# US 5,347,018 A · Process for producing sulfolane compounds > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,347,018 A - Document ID: US5347018A - Status: Granted - Kind: A - Application number: 08/127,615 - Filed: 1993-09-28 - Granted: 1994-09-13 - Earliest claimed: 1993-09-28 - Assignees: Phillips Petroleum Company - Inventors: Earl Clark, Jr.; Howard F. Efner; Jimmie J. Straw - Web page: https://patentgrep.com/patent/US5347018A ## CPC - C07D 333/48: by oxygen atoms - C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08) ## Abstract A process for producing sulfolane compounds is provided which comprises: (1) contacting a conjugated diene with sulfur dioxide under conditions sufficient to synthesize a sulfolene compound whereby a mixture of the sulfolene compound and impurities comprising unreacted sulfur dioxide is produced; (2) transferring the mixture to an impurities removal vessel containing a freezing point depressant which comprises an aromatic compound; (3) removing the impurities; (4) transferring the impurities-reduced sulfolene compound to a hydrogenation reactor; (5) contacting the impurities-reduced sulfolene compound with hydrogen, in the presence of a hydrogenation catalyst, under conditions sufficient to produce a sulfolane compound; and (6) optionally recovering the sulfolane compound. ## Claims ### Claim 1 A process comprising: (1) contacting a conjugated diene with sulfur dioxide under conditions sufficient to synthesize a mixture of a sulfolene compound and impurities; (2) transferring said mixture to an impurities removal vessel; (3) contacting said mixture of sulfolene compound and impurities with a freezing point depressant; (4) substantially removing said impurities to produce an impurities-reduced sulfolene compound; and (5) hydrogenating said impurities-reduced sulfolene compound under conditions sufficient to produce a sulfolane compound; wherein said impurities comprise unreacted sulfur dioxide; said freezing point depressant comprises an aromatic compound selected from the group consisting of naphthalenes, methylnaphthalenes, biphenyl, a derivative of benzene, and combinations of two or more thereof; said derivative of benzene is selected from the group consisting of alkyl, alkenyl, amino, halo, alkaryl, and alkaryl-aromatic compounds and is liquid at about 20.degree.-30.degree. C.; and said freezing point depressant is present in an amount sufficient to keep said sulfolene compound in liquid state. ### Claim 2 (depends on 1) A process according to claim 1 wherein said conjugated diene has the formula of R--C(R).dbd.C(R)--C(R).dbd.C(R)--R; wherein each R can be the same or different and is independently selected from the group consisting of hydrogen, hydroxyl radical, a hydrocarbyl radical, and mixtures -thereof; wherein said hydrocarbyl radical is selected from the group consisting of akyl, alkenyl, aryl, cycloalkyl, cycloalkenyl, aralkyl, alkaryl, alkylcycloalkyl, and combinations of two or more thereof. ### Claim 3 (depends on 2) A process according to claim 2 wherein said conjugated diene is selected from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 3,4-dimethyl- 2,4-hexadiene, 2,4-dodecadiene, 2-methyl-1,3-hexadiene, 4-ethyl-1,3-hexadiene, 1-cyclopentyl-1,3-pentadiene, 1-(1-cyclohexene-1-yl)-1,3-butadiene, 2-phenyl-1,3-butadiene, 3-benzyl-1,3-pentadiene, 3-p-tolyl-1,3-pentadiene and combinations of two or more thereof. ### Claim 4 (depends on 3) A process according to claim 3 wherein said conjugated diene is 1,3-butadiene. ### Claim 5 (depends on 1) A process according to claim 1 wherein said freezing point depressant is selected from the group consisting of toluene, xylenes, naphthalenes, methylnaphthalenes, biphenyl, derivatives thereof, and combinations of two or more thereof. ### Claim 6 (depends on 5) A process according to claim 5 wherein said freezing point depressant is toluene. ### Claim 7 (depends on 1) A process according to claim 1 wherein said freezing point depressant further comprises a sulfone compound selected from the group consisting of sulfolane, 3-methylsulfolane, 2,4-dimethylsulfolane, 3-ethylsulfolane, and combinations of two or more thereof. ### Claim 8 (depends on 1) A process according to claim 1 wherein the weight ratio of said freezing point depressant to said sulfolene compound is in the range of from about 1:0.001 to about 1:100. ### Claim 9 (depends on 8) A process according to claim 8 wherein said range is from about 1:0.05 to about 1:50. ### Claim 10 (depends on 9) A process according to claim 9 wherein said range is from 0.1 to 1:20. ### Claim 11 (depends on 1) A process according to claim 1 wherein said sulfolene compound is contacted with said freezing point depressant at a temperature in the range of from about 25.degree. C. to about 100.degree. C. ### Claim 12 (depends on 11) A process according to claim 11 wherein said range is from about 35.degree. C. to about 80.degree. C. ### Claim 13 (depends on 12) A process according to claim 12 wherein said range is from 45.degree. C. to 70.degree. C. ### Claim 14 (depends on 1) A process according to claim 1 wherein said sulfolene compound is contacted with said freezing point depressant under a pressure in the range of from about 0.001 to about 35 atmospheres. ### Claim 15 (depends on 14) A process according to claim 14 wherein said range is from about 0.01 to about 20 atmospheres. ### Claim 16 (depends on 15) A process according to claim 15 wherein said range is from 0.1 to 7 atmospheres. ### Claim 17 A process for preparing a sulfolane compound comprising: (1) reacting a conjugated diene with sulfur dioxide at a temperature in the range of from about 60.degree. C. to about 120.degree. C. under a pressure in the range of from about 20 psig to about 300 psig for about 2 hours to about 24 hours whereby a mixture of sulfolene compound and impurities comprising unreacted sulfur dioxide is produced; wherein said conjugated diene is selected from the group consisting of 1,3-butadiene, 2-methyl- 1,3-butadiene, 2,3-dimethyl- 1,3-butadiene, 2,3-diethyl- 1,3-butadiene, 3,4-dimethyl-2,4-hexadiene, 2,4-dodecadiene, 2-methyl-1,3-hexadiene, 4-ethyl- 1,3-hexadiene, 1-cyclopentyl-1,3-pentadiene, 1-(1-cyclohexene-1-yl)-1,3-butadiene, 2-phenyl-1,3- butadiene, 3-benzyl-1,3-pentadiene, 3-p-tolyl-1,3-pentadiene, and their homologues and analogues, and mixtures thereof; (2) transferring said mixture at a temperature in the range of from about 25.degree. C. to about 100.degree. C. to an impurities removal vessel wherein said vessel contains a freezing point depressant selected from the group consisting of benzene, toluene, xylenes, sulfolane, 3-methylsulfolane, 2,4-dimethylsulfolane, 3-ethylsulfolane, naphthalenes, methylnaphthalenes, biphenyl, derivatives thereof, and combinations of two or more thereof; (3) removing said impurities to produce an impurities-reduced sulfolene compound; (4) transferring said impurities-reduced sulfolene compound to a hydrogenation reactor; (5) contacting said impurities-reduced sulfolene compound with hydrogen, in the presence of a hydrogenation catalyst under hydrogenation conditions sufficient to produce said sulfolane compound. ### Claim 18 A process for producing sulfolane comprising: (1) contacting 1,3-butadiene with sulfur dioxide at 65.degree. C. to 80.degree. C. under 30 psig to l.20 psig to produce a mixture of sulfolene and impurities comprising unreacted sulfur dioxide; (2) transferring at said mixture to an impurities removal reactor which contains toluene; (3) removing said impurities to produce an impurities-reduced sulfolene; (4) transferring said impurities-reduced sulfolene to a hydrogenation reactor; (5) contacting said impurities-reduced sulfolene compound with hydrogen, in the presence of a hydrogenation catalyst. ### Claim 19 (depends on 7) A process according to claim 7 wherein said sulfone compound is sulfolane.