Aldol condensation of acyclic ketones with benzaldehyde and subsequent cyclodehydration to form indenes over halide cluster catalysts

• Published in: Journal of molecular catalysis. A, Chemical Vol. 255; no. 1; pp. 117 - 122
• Main Authors: Kamiguchi, Satoshi, Nishida, Satoru, Takahashi, Ikuko, Kurokawa, Hideki, Miura, Hiroshi, Chihara, Teiji
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2006; Elsevier
• Subjects: Acyclic ketone; Aldol condensation of acetone with benzaldehyde; Catalysis; Catalysis by halide cluster; Chemistry; Cyclodehydration to indene; Exact sciences and technology; General and physical chemistry; Tantalum chloride cluster; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Catalysis by halide cluster; Acyclic ketone; Cyclodehydration to indene; Tantalum chloride cluster; Aldol condensation of acetone with benzaldehyde; Cyclodehydration; Molybdenum Chlorides; Transition metal Compounds; Molecular cluster; Tantalum Bromides; Silica; Supported catalyst; Aldol condensation; Tungsten Chlorides; Halides; Chlorides; Bicyclic compound; Catalysis; Tantalum Chlorides; Catalytic reaction; Niobium Chlorides; Benzaldehyde; Transition metal; Aldehyde; Ketone; Heterogeneous catalysis; Tantalum; Indene; Benzenic compound; Catalyst; Acetone
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2006.04.005

A molecular halide cluster [(Ta 6Cl 12)Cl 2(H 2O) 4]·4H 2O catalyzed the aldol condensation of acetone with benzaldehyde to yield E-4-phenyl-3-buten-2-one above 200 °C. 3-Pentanone combined with benzaldehyde provided indenes such as E- and Z-1-ethylidene-2-methylindene, by cyclodehydration of the aldol condensation product, E-2-methyl-1-phenyl-1-penten-3-one. One of the advantages of halide cluster catalysts is thermal stability, and high temperatures above 350 °C promoted the cyclodehydration. ▪ When a molecular halide cluster [(Ta 6Cl 12)Cl 2(H 2O) 4]·4H 2O ( 1)/SiO 2 was treated in a helium stream above 200 °C, it catalyzed the aldol condensation of acetone with benzaldehyde to yield E-4-phenyl-3-buten-2-one. The bromide cluster of Ta and chloride clusters of Nb, Mo, and W of the same octahedral metal framework also catalyzed the reaction. 3,3-Dimethyl-2-butanone combined with benzaldehyde similarly yielded the corresponding aldol condensation product over 1/SiO 2 at 400 °C. On the other hand, 3-pentanone combined with benzaldehyde provided indenes such as E- and Z-1-ethylidene-2-methylindene and 2-methyl-3-vinylindene of the same carbon skeletal structure, which would be formed by cyclodehydration of the aldol condensation product, E-2-methyl-1-phenyl-1-penten-3-one. One of the advantages of halide cluster catalysts is thermal stability, and high temperatures above 350 °C promoted the cyclodehydration.