# US 2008/0306290 A1 · Process for Epoxidizing Propene > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0306290 A1 - Document ID: US20080306290A1 - Status: Published application - Kind: A1 - Application number: 12/159,404 - Filed: 2006-12-18 - Published: 2008-12-11 - Earliest claimed: 2006-12-18 - Assignees: BASF SE; The Dow Chemical Company - Inventors: Hans-Georg Gobbel; Peter Bassler; Joaquim Henrique Teles; Peter Rudolf; Ulrich Muller; Anna Forlin; Malte Schulz; Meinolf Weidenbach - Web page: https://patentgrep.com/patent/US20080306290A1 ## CPC - C07D 301/12: with hydrogen peroxide or inorganic peroxides or peracids - C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08) ## Abstract The present invention provides a process for the epoxidation of propene which comprises reacting propene with hydrogen peroxide in the presence of methanol as solvent and a titanium zeolite catalyst, the process further comprising separating propylene oxide from the reaction mixture to obtain a mixture comprising methanol, water, at least one carboxylic acid and at least one carbonyl compound, wherein the at least one carboxylic acid is at least partially neutralized, said process optionally comprising a hydrogenation stage. ## Claims ### Claim at position 1 1-19. (canceled) ### Claim 20 A process for the epoxidation of propene, comprising (a) reacting propene with hydrogen peroxide in the presence of methanol as solvent and a titanium zeolite catalyst and separating propylene oxide from the resulting reaction mixture to obtain a mixture (Ma) comprising methanol, water, at least one carboxylic acid having from 1 to 3 carbon atoms and at least one carbonyl compound having from 1 to 3 carbon atoms, wherein the carbonyl compound is an aldehyde or a ketone; (b) at least partially neutralizing the at least one carboxylic acid comprised in mixture (Ma) by adding a base to mixture (Ma) to obtain a mixture (Mb); (c) separating methanol from mixture (Mb) by distillation; (d) at least partially recycling the methanol obtained from (c) into (a). ### Claim 21 (depends on 20) The process of claim 20, wherein mixture (Ma) comprises from 55 to 85 wt % methanol, from 10 to 40 wt % water, from 0.001 to 0.5 wt % of the at least one carboxylic acid and from 0.01 to 0.2 wt % of the at least one carbonyl compound. ### Claim 22 (depends on 20) The process of claim 20, wherein in (b), an aqueous alkaline solution comprising hydroxide ions is added as base. ### Claim 23 (depends on 22) The process of claim 22, wherein the molar ratio of hydroxide ions introduced in (b) relative to carboxylic acid comprised in (Ma) is from 0.1 to 10. ### Claim 24 (depends on 20) The process of claim 20, wherein in (c), methanol is separated from mixture (Mb) which contains at least one compound having a boiling temperature lower than methanol and lower than water at a given pressure, by (c1) separating the at least one compound having a boiling temperature lower than methanol and lower than water from mixture (Mb) by distillation to obtain a mixture (Mb1) and a mixture (Mb2), wherein mixture (Mb1) comprises from 40 to 85 wt % methanol and from 10 to 55 wt % water and at most 0.1 wt % of the at least one compound having a boiling point lower than methanol and water, and wherein mixture (Mb2) comprises at least 5 wt % of the at least one compound having a boiling point lower than methanol; (c2) separating methanol from mixture (Mb1) in at least one distillation stage to obtain a mixture (Mc2i) comprising at least 85 wt % of methanol, up to 10 wt % of water and 200 ppm or less of carbonyl compounds, and a mixture (Mc2ii) comprising at least 90 wt % of water. ### Claim 25 (depends on 24) The process of claim 24, wherein the at least one compound having a boiling point lower than methanol is selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, methyl formate, formaldehyde dimethyl acetal, acetaldehyde dimethyl acetal, and a mixture of two or more thereof. ### Claim 26 (depends on 24) The process of claim 24, wherein in (c1), distillation is carried out at a pressure of from 0.5 to 5 bar. ### Claim 27 (depends on 20) The process of any of claims 20, wherein mixture (Ma) additionally comprises at least one compound comprising a hydroperoxy group and a hydroxy group, where said hydroxy group is not a portion of said hydroperoxy group. ### Claim 28 (depends on 20) The process of claim 20, wherein prior to (b), mixture (Ma) is subjected to catalytic hydrogenation. ### Claim 29 (depends on 28) The process of claim 28, wherein the hydrogenation catalyst employed for catalytic hydrogenation comprises a catalytically active metal selected from the group consisting of Pd, Pt, Rh, Ir, Os and a mixture of two or more thereof. ### Claim 30 (depends on 28) The process of claim 28, wherein catalytic hydrogenation is carried out at a temperature of from 65 to 85° C. and at a hydrogen partial pressure of from 3 to 20 bar. ### Claim 31 (depends on 30) The process according to claim 30, wherein the hydrogen partial pressure is from 3 to 13 bar. ### Claim 32 (depends on 20) The process of claim 20, wherein the mixture (Ma) additionally comprises 2-hydroperoxypropanol-1,1-hydroperoxypropanol-2 or a mixture of 2-hydroperoxy-propanol-1 and 1-hydroperoxypropanol-2, and wherein prior to (b), the mixture (Ma) is subjected to a catalytic hydrogenation to give a mixture comprising 1,2-dihydroxypropane. ### Claim 33 (depends on 32) The process of claim 32, wherein in (c), methanol is separated from mixture (Mb) which contains at least one compound having a boiling temperature lower than methanol and lower than water at a given pressure, by (c1) separating the at least one compound having a boiling temperature lower than methanol and lower than water from mixture (Mb) by distillation to obtain a mixture (Mb1) and a mixture (Mb2), wherein mixture (Mb1) comprises from 40 to 85 wt % methanol and from 10 to 55 wt % water and at most 0.1 wt % of the at least one compound having a boiling point lower than methanol and water, and wherein mixture (Mb2) comprises at least 5 wt % of the at least one compound having a boiling point lower than methanol and water; (c2) separating methanol from mixture (Mb1) in at least one distillation stage to obtain a mixture (Mc2i) comprising at least 85 wt % of methanol, up to 10 wt % of water and 200 ppm or less of carbonyl compounds, and a mixture (Mc2ii) comprising at least 90 wt % of water and 1,2-dihydroxypropane, said process further comprising (e) separating 1,2-dihydroxypropane from mixture (Mc2ii). ### Claim 34 (depends on 20) The process of claim 20, wherein the methanol which is recycled into (a) comprises not more than 200 ppm of carbonyl compounds. ### Claim 35 (depends on 28) The process of claim 28, wherein the catalyst employed for catalytic hydrogenation is at least partially regenerated by treatment with at least one suitable solvent. ### Claim 36 (depends on 35) The process of claim 35, wherein the hydrogenation catalyst employed for catalytic hydrogenation comprises a catalytically active metal selected from the group consisting of Pd, Pt, Rh, Ir, Os and a mixture of two or more thereof. ### Claim 37 (depends on 35) The process of claim 35, wherein the at least one suitable solvent is selected from the group consisting of hydrogen peroxide, methanol, water, propylene oxide, propylene glycol and methoxy propanol. ### Claim 38 (depends on 28) The process of claim 28, wherein the catalyst employed for catalytic hydrogenation is at least partially regenerated by treatment at elevated temperature in the presence of a gas comprising oxygen. ### Claim 39 (depends on 38) The process of claim 38 wherein the hydrogenation catalyst employed for catalytic hydrogenation comprises a catalytically active metal selected from the group consisting of Pd, Pt, Rh, Ir, Os and a mixture of two or more thereof. ### Claim 40 A process for the epoxidation of propene, comprising (a) reacting propene with hydrogen peroxide in the presence of methanol as solvent and a titanium zeolite catalyst and separating propylene oxide from the resulting reaction mixture to obtain a mixture (Ma) comprising from 55 to 85 wt % methanol, from 10 to 40 wt % water, from 0.001 to 0.5 wt % of at least one carboxylic acid having from 1 to 3 carbon atoms and from wherein the at least one carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, and a mixture of two or more thereof, and wherein the at least one carbonyl compound is selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, and a mixture of two or more thereof; said mixture (Ma) further comprising from 0.1 to 1 wt % of 2-hydroperoxypropanol-1,1-hydroperoxypropanol-2 or a mixture of 2-hydroperoxy-propanol-1 and 1-hydroperoxypropanol-2; and subjecting mixture (Ma) to catalytic hydrogenation at a temperature of from 65 to 85° C. and at a hydrogen partial pressure of from 3 to 20 barz to give a mixture comprising from 0.1 to 1.3 wt % 1,2-dihydroxypropane, the hydrogenation catalyst comprising a catalytically active metal selected from the group consisting of Pd, Pt, Rh, Ir, Os and a mixture of two or more thereof; (b) at least partially neutralizing the at least one carboxylic acid comprised in the mixture obtained from catalytic hydrogenation by adding an aqueous solution comprising hydroxide ions to this mixture to obtain a mixture (Mb) which contains at least one compound having a boiling temperature lower than methanol and lower than water and which is selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, methyl formate, formaldehyde dimethyl acetal, acetaldehyde dimethyl acetal, and a mixture of two or more thereof at a given pressure, wherein the molar ratio of hydroxide ions introduced relative to carboxylic acid comprised in the mixture obtained from catalytic hydrogenation is from 0.1 to 10; (c) separating methanol from mixture (Mb) by (c1) separating the at least one compound having a boiling temperature lower than methanol and lower than water from mixture (Mb) by distillation at a distillation pressure of from 0.5 to 2 bar to obtain a mixture (Mb1) and a mixture (Mb2), wherein mixture (Mb1) comprises from 40 to 85 wt % methanol and from 10 to 55 wt % water and at most 0.1 wt % of the at least one compound having a boiling point lower than methanol and water, and wherein mixture (Mb2) comprises from 5 to 50 wt % of the at least (c2) separating methanol from mixture (Mb1) in at least one distillation stage to obtain a mixture (Mc2i) comprising at least 85 wt % of methanol, up to 10 wt % of water and 200 ppm or less of carbonyl compounds, and a mixture (Mc2ii) comprising 1,2-dihydroxypropane and at least 90 wt % of water, (d) at least partially recycling the methanol obtained from (c2) into (a), the methanol comprising not more than 200 ppm of carbonyl compounds, (e) separating 1,2-dihydroxypropane from mixture (Mc2ii). ### Claim 41 (depends on 40) The process according to claim 40, wherein the hydrogen partial pressure of (a) is from 3 to 13 bar.