Ž . Journal of Molecular Catalysis A: Chemical 159 2000 411–416 www.elsevier.comrlocatermolcata Mg–Al–O– t-Bu hydrotalcite: a new and efficient heterogeneous catalyst for transesterification 1 B.M. Choudary a, ) , M. Lakshmi Kantam a , Ch. Venkat Reddy a , S. Aranganathan a , P. Lakshmi Santhi a , F. Figueras b a Indian Institute of Chemical Technology, Hyderabad 500 007, India b Institut de Recherches sur la Catalyse, CNRS, 2 aÕ. A. Einstein, 69626 Villeurbanne Cedex, France Received 15 November 1999; accepted 4 March 2000 Abstract Normal and b-ketoesters have been successfully transesterified with primary, secondary, unsaturated, allylic, cyclic, hindered alcohols and amines by Mg–Al–O– t-Bu hydrotalcite catalyst for the first time affording excellent yields of products at a faster rate under heterogeneous catalysis. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Transesterification; Mg–Al–O–t-Bu hydrotalcite; Heterogeneous catalysis 1. Introduction The substitution of liquid bases by solids is a difficult challenge that has found only recently wx partial solutions with simple alkaline oxides 1 , wx layered double hydroxides 2 , supported KF wx wx 3 and exchanged zeolites 4 . Layered double Ž . hydroxides LDHs or hydrotalcite-like com- Ž . pounds HTLCs consists of brucite-like layers with positively charged metal oxide or hydrox- wx ide layers with anions located interstitially 2. Ž . Layered double hydroxides LDHs can yield catalysts of varying basicities according to the ) Corresponding author. Tel.: q 91-40-7170921; fax: q 91-40- 7173387. Ž . E-mail address: choudary@iict.ap.nic.in B.M. Choudary . 1 IICT Communication No.: 4439. activation procedure. Calcined or modified LDH catalyses many organic transformations, such as wx hydrogen transfer 5 , aldol and Knoevenagel w x wx condensations 6,7 , Michael reactions 8 , cya- wx noethylation of alcohols 9 and epoxidation of w x olefins 10 . Transesterification is an important organic transformation and provides essential synthons for a number of complex natural products, w x pheromones and additives for paints 11 . Trans- esterification is usually catalyzed by strong acids w x w x 12 , soluble base catalysts 13,14 . The reaction employing acids and bases is incompatible to the modern synthetic industrial chemistry that desires to be highly efficient, selective, ecofriendly and preferably catalytic. Although w x w x solid acids, such as clays 15 , zeolites 16,17 , w x alumina oxides 18 , are widely explored, only hydrotalcite in the class of solid bases is re- 1381-1169r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž . PII: S1381-1169 00 00209-0