3-Chloroperoxybenzoic acid

Description

m-CPBA is a peroxycarboxylic acid that is commonly used as an oxidizing agent. It is usually available in <77% form because pure m-CPBA is shock sensitive (potentially explosive). It usually consists of ~10% m-chlorobenzoic acid and the remainder is H2O.

Chemical properties

White moist powder

The Uses of 3-Chloroperoxybenzoic acid

3-Chloroperoxybenzoic acid is a strong oxidizing agent used in the oxidation reactions such as aldehydes and ketones to esters (Bayer-Villiger-Oxidation), olefines to epoxides, sulfides to sulfoxides and sulfones, and amines to nitroalkanes, N-oxides.

The Uses of 3-Chloroperoxybenzoic acid

The SM (1 g, 3 mmol) was suspended in acetone (10 mL), cooled to 0 C, and treated portionwise with mCPBA (2.59 g, 15 mmol). The suspension became a clear solution after stirring at 0 C for 30 min. The reaction mixture was then allowed to warm up slowly to RT and was stirred for 5 h. Saturated aq NaHCO3 (50 mL) was added to give a mixture with pH 8. The resulting mixture was extracted with EtOAc (3 x 10 mL). The combined organics were washed with brine, dried (Na2SO4), and concentrated to provide crude product. [1 g]

The Uses of 3-Chloroperoxybenzoic acid

Effective oxidant for epoxidizing di-, tri-, and tetra-substituted olefins.

Definition

ChEBI: 3-chloroperbenzoic acid is a peroxy acid and a member of monochlorobenzenes.

Reactions

3-Chloroperoxybenzoic acid (MCPBA) is one of the most popular oxidation reagent in organic synthesis, because of its outstanding performance in terms of:
reactivity, combined with reducing the number of reaction steps in classical synthetic routes,
regio- and stereoselectivity,
protection of functional groups mostly not required,
high purity and yields.
Its literature covers a huge area of different syntheses and below reaction equations just can be a brief overview of its interesting applications:

Synthesis Reference(s)

Synthetic Communications, 19, p. 1271, 1989 DOI: 10.1080/00397918908054534

General Description

3-Chloroperoxybenzoic acid is sensitive to heat. Storage of 3-Chloroperoxybenzoic acid must be done so with stringent temperature control measures. It's explosion hazard is also mitigated by mixing the peroxide in a solvent slurry.

Reactivity Profile

May explode from heat, shock, friction or contamination. May ignite combustibles (wood, paper, oil, clothing, etc.). May be ignited by heat, sparks or flames.

Synthesis

3-Chloroperoxybenzoic acid(mCPBA) can be prepared by reacting m-chlorobenzoyl chloride with a basic solution of hydrogen peroxide, followed by acidification.

Hazard

3-Chloroperoxybenzoic acid(mCPBA) is danger, it has an acute oral toxicity, it can cause skin corrosion/irritation and serious eye damage/eye irritation.

Purification Methods

Recrystallise MCPBA from CH2Cl2 [Traylor & Mikztal J Am Chem Soc 109 2770 1987]. Peracid of 99+% purity can be obtained by washing commercial 85% material with phosphate buffer pH 7.5 and drying the residue under reduced pressure. Alternatively the peracid can be freed from m-chlorobenzoic acid by dissolving 50g/L of *benzene and washing with an aqueous solution buffered at pH 7.4 (NaH2PO4/NaOH) (5 x 100mL). The organic layer is dried over MgSO4 and carefully evaporated under vacuum. Necessary care should be taken in case of EXPLOSION. The solid is recrystallised twice from CH2Cl2/Et2O and stored at 0o in a plastic container as glass catalyses the decomposition of the peracid. The acid is assayed iodometrically. [Schwartz & Blumbrgs J Org Chem 29 1976 1964, Bortolini et al. J Org Chem 52 5093 1987, McDonald et al. Org Synth Coll Vol VI 276 1988, Beilstein 9 IV 972.]