Zirconium phosphate ester interchange reactions

Abstract

α-Zirconium phosphate was demonstrated to undergo ester-interchange reactions with alkyl phosphate groups. Partial interchange was found to occur in neat alkyl phosphate solutions. However, complete exchange is possible if the interlayer spacing of α-zirconium phosphate is first enlarged by intercalating an amine. The phosphate groups in α-zirconium phosphate are also labile and the supposed lack of reactivity previously reported is due to the inaccessibility of the organic phosphate groups to the interlayer spaces. Ethyl and butyl phosphates were prepared by both ester-interchange and direct precipitation methods. The reagents used contained considerable amounts of dialkyl phosphates and these are incorporated into the products along with monoalkyl phosphate. The β-phosphoglyceric acid (2-hydroxy-3-phosphono-oxypropionic acid) derivative could only be prepared by direct precipitation. This compound exhibits interesting chelation behaviour.