# US 7,408,073 B2 · Returning an olefin which is not reacted during the oxidation of olefins > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,408,073 B2 - Document ID: US7408073B2 - Status: Granted - Kind: B2 - Application number: 10/532,096 - Filed: 2003-10-23 - Published: 2006-03-16 - Granted: 2008-08-05 - Earliest claimed: 2002-10-23 - Assignees: BASF SE - Inventors: Peter Bassler; Hans-Georg Goebbel; Joaquim Henrique Teles; Peter Rudolf - Web page: https://patentgrep.com/patent/US7408073B2 ## CPC - C07D 301/12: with hydrogen peroxide or inorganic peroxides or peracids - C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08) ## Abstract Process for the continuous recirculation of the olefin which has not been reacted in the epoxidation of olefins by means of hydroperoxide to give oxiranes and is present in the offgas stream formed during the epoxidation, which comprises the steps (i) to (iii) (i) compressing and cooling the offgas stream, (ii) seperating the olefin from the offgas stream obtain in step (i) by distillation, (iii) epoxidizing the olefin seperating off in step (ii) by means of hydroperoxide. ## Claims ### Claim 1 A process for the continuous recirculation of an olefin which has not been reacted in the epoxidation of olefins by means of hydroperoxide to give oxiranes and is present in an offgas stream formed during the epoxidation, comprising: (i) compressing and cooling the offgas stream, (ii) separating the olefin from the offgas stream obtained in step (i) by distillation, (iii) epoxidizing the olefin separated off in step (ii) by means of hydroperoxide, wherein the offgas stream comprises unreacted olefin and oxygen. ### Claim 2 (depends on 1) The process as claimed in claim 1, wherein the offgas stream further comprises nitrogen. ### Claim 3 (depends on 1) The process as claimed in claim 1, wherein, in step (i), the offgas stream is compressed to a pressure of from 2 to 30 bar and cooled to from 0 to 70° C. ### Claim 4 (depends on 1) The process as claimed in claim 1, wherein compression occurs in at least two stages in step (i). ### Claim 5 (depends on 3) The process as claimed in claim 3, wherein compression occurs in at least two stages in step (i). ### Claim 6 (depends on 1) The process as claimed in claim 1, wherein the olefin is propene and the offgas stream further comprises propane. ### Claim 7 (depends on 2) The process as claimed in claim 2, wherein, in step (i), the offgas stream is compressed to a pressure of from 2 to 30 bar and cooled to from 0 to 70° C. ### Claim 8 (depends on 2) The process as claimed in claim 2, wherein compression occurs in at least two stages in step (i). ### Claim 9 (depends on 7) The process as claimed in claim 7, wherein compression occurs in at least two stages in step (i). ### Claim 10 (depends on 2) The process as claimed in claim 2, wherein the olefin is propene and the offgas stream further comprises propane. ### Claim 11 (depends on 3) The process as claimed in claim 3, wherein the olefin is propene and the offgas stream further comprises propane. ### Claim 12 (depends on 4) The process as claimed in claim 4, wherein the olefin is propene and the offgas stream further comprises propane. ### Claim 13 (depends on 3) The process as claimed in claim 3, wherein, in step (i), the offgas stream is cooled to from 30 to 40° C. and compressed to a pressure of from 12 to 20 bar. ### Claim 14 (depends on 11) The process as claimed in claim 11, wherein, in step (i), the offgas stream is cooled to from 30 to 40° C. and compressed to a pressure of from 12 to 20 bar. ### Claim 15 (depends on 7) The process as claimed in claim 7, wherein the olefin is propene and the offgas stream further comprises propane. ### Claim 16 (depends on 8) The process as claimed in claim 8, wherein the olefin is propene and the offgas stream further comprises propane. ### Claim 17 (depends on 7) The process as claimed in claim 7, wherein, in step (i), the offgas stream is cooled to from 30 to 40° C. and compressed to a pressure of from 12 to 20 bar. ### Claim 18 (depends on 15) The process as claimed in claim 15, wherein, in step (i), the offgas stream is cooled to from 30 to 40° C. and compressed to a pressure of from 12 to 20 bar. ### Claim 19 (depends on 6) The process as claimed in claim 6, wherein a mixture of propene and propane obtained in the bottoms from a column after the distillation in step (ii) is separated into propene and propane in a C3 splitter. ### Claim 20 (depends on 11) The process as claimed in claim 11, wherein a mixture of propene and propane obtained in the bottoms from a column after the distillation in step (ii) is separated into propene and propane in a C3 splitter. ### Claim 21 (depends on 12) The process as claimed in claim 12, wherein a mixture of propene and propane obtained in the bottoms from a column after the distillation in step (ii) is separated into propene and propane in a C3 splitter. ### Claim 22 (depends on 10) The process as claimed in claim 10, wherein a mixture of propene and propane obtained in the bottoms from a column after the distillation in step (ii) is separated into propene and propane in a C3 splitter. ### Claim 23 (depends on 15) The process as claimed in claim 15, wherein a mixture of propene and propane obtained in the bottoms from a column after the distillation in step (ii) is separated into propene and propane in a C3 splitter. ### Claim 24 (depends on 16) The process as claimed in claim 16, wherein a mixture of propene and propane obtained in the bottoms from a column after the distillation in step (ii) is separated into propene and propane in a C3 splitter. ### Claim 25 (depends on 19) An apparatus for carrying out a process according to claim 19, which comprises at least one reactor for preparing propene oxide, at least one apparatus for compressing the offgas stream, at least one distillation column for separating propene and propane from the offgas stream and a C3 splitter for separating propene and propane. ### Claim 26 A process for the continuous recirculation of an olefin which has not been reacted in the epoxidation of the olefin by means of hydroperoxide to give oxiranes and is present in an offgas stream formed during the epoxidation, comprising: (i) compressing and cooling the offgas stream, (ii) separating the olefin from the offgas stream obtained in step (i) by distillation, (iii) epoxidizing the olefin separated off in step (ii) by means of hydroperoxide, wherein, in step (i), the offgas stream is compressed to a pressure of from 2 to 30 bar, cooled to from 0 to 70° C., and wherein compression occurs in at least two stages in step (i), and the offgas stream comprises unreacted olefin and oxygen. ### Claim 27 (depends on 26) The process according to claim 26, wherein the olefin is propene and the offgas stream further comprises propane. ### Claim 28 A process for the continuous recirculation of an olefin which has not been reacted in the epoxidation of olefins by means of hydroperoxide to give oxiranes and is present in the offgas stream formed during the epoxidation, comprising: (i) compressing and cooling the offgas stream, (ii) separating the olefin from the offgas stream obtained in step (i) by distillation, (iii) epoxidizing the olefin separated off in step (ii) by means of hydroperoxide, wherein the olefin is propene, the offgas stream further comprises propane, in step (i), the offgas stream is compressed to a pressure of from 12 to 20 bar, cooled to from 30 to 40° C., and the offgas stream comprises unreacted olefin and oxygen. ### Claim 29 A process for the continuous recirculation of propene which has not been reacted in the epoxidation of propene by means of hydroperoxide to give propene oxide and is present in an offgas stream formed during the epoxidation, comprising: (i) compressing and cooling the offgas stream, (ii) separating propene from the offgas stream obtained in step (i) by distillation, (iii) epoxidizing the propene by means of hydroperoxide, wherein the offgas stream comprises propene, propane and oxygen, and wherein in step (i), the offgas stream is cooled to from 30 to 40° C. and compressed to a pressure of from 12 to 20 bar, a mixture of propene and propane is obtained in bottoms from a column after distillation in step (ii), and said mixture is separated into propene and propane in a C3 splitter.