Abstract
Saponification of polymethylacrylate (PMA) was carried out at 40°C with sodium hydroxide in binary mixtures of various compositions of water-acetone. In comparison to it methyl propionate, methyl isobutyrate and dimethyl glutarate were also studied. The initial rate of saponification of PMA is scarcely influenced by the composition of the medium but its value is much less than that of the low molecular esters of the similar structure. In acetone rich systems the apparent rate constant of saponification increases with the increasing degree of saponification, whereas in water rich systems it decreases. Dimethyl glutarate shows similar behaviour but the change of the rate constant is small. Some discussious are given from the stand point of view that repulsion or adsorption of the catalyst takes place by COO- or COONa groups.
