Propargyl alcohol, or 2-propyn-1-ol, is an organic compound with the formula C3H4O. It is the simplest stable alcohol containing an alkyne functional group.[3] Propargyl alcohol is a colorless viscous liquid that is miscible with water and most polar organic solvents.
Propargyl alcohol polymerizes with heating or treatment with base. It is used as a corrosion inhibitor, a metal complex solution, a solvent stabilizer and an electroplating brightener additive. It is also used as an intermediate in organic synthesis. Secondary and tertiary substituted propargylic alcohols undergo catalyzed rearrangement reactions to form α,β-unsaturated carbonyl compounds via the Meyer–Schuster rearrangement and others. It can be oxidized to propynal[4] or propargylic acid.
As an indication of the electronegativity of an sp carbon, propargyl alcohol is significantly more acidic (pKa = 13.6) compared to its sp2-containing analog allyl alcohol (pKa = 15.5), which is in turn more acidic than the fully saturated (sp3 carbons only) n-propyl alcohol (pKa = 16.1).[5]
Propargyl alcohol is produced by the copper-catalysed addition of formaldehyde to acetylene as a by-product of the industrial synthesis of but-2-yne-1,4-diol.[6] It can also be prepared by dehydrochlorination of 3-chloro-2-propen-1-ol by NaOH.[7]
Propargyl alcohol is a flammable liquid, toxic by inhalation, highly toxic by ingestion, toxic by skin absorption, and corrosive.[citation needed]
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