Anhydrides

Except for acetic anhydride, these materials are not flammable but are combustible. The products of combustion are noxious.

Compounds from this group are incompatible with aqueous acids, strong oxidizing agents, alcohols, amines, and bases. Organic anhydrides react exothermically with water. The reactions are sometimes slow due to limited miscibility, but can become violent when local heating and/or increased miscibility during the reaction accelerates the rate of reaction. The rate of reaction with water is also accelerated by acids.

Extremely corrosive and irritating to mucous membranes, eyes, respiratory tract. Burns the skin. Fumes are a serious inhalation hazard.

These substances are formed by the condensation reaction of two molecules of an organic acid with the loss of water. They have the form R1(CO)O(CO)R2, where R1 and R2 may be any of a number of different organic compounds. Compounds in this group are used in organic synthesis and as dehydrating agents in nitration, sulfonation, and other reactions.

Acetic anhydride, butyric anhydride, isobutyric anhydride, maleic anhydride, methacrylic anhydride, phthalic anhydride, propionic anhydride.