# US 10,370,310 B2 · Method for preparing 1,3-butadiene from n-butenes by oxidative dehydrogenation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,370,310 B2 - Document ID: US10370310B2 - Status: Granted - Kind: B2 - Application number: 16/069,553 - Filed: 2017-01-11 - Published: 2019-01-17 - Granted: 2019-08-06 - Earliest claimed: 2016-01-13 - Assignees: BASF SE (Isenbruck BöSl HöRschler LLP); Linde Aktiengesellschaft - Applicants: BASF SE; Linde AG - Inventors: Jan Pablo Josch; Georgios Karanikoulis; Oliver Hammen; Claudia Mossbacher; Ulrike Wenning; Anton Wellenhofer; Christine Toegel; Hendrik Reyneke - Web page: https://patentgrep.com/patent/US10370310B2 ## CPC - C07C 5/48: with oxygen as an acceptor - C07C 7/005: {Processes comprising at least two steps in series} - C07C 7/04: by distillation - C07C 7/06: by azeotropic distillation - C07C 7/08: by extractive distillation - C07C 7/09: by fractional condensation - C07C 7/11: by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids - C07C 2521/06: Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof - C07C 2523/31: combined with bismuth - C07C 2523/86: Chromium - C07C 2523/88: Molybdenum - C07C 2523/881: and iron - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS ## Abstract The invention relates to a method for producing butadiene from n-butenes having the steps: A) providing a feed gas stream a comprising n-butenes; B) feeding the feed gas stream a comprising the n-butenes and an oxygen-comprising gas into at least one oxidative dehydrogenation zone and oxidatively dehydrogenating n-butenes to butadiene, wherein a product gas stream b comprising butadiene, unreacted n-butenes, steam, oxygen, low-boiling hydrocarbons, high-boiling minor components, possibly carbon oxides and possibly inert gases is obtained; Ca) cooling the product gas stream b by contacting it with a refrigerant and condensing at least a part of the high-boiling minor components; Cb) compressing the remaining product gas stream b in at least one compression stage, wherein at least one aqueous condensate stream c1 and a gas stream c2 comprising butadiene, n-butenes, steam, oxygen, low-boiling hydrocarbons, possibly carbon oxides and possibly inert gases are obtained; Da) separating off non-condensable and low-boiling gas components comprising oxygen, low-boiling hydrocarbons, possibly carbon oxides and possibly inert gases as gas stream d2 from the gas stream c2 by absorbing the C4 hydrocarbon-comprising butadiene and n-butenes in an absorbent, wherein an absorbent stream loaded with C4 hydrocarbons and the gas stream d2 are obtained, and Db) subsequent desorption of the C4 hydrocarbons from the loaded absorbent stream in a desorption column, wherein a C4 product gas stream d1 is obtained, wherein a polymerization inhibitor is added in step Db) at the column head of the desorption column. ## Claims ### Claim 1 A method for producing butadiene from n-butenes having the steps: A) providing a feed gas stream a comprising n-butenes; B) feeding the feed gas stream a comprising n-butenes and an oxygen-comprising gas into at least one oxidative dehydrogenation zone and oxidatively dehydrogenating n-butenes to butadiene, wherein a product gas stream b comprising butadiene, unreacted n-butenes, steam, oxygen, low-boiling hydrocarbons, high-boiling minor components, optionally carbon oxides and optionally inert gases is obtained; Ca) cooling the product gas stream b by contacting it with a refrigerant and condensing at least a part of the high-boiling minor components; Cb) compressing the remaining product gas stream b in at least one compression stage, wherein at least one aqueous condensate stream c1 and a gas stream c2 comprising butadiene, n-butenes, steam, oxygen, low-boiling hydrocarbons, optionally carbon oxides and optionally inert gases are obtained; Da) separating off non-condensable and low-boiling gas components comprising oxygen, low-boiling hydrocarbons, optionally carbon oxides and optionally inert gases as a gas stream d2 from the gas stream c2 by absorbing C4 hydrocarbons comprising butadiene and n-butenes in an absorbent, wherein an absorbent stream loaded with C4 hydrocarbons and the gas stream d2 are obtained, and Db) subsequently desorbing the C4 hydrocarbons from the loaded absorbent stream in a desorption column, wherein a C4 product gas stream dl is obtained, wherein the desorption column comprises a top condenser located at a head of the column, and wherein a polymerization inhibitor is added in step Db) at the top condenser of the desorption column. ### Claim 2 (depends on 1) The method according to claim 1 further comprising: E) separating the C4 product gas stream d1 by extractive distillation using a selective solvent for butadiene into a material stream e1 comprising butadiene and the selective solvent, and a material stream e2 comprising n-butenes; F) distilling the material stream e1 comprising butadiene and the selective solvent into a material stream gl substantially comprising the selective solvent, and a material stream g2 comprising butadiene. ### Claim 3 (depends on 1) The method according to claim 1, wherein the polymerization inhibitor is added in amounts such that a concentration of the polymerization inhibitor in a liquid condensate stream obtained at the top condenser is from 10 to 1500 ppm. ### Claim 4 (depends on 3) The method according to claim 3, wherein the polymerization inhibitor is a mixture of tert-butyl catechol and 4-methoxyphenol. ### Claim 5 (depends on 1) The method according to claim 1, wherein the polymerization inhibitor is selected from the group consisting of unsubstituted or substituted catechols and hydroquinones. ### Claim 6 (depends on 1) The method according to claim 1, wherein the gas stream d2 that is separated off in step Da) is at least in part recirculated in step B). ### Claim 7 (depends on 1) The method according claim 1, wherein the step Da) comprises the steps Da1) and Da2): Da1) absorbing the C4 hydrocarbons comprising butadiene and n-butenes in a high-boiling absorbent, wherein the absorbent stream loaded with C4 hydrocarbons and the gas stream d2 are obtained, and Da2) removing oxygen from the absorbent stream of step Da1) that is loaded with C4 hydrocarbons by stripping with a non-condensable gas stream; and wherein the C4 product gas stream d1 obtained in step Db) comprises less than 100 ppm of oxygen. ### Claim 8 (depends on 1) The method according to claim 1, wherein the absorbent used in step Da) is an aromatic hydrocarbon solvent.