US3230157A - Isoprene purification process - Google Patents

Isoprene purification process Download PDF

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Publication number
US3230157A
US3230157A US195710A US19571062A US3230157A US 3230157 A US3230157 A US 3230157A US 195710 A US195710 A US 195710A US 19571062 A US19571062 A US 19571062A US 3230157 A US3230157 A US 3230157A
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isoprene
column
fraction
distillation
fraction containing
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Arthur B Hill
Parnell David Crosby
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ExxonMobil Technology and Engineering Co
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Exxon Research and Engineering Co
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/005—Processes comprising at least two steps in series
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • C07C7/05—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds
    • C07C7/08—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds by extractive distillation

Definitions

  • the problem of separating isoprene from C cuts, particularly those produced by the steam cracking of hydrocarbon, is rendered particularly diflicult because of the close relationship in properties of the several compounds and the pronounced tendencies of the more unsaturated hydrocarbons therein to polymerize.
  • the following table lists the principal C hydrocarbons that are found in admixture with isoprene in a closeout C stream from a refinery cracked stock. The table also lists the boiling points at 760 mm. of these hydrocarbons and the relative volatilities (a) (relative to isoprene as one) which are a direct measure of the ease of separation in a distillation system.
  • isoprene of high purity can be separated from a C fraction containing acetylenes and olefins as well as cyclopentadiene by first subjecting the fraction to straight distillation.
  • the presence of C olefins in the straight distillation step forces isopropylacetylene, dimethylacetylene, pentadiene 1-4 and some of the valylene overhead.
  • the C olefins enhance the volatility of those acetylenes relative to the volatility of isoprene.
  • the bottoms from this straight distillation is then subjected to extractive distillation using a volatility modifying agent such as acetone or acetonitrile in two stages.
  • the C olefins are taken overhead and the extract is charged to the second extractive distillation stage.
  • the high purity product isoprene is taken overhead from the second extractive distillation stage while the remaining valylene, cyclopentadiene, piperylene propylacetylene and allylacetylene are rejected in the extract phase.
  • the hydrocarbons contained in the extract phase are then separated from the volatility modifying agent and the latter then conditioned for recycling to the first extractive distillation phase.
  • a feed stock containing mainly C olefins, diolefins, and acetylenes (including dimethyl acetylene) obtained, for example, by fractionating a steam cracked hydrocarbon product is supplied via line 1 to a primary fractionator 2.
  • This primary fractionator separates overhead through line 3, isopropyl acetylene, dimethyl acetylene, valylene, portions of the pentene-l, and Z-methyl butene-l and most of the pentadiene 14 as well as any C and lighter hydrocarbons from the feed stream.
  • the overhead stream is condensed, collected in reflux drum 4 and part recycled to column 2 as reflux and part withdrawn via line 5.
  • Column 2 should contain about 70 plates and should be operated at a reflux ratio of about 13:1, at a pressure of about 36 p.s.i.g. and with temperatures at the top of l38-140 F. and at the bottom of l72175 F.
  • the bottom stream from the primary or straight distillation column 2 is withdrawn through line 6 and charged to the first extractive distillation stage or column 7 for the separation of the remaining C olefins and remaining pentadiene 1-4 from the other diolefins and remaining acetylenes.
  • This separation is effected by supplying the hydrocarbon stream to about the middle part of an extractive distillation column and supplying a suitable volatility modifying agent such as acetone or acetonitrile to the column above the hydrocarbon inlet as through line 8.
  • a suitable volatility modifying agent such as acetone or acetonitrile
  • a stream of volatility modifying agent is withdrawn from the bottom of column '7 and part of it is passed through a Ieboiler and back into the lower part of column 7 while the major proportion of said stream is recycled to the top of column 7.
  • the extractive distillation column 7 should contain about plates and should be operated at a reflux ratio of about 5:1.
  • the solvent or volatility modifying agent should be circulated at a ratio of about 1 to 1 on total hydrocarbon in the column.
  • Column 7 should be operated at about 30 p.s.i.g. with a temperature of about F. at the top and about 255 F. at the bottom.
  • the remaining C olefins and remaining pentadiene 1-4 are taken overhead from column 7 with a small amount of volatility modifying agent through line 10, condensed and charged to reflux drum 11. A part of the condensate is recycled to column 7 as reflux and the rem-aining portion is supplied through line 12 to the water Wash tower 13.
  • the water wash tower 13 removes the volatility modifying agent, i.e., acetone or acetonitrile from the C olefins and pentadiene 1-4 and the latter are removed through line 14 to further processing elsewhere.
  • Water and volatility modifying agent are withdrawn from the bottom of the water washer 13 and passed to a suitable recovery or concentrating system preparatory to recycling the agent to line 9 and thence to column 7.
  • the extracted isoprene product along with the remaining diolefins (piperylcne and cyclopent-adiene) and acetylenes is withdrawn from column 7 via line 15 and charged to the second extractive distillation stage or column 16. Additional volatility modifying agent is supplied to the top of column 16 via line 17 and the extractive distillation is conducted in said column to effect the separation of the isoprene from the remainder of the valylene, cyclopentadiene, p-ropylacetylene, allylacetylene and cisand trans-piperylene (pentadiene 13).
  • the column 16 should contain about 70 plates and should be operated at a reflux ratio or" about 6: 1.
  • the solvent or volatility modifying agent should be circulated at a rate of about 2 to 1 based on total hydrocarbon in the column.
  • Column 16 should be operated at about p.s.i.g. with a temperature of about 120 F. at the top and about 215 F. at the bottom.
  • the isoprene and small amount of volatility modifying agent are removed overhead from column 16 via line 18, condensed and the condensate discharged into reflux drum 19 from which a portion of the condensate is recycled to the CO'IUIIHI]. 16 as reflux and the remaining portion is discharged via line 20' into water wash tower 21.
  • the tower 21 removes the volatility modifying agent, i.e., acetone or acetonitrile from the isoprene and the high purity isoprene .product is then removed from the tower via line 22 for use as is or for further purification to remove any remaining piperylenes by simple fractionation.
  • Water and volatility modifying agent are withdrawn from the bottom of tower 21 and passed to a suitable recovery or concentrating system preparatory to recycling the agent to column 16 via makeup solvent inlet line 23 or to tower 7 via inlet line 9.
  • the extract is Withdrawn from the lower portion of column 16 via line 24 and, if desired, passed through a stripper 25 for effecting some separation of hydrocanbons which are taken overhead from solvent or volatility modifying agent which is withdrawn from the bottom of the stripper and recycled to the column 16.
  • the material taken overhead from stripper 25 is condensed and a portion of the condensate is recycled to stripper 2 as reflux.
  • the remaining portion of the condensate is charged via line 26 to water wash tower 27 which serves to make final separation of the solvent or volatility modifying agents from the hydrocarbons.
  • the washed hydrocarbons consisting principally of valylene, cyclopentadiene, propylacetylene, allylaceylene and cisand trans piperylene are removed via line 28 while water and volatility modifying agent are removed from the bottom of tower 27 via line 29 and passed to a suitable recovery and concentrating system preparatory to recycling the solvent to column 16 via line 23 or to column 7 via line 9.
  • the isoprene product removed via line 22 is of very (high purity, at least about 97 wt. percent of the total stream making it eminently suitable for the production of high quality polymeric products.
  • a final straight distillation step can be used to increase the isoprene purity to 99.5 wt. percent.
  • Example A representative feed charged to the system of the present invention is a stream cracked hydrocarbon fraction having the following composition (mol percent).
  • This feed is charged to a fractionator column 2 having 70 plates and operated at 36 p.s.i.g. with a temperature of 138 F. at the top and 172 F. at the bottom.
  • the relative material flow rates are 7,000 #/hr. of feed, 24,700 #/hr. reflux, 1,900;#/hr. overhead product withdrawn and 5,100 #/hr. of bottoms product.
  • the overhead distillate product removed through line 5 and the bottoms product removed through line 6 have the compositions (mol percent) shown in the following table.
  • stream 8 1,600 #/hr.
  • stream 9 3,700 #/hr.
  • stream 12 3,300 #/hr.
  • stream 14 1,800 #/hr.
  • the overhead distillate product removed through line 14 and the concentrate or bottoms stream (stream 15) have thecomposition (mol percent) shown in the following table.
  • Stream 15 is charged to the extractive distillation column 16 containing 70 plates and operated at 10 p.s.i.g.
  • the isoprene product stream 22 may be subjected to a final straight distillation step to raise the isoprene purity to 99.5 wt. percent.
  • An improved method for the separation of isoprene of high purity from a C hydrocarbon fraction containing C monoolefins, C diolefins including cyclopentadiene, dimethyl acetylene and C acetylenes which comprises introducing a mixture of said components directly to means for effecting a straight distillation, subjecting said mixture to a straight distillation to separate a distillate fraction containing isopropyl acetylene, dimethyl acetylene, pentadiene 1 4, valylene and a minor proportion of the isoprene from the feed and a second fraction containing C monoolefins, the major proportion of the isoprene from the feed and higher boiling compounds, subjecting said second fraction to extractive distillation in the presence of a volatility modifying solvent to separate a distillate fraction containing the C monoolefins and a second fraction containing C diolefins and higher boiling C acetylenes and subjecting the latter to a second extractive distill
  • An improved method for the separation of isoprene of high purity from a C hydrocarbon fraction containing C monoolefins, C diolefins including cyclopentadiene, dimethyl acetylene and C acetylenes which comprises introducing a mixture of said components directly to means for effecting a straight distillation, subjecting said mixture to a straight distillation to separate a distillate fraction containing isopropyl acetylene, dimethyl acetylene, pentadiene-1,4, valylene and a minor proportion of the isoprene from the feed and a second fraction containing C monoolefins, the major proportion of the isoprene from the feed and higher boiling compounds including cyclopentadiene, subjecting said second fraction to extractive distillation in the presence of a volatility modifying solvent selected from the group consisting of acetone and acrylonitrile to separate a distillate fraction containing the C monoolefins and a second fraction containing C diole
  • distillate fraction percent purity as the distillate fraction and a second fraction containing valylene, cyclopentadiene, propyl acetylene, cisand transpiperylene and allylacetylene, and subjecting the last named distillate fraction to a final straight distillation to obtain an isoprene distillate fraction of about 99.5 wt. percent purity.
  • vola tility modifying agent to hydrocarbon ratio is about 1:1 in the first extractive distillation step and about 2:1 in the second extractive distillation step.

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  • Engineering & Computer Science (AREA)
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  • Oil, Petroleum & Natural Gas (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US195710A 1962-05-18 1962-05-18 Isoprene purification process Expired - Lifetime US3230157A (en)

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Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3317627A (en) * 1963-10-25 1967-05-02 Shell Oil Co High purity alkadienes by extractive distillation
US3320138A (en) * 1962-12-22 1967-05-16 Bayer Ag Process for separating c-hydrocarbon mixtures, containing paraffinic, monoolefinic and diolefinic c-hydrocarbons by distillation with n-methylpyrrolidone
US3328479A (en) * 1965-10-04 1967-06-27 Mobil Oil Corp Purifying diolefins by selective hydrogenation and distillation
US3378465A (en) * 1963-08-28 1968-04-16 Bayer Ag Purification of solvents containing c5 dimers by azeotropic distillation with water
US3436438A (en) * 1965-12-30 1969-04-01 Nippon Zeon Co Process for the separation of conjugated diolefins
US3436437A (en) * 1965-11-17 1969-04-01 Mitsubishi Gas Chemical Co Process for recovering high purity isoprene by extractive distillation with methoxypropionitrile
US3436436A (en) * 1966-09-20 1969-04-01 Nippon Zeon Co Method for separation of conjugated diolefin by back wash in extractive distillation
US3439060A (en) * 1966-06-21 1969-04-15 Goodyear Tire & Rubber Selective removal of cyclopentadiene from a mixture containing at least one other hydrocarbon
US3492366A (en) * 1967-03-17 1970-01-27 Goodyear Tire & Rubber Removal of trace amounts of cyclopentadiene from isoprene by fluidbed adsorbent
US3496069A (en) * 1967-11-09 1970-02-17 Petro Tex Chem Corp Purification of unsaturated hydrocarbons by extractive distillation with recycle of stripper overhead
US3497566A (en) * 1967-09-05 1970-02-24 Bayer Ag Process for the production of isoprene from c5-fractions substantially free of paraffins and olefins by extractive distillation of cyclopentadiene with aniline
US3501550A (en) * 1967-09-06 1970-03-17 Bayer Ag Process for the production of pure isoprene by extractive distillation of cyclopentadiene with aqueous aniline
US3775259A (en) * 1971-08-26 1973-11-27 Shell Oil Co Isoprene recovery process by plural extractive distillations
US3860496A (en) * 1970-12-29 1975-01-14 Snam Progetti Process for the recovery of isoprene from mixtures containing the same
US3947506A (en) * 1974-04-03 1976-03-30 The Goodyear Tire & Rubber Company Recovery of isoprene
US4054613A (en) * 1975-10-20 1977-10-18 Phillips Petroleum Company Butadiene production and purification
US4128457A (en) * 1977-03-09 1978-12-05 Societa' Italiana Resine S.I.R. S.P.A. Process for the separation of butadiene by plural stage extractive distillation
US4140587A (en) * 1969-07-18 1979-02-20 Snamprogetti, S.P.A. Process for the separation of diolefins from mixtures containing the same
US4401515A (en) * 1980-03-15 1983-08-30 Japan Synthetic Rubber Co., Ltd. Process for producing 1,3-butadiene or 2-methyl-1,3-butadiene having high purity
RU2246475C2 (ru) * 2002-11-29 2005-02-20 Дядюрин Александр Павлович Способ разделения фракций углеводородов с5 разной степени
US20110178349A1 (en) * 2010-01-20 2011-07-21 Anzick Robert Kenneth Method of treating a hydrocarbon stream comprising cyclopentadiene and one or more diolefins
CN101798255B (zh) * 2009-02-11 2013-04-24 中国石油天然气股份有限公司 一种乙腈分离石油裂解碳五馏分中双烯烃的方法
US20170081260A1 (en) * 2015-09-22 2017-03-23 Fina Technology, Inc. Upgrading a c5 olefin stream
US20170362144A1 (en) * 2014-12-18 2017-12-21 Sabic Global Technologies B.V. Isoprene extraction with preserved c5 feedstock

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2426705A (en) * 1942-12-29 1947-09-02 Standard Oil Dev Co Recovery of isoprene by fractionation and extractive distillation
US2459403A (en) * 1944-07-20 1949-01-18 Standard Oil Dev Co Segregation of c5 hydrocarbons by extractive and azeotropic distillation
US2534013A (en) * 1945-06-28 1950-12-12 Standard Oil Dev Co Distilling polymer-forming hydrocarbons and removing polymer from distillation equipment
US2971036A (en) * 1958-09-17 1961-02-07 Exxon Research Engineering Co Recovery of isoprene by fractionation and extractive distillation
US3012947A (en) * 1959-06-15 1961-12-12 Exxon Research Engineering Co Recovery of high purity isoprene from light steam cracked distillate
US3059037A (en) * 1959-09-01 1962-10-16 Exxon Research Engineering Co Extractive distillation process

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2426705A (en) * 1942-12-29 1947-09-02 Standard Oil Dev Co Recovery of isoprene by fractionation and extractive distillation
US2459403A (en) * 1944-07-20 1949-01-18 Standard Oil Dev Co Segregation of c5 hydrocarbons by extractive and azeotropic distillation
US2534013A (en) * 1945-06-28 1950-12-12 Standard Oil Dev Co Distilling polymer-forming hydrocarbons and removing polymer from distillation equipment
US2971036A (en) * 1958-09-17 1961-02-07 Exxon Research Engineering Co Recovery of isoprene by fractionation and extractive distillation
US3012947A (en) * 1959-06-15 1961-12-12 Exxon Research Engineering Co Recovery of high purity isoprene from light steam cracked distillate
US3059037A (en) * 1959-09-01 1962-10-16 Exxon Research Engineering Co Extractive distillation process

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3320138A (en) * 1962-12-22 1967-05-16 Bayer Ag Process for separating c-hydrocarbon mixtures, containing paraffinic, monoolefinic and diolefinic c-hydrocarbons by distillation with n-methylpyrrolidone
US3378465A (en) * 1963-08-28 1968-04-16 Bayer Ag Purification of solvents containing c5 dimers by azeotropic distillation with water
US3317627A (en) * 1963-10-25 1967-05-02 Shell Oil Co High purity alkadienes by extractive distillation
US3328479A (en) * 1965-10-04 1967-06-27 Mobil Oil Corp Purifying diolefins by selective hydrogenation and distillation
US3436437A (en) * 1965-11-17 1969-04-01 Mitsubishi Gas Chemical Co Process for recovering high purity isoprene by extractive distillation with methoxypropionitrile
US3436438A (en) * 1965-12-30 1969-04-01 Nippon Zeon Co Process for the separation of conjugated diolefins
US3439060A (en) * 1966-06-21 1969-04-15 Goodyear Tire & Rubber Selective removal of cyclopentadiene from a mixture containing at least one other hydrocarbon
US3436436A (en) * 1966-09-20 1969-04-01 Nippon Zeon Co Method for separation of conjugated diolefin by back wash in extractive distillation
US3492366A (en) * 1967-03-17 1970-01-27 Goodyear Tire & Rubber Removal of trace amounts of cyclopentadiene from isoprene by fluidbed adsorbent
US3497566A (en) * 1967-09-05 1970-02-24 Bayer Ag Process for the production of isoprene from c5-fractions substantially free of paraffins and olefins by extractive distillation of cyclopentadiene with aniline
US3501550A (en) * 1967-09-06 1970-03-17 Bayer Ag Process for the production of pure isoprene by extractive distillation of cyclopentadiene with aqueous aniline
US3496069A (en) * 1967-11-09 1970-02-17 Petro Tex Chem Corp Purification of unsaturated hydrocarbons by extractive distillation with recycle of stripper overhead
US4140587A (en) * 1969-07-18 1979-02-20 Snamprogetti, S.P.A. Process for the separation of diolefins from mixtures containing the same
US3860496A (en) * 1970-12-29 1975-01-14 Snam Progetti Process for the recovery of isoprene from mixtures containing the same
US3775259A (en) * 1971-08-26 1973-11-27 Shell Oil Co Isoprene recovery process by plural extractive distillations
US3947506A (en) * 1974-04-03 1976-03-30 The Goodyear Tire & Rubber Company Recovery of isoprene
US4054613A (en) * 1975-10-20 1977-10-18 Phillips Petroleum Company Butadiene production and purification
US4128457A (en) * 1977-03-09 1978-12-05 Societa' Italiana Resine S.I.R. S.P.A. Process for the separation of butadiene by plural stage extractive distillation
US4401515A (en) * 1980-03-15 1983-08-30 Japan Synthetic Rubber Co., Ltd. Process for producing 1,3-butadiene or 2-methyl-1,3-butadiene having high purity
RU2246475C2 (ru) * 2002-11-29 2005-02-20 Дядюрин Александр Павлович Способ разделения фракций углеводородов с5 разной степени
CN101798255B (zh) * 2009-02-11 2013-04-24 中国石油天然气股份有限公司 一种乙腈分离石油裂解碳五馏分中双烯烃的方法
US20110178349A1 (en) * 2010-01-20 2011-07-21 Anzick Robert Kenneth Method of treating a hydrocarbon stream comprising cyclopentadiene and one or more diolefins
US20170362144A1 (en) * 2014-12-18 2017-12-21 Sabic Global Technologies B.V. Isoprene extraction with preserved c5 feedstock
US10065907B2 (en) * 2014-12-18 2018-09-04 Sabic Global Technologies B.V. Isoprene extraction with preserved C5 feedstock
US20170081260A1 (en) * 2015-09-22 2017-03-23 Fina Technology, Inc. Upgrading a c5 olefin stream
US10836691B2 (en) * 2015-09-22 2020-11-17 Fina Technology, Inc. Upgrading a C5 olefin stream

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