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Structure of dibenzoyl peroxide from X-ray crystallography.The O=C-O-O dihedral angle is 90°. The O-O distance is 1.434 Å. [20]The original 1858 synthesis by Liebig reacted benzoyl chloride with barium peroxide, [16] a reaction that probably follows this equation:
Diacyl peroxides are typically prepared by treating hydrogen peroxide with acid chlorides or acid anhydrides in the presence of base: [1] H 2 O 2 + 2 RCOCl → (RCO 2) 2 + 2 HCl H 2 O 2 + (RCO) 2 O → (RCO 2) 2 + H 2 O. The reaction competes with hydrolysis of the acylating agent but the hydroperoxide anion is a superior nucleophile relative ...
Another notable reaction is the homolysis of dibenzoyl peroxide, which results in the formation of two benzoyloxy radicals and acts as an initiator for many radical reactions. [4] Homolysis of dibenzoyl peroxide producing two benzoyloxy radicals
A standard procedure for the preparation of peresters is the acylation of tert-butyl hydroperoxide with benzoyl chloride. [6] In the reaction a large excess of tert-butyl hydroperoxide is used and the hydrogen chloride formed is removed in vacuo whereby a virtually quantitative yield is obtained.
The O-O σ bond in dibenzoyl peroxide is cleaved homolytically, distributing a radical to each benzoyloxy. Heat Certain intramolecular bonds, such as the O–O bond of a peroxide, are sufficiently weak to spontaneously homolytically dissociate near room temperature. Most bonds homolyse at temperatures above 200°C. [4]
Benzoyl peroxide ((PhC)OO) 2) generates benzoyloxyl radicals (PhCOO•), each of which loses carbon dioxide to be converted into a phenyl radical (Ph•). Methyl ethyl ketone peroxide is also common, and acetone peroxide is on rare occasions used as a radical initiator, too. Inorganic peroxides function analogously to organic peroxides.
The container dissipates heat more slowly in a higher-temperature environment, so at some critical temperature heat is generated by polymerization faster than the container can dissipate it and the reaction self-accelerates. Thus such a mixture has a SADT that depends on container size exactly as in the case of a pure organic peroxide.
Many chemical compounds that are potentially explosive have useful non-explosive applications. One large family of phlegmatizers are phthalate esters, which are used as solvents to minimize the explosive tendency of organic peroxides, such as dibenzoyl peroxide and MEKP, which are widely used initiators for polymerizations. [1]