/or second effluents to recover said polyalkylated aromatic compound(s) to form a transalkylation feed stream; and

    (b) contacting at least a portion of said transalkylation feed stream with a fourth feedstock in the presence of a transalkylation catalyst to produce a transalkylation effluent under transalkylation conditions, wherein said fourth feedstock comprises an alkylatable aromatic compound(s), said transalkylation effluent which comprises said alkylated aromatic compound.


     
    15. The process of claim 14, further comprising the steps of:

    (c) separating said transalkylation effluent to recover said alkylated aromatic compound.


     
    16. The process of claim 14, wherein said transalkylation catalyst is a molecular sieve selected from the group consisting of MCM-22, MCM-36, MCM-49 and MCM-56, beta zeolite, faujasite, mordenite, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, zeolite Y, Ultrastable Y (USY), Dealuminized Y, rare earth exchanged Y (REY), ZSM-3, ZSM-4, ZSM-18, ZSM-20, or any combination thereof.
     
    17. The process of claim 14, wherein said transalkylation conditions include a temperature of 150 to 260°C and a pressure of 696 to 4137 kPa-a (101 to 600 psia), a WHSV based on the weight of said polyalkylated aromatic compounds of about 0.5 to 100 h-1, a mole ratio of said alkylatable aromatic compound to said polyalkylated aromatic compounds of 1:1 to 10:1.
     
    18. The process of claims 1 to 8, wherein said alkylate aromatic compound is ethylbenzene.
     
    19. The process of claims 1 to 8, wherein said alkylated aromatic compound is cumene.
     


    Ansprüche

    1. Verfahren zur Herstellung einer alkylierten aromatischen Verbindung in einem Reaktor mit einer Mehrzahl von Reaktionszonen, einschließlich einer ersten Reaktionszone und einer zweiten Reaktionszone, mit den Schritten:

    (a) Einbringen eines ersten Einsatzmaterials und eines zweiten Einsatzmaterials in die erste Reaktionszone, wobei das erste Einsatzmaterial alkylierbare aromatische Verbindung(en) umfasst, wobei das zweite Einsatzmaterial Alken und mindestens 1 Gew.-% Alkan umfasst,

    (b) Inkontaktbringen des ersten Einsatzmaterials und des zweiten Einsatzmaterials mit einem ersten Katalysator in der ersten Reaktionszone, um einen ersten Abstrom herzustellen, wobei die erste Reaktionszone unter solchen Bedingungen gehalten wird, dass die erste Reaktionszone vornehmlich in flüssiger Phase ist, wobei der erste Abstrom eine alkylierte aromatische Verbindung und Alkan umfasst,

    (c) Abkühlen des ersten Abstroms ohne Abtrennung des Alkans aus dem ersten Abstrom,

    (d) Zuführen von mindestens einem Teil des abgekühlten ersten Abstroms und eines dritten Einsatzmaterials in die zweite Reaktionszone, wobei das dritte Einsatzmaterial Alken umfasst, und

    (e) Inkontaktbringen von mindestens einem Teil des abgekühlten ersten Abstroms und des dritten Einsatzmaterials mit einem zweiten Katalysator in der zweiten Reaktionszone, um einen zweiten Abstrom herzustellen, wobei die zweite Reaktionszone unter solchen Bedingungen gehalten wird, dass die zweite Reaktionszone vornehmlich in flüssiger Phase ist.


     
    2. Verfahren nach Anspruch 1, bei dem der erste und der zweite Katalysator Molekularsieb ausgewählt aus der Gruppe bestehend aus MCM-22, MCM-36, MCM-49 und MCM-56, Beta-Zeolith, Faujasit, Mordenit, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, Zeolith Y, Ultrastable Y (USY), Entaluminiertem Y, Seltenerd-ausgetauschtem Y (rare earth exchanged Y, REY), ZSM-3, ZSM-4, ZSM-18, ZSM-20 oder jedweder Kombination davon sind.
     
    3. Verfahren nach Anspruch 1, bei dem die Bedingungen in den Schritten (b) und (e) eine Temperatur von 120 bis 285°C und einen Druck von 689 bis 4601 kPa Überdruck (100 bis 667 psia), eine WHSV basierend auf dem Gewicht des Alkens von 0,1 bis 10 h-1 einschließen.
     
    4. Verfahren nach Anspruch 1, bei dem das zweite und das dritte Einsatzmaterial eine erste Alkenkomponente und eine zweite Alkenkomponente umfassen.
     
    5. Verfahren nach Anspruch 4, bei dem die erste Alkenkomponente 99 Mol-% bis 100 Mol-% von den Alkenen umfasst.
     
    6. Verfahren nach Anspruch 4, bei dem die zweite Alkenkomponente mindestens 20 Mol-% Alken umfasst.
     
    7. Verfahren nach Anspruch 4, bei dem die zweite Alkenkomponente 20 bis 80 Mol-% Alken umfasst.
     
    8. Verfahren nach Anspruch 1, bei dem das zweite Einsatzmaterial die gleiche Zusammensetzung wie das dritte Einsatzmaterial hat.
     
    9. Verfahren nach Anspruch 1, mit dem weiteren Schritt:

    (f) Trennen des zweiten Abstroms, um die alkylierte aromatische Verbindung zu gewinnen.


     
    10. Verfahren nach Anspruch 1, bei dem die alkylierte aromatische Verbindung Ethylbenzol umfasst, das erste Einsatzmaterial Benzol umfasst und das zweite Einsatzmaterial und das dritte Einsatzmaterial eine Mischung von Ethylen und Ethan umfassen.
     
    11. Verfahren nach einem der vorhergehenden Ansprüche, bei dem die alkylierte aromatische Verbindung Cumol umfasst, das erste Einsatzmaterial Benzol umfasst und das zweite Einsatzmaterial und das dritte Einsatzmaterial eine Mischung von Propylen und Propan umfassen.
     
    12. Verfahren nach einem der vorhergehenden Ansprüche, bei dem in einem weiteren Schritt das erste Einsatzmaterial und ein viertes Einsatzmaterial in einem umgehbaren Vorreaktor stromaufwärts von dem Reaktor mit Alkylierkatalysator in Kontakt gebracht werden, wobei das vierte Einsatzmaterial Alken umfasst.
     
    13. Verfahren nach einem der vorhergehenden Ansprüche, bei dem in einem weiteren Schritt der zweite Abstrom unter Alkylierbedingungen in einem Nachbehandlungsreaktor stromabwärts von dem Reaktor mit einem Alkylierkatalysator in Kontakt gebracht wird.
     
    14. Verfahren nach den Ansprüchen 1 bis 8, bei dem der zweite Abstrom die alkylierte aromatische Verbindung und polyalkylierte Verbindungen umfasst und bei dem ferner:

    (a) mindestens ein Teil des ersten und/oder zweiten Abstroms getrennt wird, um polyalkylierte aromatische Verbindung(en) zu gewinnen und einen Transalkylierungseinsatzmaterialstrom zu bilden, und

    (b) mindestens ein Teil des Transalkylierungseinsatzmaterialstroms in der Gegenwart von Transalkylierungskatalysator mit einem vierten Einsatzmaterialstrom in Kontakt gebracht wird, um unter Transalkylierungsbedingungen einen Transalkylierungsabstrom herzustellen, wobei das vierte Einsatzmaterial alkylierbare aromatische Verbindung(en) umfasst, wobei der Transalkylierungsabstrom die alkylierte aromatische Verbindung umfasst.


     
    15. Verfahren nach Anspruch 14, mit dem weiteren Schritt:

    (c) Trennen des Transalkylierungsabstroms, um die alkylierte aromatische Verbindung zu gewinnen.


     
    16. Verfahren nach Anspruch 14, bei dem der Transalkylierungskatalysator ein Molekularsieb ausgewählt aus der Gruppe bestehend aus MCM-22, MCM-36, MCM-49 und MCM-56, Beta-Zeolith, Faujasit, Mordenit, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, Zeolith Y, Ultrastable Y (USY), Entaluminiertem Y, Seltenerd-ausgetauschtem Y (rare earth exchanged Y, REY), ZSM-3, ZSM-4, ZSM-18, ZSM-20 oder jedweder Kombination davon ist.
     
    17. Verfahren nach Anspruch 14, bei dem die Transalkylierungsbedingungen eine Temperatur von 150 bis 260°C und einen Druck von 696 bis 4137 kPa Überdruck (101 bis 600 psia), eine WHSV basierend auf dem Gewicht der polyalkylierten aromatischen Verbindungen von etwa 0,5 bis 100 h-1 und ein Molverhältnis der alkylierbaren aromatischen Verbindung zu den polyalkylierten aromatischen Verbindungen von 1 : 1 bis 10 : 1 einschließen.
     
    18. Verfahren nach den Ansprüchen 1 bis 8, bei dem die alkylierte aromatische Verbindung Ethylbenzol ist.
     
    19. Verfahren nach den Ansprüchen 1 bis 8, bei dem die alkylierte aromatische Verbindung Cumol ist.
     


    Revendications

    1. Procédé pour produire un composé aromatique alkylé dans un réacteur comportant une pluralité de zones réactionnelles comprenant une première zone réactionnelle et une deuxième zone réactionnelle, ledit procédé comprenant les étapes :

    (a) d'introduction d'une première charge d'alimentation et d'une deuxième charge d'alimentation dans ladite première zone réactionnelle, ladite première charge d'alimentation comprenant un ou plusieurs composés aromatiques alkylables, ladite deuxième charge d'alimentation comprenant un alcène et au moins 1 % en poids d'un alcane ;

    (b) de mise en contact de ladite première charge d'alimentation et de ladite deuxième charge d'alimentation avec un premier catalyseur dans ladite première zone réactionnelle pour produire un premier effluent, ladite première zone réactionnelle étant maintenue dans des conditions telles que ladite première zone réactionnelle soit principalement en phase liquide, ledit premier effluent comprenant un composé aromatique alkylé et un alcane ;

    (c) de refroidissement dudit premier effluent sans séparation dudit alcane dudit premier effluent ;

    (d) d'introduction d'au moins une partie dudit premier effluent refroidi et d'une troisième charge d'alimentation dans ladite deuxième zone réactionnelle, ladite troisième charge d'alimentation comprenant un alcène ; et

    (e) de mise en contact de ladite au moins une partie dudit premier effluent refroidi et de ladite troisième charge d'alimentation avec un second catalyseur dans ladite deuxième zone réactionnelle pour produire un second effluent, ladite deuxième zone réactionnelle étant maintenue dans des conditions telles que ladite deuxième zone réactionnelle soit principalement en phase liquide.


     
    2. Procédé suivant la revendication 1, dans lequel lesdits premier et second catalyseurs consistent en un tamis moléculaire choisi dans le groupe consistant en MCM-22, MCM-36, MCM-49 et MCM-56, zéolite bêta, faujasite, mordénite, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, zéolite Y, Y Ultrastable (USY), Y désaluminisée, Y ayant subi un échange avec des terres rares (REY), ZSM-3, ZSM-4, ZSM-18, ZSM-20 ou n'importe laquelle de leurs associations.
     
    3. Procédé suivant la revendication 1, dans lequel lesdites conditions dans les étapes (b) et (c) comprennent une température de 120 à 285°C et une pression de 689 à 4601 kPa-a (100 à 667 psia), une WHSV sur la base du poids de l'alcène de 0,1 à 10 h-1.
     
    4. Procédé suivant la revendication 1, dans lequel lesdites deuxième et troisième charges d'alimentation comprennent un premier constituant du type alcène et un second constituant du type alcène.
     
    5. Procédé suivant la revendication 4, dans lequel ledit premier constituant du type alcène comprend 99 % en moles à 100 % en moles desdits alcènes.
     
    6. Procédé suivant la revendication 4, dans lequel ledit second constituant du type alcène comprend au moins 20 % en moles d'alcène.
     
    7. Procédé suivant la revendication 4, dans lequel ledit second constituant du type alcène comprend 20 à 80 % en moles d'alcène.
     
    8. Procédé suivant la revendication 1, dans lequel ladite deuxième charge d'alimentation a la même composition que ladite troisième charge d'alimentation.
     
    9. Procédé suivant la revendication 1, comprenant en outre l'étape :

    (f) de séparation dudit second effluent pour récupérer ledit composé aromatique alkylé.


     
    10. Procédé suivant la revendication 1, dans lequel ledit composé aromatique alkylé comprend l'éthylbenzène, ladite première charge d'alimentation comprend le benzène, et ladite deuxième charge d'alimentation et ladite troisième charge d'alimentation comprennent un mélange d'éthylène et d'éthane.
     
    11. Procédé suivant l'une quelconque des revendications précédentes dans lequel ledit composé aromatique alkylé comprend le cumène, ladite première charge d'alimentation comprend le benzène et ladite deuxième charge d'alimentation et ladite troisième d'alimentation comprennent un mélange de propylène et de propane.
     
    12. Procédé suivant l'une quelconque des revendications précédentes, comprenant l'étape supplémentaire de mise en contact de ladite première charge d'alimentation et d'une quatrième charge d'alimentation avec un catalyseur d'alkylation dans un préréacteur apte à la dérivation en amont dudit réacteur, ladite quatrième charge d'alimentation comprenant un alcène.
     
    13. Procédé suivant l'une quelconque des revendications précédentes, comprenant l'étape supplémentaire de mise en contact dudit second effluent dans des conditions d'alkylation avec un catalyseur d'alkylation dans un réacteur de finition en aval dudit réacteur.
     
    14. Procédé suivant l'une quelconque des revendications 1 à 8, dans lequel ledit second effluent comprend ledit composé aromatique alkylé et des composés aromatiques poly-alkylés, ledit procédé comprenant en outre :

    (a) la séparation d'au moins une partie desdits premier et/ou second effluents pour récupérer ledit ou lesdits composés aromatiques polyalkylés pour former un courant de charge d'alimentation de transalkylation ; et

    (b) la mise en contact d'au moins une partie dudit courant de charge de transalkylation avec une quatrième charge d'alimentation en présence d'un catalyseur de transalkylation pour produire un effluent de transalkylation dans des conditions de transalkylation, ladite quatrième charge d'alimentation comprenant un ou plusieurs composés aromatiques alkylables, ledit effluent de transalkylation qui comprend ledit composé aromatique alkylé.


     
    15. Procédé suivant la revendication 14, comprenant en outre les étapes :

    (c) de séparation dudit effluent de transalkylation pour récupérer ledit composé aromatique alkylé.


     
    16. Procédé suivant la revendication 14, dans lequel ledit catalyseur de transalkylation est un tamis moléculaire choisi dans le groupe consistant en MCM-22, MCM-36, MCM-49 et MCM-56, zéolite bêta, faujasite, mordénite, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, zéolite Y, Y Ultrastable (USY), Y désaluminisée, Y ayant subi un échange avec des terres rares (REY), ZSM-3, ZSM-4, ZSM-18, ZSM-20 ou n'importe laquelle de leurs associations.
     
    17. Procédé suivant la revendication 14, dans lequel lesdites conditions de transalkylation comprennent une température de 150 à 260°C et une pression de 696 à 4137 kPa-a (101 à 600 psia), une WHSV sur la base du poids desdits composés aromatiques polyalkylés d'environ 0,5 à 100 h-1, un rapport molaire dudit composé aromatique alkylable auxdits composés aromatiques polyalkylés de 1:1 à 10:1.
     
    18. Procédé suivant les revendications 1 à 8, dans lequel ledit composé aromatique alkylé est l'éthylbenzène.
     
    19. Procédé suivant les revendications 1 à 8, dans lequel ledit composé aromatique alkylé est le cumène.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description