US2441095A - Conversion of alkyl aromatic hydrocarbons into alkenyl aromatic hydrocarbons - Google Patents

Conversion of alkyl aromatic hydrocarbons into alkenyl aromatic hydrocarbons Download PDF

Info

Publication number
US2441095A
US2441095A US691860A US69186046A US2441095A US 2441095 A US2441095 A US 2441095A US 691860 A US691860 A US 691860A US 69186046 A US69186046 A US 69186046A US 2441095 A US2441095 A US 2441095A
Authority
US
United States
Prior art keywords
conversion zone
alkyl
conversion
zone
aromatic hydrocarbons
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US691860A
Inventor
Harry A Cheney
Sumner H Mcallister
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shell Development Co
Original Assignee
Shell Development Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shell Development Co filed Critical Shell Development Co
Priority to US691860A priority Critical patent/US2441095A/en
Application granted granted Critical
Publication of US2441095A publication Critical patent/US2441095A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C15/00—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts
    • C07C15/40—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts substituted by unsaturated carbon radicals
    • C07C15/42—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts substituted by unsaturated carbon radicals monocyclic
    • C07C15/44—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts substituted by unsaturated carbon radicals monocyclic the hydrocarbon substituent containing a carbon-to-carbon double bond
    • C07C15/46—Styrene; Ring-alkylated styrenes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C4/00—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
    • C07C4/08—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule
    • C07C4/12—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule from hydrocarbons containing a six-membered aromatic ring, e.g. propyltoluene to vinyltoluene
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S585/00—Chemistry of hydrocarbon compounds
    • Y10S585/8995—Catalyst and recycle considerations
    • Y10S585/905—Catalyst and recycle considerations by-product conversion to feed

Definitions

  • the present invention relates to the producfrom alkyl aromatic hydrocarbons containing at least one alkyl group of at least three carbon atoms. 'I'he invention relates more particularly to theproduction of vinyl aromatic hydrocarbons from alkyl aromatic hydrocarbons containing at least one substituent isopropyl group.
  • a speciic embodiment of the invention relates to the production of styrene from isopropyl benzene.
  • olefin-substituted aromatic hydrocarbons are employed as starting or intermediate materials in a great number of important iields of application.
  • the vinyl aromatic hydrocarbons for example, are of value as starting materials in the production of synthetic rubber and a wide variety of chemical derivatives.
  • the alkyl aromatic hydrocarbons constitute an important potential source of olefin-substituted aromatics.
  • esses are, however, dependent upon the alkyl aromatic corresponding to the desired olefin-substituted aromatic as charge.
  • Processes have been disclosed heretofore for the production of olefin-substituted aromatics from alkyl aromatics having a greater number of carbon atoms.
  • Such processes as disclosed heretofore are, however, generally handicapped by a low yield of the olefin-substituted hydrocarbon. They generally unavoidably involve accompanying side reactions which often predominate, thereby not only producing an exceedingly low yield of the desired olefin-substituted aromatic hydrocarbon but also converting at least i a substantial part of the charge to less valuable by-products.
  • Such is the case when producing, for example, styrene from isopropyl benzene by processes disclosed heretofore.
  • the resulting reaction product generally comprises not only an exceedingly small proportion of styrene but also Such procy consists predominantly of such products as alpha-methyl styrene and hydrogen, as well as considerable amounts of benzene and propylene.
  • a further object of the invention is the provision of an improved process for the more eilicient production of an olen-substituted aromatic hydrocarbon from an aykyl aromatic hydrocarbon having at least one alkyl group connected to the aromatic nucleus lby carbon to carbon linkage of a secondary carbon atom in the alkyl group to a carbon atom in the aromatic nucleus.
  • Still another object of the invention is the provision of an improved process for -the more efficient production of vinyl aromatic hydrocar- 4bons from alkyl aromatic hydrocarbons having at least one isopropyl group directly attached to a carbon atom in the aromatic ring.
  • a more particular object of the invention is the provision of an improved process for the more efficient production of styrene from isopropyl benzene.
  • an alkyl aromatic hydrocarbon containing at least one alkyl group of at least three carbon atoms is subjected to controlled destructive dehydrogenation conditions in a first conversionv 1 oledn group as the number of carbon atoms in corresponding alkyl groups of the alkyl aromatic product hydrogen.
  • the olefin-substituted aromatic hydrocarbon having a lesser number of carbon atoms to the molecule than the alkyl aromatic charge thus formed is separated from the eiiluence of the iirst conversion zone.
  • At least a portion of the remainder of the eiiluence of the first conversion zone comprising the ole- 1in-substituted aromatic hydrocarbon and byproduct hydrogen is subjected to hydrogenating conditions in a second conversion zone, thereby saturating the olenic side chain and reconverting the olefin-substituted aromatic hydrocarbon to the alkyl aromatic hydrocarbon originally charged.
  • At least a portion of the eiliuence from the secondconversion zone comprising alkyl aromatic hydrocarbon is returned to the rst conversion zone.
  • a particular advantage of the invention resides in the ability to produce more eiliciently olefinsubstituted aromatic hydrocarbons having an oleflnic linkage between the alpha and beta carbon atoms of the substituent olefin group from alkyl aromatic hydrocarbons containing at least one alkyl group directly connected by carbon-tocarbon linkage of a secondary carbon atom in the alkyl group to a nuclear carbon atom in the aromatic ring.
  • an alkyl aromatic hydrocarbon containing at least one alkyl group directly connected to the aromatic nucleus by a direct carbon-to-carbon linkage of a nuclear carbon atom with a secondary carbon atom in the alkyl group is subjected to the controlled destructive dehydrogenation conditions in the first conversion zone, there is brought about a scission of one of the alpha to beta carbon linkages in the substituent alkyl group with the formation of a reaction -product comprising an olen-substituted aromatic hydrocarbon containing an olefinic linkage between the remaining alpha and beta carbon atoms of the substituent group.
  • the process of the invention is broadly applicable to the conversion of alkyl substituted aromatic hydrocarbons to olefin-substituted aromatic hydrocarbons having a lesser number of carbon atoms to the molecule, it is preferred to use as charge the alkyl aromatic hydrocaibon having at least three but not' more than six carbon atoms in the substituent alkyl side chain.
  • Alkyl aromatics which may be converted in accordance with the process of the invention comprise, for example, isopropylbenzene, di-isopropylbenzene, n propylbenzenes, isobutylbenzene, amylbenzenes, methyl-isopropylbenzenes, methylpropylbenzene, methylisobutylbenzene, methylbutylbenzene, butyiamylbenzene, isobutyl mesityiene, isopropylisobutylbenzene, isoamylbenzene, propylmesitylene, isobutyl mesitylene, isoarnylmesitylene, tert-butylbenzene and tert-p-dibutyl, benzene.
  • the invention is of particular value in the production of olefin-substituted aromatics having an oleiinic bond between the alpha and beta carbon atoms of the substituent olenic group from alkyl aromatics having a substituent alkyl group directly connected by carbonto-carbon linkage of a secondary carbon atom of the alkyl group to a nuclear carbon atom of the aromatic nucleus.
  • this preferred class of materials comprise, for example, isopropylbenzene, di-isopropylbenzene, propylisopropylbenzene, methylisopropylbenzene, 2 phenylbutane, 2-phenylpentane, S-phenylpentane, etc.
  • a particularly preferred embodiment of the invention comprises the production of vinyl aromatics from alkyl aromatic hydrocarbons containing at least one isopropyl group directly connected to the aromatic nucleus.
  • Members of this particularly preferred group of charge material are, for example, isopropylbenzene, and the alkylsubstituted isopropylbenzenes such as methylisopropylbenzenes, di-isopropylbenzene, ethylisopropylbenzene, propyl-isopropylbenzene, etc.
  • the alkyl aromatics employed as charge to the process ofthe invention are obtained from any suitable source. They may be separated from the complex products obtained in many of the pyrogenio or catalytic hydrocarbon conversion processes, or they may be a product of synthesis such as obtained, for example, by the alkylation of an aromatic hydrocarbon with a suitable oleiin.
  • isopropylbenzene is produced by the alkylatlon of benzene with propylene under suitable alkylating conditions and with the aid of a suitable alkylation catalyst such as, for example, sulfuric acid, aluminum chloride, phosphoric acids or the like.
  • the alkyl aromatic charge in the process of the invention need not necessarily consist of only a single alkyl aromatic hydrocarbon, but may cornprise a mixture of two or more such hydrocarbons.
  • the charge to the process of the invention may furthermore comprise other hydrocarbons capable or not of undergoing conversion underl the conditions of execution of the process of the invention, as well as inert gaseous materials such as nitrogen. normally gaseous paraillns, steam, etc.
  • the controlled destructive dehydrogenation of the alkyl aromatics in the first conversion zone is obtained by the maintenance therein of well deiined thermal or catalytic conditions.
  • Suitable thermal conditions comprise a temperature in the range of from about 650 C. to about 900 C. and preferably from about 650 C. to about 850 C.
  • the reaction zone may optionally contain suitable inert contact materials such as, for example, crushed brick, quartz chips, or the like.
  • the residence time of reactants in the reaction zone is maintained sufiiciently short to attain fission of carbon-to-carbon linkage in the alkyl chain in the absence of any substantial complete dealkylation.
  • the residence time may range, for example, from about 0.05 second to about 5 seconds, a time of less than one second being preferred; a higher contact time may, however, be resorted to within the scope of the invention.
  • Atmospheric or subatrnospheric pressures may be resorted to.
  • the use of relatively low superatmospheric pressures ranging, for example, from pressures slightly above atmospheric to about 100 pounds gauge are somewhat preferred.
  • diluent gases or vapors such as, for example, steam, are preferably introduced into the reaction zone.
  • Suitable catalysts comprise broadly the oxides or suldes of the heavy metals, such as the oxides or sulfides of the metals of the groups V, VI and VlII of the periodic table such as, for example, the oxides and suldes of one or more of the following: tungsten, molybdenum, chromium, vanadium, copper, iron, cobalt, nickel; solid adsorptive materials such as adsorptive alumina, activated alumina, bauxite; adsorptive siliceous materials such 'as the naturally occurring or synthetically produced silica-alumiha catalysts; mixtures oi at least one of the heavy metal oxides or sulfides with an oxide of aluminum. magnesium or silicon.
  • Particularly suitable catalysts comprise the adsorptlve materials such as activated alumina, bauxite, activated carbonI magnesia 'or zirconia optionally in combination with one or more of the following: an alkaline earth metal. alkali metal, an oxide or sulfide of an Ialkaline earth metal or alkali metal.
  • Preferred catalysts comprise those containing an adsorptive alumina in combination with an oxide or sulfide of calcium, lithium, strontium or cerium.
  • Temperatures to be maintained in the ilrst conversion zone when resorting to the use of catalytically controlled dehydrogenation therein comprise temperatures in the range of from about 350 C. to about 750 C. and preferably from about 400 C. to about 650 C.
  • the contact time is controlled to eect substantial fission of the Ialkyl side chain in the absence of any substantial complete dealkylation of the alkyl aromatic.
  • Contact times of from about 0.1 to about seconds have been found suitable. Higher contact times may, however, be resorted to within the scope of the invention.
  • Subatmospheric, atmospheric or superatmospheric pressures may be employed when resorting to the use of catalysts. Pressures ranging from about atmospheric to about 150 pounds are, however. somewhat preferred.
  • diluent gases such as steam, nitrogen and the like
  • the introduction of hydrogen into the nrst conversion zone is, however, preferably avoided since such often has been found to increase undesired side reactions such as, for example, the removal of the entire side chain from the aromatic nucleus.
  • the alkyl aromatics will undergo a destructive dehydrogenation in the first conversion zone consisting of the scission of a carbon-to-carbon linkage in the substituent alkyl chain of a portion of the alkyl aromatic charge with the formation of olensubstituted aromatic hydrocarbons containing a lesser number of carbon atoms to the molecule than the lalkyl aromatic charged.
  • concomitant with the destructive dehydrogenation reaction a substantial portion oi the charge will undergo straight dehydrogenation of the alkyl side chain with the formation of hydrogen and an olensubstituted aromatic having the same number of carbon atoms to the molecule as the alkyl aromatic charged.
  • alkyl aromatlcs containing an alkyl chain directly connected to the aromatic nucleus by means of a secondary carbon atom in the alkyl group will undergo a ssion of an alpha to beta carbon linkage resulting in the unsaturation of the remaining alpha to beta carbon linkage.
  • reaction product comprising CII-X Ar-CH and Ar-CH Y each indicate an alkyl group or hydrogen.
  • Hydrogenating conditions in the second conversion zone of the process comprise the use o! a suitable hydrogenation catalyst.
  • Suitable hydrogenation catalysts comprises for emple those consisting ⁇ essentially oi a hydrogenating metal. such as nickel, iron, cobalt and themetals of the platinum group.
  • the hydrogenating metals may suitably be employed in combination with one or more of the dimcuitly reducibie metal oxides such as thoria, ceria, mrconia and titanic..
  • Temperatures in the range of for example from about 25 C. to 175 C. and preferably from about 50 C. to about 125 C. and pressures in the range of from about atmospheric to 500 lbs. and preierably from about 50 to 100 lbs. have been found suitable.
  • the invention is in no wise limited by the nature of catalyst or the specliic conditions employed in the second conversion zone.
  • the specific conditions employed therein will generally be dependent to some degree upon the para ticular hydrocarbon charged and the catalyst employed.
  • Hydrogenating conditions are, however, preferably chosen which will eect the saturation of the substituent oleiln group of the olefin aro,- matic in the absence of any substantialhydrogenation of the aromatic nucleus.
  • the reaction zone may comprise any suitable type of reactor such as, for example, an elongated externally heated coil andor a reaction chamber of enlarged cross-sectional area. In the drawing the reaction zone is depicted by a reaction chamber 2.
  • the isopropyl benzene is subjected to thermal or catalytic controlled destructive dehydrogenation conditions as dened above.
  • Preferred destructive dehydrogenating conditions comprise, i'or example, the use or a catalyst consisting of adsorptive alumina containing an alkaline earth metal or oxide thereof, such as for example activated alumina in combination with calcium pxide.
  • Suitable temperatures in the rangeof for example from 450 C. to 750 C. are maintained in the reactor 2 by suitable heating means such as for example heater t.
  • Suitable conversion of the isopropylbenzene is obtained by contact in reactor 2 with a catalyst comprising adsorptive alumina and a promoting amount of calcium oxide at a temperature in the range of from about .400 C. to about 650 C., preierably 490 C. to 590 C., Iand a pressure of from about atmosphericto about pounds.
  • the temperature is maintained in reactor 2 by means of any suitable heating means such as for example a heater S.
  • the time of contact of reactants and catalyst is maintained in the range of from about 0.02 to about 15seconds and preferably between about 0.1 ⁇ and 5 seconds.
  • a gaseous fraction comprising by-product hydrogen is separated from a liquid fraction comprising styrene, alpha-methylstyrene and isopropylbenzene.
  • the liquid fraction is passed from fractionator 6 through line 8 into a fractionator 9.
  • Within fractionator 9 a vapor fraction comprising styrene is separated and eliminated from the system as a nal product through valved line I0.
  • a fraction comprising isopropylbenzene and alpha-methylstyrene is separated within fractionator 9 and passed therefrom through line I2 to a fractionator I3.. Any materials higher boiling than isopropylbenzene which may have been formed to some degree in the system are separated as bottoms in fractionator 9 and removed therefrom through valved line I4.
  • fractionator I3 a vapor fraction comprising isopropylbenzene is separated from a liquid fraction comprising alpha-methylstyrene.
  • the vapor fraction is taken overhead from fractionator I3 and passed through line I6 into line I leading to reactor 2.
  • the liquid fraction is taken from fractionator I3 and forced through line Il into a second reaction zone.
  • the second reaction zone may constitute any suitablereaction zone of elongated restricted and/or enlarged cross-sectional area. In the drawing the second reaction zone is represented by reaction chamber I8. Overhead from fractionator 6 comprising the by-product hydrogen formed in reactor 2 is forced through line I9 into reactor I8.
  • Suitable hydro- .genating conditions comprise, for example, the ⁇ use of a catalyst comprising Raney nickel at a temperature in the range of from about 50 C. to about 100 C. and a pressure of from about 50 to about 100 pounds gauge.
  • catalytic hydrogenating conditions using a Raney nickel catalyst have been set forth as suitable, it is to be stressed that the invention is in no wise limited to the use of specific hydrogenating conditions or catalysts to effect the desired hydrogenation within reactor I8.
  • suitable hydrogenating catalysts comprise, for example, the heavy metal sulfides.
  • Effective hydrogenating conditions employing a heavy metal sulfide-type catalyst comprise the use of a nickel sulde-tungsten sulfide catalyst at a temperature of from about 250 C. to about 350 C. at a pressure of from about atmospheric to about 10 atmospheres or higher. Hydrogen produced within the system is preferably permitted to build up during the recycling thereof to attain a molar excess oi' hydrogen over hydrocarbons to be hydrogenated in reactor I8.
  • Additional hydrogen from an outside source may be introduced into the system through valved line 2I when needed Eiiluence from reactor I8 comprising isopropylbenzene and some unconverted alpha-methylstyrene is passed through valved line 22 into fraction-ator 23.
  • a gaseous fraction comprising residual gases formed within the system is separated from a liquid fraction comprising isopropylbenzene and alpha-methylstyrene. The liquid is passed from fractionator 23 through line 24 into fractionator I3.
  • Gaseous overhead is taken from fractionator 23 through valved line 25 and may be passed in part into line I9 and if desired in part into line I.
  • recycle thereof to reactor 2 is preferably avoided since the introduction of hydrogen into reactor 2 favors complete dealkylation of isopropylbehzene to reaction products consisting essentially of benzene and propylene, thereby seriously detracting from the efficiency of the process.
  • Diluent materials such as for example inert gases or steam may be introduced into the system by means of valved line 21. Elimination of gases from the system is accomplished by bleeding from valved line 28 and/or valved line 29. If desired gaseous materials may be bled from valved lines 28 and/or 29 and subjected in part or entirety to a purification or separation process and a portion of the thus treated gas returned into the system.
  • the unitary process of the invention provides a method for the substantially complete conversion in a, continuous highly eicient operation of substantially all of .the alkyl aromatic hydrocarbon charged to the system to a final product consisting essentially only of olefin-substituted aromatic hydrocarbon containing a lesser number of carbon atoms to the molecule than the hydrocarbon charge.
  • the process of the invention because of its complete utilization within the system of the products of straight dehydrogenation, unavoidably encountered to a substantial degree, enables the full realization of the advantages inherent in the use of dehydrogenation catalysts to obtain the desired controlled destructive dehydrogenation without the substantial loss of charge material encountered in the production of olefin aromatics from alkyl aromatics of a greater number of carbon atoms by methods available heretofore.
  • 'zone consisting of an externally heated unpacked tubular reactor4 wherein it is subjected to a temperature of about 750 C. for aperiod of 0.1 second at substantially atmospheric pressure.
  • Eiiiuence from the rst reactor is passed through a cooler into a iirst product separating zone consisting of a series of fraotionators wherein a gaseous fraction consisting essentially of hydrogen and liquid fractions consisting essentially of styrene and alpha-methylstyrene respectively are separated from the reaction products.
  • Th'e alphamethylstyrene and normally gaseous fractions are passed into a second conversion zone ⁇ consisting of a reaction chamber equipped with stirring means.
  • the alpha-methylstyrene-hydrogen mixture is subjected to catalytic hydrogenating conditions in the temperature range of from 50 C. to 100 C., and a pressure of about 70 pounds in the presence of a Raney nickel catalyst. A contact time in the range of from about 5 to 12 minutes is maintained.
  • Eiuence from the second'reaction zone is passed through a cooler into a fractionator wherein a normally gaseous fraction is separated from a liquid fraction consisting of isopropylbenzene and unconverted alpha-methylstyrene.
  • the liquid fraction consisting of isopropylbenzene and alphamethylstyrene is recycled to the first product separating zone.
  • Example II Isopropylbenzene is subjected to catalytic demethanation in a first reactor by contact with a. catalyst consisting of calcium-promoted activated alumina at substantially atmospheric pressure. 'I'he temperature in the first reactor is maintained in the range of from 550 C. to 560 C. Steam is added to the ispropylbenzene charge and the mixture introduced into the first reactor at a. rate of 50 mols of ispropylbenzene and 100 mols of steam per liter of catalyst per hour. Eiiiuence from the iirst reactor is 'passed through a cooler into a first product separating zone consisting of a series of fractionators wherein a gaseous.
  • fraction consisting essentially of hydrogen and two liquid fractions consisting essentially of styrene and alpha-methylstyrene, respectiveiy, are separated from the reaction products.
  • the alpha-methylstyrene and normally gaseous fractions are passed into a second con- Version zone consisting of a reaction chamber equipped with stirring means.
  • the alpha-methylstyrene-hydrogen mixture is subjected to catalytic hydrogenating conditions in the temperature range of from 50 C. to 100 C. and a pressure of about 70 pounds in the presence of a Raney nickel catalyst.
  • a contact time in the range of from about 5 to 12 minutes is maintained.
  • Eiiluence from the second reaction zone is passed through a cooler into a fractionator wherein a normally gaseous fraction is separated from a liquid fraction consisting of isopropylbenzene and unconverted alphamethylstyrene.
  • the liquid fraction consisting of isopropyl-benzene and alpha-methylstyrene is v recycled to the rst product separating zone.
  • Example I-II In a repetition of the process of Example II under substantially identical conditions but with the exception that a catalyst consisting of adsorptive alumina is employed in the first reactor at a temperature of 650 C., a conversion per pass of ethyl isopropylbenzene of 58% is obtained in the first conversion zone with a yield of 11% styrene and 62% alpha-methylstyrene.
  • Example IV In al repetition of the process of Example II under substantially identical conditions but with theuse of another calcium-promoted adsorptive alumina catalyst at a temperature of 650 C. in the iirst reactor aconversion per pass of isopropylbenzene of 49% is obtained in the first conversion zone with a yield of 12% styrene and 65% alpha-methylstyrene.
  • Cymene is subjected to catalytic demethanation in a first reactor by contact with a catalyst consisting of calcium-promoted activated alumina at substantially atmospheric pressure at a temperature of about '730 C. 1.5 mols of steam per mol of cymene charge is employed and. the mixture passed through the irst reactor at the rate of 2.5 mols of the cymene-steam mixture per liter of catalyst per hour. Efiluence from the rst reactor is passed through a cooler into a iirst product separating zone consisting of a series of fractionators wherein a gaseous fraction consisting essentially of hydrogen and two liquid fractions consisting essentially of p-methylstyrene and asym.
  • a catalyst consisting of calcium-promoted activated alumina at substantially atmospheric pressure at a temperature of about '730 C. 1.5 mols of steam per mol of cymene charge is employed and. the mixture passed through the ir
  • methyl p-tolylethylene respec-' tively, are separated from the reaction products.
  • the asym. methyl p-tolylethylene and normally gaseous fractions are introduced into a second conversion zone wherein they are contacted with a nickel-tungsten-sulde catalyst at a pressure of 4.5 atmospheres and a temperature of about 300 C. at a liquid hourly space velocity of 2.
  • Eiiiuence from the second reaction zone is passed through a cooler into a fractionator wherein a normally gaseous fraction is separated from a liquid fraction comprising cymene and unconverted asym. methyl p-tolylethylene.
  • the liquid fraction consisting of cymene and asym.' methyl p-tolylethylene is recycled to the first product separating zone. Hydrogenation of substantially all lay-product asym. methyl p-tolylethylene to cymene is attained within the system. A conversion per pass of cymene of 60% is obtained in the first conversion zone.
  • a process for the production of styrene s 11 which comprises subjecting isopropylbenzene to destructive dehydrogenating conditions in a. rst conversion zone, thereby eilecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-methylstyrene and hydrogen in said iirst conversion zone, separating styrene from the eiiluence of said rst conversion zone, subjecting the remaining eiiiuence of said first conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of alpha-methylstyrene Vto isopropylbenzene in said second ⁇ conversion zone.' and passing eiiiuence from said second conversion zone to said first conversion zone.
  • a process for the production of styrene which comprises subjecting isopropylbenzene to destructive dehydrogenating conditions at a temperature of from about 350 C. to about 750 C.in the presence of a dehydrogenation catalyst in a first conversion zone, thereby effecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-methyistyrene and hydrogen in said first conversion zone, separating hydrocarbons comprising styrene from the eiiluence of said rst conversion zone, subjecting at least a part of the remaining eilluence of said first conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of aJpha-methylstyrene to isopropylbenzene in said second conversion zone, and passing at least a part of the eiiiuence from said second conversion zone to said rst conversion zone.
  • a process for the production of styrene which comprises subjecting isopropylbenzene to destructive dehydrogenating conditions at a temperature of from about A400 C. to about 650 C. in the presence of a dehydrogenation catalyst in a rst conversion zone, thereby effecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-methylstyrene and hydrogen in said rst conversion zone, separating a, fraction comprising styrene from the eiiluence of said rst conversion zone, subjecting the remaining eiiiuence of said rst conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of alphamethylstyrene to isopropylbenzene in said second conversion zone, and passing eiiiuence from said second conversion zone to said first conversion zone.
  • a process for the production'of styrene which comprises subjecting hydrocarbons comprising isopropylbenzene to destructive dehydrogenating conditions at a temperature of from about 400 C. to about 650 C. in the presence of a dehydrogenation catalyst comprising adsorptive alumina in a first conversion zone, thereby effecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-methylstyrene and hydrogen in said first conversion zone, separating a fraction comprising styrene from the emuence of said first conversion zone, subjecting the remaining eiiiuence of said rst conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of alpha-methylstyrene to isopropylbenzene in said second conversion zone, and passing eiliuence from said second conversion zone to said first conversion zone.
  • a process for the production of styrene which comprises subjecting isopropylbenzene to thermal destructive dehydrogenating conditions at a temperature of from about 650 C. to about 900 C. and a residence'time of from about'0.05 to about seconds in a iirst conversion 20m2, thi???- by eecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-- methylstyrene and hydrogen in said first conversion zone, separating styrene from the eluence of said conversion zone, subjecting at least a part of the remaining effiuence of said rst conversion zone to hydrogenating conditions in a second conversion zone. thereby effecting the hydrogenation of alpha-methylstyrene to isopropylbenzene in said second conversion zone, and passing eiliuence from said second conversion zone to said first conversion zone.
  • a process tor the production of vinyl-substituted aromatic hydrocarbons which comprises subjecting alkyl aromatics having at least one substituent isopropyl group directly attached to the aromatic nucleus to destructive dehydrogenating conditions in la iirst conversion zone, thereby effecting the conversion of said alkyl aromatics to a reaction product comprising vinyl aromatics, olefin-substituted aromatics having the same number of carbon atoms as said alkyl aromatic charge and hydrogen in said first conversion zone, separating vinyl aromatics from the eiliuence of said iirst conversion zone, subjecting the remaining efiiuence of said rst conversion zone to hydrogenating conditions in a second conversion zone, thereby eiecting the hydrogenation of oleiin-substituted aromatics to alkyl aromatics in said second conversion zone, and passing eluence from said second conversion zone to said first conversion zone.
  • a process for the production of vinyl-substituted aromatic hydrocarbons from alkyl aromatic hydrocarbons having at least one substituent isopropyl group directly attached to the aromatic nucleus which comprises subjecting alkyl aromatics having at least one substituent isopropyl group directly attached to the aromatic nucleus to destructive dehydrogenating conditions at a temperature inthe range of from about 350 C. to about 750 C.
  • a process for the production of olefin-substituted aromatic hydrocarbons containing a lesser number of carbon atoms from alkyl aromatic hydrocarbons containing a greater number of carbon atoms which comprises subjecting alkyl aromatic hydrocarbons having a substituent alkyl group of at least three carbon atoms connected by a secondary carbon atom in the alkyl group to a carbon atom in the aromatic nucleus to destructive dehydrogenating conditions in a and hydrogen in said first conversion zone, separating olen-substituted aromatic hydrocarbons having a lesser number of carbon atoms than said alkyl aromatic charge from the efiluence ofsaid rst conversion zone, subjecting at least a part of the remaining eiiluence of said first conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of olefin-substituted aromatic hydrocarbons to alkyl aromatic hydrocarbons in said second conversion zone and passing emuence from said second conversion zone to
  • a process for the production of olefin-substituted aromatic hydrocarbons having a lesser number of carbon atoms to the molecule from alkyl aromatic hydrocarbons having a greater number of carbon atoms to the molecule which' comprises subjecting alkyl aromatics having at least one substituent alkyl group of at least three carbon atoms connected by a secondary 'carbon atom in the alkyl group to a carbon -atom in the aromatic nucleus to destructive dehydrogenating conditions at a temperature in the range of irom about 350 to about 750 C.
  • a process for the production of olefin-substituted aromatic hydrocarbons yhaving a lesser number of carbon atoms to the molecule from alkyl aromatic hydrocarbons having a greater number of carbon atoms to the molecule which least one substituted alkyl group of at least three carbon atoms to destructive dehydrogenating conditions in a first conversion zone, thereby eilecting the conversion of alkyl aromatics to a reaction product comprising olefin-substituted aro,- matics having the same number of carbon atoms as the alkyl aromatic charge, oleiln-substituted aromatics having a lesser number of carbon atoms than the alkyl aromatic charge and hydrogen in said first conversion zone, separating olefin-substituted aromatic hydrocarbons having a lesser number of carbon atoms than the aromatic charge from the eilluence of the first conversion zone, subjecting the remainder of said eiiluence of the nrst conversion zone to hydrogenat
  • alkyl aromatic hydrocarbons having a greater number of carbon atoms to the molecule which comprises subjecting alkyl aromatics having at least one substituent alkyl group of atleast three carbon atoms to thermal destructive dehydrogenating conditions at a temperature in the range of from about 650 C. to about 900 C, and a residence time of from about 0.05 to about 5 seconds in a first conversion zone, thereby effecting the conversion of alkyl aromatics to a reaction product comprising.
  • olefin-substituted aromatics having the same number of carbon atoms as the alkyl aromatic charge, oleiln-substituted aromatics having a lesser number of carbon atoms than the alkyl aromatic charge and hydrogen in said ilrst conversion zone, separating oleiln-substituted aromatic hydrocarbons having -a lesser number of carbon atoms than the aromatic charge from the eilluence of the ilrst conversion' zone, subjecting the remainder of said eilluence oi the iirst conversion zone to hydrogenating conditions in 4a second conversion zone, thereby effecting th'e conversion of olefin-substituted aromatics to alkyl aromatics in said second conversion zone, and passing. at least a part oi' the eilluence of said second conversion zone to said rst conversion zone.
  • a process for the production of olen-substituted aromatic hydrocarbons having a lesser number of carbon atoms to the molecule from alkyl aromatic hydrocarbons having a greater number of carbon atoms to the molecule which comprises subjecting alkyl aromatics having at least one substituent alkyl group of at least three carbon atoms to destructive dehydrogenating conditions at a temperature in the range of from about 350 C. to about 750 C. in the presence o!
  • a dehydrogenation catalyst in a first conversion zone thereby effecting the conversion of alkyl aromatics to a reaction product comprising oleilnsubstituted aromatics having th'e same number of carbon atoms as'the alkyl aromatic charge, olefin-substituted aromatics having a lesser number of carbon atoms than the alkyl aromatic charge and hydrogen in said first conversion zone, separating olefin-substituted aromatic hydrocarbons having a lesser number of carbon atoms than the aromatic charge from the eilluence of the first conversion zone,l subjecting the remainder of said eilluence of the rst conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the conversion oi' oleiln-substituted -aromatics to alkyl aromatics in said 4second conversion zone, and passing at least a part of the eiliuence of said second conversion zone to said rst conversion zone.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Description

ay 4, B948. H. A. CHENEY Er AL 2,443,095
CONVERSION OF ALKYL AROMATIC HYDROCARBNS INTO ALKENYL AROMATIC HYDROCRBONS Filed Aug. zo, 194e 2| Rencflon 15;.. e :rt-z
Patented May 4, 1948 CONVERSION F ALKYL AROMATIC HYDRO- CARBONS INTO ALKENYL AROMATIC HY- DROCARBONS Harry A. Cheney, Berkeley, and Sumner H. Mc- Allister, Lafayette, Calii., assignors to Shell Development Company, San Francisco, Calif., a
- corporation of Delaware Application August zo, 194s, serial No. 691,860
12 claim (c1. 26o-ess) The present invention relates to the producfrom alkyl aromatic hydrocarbons containing at least one alkyl group of at least three carbon atoms. 'I'he invention relates more particularly to theproduction of vinyl aromatic hydrocarbons from alkyl aromatic hydrocarbons containing at least one substituent isopropyl group. A speciic embodiment of the invention relates to the production of styrene from isopropyl benzene.
'I'he olefin-substituted aromatic hydrocarbons are employed as starting or intermediate materials in a great number of important iields of application. The vinyl aromatic hydrocarbons, for example, are of value as starting materials in the production of synthetic rubber and a wide variety of chemical derivatives. The alkyl aromatic hydrocarbons constitute an important potential source of olefin-substituted aromatics. Thus a straightforward dehydrogenation of an alkyl aromatic provides the corresponding olensubstituted aromatic hydrocarbon. esses are, however, dependent upon the alkyl aromatic corresponding to the desired olefin-substituted aromatic as charge. These processes therefore exclude the use of alkyl aromatics often more readily available or produced more economically than the alkyl aromatic corresponding to the olefin-substituted aromatic required. They are rendered particularly unattractive where the alkyl aromatic corresponding to the olen-substituted aromatic is itself in greater demand than the latter. This is often the case, for example, with hydrocarbons such as ethyl benzene' and styrene. The demand for ethyl benzenes as such occasions a need for a source of styrene other than this alkyl aromatic.
Processes have been disclosed heretofore for the production of olefin-substituted aromatics from alkyl aromatics having a greater number of carbon atoms. Such processes as disclosed heretofore are, however, generally handicapped by a low yield of the olefin-substituted hydrocarbon. They generally unavoidably involve accompanying side reactions which often predominate, thereby not only producing an exceedingly low yield of the desired olefin-substituted aromatic hydrocarbon but also converting at least i a substantial part of the charge to less valuable by-products. Such is the case when producing, for example, styrene from isopropyl benzene by processes disclosed heretofore. The resulting reaction product generally comprises not only an exceedingly small proportion of styrene but also Such procy consists predominantly of such products as alpha-methyl styrene and hydrogen, as well as considerable amounts of benzene and propylene.
It is an object of the present invention to vprovide an improved, continuous, unitary process for the more eiilcient production of olefin-substituted aromatic hydrocarbons of a. lesser number of carbon -atoms from alkyl aromatic hydrocarbons containing at least one alkyl group of at least three carbon atoms wherein a greater part of the alkyl aromatic hydrocarbons charged are converted to said olefin-substituted aromatic hydrocarbon.
A further object of the invention is the provision of an improved process for the more eilicient production of an olen-substituted aromatic hydrocarbon from an aykyl aromatic hydrocarbon having at least one alkyl group connected to the aromatic nucleus lby carbon to carbon linkage of a secondary carbon atom in the alkyl group to a carbon atom in the aromatic nucleus.
Still another object of the invention is the provision of an improved process for -the more efficient production of vinyl aromatic hydrocar- 4bons from alkyl aromatic hydrocarbons having at least one isopropyl group directly attached to a carbon atom in the aromatic ring.
A more particular object of the invention is the provision of an improved process for the more efficient production of styrene from isopropyl benzene. Other objects and advantages of the invention will become apparent from the following detailed description thereof.
In accordance with the process of the invention an alkyl aromatic hydrocarbon containing at least one alkyl group of at least three carbon atoms is subjected to controlled destructive dehydrogenation conditions in a first conversionv 1 oledn group as the number of carbon atoms in corresponding alkyl groups of the alkyl aromatic product hydrogen. The olefin-substituted aromatic hydrocarbon having a lesser number of carbon atoms to the molecule than the alkyl aromatic charge thus formed is separated from the eiiluence of the iirst conversion zone. At least a portion of the remainder of the eiiluence of the first conversion zone comprising the ole- 1in-substituted aromatic hydrocarbon and byproduct hydrogen is subjected to hydrogenating conditions in a second conversion zone, thereby saturating the olenic side chain and reconverting the olefin-substituted aromatic hydrocarbon to the alkyl aromatic hydrocarbon originally charged. At least a portion of the eiliuence from the secondconversion zone comprising alkyl aromatic hydrocarbon is returned to the rst conversion zone.
A particular advantage of the invention resides in the ability to produce more eiliciently olefinsubstituted aromatic hydrocarbons having an oleflnic linkage between the alpha and beta carbon atoms of the substituent olefin group from alkyl aromatic hydrocarbons containing at least one alkyl group directly connected by carbon-tocarbon linkage of a secondary carbon atom in the alkyl group to a nuclear carbon atom in the aromatic ring. When an alkyl aromatic hydrocarbon containing at least one alkyl group directly connected to the aromatic nucleus by a direct carbon-to-carbon linkage of a nuclear carbon atom with a secondary carbon atom in the alkyl group is subjected to the controlled destructive dehydrogenation conditions in the first conversion zone, there is brought about a scission of one of the alpha to beta carbon linkages in the substituent alkyl group with the formation of a reaction -product comprising an olen-substituted aromatic hydrocarbon containing an olefinic linkage between the remaining alpha and beta carbon atoms of the substituent group.
Although the process of the invention is broadly applicable to the conversion of alkyl substituted aromatic hydrocarbons to olefin-substituted aromatic hydrocarbons having a lesser number of carbon atoms to the molecule, it is preferred to use as charge the alkyl aromatic hydrocaibon having at least three but not' more than six carbon atoms in the substituent alkyl side chain. Alkyl aromatics which may be converted in accordance with the process of the invention comprise, for example, isopropylbenzene, di-isopropylbenzene, n propylbenzenes, isobutylbenzene, amylbenzenes, methyl-isopropylbenzenes, methylpropylbenzene, methylisobutylbenzene, methylbutylbenzene, butyiamylbenzene, isobutyl mesityiene, isopropylisobutylbenzene, isoamylbenzene, propylmesitylene, isobutyl mesitylene, isoarnylmesitylene, tert-butylbenzene and tert-p-dibutyl, benzene.
As stated above, the invention is of particular value in the production of olefin-substituted aromatics having an oleiinic bond between the alpha and beta carbon atoms of the substituent olenic group from alkyl aromatics having a substituent alkyl group directly connected by carbonto-carbon linkage of a secondary carbon atom of the alkyl group to a nuclear carbon atom of the aromatic nucleus. Examples of this preferred class of materials comprise, for example, isopropylbenzene, di-isopropylbenzene, propylisopropylbenzene, methylisopropylbenzene, 2 phenylbutane, 2-phenylpentane, S-phenylpentane, etc.
A particularly preferred embodiment of the invention comprises the production of vinyl aromatics from alkyl aromatic hydrocarbons containing at least one isopropyl group directly connected to the aromatic nucleus. Members of this particularly preferred group of charge material are, for example, isopropylbenzene, and the alkylsubstituted isopropylbenzenes such as methylisopropylbenzenes, di-isopropylbenzene, ethylisopropylbenzene, propyl-isopropylbenzene, etc.
The alkyl aromatics employed as charge to the process ofthe invention are obtained from any suitable source. They may be separated from the complex products obtained in many of the pyrogenio or catalytic hydrocarbon conversion processes, or they may be a product of synthesis such as obtained, for example, by the alkylation of an aromatic hydrocarbon with a suitable oleiin. Thus isopropylbenzene is produced by the alkylatlon of benzene with propylene under suitable alkylating conditions and with the aid of a suitable alkylation catalyst such as, for example, sulfuric acid, aluminum chloride, phosphoric acids or the like.
The alkyl aromatic charge in the process of the invention need not necessarily consist of only a single alkyl aromatic hydrocarbon, but may cornprise a mixture of two or more such hydrocarbons. The charge to the process of the invention may furthermore comprise other hydrocarbons capable or not of undergoing conversion underl the conditions of execution of the process of the invention, as well as inert gaseous materials such as nitrogen. normally gaseous paraillns, steam, etc.
The controlled destructive dehydrogenation of the alkyl aromatics in the first conversion zone is obtained by the maintenance therein of well deiined thermal or catalytic conditions. Suitable thermal conditions comprise a temperature in the range of from about 650 C. to about 900 C. and preferably from about 650 C. to about 850 C. The reaction zone may optionally contain suitable inert contact materials such as, for example, crushed brick, quartz chips, or the like. The residence time of reactants in the reaction zone is maintained sufiiciently short to attain fission of carbon-to-carbon linkage in the alkyl chain in the absence of any substantial complete dealkylation. The residence time may range, for example, from about 0.05 second to about 5 seconds, a time of less than one second being preferred; a higher contact time may, however, be resorted to within the scope of the invention. Atmospheric or subatrnospheric pressures may be resorted to. The use of relatively low superatmospheric pressures ranging, for example, from pressures slightly above atmospheric to about 100 pounds gauge are somewhat preferred. When employing the higher ltemperatures of the above described temperature range, diluent gases or vapors such as, for example, steam, are preferably introduced into the reaction zone.
. Catalytic conditions of controlled destructive dehydrogenation are preferably employed in the rst conversion zone. Suitable catalysts comprise broadly the oxides or suldes of the heavy metals, such as the oxides or sulfides of the metals of the groups V, VI and VlII of the periodic table such as, for example, the oxides and suldes of one or more of the following: tungsten, molybdenum, chromium, vanadium, copper, iron, cobalt, nickel; solid adsorptive materials such as adsorptive alumina, activated alumina, bauxite; adsorptive siliceous materials such 'as the naturally occurring or synthetically produced silica-alumiha catalysts; mixtures oi at least one of the heavy metal oxides or sulfides with an oxide of aluminum. magnesium or silicon.
Particularly suitable catalysts comprise the adsorptlve materials such as activated alumina, bauxite, activated carbonI magnesia 'or zirconia optionally in combination with one or more of the following: an alkaline earth metal. alkali metal, an oxide or sulfide of an Ialkaline earth metal or alkali metal. Preferred catalysts comprise those containing an adsorptive alumina in combination with an oxide or sulfide of calcium, lithium, strontium or cerium.
Temperatures to be maintained in the ilrst conversion zone when resorting to the use of catalytically controlled dehydrogenation therein comprise temperatures in the range of from about 350 C. to about 750 C. and preferably from about 400 C. to about 650 C. The contact time is controlled to eect substantial fission of the Ialkyl side chain in the absence of any substantial complete dealkylation of the alkyl aromatic. Contact times of from about 0.1 to about seconds have been found suitable. Higher contact times may, however, be resorted to within the scope of the invention. Subatmospheric, atmospheric or superatmospheric pressures may be employed when resorting to the use of catalysts. Pressures ranging from about atmospheric to about 150 pounds are, however. somewhat preferred. Introduction of diluent gases such as steam, nitrogen and the like into the catalyst-containing zone may be resorted to. The introduction of hydrogen into the nrst conversion zone is, however, preferably avoided since such often has been found to increase undesired side reactions such as, for example, the removal of the entire side chain from the aromatic nucleus.
Under the above-defined conditions the alkyl aromatics will undergo a destructive dehydrogenation in the first conversion zone consisting of the scission of a carbon-to-carbon linkage in the substituent alkyl chain of a portion of the alkyl aromatic charge with the formation of olensubstituted aromatic hydrocarbons containing a lesser number of carbon atoms to the molecule than the lalkyl aromatic charged. concomitant with the destructive dehydrogenation reaction a substantial portion oi the charge will undergo straight dehydrogenation of the alkyl side chain with the formation of hydrogen and an olensubstituted aromatic having the same number of carbon atoms to the molecule as the alkyl aromatic charged. Under the prescribed destructive dehydrogenation conditions alkyl aromatlcs containing an alkyl chain directly connected to the aromatic nucleus by means of a secondary carbon atom in the alkyl group will undergo a ssion of an alpha to beta carbon linkage resulting in the unsaturation of the remaining alpha to beta carbon linkage. Thus an aryl compound of the general formula CHgX HzY
result in the obtaining of a, reaction product comprising CII-X Ar-CH and Ar-CH Y each indicate an alkyl group or hydrogen. In
6 addition to the formation oi these products of lesser carbon atoms. a substantial part ci the charge will undergo a straight dehydrogenation of the substituent alkyl group to result in an ole; iin-substituted aromatic hydrocarbon having the same number of carbon atoms as the alim aromatic charged and hydrogen.
Hydrogenating conditions in the second conversion zone of the process comprise the use o! a suitable hydrogenation catalyst. Suitable hydrogenation catalysts comprises for emple those consisting` essentially oi a hydrogenating metal. such as nickel, iron, cobalt and themetals of the platinum group. The hydrogenating metals may suitably be employed in combination with one or more of the dimcuitly reducibie metal oxides such as thoria, ceria, mrconia and titanic.. Temperatures in the range of for example from about 25 C. to 175 C. and preferably from about 50 C. to about 125 C. and pressures in the range of from about atmospheric to 500 lbs. and preierably from about 50 to 100 lbs. have been found suitable. The invention is in no wise limited by the nature of catalyst or the specliic conditions employed in the second conversion zone. The specific conditions employed therein will generally be dependent to some degree upon the para ticular hydrocarbon charged and the catalyst employed. Hydrogenating conditions are, however, preferably chosen which will eect the saturation of the substituent oleiln group of the olefin aro,- matic in the absence of any substantialhydrogenation of the aromatic nucleus.
In order to set forth more fully the nature of the invention it will be dcribed in detail herein- Alkyl aromatic hydrocarbons comprising, for
example isopropylbenzene, taken from any out side source, is forced through line i into a reaction zone. The reaction zone may comprise any suitable type of reactor such as, for example, an elongated externally heated coil andor a reaction chamber of enlarged cross-sectional area. In the drawing the reaction zone is depicted by a reaction chamber 2. Within reactor 2 the isopropyl benzene is subjected to thermal or catalytic controlled destructive dehydrogenation conditions as dened above.
Preferred destructive dehydrogenating conditions comprise, i'or example, the use or a catalyst consisting of adsorptive alumina containing an alkaline earth metal or oxide thereof, such as for example activated alumina in combination with calcium pxide. Suitable temperatures in the rangeof for example from 450 C. to 750 C. are maintained in the reactor 2 by suitable heating means such as for example heater t.
Suitable conversion of the isopropylbenzene is obtained by contact in reactor 2 with a catalyst comprising adsorptive alumina and a promoting amount of calcium oxide at a temperature in the range of from about .400 C. to about 650 C., preierably 490 C. to 590 C., Iand a pressure of from about atmosphericto about pounds. The temperature is maintained in reactor 2 by means of any suitable heating means such as for example a heater S. The time of contact of reactants and catalyst is maintained in the range of from about 0.02 to about 15seconds and preferably between about 0.1` and 5 seconds.
Under these conditions demethanatlon of the isopropylbenzene will occur in reactor 2 with the formation of a reaction product comprising styrene. Simultaneously with the demethanation of one portion of the charge, straight dehydrogenation of another substantial part of the isopropylbenzene charge will occur with the formation of alpha-methylstyrene and by-product hydrogen. Although the presence of the catalyst increases the total amount or charge converted, it will of necessity increase the portion of the charge undergoing straight dehydrogenation. An outstanding advantage of the invention resides in the fact that such increase in straight dehydrogenation of the charge is offset as described more fully below by substantially complete reconversion within the system of the products of the straight dehydrogenation to the starting material. The process of the invention therefore brings within the realm of practicabllity a full realization of the advantages inherent in the use of catalysts to effeet the desired demethanation without the disadvantages encountered In processes available heretofore, involving the conversion of at least a substantial proportion of the charge material to products other than styrene.
Eluence from reactor 2 comprising styrene, alpha-metlrvlstyrene, and hydrogen and some lunconverted isopropylbenzene, is passed through line 5 into a product separating zone indicated in the drawing by fractionator 6. Within fractionator 6 a gaseous fraction comprising by-product hydrogen is separated from a liquid fraction comprising styrene, alpha-methylstyrene and isopropylbenzene. The liquid fraction is passed from fractionator 6 through line 8 into a fractionator 9. Within fractionator 9 a vapor fraction comprising styrene is separated and eliminated from the system as a nal product through valved line I0. A fraction comprising isopropylbenzene and alpha-methylstyrene is separated within fractionator 9 and passed therefrom through line I2 to a fractionator I3.. Any materials higher boiling than isopropylbenzene which may have been formed to some degree in the system are separated as bottoms in fractionator 9 and removed therefrom through valved line I4.
Within fractionator I3 a vapor fraction comprising isopropylbenzene is separated from a liquid fraction comprising alpha-methylstyrene. The vapor fraction is taken overhead from fractionator I3 and passed through line I6 into line I leading to reactor 2. The liquid fraction is taken from fractionator I3 and forced through line Il into a second reaction zone. The second reaction zone may constitute any suitablereaction zone of elongated restricted and/or enlarged cross-sectional area. In the drawing the second reaction zone is represented by reaction chamber I8. Overhead from fractionator 6 comprising the by-product hydrogen formed in reactor 2 is forced through line I9 into reactor I8. Within reactor I8 the mixture of alpha-methylstyrene and byproduct hydrogen is subjected to hydrogenating conditions effecting the hydrogenation of the alpha-methylstyrene to isopropylbenzene, Hydiogenation of the alpha-methylstyrene may be carried out under suitable hydrogenating conditions effecting the hydrogenation of alpha-methylstyrene to isopropylbenzene. Suitable hydro- .genating conditions comprise, for example, the` use of a catalyst comprising Raney nickel at a temperature in the range of from about 50 C. to about 100 C. and a pressure of from about 50 to about 100 pounds gauge. Although catalytic hydrogenating conditions using a Raney nickel catalyst have been set forth as suitable, it is to be stressed that the invention is in no wise limited to the use of specific hydrogenating conditions or catalysts to effect the desired hydrogenation within reactor I8. Other suitable hydrogenating catalysts comprise, for example, the heavy metal sulfides. Effective hydrogenating conditions employing a heavy metal sulfide-type catalyst comprise the use of a nickel sulde-tungsten sulfide catalyst at a temperature of from about 250 C. to about 350 C. at a pressure of from about atmospheric to about 10 atmospheres or higher. Hydrogen produced within the system is preferably permitted to build up during the recycling thereof to attain a molar excess oi' hydrogen over hydrocarbons to be hydrogenated in reactor I8. Additional hydrogen from an outside source may be introduced into the system through valved line 2I when needed Eiiluence from reactor I8 comprising isopropylbenzene and some unconverted alpha-methylstyrene is passed through valved line 22 into fraction-ator 23. Within fractionator 23 a gaseous fraction comprising residual gases formed within the system is separated from a liquid fraction comprising isopropylbenzene and alpha-methylstyrene. The liquid is passed from fractionator 23 through line 24 into fractionator I3.
Gaseous overhead is taken from fractionator 23 through valved line 25 and may be passed in part into line I9 and if desired in part into line I. However, when the hydrogen content of the gas passing through line 25 is high, recycling thereof to reactor 2 is preferably avoided since the introduction of hydrogen into reactor 2 favors complete dealkylation of isopropylbehzene to reaction products consisting essentially of benzene and propylene, thereby seriously detracting from the efficiency of the process.
Diluent materials such as for example inert gases or steam may be introduced into the system by means of valved line 21. Elimination of gases from the system is accomplished by bleeding from valved line 28 and/or valved line 29. If desired gaseous materials may be bled from valved lines 28 and/or 29 and subjected in part or entirety to a purification or separation process and a portion of the thus treated gas returned into the system.
It is seen from the foregoing that the unitary process of the invention provides a method for the substantially complete conversion in a, continuous highly eicient operation of substantially all of .the alkyl aromatic hydrocarbon charged to the system to a final product consisting essentially only of olefin-substituted aromatic hydrocarbon containing a lesser number of carbon atoms to the molecule than the hydrocarbon charge. The process of the invention, because of its complete utilization within the system of the products of straight dehydrogenation, unavoidably encountered to a substantial degree, enables the full realization of the advantages inherent in the use of dehydrogenation catalysts to obtain the desired controlled destructive dehydrogenation without the substantial loss of charge material encountered in the production of olefin aromatics from alkyl aromatics of a greater number of carbon atoms by methods available heretofore.
The following examples further illustrate the process of the invention:
'zone consisting of an externally heated unpacked tubular reactor4 wherein it is subjected to a temperature of about 750 C. for aperiod of 0.1 second at substantially atmospheric pressure. Eiiiuence from the rst reactor is passed through a cooler into a iirst product separating zone consisting of a series of fraotionators wherein a gaseous fraction consisting essentially of hydrogen and liquid fractions consisting essentially of styrene and alpha-methylstyrene respectively are separated from the reaction products. Th'e alphamethylstyrene and normally gaseous fractions are passed into a second conversion zone` consisting of a reaction chamber equipped with stirring means. In the second reactor the alpha-methylstyrene-hydrogen mixture is subjected to catalytic hydrogenating conditions in the temperature range of from 50 C. to 100 C., and a pressure of about 70 pounds in the presence of a Raney nickel catalyst. A contact time in the range of from about 5 to 12 minutes is maintained. Eiuence from the second'reaction zone is passed through a cooler into a fractionator wherein a normally gaseous fraction is separated from a liquid fraction consisting of isopropylbenzene and unconverted alpha-methylstyrene. The liquid fraction consisting of isopropylbenzene and alphamethylstyrene is recycled to the first product separating zone. Hydrogenation within the system of substantially all by-product alpha-methylstyrene to isopropylbenzene is attained. A conver-l sion per pass of isopropylbenzene of 68% is obtained `in the first reactor with' a yield of 33%. styrene and 20% alpha-methylstyrene.
Example II Isopropylbenzene is subjected to catalytic demethanation in a first reactor by contact with a. catalyst consisting of calcium-promoted activated alumina at substantially atmospheric pressure. 'I'he temperature in the first reactor is maintained in the range of from 550 C. to 560 C. Steam is added to the ispropylbenzene charge and the mixture introduced into the first reactor at a. rate of 50 mols of ispropylbenzene and 100 mols of steam per liter of catalyst per hour. Eiiiuence from the iirst reactor is 'passed through a cooler into a first product separating zone consisting of a series of fractionators wherein a gaseous. fraction consisting essentially of hydrogen and two liquid fractions consisting essentially of styrene and alpha-methylstyrene, respectiveiy, are separated from the reaction products. The alpha-methylstyrene and normally gaseous fractions are passed into a second con- Version zone consisting of a reaction chamber equipped with stirring means. In the second reactor the alpha-methylstyrene-hydrogen mixture is subjected to catalytic hydrogenating conditions in the temperature range of from 50 C. to 100 C. and a pressure of about 70 pounds in the presence of a Raney nickel catalyst. A contact time in the range of from about 5 to 12 minutes is maintained. Eiiluence from the second reaction zone is passed through a cooler into a fractionator wherein a normally gaseous fraction is separated from a liquid fraction consisting of isopropylbenzene and unconverted alphamethylstyrene. The liquid fraction consisting of isopropyl-benzene and alpha-methylstyrene is v recycled to the rst product separating zone.
Hydrogenation within the system of substantially al1 by-produet alpha-methylstyrene to isopropylbenzeney is attained. A conversion per pass of isopropylbenzene of 19.5% is obtained in the first reactor with a yield of 32% styrene and 16% alpha-methylstyrene.
Example I-II In a repetition of the process of Example II under substantially identical conditions but with the exception that a catalyst consisting of adsorptive alumina is employed in the first reactor at a temperature of 650 C., a conversion per pass of ethyl isopropylbenzene of 58% is obtained in the first conversion zone with a yield of 11% styrene and 62% alpha-methylstyrene.
Example IV In al repetition of the process of Example II under substantially identical conditions but with theuse of another calcium-promoted adsorptive alumina catalyst at a temperature of 650 C. in the iirst reactor aconversion per pass of isopropylbenzene of 49% is obtained in the first conversion zone with a yield of 12% styrene and 65% alpha-methylstyrene.
In the yforegoing examples, because of the continuous reconversion of the by-product hydrogen and alpha-methylstyrene to isopropylbenzene and the .reintroduction of the latter into the controlled destructive dehydrogenation zone, an
Cymene is subjected to catalytic demethanation in a first reactor by contact with a catalyst consisting of calcium-promoted activated alumina at substantially atmospheric pressure at a temperature of about '730 C. 1.5 mols of steam per mol of cymene charge is employed and. the mixture passed through the irst reactor at the rate of 2.5 mols of the cymene-steam mixture per liter of catalyst per hour. Efiluence from the rst reactor is passed through a cooler into a iirst product separating zone consisting of a series of fractionators wherein a gaseous fraction consisting essentially of hydrogen and two liquid fractions consisting essentially of p-methylstyrene and asym. methyl p-tolylethylene, respec-' tively, are separated from the reaction products. The asym. methyl p-tolylethylene and normally gaseous fractions are introduced into a second conversion zone wherein they are contacted with a nickel-tungsten-sulde catalyst at a pressure of 4.5 atmospheres and a temperature of about 300 C. at a liquid hourly space velocity of 2. Eiiiuence from the second reaction zone is passed through a cooler into a fractionator wherein a normally gaseous fraction is separated from a liquid fraction comprising cymene and unconverted asym. methyl p-tolylethylene. The liquid fraction consisting of cymene and asym.' methyl p-tolylethylene is recycled to the first product separating zone. Hydrogenation of substantially all lay-product asym. methyl p-tolylethylene to cymene is attained within the system. A conversion per pass of cymene of 60% is obtained in the first conversion zone. The invention claimed is:
1. A process for the production of styrene s 11 which comprises subjecting isopropylbenzene to destructive dehydrogenating conditions in a. rst conversion zone, thereby eilecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-methylstyrene and hydrogen in said iirst conversion zone, separating styrene from the eiiluence of said rst conversion zone, subjecting the remaining eiiiuence of said first conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of alpha-methylstyrene Vto isopropylbenzene in said second` conversion zone.' and passing eiiiuence from said second conversion zone to said first conversion zone.
2. A process for the production of styrene which comprises subjecting isopropylbenzene to destructive dehydrogenating conditions at a temperature of from about 350 C. to about 750 C.in the presence of a dehydrogenation catalyst in a first conversion zone, thereby effecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-methyistyrene and hydrogen in said first conversion zone, separating hydrocarbons comprising styrene from the eiiluence of said rst conversion zone, subjecting at least a part of the remaining eilluence of said first conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of aJpha-methylstyrene to isopropylbenzene in said second conversion zone, and passing at least a part of the eiiiuence from said second conversion zone to said rst conversion zone.
3. A process for the production of styrene which comprises subjecting isopropylbenzene to destructive dehydrogenating conditions at a temperature of from about A400 C. to about 650 C. in the presence of a dehydrogenation catalyst in a rst conversion zone, thereby effecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-methylstyrene and hydrogen in said rst conversion zone, separating a, fraction comprising styrene from the eiiluence of said rst conversion zone, subjecting the remaining eiiiuence of said rst conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of alphamethylstyrene to isopropylbenzene in said second conversion zone, and passing eiiiuence from said second conversion zone to said first conversion zone.
4. A process for the production'of styrene which comprises subjecting hydrocarbons comprising isopropylbenzene to destructive dehydrogenating conditions at a temperature of from about 400 C. to about 650 C. in the presence of a dehydrogenation catalyst comprising adsorptive alumina in a first conversion zone, thereby effecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-methylstyrene and hydrogen in said first conversion zone, separating a fraction comprising styrene from the emuence of said first conversion zone, subjecting the remaining eiiiuence of said rst conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of alpha-methylstyrene to isopropylbenzene in said second conversion zone, and passing eiliuence from said second conversion zone to said first conversion zone.
5. A process for the production of styrene which comprises subjecting isopropylbenzene to thermal destructive dehydrogenating conditions at a temperature of from about 650 C. to about 900 C. and a residence'time of from about'0.05 to about seconds in a iirst conversion 20m2, thi???- by eecting the conversion of isopropylbenzene to a reaction product comprising styrene, alpha-- methylstyrene and hydrogen in said first conversion zone, separating styrene from the eluence of said conversion zone, subjecting at least a part of the remaining effiuence of said rst conversion zone to hydrogenating conditions in a second conversion zone. thereby effecting the hydrogenation of alpha-methylstyrene to isopropylbenzene in said second conversion zone, and passing eiliuence from said second conversion zone to said first conversion zone.
6. A process tor the production of vinyl-substituted aromatic hydrocarbons which comprises subjecting alkyl aromatics having at least one substituent isopropyl group directly attached to the aromatic nucleus to destructive dehydrogenating conditions in la iirst conversion zone, thereby effecting the conversion of said alkyl aromatics to a reaction product comprising vinyl aromatics, olefin-substituted aromatics having the same number of carbon atoms as said alkyl aromatic charge and hydrogen in said first conversion zone, separating vinyl aromatics from the eiliuence of said iirst conversion zone, subjecting the remaining efiiuence of said rst conversion zone to hydrogenating conditions in a second conversion zone, thereby eiecting the hydrogenation of oleiin-substituted aromatics to alkyl aromatics in said second conversion zone, and passing eluence from said second conversion zone to said first conversion zone.
7. A process for the production of vinyl-substituted aromatic hydrocarbons from alkyl aromatic hydrocarbons having at least one substituent isopropyl group directly attached to the aromatic nucleus which comprises subjecting alkyl aromatics having at least one substituent isopropyl group directly attached to the aromatic nucleus to destructive dehydrogenating conditions at a temperature inthe range of from about 350 C. to about 750 C. in the presence of a dehydrogenation catalyst in a rst conversion zone, thereby effecting the conversion of said alkyl aromatics to a reaction product comprising olefin-substituted aromatics having the same number of carbon atoms as the alkyl aromatic charge, vinylsubstituted aromatics and hydrogen in said rst conversion zone, separating vinyl-substituted aromatic hydrocarbons from the eiliuence of the rst conversion zone, subjecting the remainder of said efiluence of the iirst conversion zone to hydrogenating conditions in a second conversion zone, thereby eiecting the conversion of olefin-substituted aromatics to alkyl aromatics in said second conversion zone, and passing at least a part of the eiliuence of said second conversion zone to said iirst conversion zone.
8. A process for the production of olefin-substituted aromatic hydrocarbons containing a lesser number of carbon atoms from alkyl aromatic hydrocarbons containing a greater number of carbon atoms which comprises subjecting alkyl aromatic hydrocarbons having a substituent alkyl group of at least three carbon atoms connected by a secondary carbon atom in the alkyl group to a carbon atom in the aromatic nucleus to destructive dehydrogenating conditions in a and hydrogen in said first conversion zone, separating olen-substituted aromatic hydrocarbons having a lesser number of carbon atoms than said alkyl aromatic charge from the efiluence ofsaid rst conversion zone, subjecting at least a part of the remaining eiiluence of said first conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the hydrogenation of olefin-substituted aromatic hydrocarbons to alkyl aromatic hydrocarbons in said second conversion zone and passing emuence from said second conversion zone to said iirst conversion zone.
9. A process for the production of olefin-substituted aromatic hydrocarbons having a lesser number of carbon atoms to the molecule from alkyl aromatic hydrocarbons having a greater number of carbon atoms to the molecule which' comprises subjecting alkyl aromatics having at least one substituent alkyl group of at least three carbon atoms connected by a secondary 'carbon atom in the alkyl group to a carbon -atom in the aromatic nucleus to destructive dehydrogenating conditions at a temperature in the range of irom about 350 to about 750 C. in the presence of a dehydrogenation catalyst in a ilrst conversion zone, thereby effecting the conversion of alkyl aromatics to a reaction product comprising olefinsubstituted aromatics having the same number of carbon atoms as the alkyl aromatic charge, olefin-substituted aromatics having a lesser number oi carbon atoms than the alkyl -aromatic charge and hydrogen in said ilrst conversion zone, separating olefin-substituted aromatic hydrocarbons having a lesser number of carbon atoms than the aromatic charge from the eiliuence of the rst conversion zone, subjecting the remainder of said eilluence of the first conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the conversion of olensubstituted aromatics to alkyl aromatics in said second conversion zone, and passing at least a part of the eilluence of said second conversion zone to said ilrst conversion zone.
10. A process for the production of olefin-substituted aromatic hydrocarbons yhaving a lesser number of carbon atoms to the molecule from alkyl aromatic hydrocarbons having a greater number of carbon atoms to the molecule which least one substituted alkyl group of at least three carbon atoms to destructive dehydrogenating conditions in a first conversion zone, thereby eilecting the conversion of alkyl aromatics to a reaction product comprising olefin-substituted aro,- matics having the same number of carbon atoms as the alkyl aromatic charge, oleiln-substituted aromatics having a lesser number of carbon atoms than the alkyl aromatic charge and hydrogen in said first conversion zone, separating olefin-substituted aromatic hydrocarbons having a lesser number of carbon atoms than the aromatic charge from the eilluence of the first conversion zone, subjecting the remainder of said eiiluence of the nrst conversion zone to hydrogenatlng conditions in a second conversion zone, thereby ei'- iecting the conversion of olefin-substituted aromatics to alkyl aromatics in said second couver,- sio'n zone, and passing at least a part or the emuence of said second conversion zone to said first conversion zone.
stituted aromatic hydrocarbons having a lesser number of carbon atoms to the molecule from alkyl aromatic hydrocarbons having a greater number of carbon atoms to the molecule which comprises subjecting alkyl aromatics having at least one substituent alkyl group of atleast three carbon atoms to thermal destructive dehydrogenating conditions at a temperature in the range of from about 650 C. to about 900 C, and a residence time of from about 0.05 to about 5 seconds in a first conversion zone, thereby effecting the conversion of alkyl aromatics to a reaction product comprising. olefin-substituted aromatics having the same number of carbon atoms as the alkyl aromatic charge, oleiln-substituted aromatics having a lesser number of carbon atoms than the alkyl aromatic charge and hydrogen in said ilrst conversion zone, separating oleiln-substituted aromatic hydrocarbons having -a lesser number of carbon atoms than the aromatic charge from the eilluence of the ilrst conversion' zone, subjecting the remainder of said eilluence oi the iirst conversion zone to hydrogenating conditions in 4a second conversion zone, thereby effecting th'e conversion of olefin-substituted aromatics to alkyl aromatics in said second conversion zone, and passing. at least a part oi' the eilluence of said second conversion zone to said rst conversion zone.
12. A process for the production of olen-substituted aromatic hydrocarbons having a lesser number of carbon atoms to the molecule from alkyl aromatic hydrocarbons having a greater number of carbon atoms to the molecule which comprises subjecting alkyl aromatics having at least one substituent alkyl group of at least three carbon atoms to destructive dehydrogenating conditions at a temperature in the range of from about 350 C. to about 750 C. in the presence o! a dehydrogenation catalyst in a first conversion zone, thereby effecting the conversion of alkyl aromatics to a reaction product comprising oleilnsubstituted aromatics having th'e same number of carbon atoms as'the alkyl aromatic charge, olefin-substituted aromatics having a lesser number of carbon atoms than the alkyl aromatic charge and hydrogen in said first conversion zone, separating olefin-substituted aromatic hydrocarbons having a lesser number of carbon atoms than the aromatic charge from the eilluence of the first conversion zone,l subjecting the remainder of said eilluence of the rst conversion zone to hydrogenating conditions in a second conversion zone, thereby effecting the conversion oi' oleiln-substituted -aromatics to alkyl aromatics in said 4second conversion zone, and passing at least a part of the eiliuence of said second conversion zone to said rst conversion zone.
HARRY A. CHENEY. SUMNER H. MCALLIS'I'ER.
REFERENCES CITED The following references are oi record in the ille of this patent:
UNITED STATES PATENTS Number Name Date 2,182,313 'Dreisbach Dec. 5, 1939 2,182,431 Groll et al Dec. 5, 1939 2,198,185
1l. A process for the production oi oleiinsub- Stanley et al. Apr. '23, 1940
US691860A 1946-08-20 1946-08-20 Conversion of alkyl aromatic hydrocarbons into alkenyl aromatic hydrocarbons Expired - Lifetime US2441095A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US691860A US2441095A (en) 1946-08-20 1946-08-20 Conversion of alkyl aromatic hydrocarbons into alkenyl aromatic hydrocarbons

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US691860A US2441095A (en) 1946-08-20 1946-08-20 Conversion of alkyl aromatic hydrocarbons into alkenyl aromatic hydrocarbons

Publications (1)

Publication Number Publication Date
US2441095A true US2441095A (en) 1948-05-04

Family

ID=24778268

Family Applications (1)

Application Number Title Priority Date Filing Date
US691860A Expired - Lifetime US2441095A (en) 1946-08-20 1946-08-20 Conversion of alkyl aromatic hydrocarbons into alkenyl aromatic hydrocarbons

Country Status (1)

Country Link
US (1) US2441095A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2592589A (en) * 1948-07-08 1952-04-15 Koppers Co Inc Production and separation of isomeric isopropylnaphthalenes
US2939889A (en) * 1956-05-25 1960-06-07 Dow Chemical Co Process for the preparation of styrene from nu-propylbenzene
US3344201A (en) * 1965-06-07 1967-09-26 Seymour C Schuman Production of styrene
US4300007A (en) * 1977-10-05 1981-11-10 Polyakov Sergei A Method for preparing C3 -C4 olefins and vinylaromatic compounds

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2182313A (en) * 1937-11-12 1939-12-05 Dow Chemical Co Pyrolysis of secondary-butylbenzene derivatives
US2182431A (en) * 1935-07-15 1939-12-05 Shell Dev Dehydrogenation of organic compounds
US2198185A (en) * 1936-10-30 1940-04-23 Stanley Herbert Muggleton Production of aryl substituted olefins

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2182431A (en) * 1935-07-15 1939-12-05 Shell Dev Dehydrogenation of organic compounds
US2198185A (en) * 1936-10-30 1940-04-23 Stanley Herbert Muggleton Production of aryl substituted olefins
US2182313A (en) * 1937-11-12 1939-12-05 Dow Chemical Co Pyrolysis of secondary-butylbenzene derivatives

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2592589A (en) * 1948-07-08 1952-04-15 Koppers Co Inc Production and separation of isomeric isopropylnaphthalenes
US2939889A (en) * 1956-05-25 1960-06-07 Dow Chemical Co Process for the preparation of styrene from nu-propylbenzene
US3344201A (en) * 1965-06-07 1967-09-26 Seymour C Schuman Production of styrene
US4300007A (en) * 1977-10-05 1981-11-10 Polyakov Sergei A Method for preparing C3 -C4 olefins and vinylaromatic compounds

Similar Documents

Publication Publication Date Title
US3557235A (en) Production of ethylbenzene and benzene from toluene
EP0205003A1 (en) Product recovery method for an aromatic hydrocarbon alkylation process
US2416184A (en) Conversion of hydrocarbons
US2456584A (en) Conversion of dimethyl ether
US3379784A (en) Process for preparing polyalkyltetrahydronaphthalenes
US3525776A (en) Alkylation-dehydrogenation process
US2396965A (en) Hydrocarbon conversion
JPH04502451A (en) Production of alkylbenzene
US2441095A (en) Conversion of alkyl aromatic hydrocarbons into alkenyl aromatic hydrocarbons
US2589057A (en) Alkylation-dealkylation process
US2422673A (en) Treatment of alkyl aromatic hydrocarbons
US2748178A (en) Condensation of an aromatic compound with an unsaturated organic compound in the presence of an alkali metal and a peroxy compound
US3373217A (en) Hydrogenolysis of sym-diphenylethane to ethylbenzene
US2721886A (en) Catalyzed condensation of aromatic compounds with unsaturated organic compounds
US2688044A (en) Condensation of aromatic compounds with unsaturated organic compounds in the presence of mixed catalysts
US3515765A (en) Catalytic conversion process
US2860173A (en) Manufacture of isopropyl benzene by alkylation
US2769850A (en) Alkylation reactions
US2572724A (en) Propylene tetramer production
US2198185A (en) Production of aryl substituted olefins
US2389215A (en) Process for dehydrogenating a hydrocarbon
US2721885A (en) Condensation of aromatic compounds with unsaturated organic compounds in the presence of composite catalysts
US3402212A (en) Dehydrogenation of ethylbenzene to styrene
US2758140A (en) Noncatalytic condensation of aromatic compounds with unsaturated hydrocarbons
US2386969A (en) Production of xylene