U. Costantino et al., METAL EXCHANGED LAYERED ZIRCONIUM HYDROGEN PHOSPHATE AS BASE CATALYSTOF THE MICHAEL REACTION, Catalysis letters, 22(4), 1993, pp. 333-336
Layered zirconium hydrogen phosphate, exfoliated by intercalation of p
ropylamine and then exchanged with alkali metal ions has proved to be
an excellent catalyst for Michael addition of beta-dicarbonyl compound
s. The reactions occur with high yield, in mild conditions and with ea
se of work up. The catalyst, recovered from the reaction vessel, may b
e reused several times.