Sulfolane
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2008-05-20T14:22:48Z
Beetstra
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Reverted edits by [[Special:Contributions/Paperscience|Paperscience]] ([[User talk:Paperscience|talk]]) to last version by Harold f
{{Chembox new
| Name = Sulfolane
| ImageFileL1 = Sulfolane-2D-skeletal.png
| ImageSizeL1 = 80px
| ImageNamL1e = Sulfolane
| ImageFileR1 = Sulfolane-3D-balls.png
| ImageSizeR1 = 120px
| ImageNameR1 = Ball-and-stick model of the sulfolane molecule
| IUPACName = Tetrahydrothiophene 1,1-dioxide
| OtherNames = sulfolane<br />tetramethylene sulfone
| Section1 = {{Chembox Identifiers
| SMILES = O=S1(CCCC1)=O
| CASOther = {{{CAS|126-33-0}}}
}}
| Section2 = {{Chembox Properties
| Formula = C<sub>4</sub>H<sub>8</sub>O<sub>2</sub>S
| MolarMass = 120.17 g/mol
| Appearance = clear colorless liquid
| Density = 1.261 g/cm<sup>3</sup>, liquid
| Solubility = fully soluble
| MeltingPt = 27.5 °C
| BoilingPt = 285 °C
| Viscosity = 0.01007 [[Pascal second|Pa·s]] at 25°C<!-- Liquids only, omit if data unavailable. You may use if you prefer -->
}}
| Section3 = {{Chembox Structure
| Dipole = 4.35 [[Debye|D]]
}}
| Section7 = {{Chembox Hazards
| Autoignition = 528 °C
| ExternalMSDS =
| NFPA-H = 2
| NFPA-F = 1
| NFPA-R =
| FlashPt = 165 °C
| RPhrases = {{R22}}
| SPhrases = {{S23}}, {{S24}}, {{S25}}
}}
}}
'''Sulfolane''' (also ''tetramethylene sulfone'', [[IUPAC nomenclature|systematic name]]: '''2,3,4,5-tetrahydrothiophene-1,1-dioxide''') is a clear, colorless [[liquid]] commonly used in the chemical industry as an extractive distillation [[solvent]] or reaction solvent. Sulfolane was originally developed by the [[Shell Oil Company]] in the 1960s as a solvent to purify [[butadiene]]. Sulfolane is an [[aprotic]] [[organosulfur compound]], and it is readily soluble in water.
==Chemical Properties==
Sulfolane is classified as a [[sulfone]], a group of organosulfur compounds containing a sulfonyl functional group. The sulfonyl group is a [[sulfur]] atom doubly bonded to two [[oxygen]] atoms. The [[sulfur]]-[[oxygen]] double bond is highly polar, allowing for its high solubility in water, while the four carbon ring provides [[non-polar]] stability. These properties allow it to be miscible in both water and [[hydrocarbons]], resulting in its widespread use as a solvent for purifying [[hydrocarbon]] mixtures.
==Synthesis==
The original method developed by the [[Shell Oil Company]] was to first allow [[butadiene]] to react with [[sulfur dioxide]]. This yields [[sulfolene]], which was then [[hydrogenated]] using [[Raney nickel]] as a catalyst to give sulfolane.
[[Image:sulfolanesynthesis.png|500px]]
Shortly thereafter, it was discovered that both the product yield and the lifetime of the [[catalyst]] could be improved by adding [[hydrogen peroxide]] and then [[neutralizing]] to a [[pH]] of roughly 5-8 before [[hydrogenation]].
Developments have continued over the years, including in the [[catalysts]] used. Recently, it was found that Ni-B/MgO showed superior catalytic activity to that of [[Raney nickel]] and other common catalysts that have been used in the [[hydrogenation]] of sulfolene.
Other syntheses have also been developed, such as [[oxidizing]] [[tetrahydrothiophene]] with [[hydrogen peroxide]]. This first produces tetramethylene sulfoxide, which can then be further [[oxidized]] to tetramethylene sulfone. Because the first [[oxidation]] takes place at low temperature and the second at relatively higher temperature, the reaction can be controlled at each stage. This gives greater freedom for the manipulation of the reaction, which can potentially lead to higher yields and purity.
==Uses==
Sulfolane is widely used as an industrial [[solvent]], especially in the extraction of [[aromatic]] [[hydrocarbons]] from [[hydrocarbon]] mixtures and to purify [[natural gas]].
The first large scale commercial use of sulfolane, the sulfinol process, was first implemented by [[Shell Oil Company]] in March of 1964 at the Person gas plant near Karnes City, Texas. The sulfinol process purifies natural gas by removing H<sub>2</sub>S, CO<sub>2</sub>, COS and mercaptans from natural gas with a mixture of alkanolamine and sulfolane.
Shortly after the sulfinol process was implemented, sulfolane was found to be highly effective in separating high purity [[aromatic]] compounds from [[hydrocarbon]] mixtures using [[liquid-liquid extraction]]. This process is still widely used today in [[refineries]] and the [[petrochemical]] industry. Because sulfolane is the most efficient industrial [[solvent]] for purifying [[aromatics]], they operate at the lowest solvent-to-feed ratio, making sulfolane units highly cost effective. In addition, it is selective in a range that complements distilliation; where sulfolane can’t separate two compounds, distillation easily can and vice versa, keeping sulfolane units useful for a wide range of compounds with minimal additional cost.
While sulfolane is highly stable and can therefore be reused many times, it does eventually break down into [[acidic]] byproducts. A number of measures have been developed to remove these byproducts, allowing the sulfolane to be reused and increase the lifetime of a given supply. Some methods that have been developed to regenerate spent sulfolane include vacuum and steam [[distillation]], back extraction, adsorption, and anion-cation exchange resin columns.
==See also==
*[[Sulfolene]]
*[[Tetrahydrothiophene]]
*[[Methylsulfonylmethane]]
==References==
{{Citationstyle|date=September 2007}}
{{reflist}}
*[http://www.uop.com/objects/55%20Sulfolane.pdf UOP Document: Sulfolane Process]
*[http://www.rohmax.com/en/oiladditives?content=/en/oiladditives/products_application/sulfolane RohMax.com: Sulfolane, a specialty solvent]
*[http://www.chemicalland21.com/industrialchem/solalc/SULFOLANE.htm ChemicalLand21.com: Sulfolane Industrial Chemical Data]
*[http://www.chemindustry.com/chemicals/801185.html ChemIndustry.com search: Sulfolane]
*Young, Eldred E. (Shell International Research) BE Patent 616856, 1962
*Goodenbour, John W.; Carlson, George J. (Shell International Research) BE Patent 611850, 1962
*Ge, Shaohui; Wu, Zhijie; Zhang, Minghui; Li, Wei; Tao, Keyi.''Industrial & Engineering Chemistry Research'','''2006'''''45(7)'', 2229-2234,
*Sharipov, A. Kh.''Russian Journal of Applied Chemistry'''''2003''',''76(1)'', 108-113.
*Dunn, C. L.; Freitas, E. R.; Hill, E. S.; Sheeler, J. E. R., Jr. Proc., Ann. Conv. Nat. Gas Processors Assoc. Am.,''Tech. Papers'''''1965''',''44'' 55-8
*Broughton, Donald B.; Asselin, George F. UOP Process Div., Universal Oil Prod. Co., Des Plaines, IL, USA. World Petrol. Congr., Proc., 7th'''1968''', Meeting Date 1967,''4'' 65-73. Publisher: Elsevier Publ. Co. Ltd., Barking, Engl
*Lal, Raj Kumar Jagadamba; Bhat, Sodankoor Garadi Thirumaleshwara. (Indian Petrochemicals Corp. Ltd., India). Eur. Pat. Appl. 1989-308019 (1991)
*Van der Wiel, A.''Nature'''''1960''',''187'' 142-3.
*Block, E.''Reactions of Organosulfur Compounds''; Academic: New York, 1978
*Belen'kii, L.I.''Chemistry of Organosulfur Compounds''; Horwood: New York, 1990
[[Category:Solvents]]
[[Category:Sulfones]]
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[[ja:スルホラン]]
[[zh:环丁砜]]