Organic anhydride

The latter method typically requires less severe conditions than the former because of the labile nature of the organic anhydride (87,137). Both of these reactions can result in explosions and significant precautions should be taken prior to any attempted synthesis of a peracid (87). For soHd peracids the reaction mixture can be neutralized with sodium hydroxide and the resulting fUtercake washed with water. In the case of the sulfuric acid mediated reaction the peracid has sodium sulfate incorporated in the cake (135). The water of hydration present in the sodium sulfate is desirable to prevent detonation or deflagration of the soHd peracid when isolated in a dry state (87,138,139). 

As a very general rule it may be said that the amines are fast curing and give good chemical resistance but most are skin sensitive. The organic anhydrides are less toxic and in some cases give cured resins with very high heat distortion temperatures. They do not cross-link the resins at room temperature. 

The acylation reaction of PS with organic anhydrides, such as maleic and acetic anhydrides, are very important for synthesizing polyfunctional (carbonyl-, carboxyl-, keto-, olefinic) PS. The incorporation of these groups to PS caused an increase of adhesion capability, physico-mechanical properties, elasticity, and photosensitivity [41-46]. 

Attack by other nucleophiles YH (such as amines, acids, carbanions) followed by alkoxycarbonylation has also been observed [23-28]. When the nucleophile is an organic anhydride, the final product is a /i-acyloxyanhydride (Eq. 14) [29]. 

Boonstra, M.G., Pizzi, A., Tekely, P. and Pendlebury, J. (1997). A study of the influence of solvents on the modification of wood with organic anhydrides. Holzforschung, 51(1), 62-66. 

Organic Anhydrides Acetic Anhydride Phthalic Anhydride Propionic Anhydride... 

The latter method (eq. 8) typically requires less severe conditions than the former because of the labile nature of the organic anhydride. Both of these reactions can result in explosions, and significant precautions should be taken prior to any attempted synthesis of a peracid. 

On a laboratory scale, one particular method of producing in situ peracids for epoxidation of a wide range of substrates under mild conditions is via the use of urea hydrogen peroxide (UHP) in the presence of organic anhydrides.27 The anhydride must be added slowly to the UHP, solvent and substrate to generate the peracid. If the UHP is added to the substrate, solvent and anhydride, the unstable and potentially explosive diacyl peroxides can be formed. Table 3.2 illustrates a number of substrates which have been epoxidized using this reagent system. 

A10j Na Aqueous solution is a strong base. Incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, cellulose nitrate, cresols, caprolactam solution, chlorocarbons, epichlorohydrin, ethylene dichloride, isocyanates, ketones, glycols, nitrates, phenols, vinyl acetate. Exothermic deconqjosition with maleic anhydride. May increase the explosive sensitivity of nitromethane. Attacks aluminum, copper, tin, and zinc. 

AMINOBENZENESULFONIC ACID or p-AMINOBENZENESULFONIC ACID (121-57-3) CsH NOjS HjO Decomposes on contact with strong acids, forming sulfur trioxide. The aqueous solution is acidic reaction with strong bases. Incompatible with alkylene oxides, aliphatic amines, alkanolamines, amides, ammonia, epichlorohydrin, organic anhydrides, isocyanates, oxidizers, vinyl acetate. On small fires, use dry chemical powder (such as Purple-K-Powder), Halon , water spray, or CO2 extinguishers. 

---