Maleic Anhydride saponification

Paste rosin sizes are supplied as viscous pastes containing 60—80% solids. These sizes may contain unmodified or fortified rosin that has reacted (ie, been fortified) with either maleic anhydride [108-31-6] or fumaric acid [110-17-8] (see Fig. 3). In either case, the unmodified or fortified rosin is treated with aqueous alkaH so that the degree of neutralization, ie, saponification, varies from 75—100% depending on the physical state desired for the commercial product. Before use, the paste size must be converted to a stable, dilute rosin size emulsion by careful sequential dilution with warm water foUowed by cold water, with good agitation. 

The total synthesis of complicated polycyclic closed-shell cage compounds represents one of the top achievements of modern synthesis. Progress in this area is mainly due to the ingenious use of the Diels-Alder cycloaddition, as is illustrated in the synthesis of basketene 357 (Scheme 2.123). " In this case the Diels-Alder reaction between diene 358 (the valent isomer form of cyclooctate-traene) and maleic anhydride leads in one step to the construction of the tricyclic structure 359 in quantitative yield. Subsequent [2 -I- 2] cycloaddition (see below) leads to product 360, which has the required structure but additional substituents. Saponification and oxidative decarboxylation of 360 gives basketene 357. 

Properties White, waxlike solid characteristic odor. Soluble in water freely soluble in alcohol, glycerol, carbon tetrachloride, acetone, xylene. Saponification value 240-253 stable in acid and neutral solutions hydrolyzes in alkaline solutions. Derivation By esterification of maleic anhydride with 2-ethylhexyl alcohol followed by addition of sodium bisulfite. 

In the elaboration of a method for the determination of maleic anhydride (together with maleate esters), homogeneous alkaline hydrolysis is prevented by the dimerization of these species. A two-phase saponification was recommended. 

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