Synthesis and application of layered double hydroxide-hosted 2-aminoterephthalate for the Knoevenagel condensation reaction

2-Aminoterephthalate anion has been readily intercalated into a Zn(II)-Al(III) layered double hydroxide host by co-precipitation method. The intercalated material was characterized by powder X-ray diffraction, chemical analysis, thermogravimetric analysis and FTIR. The d-spacing observed by XRD for the LDH-ATA and the molecular structure of 2-aminoterephthalate anion (ATA) suggested that the 2-aminoterephthate anion was orientated with long axis perpendicularly to the LDH layers. The material showed good activity and selectivity for the Knoevenagel condensation reaction between 4-nitrobenzaldehyde and ethyl cyanoacetate under mild reaction conditions. The catalyst could be reused for three times with consistent product yield.