Adsorption of Diols on Silica Gel Modified by Phenylboronic Acid
Diols are key intermediate materials for polymers. Conventional distillation techniques for the separation of diols require a substantial energy input. Alternatively, in this paper we examine an adsorption technique to recover and separate diols. Silica gels modified by boronate were used as a selective adsorbent for diols. First, using potentiometric titration, we examined the number and p<I>K</I><SUB>a</SUB> of the active site included in the gels. The values of the p<I>K</I><SUB>a</SUB> of the boronate were larger than that of phenylboronic acid. From the adsorption experiments on the resin, we found that main adsorption mechanism was a complex formation between neutral boronic acid and the diols. A pH value smaller than p<I>K</I><SUB>a</SUB> (=10) of boronate is desirable for the adsorption of diols. Silica gels modified by phenylboronic acid effectively adsorbed the hydrophobic diols. The adsorption capacity of vicinal and 1,3-diols were similar.
- Journal of chemical engineering of Japan
Journal of chemical engineering of Japan 40(1), 26-30, 2007-01-01
The Society of Chemical Engineers, Japan