Catalysis Communications
Short Communication
MgO/SnO2/WO3 as catalysts for synthesis of ε-caprolactone over
oxidation of cyclohexanone with peracetic acid
⁎
Zhang Guangxu , Ren Xiaocong, Zhang Hongbo, Peng Yu, Gui Shaoyong
School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 15 July 2014
Received in revised form 21 August 2014
Accepted 22 August 2014
Available online 30 August 2014
Different Mg/Sn/W mixed oxides prepared by precipitation were used as catalysts in the Baeyer–Villiger oxida-
tion of cyclohexanone with a mixture of 50% hydrogen peroxide and acetic acid as oxidant. The Mg/Sn/W
oxide obtained by precipitation from NH3·H2O was found to be the catalyst providing the highest yield of
ε-caprolactone and initial catalytic activity among all samples.
© 2014 Elsevier B.V. All rights reserved.
Keywords:
Baeyer–Villiger oxidation
MgO/SnO2/WO3 catalysts
Peracetic acid
ε-Caprolactone
1. Introduction
benign and environmental friendly than organic oxidants in the BV
reaction.
The Baeyer–Villiger (BV) reaction which converts ketones to esters
was first reported by Baeyer and Villiger in 1899 [1]. The corresponding
ε-caprolactone is an important synthetic intermediate to produce poly-
esters [2,3]. Since then, the BV reaction has become a fine organic syn-
thesis method, which has been reported by large numbers of books
and papers [4,5].
The BV reaction only takes place in the presence of catalysts, and the
reaction gives a high yield especially in the presence of heterogeneous
catalysts [6,7]. So various heterogeneous catalysts such as zeolites [8],
solid acid [9], clays [10,11], As [12], titanium silicalite [13], Sn-
incorporated zeolites [14], silica-incorporated transition metal ions
[15], and metal complexes [16] have also been proved effective in the
past decade. In recent years, hydrotalcites supported Sn or Al/Mg were
found to be effective catalysts for the BV oxidation of cyclohexanone
with H2O2 [17,18].
Recently our lab reported the synthesis of ε-caprolactone by
oxidation of cyclohexanone with monoperoxy succinic acid. The re-
sults were excellent [20]. In this work, we optimized the operating
conditions and used peracetic acid instead of monoperoxy succinic
acid to oxidize cyclohexanone. We reported the oxidation of cyclo-
hexanone by using Mg/Sn/W oxides as a catalyst and 50% hydrogen
peroxide/acetic acid mixture as oxidant. We creatively put forward
a new catalyst that added W ions into the Mg/Sn oxides in the BV re-
action. A series of MgO/SnO2/WO3 catalysts which were respective-
ly precipitated by NH3·H2O, Na2CO3, NaHCO3, NaOH, (NH4)2CO3
were comparatively characterized for their structural and textural
properties.
2. Experimental
The discovery of Ti-silicalite (TS-1) came into the revolution in the
use of heterogeneous catalysts in oxidation processes, and it revealed
that Ti-peroxide species could activate H2O2 in various oxidation reac-
tions [19]. Above all the researches, metal ions especially Sn and Mg
were found to be effective in the BV reaction. In general, different new
catalysts were developed by using hydrogen peroxide which is more
2.1. Preparation of catalysts
All the substrate materials, MgCl2·6H2O, SnCl4·5H2O and H2WO4
were obtained from Sinopharm Chemical Reagent Co., Ltd.
A solution containing 112.5 g MgCl2·6H2O and 28 g SnCl4·5H2O in
200 mL of deionized water was used. Then five different precipitants
in 200 mL of deionized water were dropped into the above solution
respectively at pH 9.5 at 30 °C under mechanical agitation. The five
solutions were added with 9.5 g H2WO4 and kept stirring until its
color becomes white respectively during precipitation. The solids were
⁎
Corresponding author. Tel./fax: +86 27 87859019.
1566-7367/© 2014 Elsevier B.V. All rights reserved.