Peracetic Acid

Abstract

[79-21-0] C2H4O3 (MW 76.06) (electrophilic reagent capable of reacting with many functional groups; delivers oxygen to alkenes, sulfides, selenides, and amines) Alternate Name: peroxyacetic acid. Physical Data: mp 0 °C; bp 25 °C/12 mmHg; d 1.038 g cm−3 at 20 °C. Solubility: sol acetic acid, ethyl acetate, CHCl3, acetone, benzene, CH2Cl2, ethylene dichloride, water. Form Supplied in: 40% solution in acetic acid (d 1.15 g cm−3) having approximately the following composition by weight: peracetic acid, 40–42%; H2O2, 5%; acetic acid, 40%; H2SO4, 1%; water, 13%; diacetyl peroxide, nil; other organic compounds, nil; stabilizer, 0.05%. A solution of the peracid in ethyl acetate is also available commercially. Analysis of Reagent Purity: assay using iodometry;2 estimation of diacetyl peroxide.3 Preparative Methods: prepared in the laboratory by reacting Acetic Acid with hydrogen peroxide in the presence of catalytic quantities (1% by weight) of Sulfuric Acid; when 30% H2O2 is used the concentration of the peracid reagent obtained is less than 10%.1a If a stronger solution of the reagent is required, 70–90% H2O2 must be used. Caution: for hazards see Hydrogen Peroxide. Hydrogen Peroxide–Urea (which is commercially available and is safe to handle) has been used as a substitute for anhydrous hydrogen peroxide.3 In the preparation of peracetic acid from acetic anhydride and H2O2, the dangerously explosive diacetyl peroxide may become the major product if the reaction is not carried out properly.1a Purification: peracetic acid is rarely prepared in pure undiluted form for safety reasons. The commercially available material contains acetic acid, water, H2O2, and H2SO4. After neutralization of the sulfuric acid, this reagent is satisfactory for most reactions. If water is undesirable, an ethyl acetate solution of the reagent may be used. Details for the preparation of the H2O2-free reagent are available.4 Handling, Storage, and Precautions: peracetic acid is an explosive compound but is safe to handle at room temperature in organic solutions containing less than 55%. Use in a fume hood. Since peroxides are potentially explosive, a safety shield should generally be used.5 Peracetic acid can be stored at 0 °C with essentially no loss of active oxygen and at rt with only negligible losses over several weeks.