The layered zirconium [N-(phosphonomethyl)iminodiacetic acid-phosphate] Zr(HPO4)1.34[O3PCH2N- (CH2CO2H)2]0.66·H2O can only be prepared in the series of the zirconium phosphonate-phosphates Zr(HPO4)2-x [O3PCH2N(CH2CO2H)2]x·H2O (ZPPMIDA) by the reaction of zirconium oxychloride with phosphonic acid and H2O3PCH2N(CH2CO2H)2 in the designed x range of 0 < x < 2, which had been monitored by using the phosphorus integration value ratio of HPO42- and [O3PCH2N(CH2CO2H)2]2- group in the 31P MAS NMR spectra. After intercala- tion of n-butyl amine, the 31P chemical shift of HPO42- group at - 8.0￣- 10.0 ppm moved to 6.0 ppm with a change of 14.0￣16.0 ppm and that of [O3PCH2N(CH2CO2H)2]2- group at - 29.1 ppm changed only 0.5 ppm. Due to the pil- lared effect of [O3PCH2N(CH2CO2H)2]2- groups on the interlayer spacing, intercalated amines such as n-butylamine, n-hexyl amine and n-octyl amine easily reacted with HPO42- group in ZPPMIDA (x=0.66) rather than that in α- ZrP, and carboxylic group (-CO2H) in ZPPMIDA (x=0.66).
