Manufacture of xylenes from reformate

Abstract

A process is provided for the production of xylenes from reformate. The process is carried out by methylating the benzene, toluene, or both present in the reformate to produce a resulting product having a higher xylenes content than the reformate. Greater than equilibrium amounts of para-xylene can be produced by the process.

What is claimed is:  
     
         1 . A process for producing xylenes from reformate, which process comprises: 
 (a) providing a reformate containing benzene, toluene or mixtures thereof in methylation reaction zone; and,    (b) methylating at least a portion of the benzene, toluene, or mixtures thereof present in said reformate in said methylation reaction zone with a methylating agent under vapor phase conditions effective for the methylation and in the presence of a catalyst effective for the methylation to produce a resulting product having a higher xylenes content than said reformate.    
     
     
         2 . A process recited in  claim 1 , wherein said reformate is formed in an aromatization zone and at least a portion of the reformate formed in said aromatization zone is transferred to said methylation reaction zone.  
     
     
         3 . The process recited in  claim 2 , wherein said reformate is transferred to said methylation reaction zone without interstage separation.  
     
     
         4 . The process recited in  claim 1 , wherein a hydrocarbon stream comprising benzene, toluene, or mixtures thereof is added to said reformate present in said methylation reaction zone.  
     
     
         5 . The process recited in  claim 1 , wherein hydrogen is supplied to said methylation reaction zone.  
     
     
         6 . The process recited in  claim 1 , wherein said conditions include a temperature from about 300° C. to about 700° C., a pressure from about 1 to 1000 psig, a weight hourly space velocity of between about 0.1 and about 200, a molar ratio of methylating agent to toluene between about 0.1:1 to about 20:1 and a weight hourly space velocity of between about 0.1 and about 200.  
     
     
         7 . The process recited in  claim 6 , wherein said catalyst comprises an intermediate pore size molecular sieve.  
     
     
         8 . The process recited in  claim 7 , wherein said intermediate pore size molecular sieve is selected from the group consisting of AEL, AFI, MWW, MFI, MEL, MFS, MEI, MTW, EUO, MTT, HEU, 
 FER, and TON.    
     
     
         9 . The process recited in  claim 7 , wherein said intermediate pore size molecular sieve is selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48, ZSM-50, ZSM-57, MCM-22, MCM-49, MCM-56, and SAPO-11.  
     
     
         10 . The process recited in  claim 9 , wherein said catalyst further comprises at least one hydrogenation/dehydrogenation metal.  
     
     
         11 . The process recited in  claim 10 , wherein said at least one hydrogenation/dehydrogenation metal is a Group VIII metal.  
     
     
         12 . The process recited in  claim 9 , wherein said molecular sieve is MFI or MEL.  
     
     
         13 . The process recited in  claim 7 , wherein said molecular sieve further comprises a selectivating agent.  
     
     
         14 . The process recited in  claim 13 , wherein said selectivating agent is selected from the group consisting of silica, coke, phosphorus, alkaline earth metal oxide, rare earth metal oxides, lanthanum oxide, boron oxide, titania, antimony oxide, manganese oxide, titania and mixtures thereof.  
     
     
         15 . The process recited in  claim 14 , wherein said molecular sieve is ZSM-5.  
     
     
         16 . The process recited in  claim 7 , wherein said methylating agent is selected from the group consisting of methanol, dimethylether, methylchloride, methylbromide, methylcarbonate, acetaldehyde, dimethoxyethane, acetone, and dimethylsulfide.  
     
     
         17 . The process recited in  claim 7 , wherein said methylating agent is injected into said methylation reaction zone through more than one feed point.  
     
     
         18 . The process recited in  claim 7 , wherein said methylating agent is formed from synthesis gas.  
     
     
         19 . The process recited in  claim 1 , wherein said reformate is formed by the catalytic reforming of naphtha.  
     
     
         20 . The process recited in  claim 19 , wherein said reforming is carried out a temperature in the range of from about 427° C. to about 565° C., a pressure in the range of from about 50 psig (446 kPa) to about 500 psig (3,549 kPa), a mole ratio of hydrogen to hydrocarbons from 1:1 to 10:1 and a liquid hour space velocity of between 0.3 and 5 and in the presence of a catalyst suitable for the catalytic reforming of naphtha.  
     
     
         21 . The process recited in  claim 20 , wherein the catalyst used in said reforming is a bifunctional catalyst.  
     
     
         22 . The process recited in  claim 21 , wherein said bifunctional catalyst is an acidic reforming catalyst comprising a metallic oxide support and a Group VIII metal.  
     
     
         23 . The process recited in  claim 22 , wherein said metallic oxide support of said bifunctional catalyst is silica or alumina and said Group VIII metal is platinum.  
     
     
         24 . The process recited in  claim 22 , wherein said bifunctional catalyst further comprises a metal promoter.  
     
     
         25 . The process recited in  claim 24 , wherein said metal promoter is tin, rhenium, or mixtures thereof.  
     
     
         26 . The process recited in  claim 20 , wherein the catalyst used in said reforming is a monofunctional catalyst.  
     
     
         27 . The process recited in  claim 26 , wherein said monofunctional catalyst comprises a molecular sieve selected from the group consisting of zeolite L, zeolite X, zeolite Beta, zeolite Y, and ETS-10.  
     
     
         28 . The process recited in  claim 27 , wherein said monofunctional catalyst further comprises from about 0.1 to about 5% of at least one hydrogenation/dehydrogenation metal selected from the group consisting of a Group VIII metal, Group VIIB metal, or mixtures thereof, based on the weight of the catalyst.  
     
     
         29 . The process recited in  claim 25 , wherein said monofunctional catalyst further comprises a metal promoter and said Group VIII metal is platinum.  
     
     
         30 . The process recited in  claim 1 , wherein said reformate is formed by the dehydrocyclo-oligomerization of C 2 -C 5  aliphatics.  
     
     
         31 . The process recited in  claim 30 , wherein a catalyst comprising an intermediate pore size molecular sieve is used in the dehydrocyclo-oligomerization of C 2 -C 5  aliphatics.  
     
     
         32 . The process recited in  claim 31 , wherein said intermediate pore size molecular sieve is selected from the group consisting of AEL, AFI, MWW, MFI, MEL, MFS, MEI, MTW, EUO, MTT, HEU, FER, and TON.  
     
     
         33 . The process recited in  claim 31 , wherein said intermediate pore size molecular sieve is selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48, ZSM-50, ZSM-57, MCM-22, MCM-49, MCM-56, and SAPO-11.  
     
     
         34 . The process recited in  claim 31 , wherein said molecular sieve further comprises a selectivating agent.  
     
     
         35 . The process recited in  claim 34 , wherein said selectivating agent is selected from the group consisting of silica, coke, phosphorus, alkaline earth metal oxide, rare earth metal oxides, lanthanum oxide, boron oxide, titania, antimony oxide, manganese oxide, titania and mixtures thereof.  
     
     
         36 . The process recited in  claim 35 , wherein said molecular sieve is MFI.  
     
     
         37 . The process recited in  claim 36 , wherein said molecular sieve is ZSM-5.  
     
     
         38 . The process recited in  claim 1 , wherein said reformate is formed by the cracking of hydrocarbons.  
     
     
         39 . The process recited in  claim 38 , wherein said cracking of hydrocarbons is accomplished in a catalytic cracking process.  
     
     
         40 . The process recited in  claim 38 , wherein said cracking of hydrocarbons is accomplished in a steam cracking process.  
     
     
         41 . The process recited in  claim 1 , wherein at least 7 weight percent of the benzene and/or toluene present in said reformate is converted to xylenes.  
     
     
         42 . The process recited in  claim 13 , wherein the resulting product contains greater than equilibrium amounts of para-xylene.  
     
     
         43 . The process recited in  claim 13 , wherein the resulting product contains more than 80 weight percent of para-xylene based on the total weight of the xylenes produced by said process.  
     
     
         44 . An integrated process for upgrading a petroleum naphtha which comprises the steps of: 
 (a) aromatizing naphtha in an aromatization zone under aromatization conditions and in the presence of a catalyst effective for the aromatization of the naphtha to produce a reformate containing benzene, toluene or mixtures thereof;    (b) transferring at least a portion of said reformate from said aromatization zone to a methylation reaction zone; and    (c) methylating in said methylation reaction zone at least a portion of the benzene, toluene, or mixtures thereof present in said reformate with a methylating agent under conditions effective for the methylation and in the presence of a catalyst effective for the methylation to produce a resulting product having a higher xylenes content than said reformate;    wherein said reformate is transferred from said aromatization zone to said methylation reaction zone without interstage separation.    
     
     
         45 . The process recited in  claim 44 , wherein the methylation reaction is carried out in vapor phase.  
     
     
         46 . The process recited in  claim 44 , wherein said aromatization zone and methylation reaction zone are in series flow arrangement.  
     
     
         47 . The process recited in  claim 44 , wherein a hydrocarbon stream comprising benzene, toluene, or mixtures thereof is added to said reformate present in said methylation reaction zone.  
     
     
         48 . The process recited in  claim 44 , wherein hydrogen is supplied to said methylation reaction zone  
     
     
         49 . The process recited in  claim 45 , wherein said methylation is carried out at a temperature from about 300° C. to about 700° C., a pressure from about 1 to 1000 psig, a weight hourly space velocity of between about 0.1 and about 200, a molar ratio of methylating agent to toluene between about 0.1:1 to about 20:1 and a weight hourly space velocity of between about 0.1 and about 200.  
     
     
         50 . The process recited in  claim 49 , wherein said catalyst in said methylation zone comprises an intermediate pore size molecular sieve.  
     
     
         51 . The process recited in  claim 50 , wherein said intermediate pore size molecular sieve is selected from the group consisting of AEL, AFI, MWW, MFI, MEL, MFS, MEI, MTW, EUO, MTT, HEU, FER, and TON.  
     
     
         52 . The process recited in  claim 50 , wherein said intermediate pore size molecular sieve is selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48, ZSM-50, ZSM-57, MCM-22, MCM-49, MCM-56, and SAPO-11.  
     
     
         53 . The process recited in  claim 52 , wherein said catalyst further comprises at least one hydrogenation/dehydrogenation metal.  
     
     
         54 . The process recited in  claim 53 , wherein said at least one hydrogenation/dehydrogenation metal is a Group VIII metal.  
     
     
         55 . The process recited in  claim 52 , wherein said molecular sieve further comprises a selectivating agent.  
     
     
         56 . The process recited in  claim 55 , wherein said selectivating agent is selected from the group consisting of silica, coke, phosphorus, alkaline earth metal oxide, rare earth metal oxides, lanthanum oxide, boron oxide, titania, antimony oxide, manganese oxide, titania and mixtures thereof.  
     
     
         57 . The process recited in  claim 56 , wherein said molecular sieve is MFI or MEL.  
     
     
         58 . The process recited in  claim 44 , wherein said aromatization is carried out a temperature in the range of from about 427° C. to about 565° C., a pressure in the range of from about 50 psig (446 kPa) to about 500 psig (3,549 kPa), a mole ratio of hydrogen to hydrocarbons from 1:1 to 10:1 and a liquid hour space velocity of between 0.3 and 5.  
     
     
         59 . The process recited in  claim 58 , wherein the catalyst used in said reforming is a bifunctional catalyst.  
     
     
         60 . The process recited in  claim 59 , wherein said bifunctional catalyst is an acidic reforming catalyst comprising a metallic oxide support and a Group VIII metal.  
     
     
         61 . The process recited in  claim 60 , wherein said metallic oxide support of said bifunctional catalyst is silica or alumina and said Group VIII metal is platinum.  
     
     
         62 . The process recited in  claim 60 , wherein said bifunctional catalyst further comprises a metal promoter.  
     
     
         63 . The process recited in  claim 62 , wherein said metal promoter is tin, rhenium, or mixtures thereof.  
     
     
         64 . The process recited in  claim 53 , wherein the catalyst used in said reforming is a monofunctional catalyst.  
     
     
         65 . The process recited in  claim 64 , wherein said monofunctional catalyst comprises a molecular sieve selected from the group consisting of zeolite L, zeolite X, zeolite Beta, zeolite Y, and ETS-10.  
     
     
         66 . The process recited in  claim 65 , wherein said monofunctional catalyst further comprises from about 0.1 to about 5% of at least one hydrogenation/dehydrogenation metal selected from the group consisting of a Group VIII metal, Group VIIB metal, or mixtures thereof, based on the weight of the catalyst.  
     
     
         67 . The process recited in  claim 66 , wherein said monofunctional catalyst further comprises a metal promoter and said Group VIII metal is platinum.  
     
     
         68 . The process recited in  claim 44 , wherein said methylating agent is selected from the group consisting of methanol, dimethylether, methylchloride, methylbromide, methylcarbonate, acetaldehyde, dimethoxyethane, acetone, and dimethylsulfide.  
     
     
         69 . The process recited in  claim 44 , wherein said methylating agent is injected into said methylation reaction through more than one feed point.  
     
     
         70 . The process recited in  claim 44 , wherein said methylating agent is formed from synthesis gas.  
     
     
         71 . The process recited in  claim 55 , wherein the resulting product contains greater than equilibrium amounts para-xylene.  
     
     
         72 . The process recited in  claim 44 , wherein at least 7 weight percent of the benzene and/or toluene present in said reformate is converted to xylenes.  
     
     
         73 . The process recited in  claim 55 , wherein the resulting product contains more than 60 weight percent of para-xylene based on the total weight of the xylenes produced in said methylation reaction zone by the methylation of said benzene, toluene, or mixtures thereof.