Monatsh Chem (2012) 143:1199–1203
DOI 10.1007/s00706-011-0706-0
ORIGINAL PAPER
Polyacrylonitrile fiber mat supported solid acid catalyst
for acetalization
Linjun Shao
Xuezheng Liang
•
Yijun Du
•
•
Guiying Xing
•
Weixi Lv
•
Chenze Qi
Received: 26 September 2011 / Accepted: 13 December 2011 / Published online: 12 January 2012
Ó Springer-Verlag 2012
Abstract A novel polyacrylonitrile hybrid fiber mat
supported solid acid catalyst was prepared by electrospin-
ning, and its catalytic activities were carefully investigated
through acetalization reactions. The results showed that
this hybrid fiber mat exhibits high activity for the reactions,
with average yields over 95%. Besides having catalytic
activities similar to the solid acid, the heterogeneous solid
acid/polyacrylonitrile mat can be reused in six runs without
significant loss of catalytic activities. The large size of the
hybrid fiber mat greatly facilitates recovery of the catalyst
from the reaction mixture. The high and stable catalytic
activities of the hybrid fiber mat hold great potential for
green chemical processes and preparation of membrane
reactors in the future.
unrecyclable sulfonic acids [3–5]. Sulfonated carbonaceous
materials are used in some of the most widely used
methods to synthesize solid acids via carbonization and
sulfonation [6–8]. However, almost all solid acids prepared
in this way are powders. Separation and recycling of par-
ticulate catalysts from the reaction mixture is a tedious and
time-consuming process due to the large pressure drop in
filtration.
Electrospinning is a facile method to fabricate organic,
inorganic, and hybrid fibers with diameters ranging from
tens of nanometers to several micrometers [9–11]. Such
thin fibers are widely used in fiber textiles, sensors, bio-
materials, and catalyst carriers due to their unique surface
area-to-volume ratios. Recently, both natural (silk fibroin,
casein, cellulose, chitosan, etc.) and synthetic polymers
[polystyrene, polyvinyl alcohol, polycaprolactone, poly-
sulfone, polyacrylonitrile (PAN), etc.] have been suc-
cessfully prepared into fiber mats by electrospinning [12,
Keywords Membrane Á Acidity Á Catalysis Á
Green chemistry
13]. When a catalyst is coelectrospun into a polymer mat
Introduction
matrix, the active molecular species are anchored both on
the surface and in the interior of the fiber. Due to the low
diffusion resistance of the mat fiber network, the sub-
strate can diffuse on the surface and into the fiber easily,
and all the active species of the catalyst can be fully
used.
Acid catalysts have played an important role in chemical
industries for production of various important chemicals
[
1, 2]. Over 15 million tons of sulfuric acid is consumed
annually as an unrecyclable catalyst, resulting in great
environmental pollution. Preparation of environmentally
friendly acid catalysts is highly demanded, and various
solid acids have been developed for replacement of
Due to their excellent spinnability and chemical stabil-
ity, acrylonitrile-based homo- and copolymers have been
the most widely used polymers to prepare fiber mats as
supporting materials for catalyst [14, 15]. However, to the
best of our knowledge, they have not yet been applied to
immobilize solid acid catalysts. The much larger structure
of the fiber mats results in much easier separation and
recycling of solid acid from the mixture. Furthermore,
these fiber mats could be prepared into a membrane reactor
for continuous catalytic reaction in the future.
L. Shao Á Y. Du Á G. Xing Á W. Lv Á X. Liang Á C. Qi (&)
Institute of Applied Chemistry, Shaoxing University,
Shaoxing, China
e-mail: qichenze@usx.edu.cn
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