Protolytic properties of silica modified with maleinized linseed oil

The protolytic equilibria on the surface of silicas coated with a layer of maleinized linseed oil (MLO), a new type of carboxylic cation exchangers, were studied using potentiometric titration. The ionexchange capacity of the sorbents was determined, a parameter that first increases and then decreases with increasing concentration of MLO on the silica surface. For the dibasic carboxy groups of MLO, pKa=3.99±0.04 and 4.73±0.04, values close to pKa for succinic acid, a homogeneous analogue of the system under study.