Res. Chem. Intermed.
, Vol. 29, No. 1, pp. 83– 90 (2003)
Also available online - www.vsppub.com
Metameric esters ketonization in the vapor phase over solid
, H. GRABOWSKA
and L. SYPER
Department of Catalysis, W. Trzebiatowski Institute of Low Temperature and Structure Research,
Polish Academy of Sciences, 50-950 Wrocaw 2, P.O. Box 1410, Poland
Institute of Organic Chemistry, Biochemistry and Biotechnology, Technical University of Wrocaw,
Received 29 May 2002; accepted 8 October 2002
Abstract—Ketonization of metameric esters n-hexyl acetate and ethyl n-hexanoate was carried out in
the vapor phase over Sn-Ce-Rh-O catalyst at 370
C and at 1 and 3 h
load. In both cases the main
products were dimethyl ketone, dipentyl ketone and methyl pentyl ketone; however, the compositions
and ratios of the products obtained from both esters were different. The transformation pathways of
both esters were inferred based on the quantitative differences in the composition of the products.
The ratios of the particular compounds obtained during transformation of both esters indicate that
the reactions proceeded simultaneously — through ¯-ketoesters with partial thermal decomposition
of esters and secondary condensation of the formed aldehydes. Also the way of creation of ketones
resulting from secondary condensation was proposed.
: Esters; ketonization; ketones; tin catalyst.
The metameric esters R
can be obtained through
the Tishchenko reaction from the aldehydes R
CHO and R
CHO [1, 2]. Of course,
as a result of a classical decomposition of both esters in the retro-Tishchenko
reaction the same products, i.e. both aldehydes, are obtained . The use of
metameric esters for ketonization studies should then facilitate the observation of
the following phenomenon of asymmetry in the composition of ester ketonization
Contrary to the literature on the conversion of secondary alcohols to ketones over
heterogeneous catalysts , the production of ketones from primary alcohols and
esters is comparatively rarely described.
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