Sulfonate

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: To isolate sulfonate salts, these solutons are treated with base: Classically, alkylsulfonates can prepared by the Strecker sulfite alkylation, in which sulfite displaces a halide: : : Alkyl and arylsulfonates also arise by hydrolysis of sulfonyl chlorides: : ==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. ==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: : 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: : This route is employed commercially to produce ethylphenol from ethylbenzene. ==Uses and occurrences==

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. usually involves removal of calcium ions in water using a sulfonated ion-exchange resin. 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. 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), • Triflate (trifluoromethanesulfonate), • Ethanesulfonate (esilate, esylate), • Tosylate (p-toluenesulfonate), p- • Benzenesulfonate (besylate), • Closilate (closylate, chlorobenzenesulfonate), • Camphorsulfonate (camsilate, camsylate), • Pipsylate (p-iodobenzenesulfonate derivative), p-, where R is any group. • Nosylate (o- or p-nitrobenzenesulfonate), o- or p- ==See also==