Process for producing sulfolane compounds

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.

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.