Monomeric and polymeric derivatives of 5-aminoisophthalic acid as selective inhibitors of the β-polymorph of L-glutamic acid

The effect of 5-aminoisophthalic acid, 3, 5-acetamidoisophthalic acid, 4, a polymer-bound 5-amidoisophthalic acid, 5, and a cross-linked analogue of the latter, 5*, on crystallisations of l-glutamic acid from water were examined. The metastable α-polymorph was crystallised in the presence of additive at minimum loadings of 10, 5 and 1% w/w for 3, 4 and 5, respectively. The cross-linked polymer 5* was less effective compared to the parent polymer 5.