Sulfinic acid

Sulfinic acids are a class of chemical compounds containing organically bound sulfur and oxygen of the general structure R-S (= O) -OH, where R is an alkyl or aryl radical. The ground substance sulfinic acid has the structure H -S ( = O) -OH and is tautomerically to sulfoxylic. The salts of sulfinic acids are the sulfinates.

Production and representation

Sulfinic acids occur as an intermediate in the oxidation of thiols, but they may not be so insulated. Sulfinic acids can be represented using Grignard compounds and sulfonyl chlorides.

In the Grignard reaction, the organometallic reagent is reacted with sulfur dioxide to a sulfinic acid:

Sulfonyl chlorides are reduced by zinc dust and water to sulfinic:

Properties

The low molecular weight agents are viscous oils, the higher homologues are crystalline substances, most are soluble in water. Many sulfinic acids are unstable. All sulfinic acids are oxidized by atmospheric oxygen to form sulfonic acids. Also the absence of air it gradually disproportionate.

The sulfinic acids are moderately strong acids (pKa ≈ 2-3) and form stable salts, the sulfinic acid salts. More stable derivatives are for example the aufzufassenden as cyclic esters sultine.

Reactions

A treatment with reducing agents such as nascent hydrogen - such as zinc and hydrochloric acid - resulting thiols:

The sulfinic acid salts react with haloalkanes to sulfones:

In the reaction with thionyl chloride arising from the sulfinic Sulfinsäurehalogenide ( sulfinyl ); these highly reactive substances - for example, by the action of triethylamine - will be converted to the ketene analog Sulfines ( IUPAC Thioaldehydoxide and Thioketonoxide ):