# US 8,569,562 B2 · Purification of isoprene from renewable resources > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,569,562 B2 - Document ID: US8569562B2 - Status: Granted - Kind: B2 - Application number: 12/969,440 - Filed: 2010-12-15 - Published: 2011-07-21 - Granted: 2013-10-29 - Earliest claimed: 2009-12-18 - Assignees: Danisco US Inc.; The Goodyear Tire & Rubber Company - Applicants: Frank J. Feher; John Kaluen Kan; Joseph C. McAuliffe; Thomas F. McCall; Stephan Rodewald; Timothy Alan Sabo; Tang Hong Wong; Christopher D. Ploetz; Lawrence J. Pickert - Inventors: Frank J. Feher; John Kaluen Kan; Joseph C. McAuliffe; Thomas F. McCall; Stephan Rodewald; Timothy Alan Sabo; Tang Hong Wong; Christopher D. Ploetz; Lawrence J. Pickert - Web page: https://patentgrep.com/patent/US8569562B2 ## CPC - C07C 11/18: Isoprene - B01D 11/0426: {Counter-current multistage extraction towers in a vertical or sloping position} - B01D 11/0492: {Applications, solvents used} - C07C 7/04: by distillation - C07C 7/10: by extraction, i.e. purification or separation of liquid hydrocarbons with the aid of liquids - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract Methods and apparatus for the purification of isoprene, such as the purification of a bioisoprene composition from fermentor off-gas. The apparatus includes two columns that process the fermentor off-gas, which includes isoprene and various impurities. A solvent is added to the off-gas in the first column, and the isoprene is stripped from the solvent in the second column. Also provided is a downstream further purification process. Also provided are the resulting purified isoprene compositions. ## Claims ### Claim 1 A method of purifying isoprene from a fermentor off-gas comprising: contacting a fermentor off-gas, wherein the off-gas comprises a bioisoprene composition comprising isoprene, volatile impurity, and bio-byproduct impurity, with a solvent in a first column to form: an isoprene-rich solution comprising the solvent, a major portion of the isoprene and a major portion of the bio-byproduct impurity present in the off-gas; and a vapor comprising a portion of the volatile impurity present in the off-gas; transferring the isoprene-rich solution from the first column to a second column; and stripping isoprene from the isoprene-rich solution in the second column to form: an isoprene-lean solution comprising a portion of the bio-byproduct impurity present in the off-gas; and a purified isoprene composition. ### Claim 2 (depends on 1) The method of claim 1 wherein the volatile impurity comprises a compound selected from the group consisting of H2O, CO2, N2, H2, CO and O2. ### Claim 3 (depends on 1) The method of claim 1, wherein the bio-byproduct impurity comprises a compound selected from the group consisting of ethanol, acetone, methanol, acetaldehyde, methacrolein, methyl vinyl ketone, 3-methylfuran, 2-methyl-2-vinyloxirane, cis- and trans-3-methyl-1, 3-pentadiene,a C5 prenyl alcohol (such as 3-methyl-3-buten-1-ol or 3-methyl-2-buten-1-ol), 2-heptanone, 6-methyl-5-hepten-2-one, 2,4,5-trimethylpyridine, 2,3,5-trimethylpyrazine, citronellal, methanethiol, methyl acetate, 1-propanol, diacetyl, 2-butanone, 2- methyl-3-buten-2-ol, ethyl acetate, 2-methyl-1-propanol, 3-methyl-1-butanal, 3-methyl-2-butanone, 1-butanol, 2-pentanone, 3-methyl-1-butanol, ethyl isobutyrate, 3-methyl-2-butenal, butyl acetate, 3-methylbutyl acetate, 3-methyl-3-buten-1-yl acetate, 3-methyl-2-buten-1-yl acetate, (E)-3,7-dimethyl-1,3,6-octatriene, (Z)-3 ,7-dimethyl-1,3,6-octatriene, (E,E)-3,7,11-trimethyl-1,3 ,6,10-dodecatetraene, (E)-7,11-dimethyl-3-methylene-1,6,10-dodecatriene,3-hexen-1-ol,3-hexen-1-yl acetate, limonene, geraniol (trans-3,7-dimethyl-2,6-octadien-1-ol), and citronellol (3,7-dimethyl-6-octen-1-ol). ### Claim 4 (depends on 1) The method of claim 1, wherein the solvent has a boiling point of greater than about 177° C. ### Claim 5 (depends on 1) The method of claim 1, wherein the solvent has a CO2 Ostwald coefficient at 54° C. of less than about 1.25. ### Claim 6 (depends on 1) The method of claim 1, wherein the solvent has a Kauri-butanol value of less than about 50. ### Claim 7 (depends on 1) The method of claim 1, wherein the solvent has an Aniline Point of greater than about 66° C. ### Claim 8 (depends on 1) The method of claim 1, wherein the solvent has a kinematic viscosity at 40° C. is less than about 2.5 centistokes (cSt). ### Claim 9 (depends on 1) The method of claim 1, wherein the solvent has a surface tension at 25° C. from about 20 to 30 dyne/cm. ### Claim 10 (depends on 1) The method of claim 1, wherein the solvent has an average molecular weight from about 125 to about 225 u. ### Claim 11 (depends on 1) The method of claim 1 wherein the solvent is an isoparaffin or a paraffin. ### Claim 12 (depends on 1) The method claim 1, wherein the solvent further comprises a polymerization inhibitor. ### Claim 13 (depends on 1) The method of claim 1, further comprising reducing the temperature of the fermentor off-gas prior to contacting the solvent in the first column. ### Claim 14 (depends on 1) The method of claim 1, further comprising transferring the fermentor off-gas to an isolation unit, thereby stabilizing the off-gas pressure, prior to contacting the fermentor off-gas with the solvent in the first column. ### Claim 15 (depends on 1) The method of claim 1, further comprising at least partially condensing the fermentor off-gas prior to contacting the solvent in the first column. ### Claim 16 (depends on 1) The method of claim 1, wherein the contacting the fermentor off-gas with a solvent in a first column comprises supplying stripping vapor from a bottom of the first column. ### Claim 17 (depends on 1) The method of claim 1, wherein the contacting the fermentor off-gas with a solvent in a first column further comprises adding steam to the first column. ### Claim 18 (depends on 1) The method of claim 1, wherein the stripping isoprene from the isoprene-rich solution in the second column comprises adding steam to the second column. ### Claim 19 (depends on 1) The method of claim 1, further comprising: purifying the isoprene-lean solution to remove a major portion of the bio-byproduct impurity; and transferring the isoprene-lean solution to the first column for reuse. ### Claim 20 (depends on 19) The method of claim 19, wherein purifying the isoprene-lean solution comprises treating the isoprene-lean solution with an adsorption system. ### Claim 21 (depends on 19) The method of claim 19, wherein purifying the isoprene-lean solution comprises distillation. ### Claim 22 (depends on 1) The method of claim 1, further comprising reducing the temperature of the isoprene-lean solution prior to removing a major portion of the bio-byproduct impurity. ### Claim 23 (depends on 1) The method of claim 1, comprising further purifying the purified isoprene composition. ### Claim 24 (depends on 23) The method of claim 23, wherein further purifying the purified isoprene composition comprises distillation. ### Claim 25 (depends on 23) The method of claim 23, wherein further purifying the purified isoprene composition comprises treating the purified isoprene composition with an adsorption system. ### Claim 26 (depends on 1) The method of claim 1, further comprising removing from the vapor a portion of the isoprene. ### Claim 27 (depends on 1) The method of claim 1, wherein the fermentor off-gas is provided to the first column at a pressure greater than atmospheric. ### Claim 28 (depends on 1) The method of claim 1, wherein the purified isoprene composition has a purity greater than about 90%. ### Claim 29 (depends on 1) The method of claim 1, wherein the purified isoprene composition comprises less than about 25% bio-byproduct impurity relative to the amount of bio-byproduct impurity of the fermentor off-gas. ### Claim 30 (depends on 1) The method of claim 1, wherein the purified isoprene composition comprises less than about 25% volatile impurity relative to the amount of volatile impurity of the fermentor off-gas. ### Claim 31 (depends on 1) A purified isoprene composition prepared by the method of claim 1. ### Claim 32 (depends on 23) The method of claim 23, wherein the further purifying comprises contacting the purified isoprene composition with water or a base and water. ### Claim 33 A method of purifying isoprene from a fermentor off-gas comprising: contacting a fermentor off-gas comprising isoprene, volatile impurity, and bio-byproduct impurity, with a solvent in a first column to form: an isoprene-rich solution comprising the solvent, a major portion of the isoprene and a major portion of the bio-byproduct impurity present in the off-gas; and a vapor comprising a portion of the volatile impurity present in the off-gas; transferring the isoprene-rich solution from the first column to a second column; and stripping isoprene from the isoprene-rich solution in the second column to form: an isoprene-lean solution comprising a portion of the bio-byproduct impurity present in the off-gas; and a purified isoprene composition; further comprising extracting at least one of methanol, acetone, or methyl acetate from the isoprene-lean solution.