Chemistry:Sulfonate
In organosulfur chemistry, a sulfonate is a salt or anion of a sulfonic acid. The formula for this functional group is RSO−
3. Sulfonates are the conjugate bases of sulfonic acids. Sulfonates are generally stable in water, non-oxidizing, and colorless. Many useful compounds and even some biochemicals are sulfonates. Most detergents and surfactants are sulfonates. These include alkylbenzene sulfonates, 𝛼-olefin sulfonates, and paraffin sulfonates.[1]
Preparation
Sulfonates are generally prepared by deprotonation (neutralization) of sulfonic acids. Because sulfonic acids are strong acids, they spontaneously convert to sulfonates when dissolved in water:
RSO
3H → RSO−
3 + H+
To isolate sulfonate salts, these solutons are treated with base:
RSO
3H + NaOH → RSO
3Na + H
2O
Classically, alkylsulfonates can prepared by the Strecker sulfite alkylation,[2] in which sulfite displaces a halide:[3]
- RBr + Na
2SO
3 → RSO
3Na + NaBr
Arylsulfonates are produced by sulfonation of the arene using sulfur trioxide, sulfuric acid, or related reagents, followed by deprotonation of the resulting acid:[4]
- ArH + H
2SO
4 → ArSO
3H + H
2O - ArSO
3H + NaOH → ArSO
3Na + H
2O
Alkyl and arylsulfonates also arise by hydrolysis of sulfonyl chlorides:[5]
- RSO
2Cl + NaOH → ArSO
3Na + NaCl
Structure
The structure of many sulfonate salts (and esters and acids) have been verified by X-ray crystallography. The sulfur site at the center of a tetrahedron, with three oxygen and a carbon at the vertices. For the salts, the S-O distances are near 144 picometers in length. Crystals typically contain water of crystallization, reflecting the highly ionic nature of these salts.[6]
Reactions
Being weakly basic, sulfonate salts are poor nucleophiles. Their alkylation requires strongly electrophilic alkylating agents. Sulfonates react with phosphorus pentachloride and related chlorinating agents to give the sulfonyl chloride:[7]
- RSO
3Na + PCl
5 → RSO
2Cl + POCl
3 + NaCl
Alkaline fusion
Arylsulfonates undergo hase hydrolysis to give (after acidic workup) phenols. This route (ArH to ArSO3H to ArOH) was once a major route to phenols. This reaction, called alkaline fusion, requires temperatures in the 200-300 °C range:[8][9]
- ArSO
3Na + NaOH → ArONa + Na
2SO
3
This route is employed commercially to produce ethylphenol from ethylbenzene.[10]
Uses and occurrences
-
sodium alkylbenzene sulfonate -
-
-
perfluorooctanesulfonate, an "everwhere chemical" -
Allura Red AC, a red dye, was once used in foods -
.svg)
Sulfonate salts are widely used surfactants and detergents. Alkylbenzenesulfonates are detergents found in shampoos, toothpaste, laundry detergent, dishwashing liquid, etc. They are also used as ion exchange resins.
Lignosulfonates (LS's) are derived from lignin, an abundant waste product from papermaking that is otherwise burned as fuel. LS's are water-soluble anionic polyelectrolytes that are mainly used as Dispersants but have many niche applications.[11] In the sulfite process for paper-making, lignin is removed from the lignocellulose by treating wood chips with solutions of sulfite and bisulfite ions. These reagents cleave the bonds between the cellulose and lignin components as well as C-O bonds within the lignin itself.
Some alkylsulfonates occur naturally. Taurine (2-aminoethanesulfonate) is widely distributed in mammalian tissues, as well as a component of Red Bull energy drinks. Coenzyme-M (2-mercaptoethanesulfonic acid) is the methyl-carrying cofactor in methanogenesis.
Examples
- Mesylate (methanesulfonate), CH
3–SO−
3 - Triflate (trifluoromethanesulfonate), CF
3–SO−
3 - Ethanesulfonate (esilate, esylate), CH
3CH
2–SO−
3 - Tosylate (p-toluenesulfonate), p-CH
3–C
6H
4–SO−
3 - Benzenesulfonate (besylate), C
6H
5–SO−
3 - Closilate (closylate, chlorobenzenesulfonate), Cl–C
6H
4–SO−
3 - Camphorsulfonate (camsilate, camsylate), (C
10H
15O)–SO−
3 - Pipsylate (p-iodobenzenesulfonate derivative), p-I–C
6R
4–SO−
3, where R is any group.[12] - Nosylate (o- or p-nitrobenzenesulfonate), o- or p-O
2N–C
6H
4–SO−
3
See also
References
- ↑ Holmberg, Krister (2019). "Surfactants". Ullmann's Encyclopedia of Industrial Chemistry. pp. 1–56. doi:10.1002/14356007.a25_747.pub2. ISBN 978-3-527-30673-2.
- ↑ Adolf Strecker (1868). "Ueber eine neue Bildungsweise und die Constitution der Sulfosäuren". Annalen der Chemie und Pharmacie 148 (1): 90–96. doi:10.1002/jlac.18681480108. https://zenodo.org/records/1427281/files/article.pdf.
- ↑ C. S. Marvel, M. S. Sparberg (1930). "Sodium 2-Bromoethanesulfonate". Organic Syntheses 10: 96. doi:10.15227/orgsyn.010.0096.
- ↑ Louis F. Fieser (1936). "2- and 3-Phenanthrenesulfonic Acids". Organic Syntheses 16: 63. doi:10.15227/orgsyn.016.0063.
- ↑ E. Wertheim (1935). "Orthanilic Acid". Organic Syntheses 15: 55. doi:10.15227/orgsyn.015.0055.
- ↑ Arshad, Muhammad Nadeem; Tahir, M. Nawaz; Khan, Islam Ullah; Shafiq, Muhammad; Siddiqui, Waseeq Ahmad (2008). "Sodium 2-iodobenzenesulfonate monohydrate". Acta Crystallographica Section E 64 (12): m1628. doi:10.1107/S1600536808039202. PMID 21581218. Bibcode: 2008AcCrE..64m1628A.
- ↑ Roger Adams, C. S. Marvel, H. T. Clarke, G. S. Babcock, T. F. Murray (1921). "Benzenesulfonyl Chloride". Organic Syntheses 1: 21. doi:10.15227/orgsyn.001.0021.
- ↑ W. W. Hartman (1923). "p-Cresol". Organic Syntheses 3: 37. doi:10.15227/orgsyn.003.0037.
- ↑ Arthur W. Weston, C. M. Suter (1941). "3,5-Dihydroxybenzoic Acid". Organic Syntheses 21: 27. doi:10.15227/orgsyn.021.0027.
- ↑ Fiege, Helmut; Voges, Heinz-Werner; Hamamoto, Toshikazu; Umemura, Sumio; Iwata, Tadao; Miki, Hisaya; Fujita, Yasuhiro; Buysch, Hans-Josef et al. (2000). "Phenol Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a19_313. ISBN 978-3-527-30385-4.
- ↑ Lebo, Stuart E. Jr.; Gargulak, Jerry D.; McNally, Timothy J. (2015). "Kirk-Othmer Encyclopedia of Chemical Technology". Kirk‑Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. pp. 1–26. doi:10.1002/0471238961.12090714120914.a01.pub3. ISBN 978-0-471-23896-6.
- ↑ Beisler, J. A.; Sato, Y. (1971). "Chemistry of carpesterol, a novel sterol from Solanum xanthocarpum". The Journal of Organic Chemistry 36 (25): 3946–3950. doi:10.1021/jo00824a022. ISSN 0022-3263. PMID 5127991.
 |  |
