 | |
 | |
| Names | |
|---|---|
| Preferred IUPAC name 1λ6-Thiolane-1,1-dione | |
Other names
| |
| Identifiers | |
| |
3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
|
| ECHA InfoCard | 100.004.349 |
| EC Number |
|
| RTECS number |
|
| UNII | |
| UN number | 3334 |
| |
| |
| Properties | |
| (CH2)4SO2 | |
| Molar mass | 120.17 g·mol−1 |
| Appearance | Colorless liquid |
| Density | 1.261 g/cm3, liquid |
| Melting point | 27.5 °C (81.5 °F; 300.6 K) |
| Boiling point | 285 °C (545 °F; 558 K) |
| miscible | |
| Viscosity | 0.01007Pa·s at 25 °C |
| Structure | |
| 4.35D | |
| Hazards | |
| GHS labelling: | |
 | |
| Warning | |
| H302 | |
| P264,P270,P301+P312,P330,P501 | |
| NFPA 704 (fire diamond) | |
| Flash point | 165 °C (329 °F; 438 K) |
| 528 °C (982 °F; 801 K) | |
| Related compounds | |
Related compounds | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Sulfolane (alsotetramethylene sulfone,systematic name:1λ6-thiolane-1,1-dione) is anorganosulfur compound, formally a cyclicsulfone, with the formula(CH2)4SO2. It is a colorlessliquid commonly used in the chemical industry as asolvent for extractive distillation and chemical reactions. Sulfolane was originally developed by theShell Oil Company in the 1960s as a solvent to purifybutadiene.[1][2] Sulfolane is apolar aprotic solvent, and it is miscible with water.
Sulfolane is classified as asulfone, a group of organosulfur compounds containing a sulfonylfunctional group. The sulfone group is asulfur atom doubly bonded to twooxygen atoms and singly bonded to two carbon centers. The sulfur-oxygen double bond is polar, conferring good solubility in water, while the four carbon ring providesnon-polar stability. These properties allow it to be miscible in both water andhydrocarbons, resulting in its widespread use as a solvent for purifying hydrocarbon mixtures.
The original method developed by theShell Oil Company was to first allow butadiene to react withsulfur dioxide via acheletropic reaction to givesulfolene. This was thenhydrogenated usingRaney nickel as a catalyst to give sulfolane.[3][4]
Shortly thereafter, it was discovered that both the product yield and the lifetime of thecatalyst could be improved by addinghydrogen peroxide and thenneutralizing to apH 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 oxidizingtetrahydrothiophene with hydrogen peroxide. This reaction produces tetramethylene sulfoxide, which can then be further oxidized. Because the firstoxidation occurs at low temperature and the second at 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.
Sulfolane is widely used as an industrialsolvent, especially in the extraction ofaromatic hydrocarbons from hydrocarbon mixtures and to purifynatural gas.[3] The first large scale commercial use of sulfolane, the sulfinol process, was first implemented byShell Oil Company in March 1964 at the Person gas plant near Karnes City, Texas. The sulfinol process purifies natural gas by removingH2S,CO2,COS and mercaptans from natural gas with a mixture ofalkanolamine 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 usingliquid-liquid extraction. This process is widely used inrefineries and thepetrochemical industry. Because sulfolane is one of the most efficient industrial solvents for purifying aromatics, the process operates at a relatively low solvent-to-feed ratio, making sulfolane relatively cost effective compared to similar-purpose solvents. In addition, it is selective in a range that complementsdistillation; where sulfolane cannot separate two compounds, distillation easily can and vice versa, keeping sulfolane units useful for a wide range of compounds with minimal additional cost.
Whereas sulfolane is highly stable and can therefore be reused many times, it does eventually degrade intoacidic 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.
Sulfolane is also added to hydrofluoric acid as a vapor suppressant,[5] commonly for use in a refinery'salkylation unit. This "modified" hydrofluoric acid is less prone to vaporization if released in its liquid form.
Groundwater in parts of the city ofNorth Pole, Alaska, has been contaminated with sulfolane due to pollution from a now-closed petroleum refinery.[6] Due to this contamination, affected residents have been supplied with alternative potable water sources.[6] Animal studies on the toxicity of sulfolane are ongoing, funded through the US federal government'sNational Toxicology Program.[7] No long-termin vivo animal studies have been done, which prevents any firm conclusion as to whether sulfolane is a carcinogen, althoughin vitro studies have failed to demonstrate any cancerous changes in bacterial or animal cells. In animal studies, high doses of sulfolane have induced negative impacts on the central nervous system, including hyperactivity, convulsions and hypothermia; the impacts of lower doses, especially over the long-term, are still being studied.[8]
 | This article includes a list ofgeneral references, butit lacks sufficient correspondinginline citations. Please help toimprove this article byintroducing more precise citations.(November 2019) (Learn how and when to remove this message) |
