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Aldol condensation of benzaldehyde and heptanal: a comparative study of laboratory and industrially prepared Mg–Al mixed oxides
Author(s) -
Vrbková Eva,
Tišler Zdeněk,
Vyskočilová Eliška,
Kadlec David,
Červený Libor
Publication year - 2018
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5336
Subject(s) - heptanal , benzaldehyde , chemistry , aldol condensation , catalysis , aldehyde , physisorption , thermogravimetry , nuclear chemistry , organic chemistry , inorganic chemistry
BACKGROUND Several layered double hydroxides (with Mg:Al ratio varying from 2:1 to 4:1) were prepared by a co‐precipitation method at constant pH value. The activity of laboratory prepared samples was compared with that of industrially prepared layered double hydroxides with the same Mg/Al ratio in aldol condensation of benzaldehyde with heptanal. RESULTS Characterization of all solid catalysts was performed using different techniques (ICP‐MS, thermogravimetry, X‐ray diffraction, DRIFT spectroscopy, nitrogen physisorption method, scanning electron microscopy). Acido‐basic properties of prepared materials were investigated using ammonia (carbon dioxide, respectively) temperature programmed desorption. Heptanal conversion and selectivity to two main products, i.e. 2‐pentylcinnamylaldehyde (jasmine aldehyde) and 2‐pentylnon‐2‐enal, were monitored. All catalysts resulted in heptanal conversions higher than 95%. CONCLUSION The highest selectivity to jasmine aldehyde (66% at 70% heptanal conversion, 46% theoretical yield) was obtained using ESM 3:1 catalyst (100°C, heptanal:benzaldehyde = 1:2 molar, solvent‐free synthesis). © 2017 Society of Chemical Industry