Tetrahedron Letters
Nano-sized polydopamine-based biomimetic catalyst for the efficient
synthesis of cyclic carbonates
a,
Zifeng Yang a,b, Jian Sun a, Xiaomin Liu a, Qian Su a, Ying Liu a, Qian Li b, , Suojiang Zhang
⇑
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a Beijing Key Laboratory of Ionic Liquids Clean Process, Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of
Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China
b School of Chemistry and Chemical Engineering, Henan University, Kaifeng 475001, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Polydopamine (PDA) is a biocompatible and biomimetic material. Herein, nano-sized PDA sphere was
prepared and the combination of alkali metal halide and PDA was investigated as a catalyst for the syn-
thesis of cyclic carbonates from epoxide and carbon dioxide. It was found that the activity of PDA could be
obviously enhanced in the presence of alkali metal salts. After reaction, the catalyst and the products
could be separated easily, and the catalyst was reusable. The origin of the high catalytic efficiency and
the reaction mechanism were also discussed.
Received 17 January 2014
Revised 26 March 2014
Accepted 10 April 2014
Available online 20 April 2014
Keywords:
Polydopamine
Ó 2014 Published by Elsevier Ltd.
Carbon dioxide
Cyclic carbonates
Synergistic catalysis
Alkali metal halide
Recently, the increasing pressure of CO2 released by human
being promotes a high requirement of C1 conversion. As one of
the most important branches of C1 chemistry, the synthesis of cyc-
lic carbonates via the reaction between CO2 and epoxides
(Scheme 1) was investigated intensively,1 and thus various cata-
lysts have been developed so far including alkali metal halides
based binary catalysts,2–7 and biomass supported catalysts.8 It is
worth mentioning that the combinations of low cost, stable, and
nucleophilic alkali metal halides with promoters such as b-CD,2
cellulose,3 formic acid,4 lignin,5 amino acids,6 and H2O7 provide a
good chance in developing cheap and environmentally benign cat-
alysts. It is believed that continuous efforts on the development of
new promoters would achieve further enhancement in efficiency
under moderate conditions.
Inspired by mussels marine animals which can be glued on the
rocks by their mussel adhesive proteins, most recently, Lee et al.
introduced a distinctive approach to surface modification in which
self-polymerization of dopamine (Fig. 1c) produced an adherent
polydopamine (PDA) coating on a wide variety of materials by a
simple dip-coating with dopamine solution.9 The formed surface
modification method has been explored for many applications,
including improving the hemocompatibility of biomaterials and
tuning the cell behaviors on their surfaces,10,11 Li-ion batteries,12
enzyme immobilization,13 controlled drug release, and water treat-
ment.14,15 Thus, it becomes a popular method to confer multi-func-
tionality to solid–liquid interfaces through the formed
biocompatible PDA thin films.9 Moreover, PDA could be considered
as a good promoter for the synthesis of cyclic carbonates because
of abundant hydroxyl groups and active N (ANH, AN@) in the
structure (Fig. 1b).4,7
Development of cheap, efficient, and environmentally benign
catalysts for the synthesis of cyclic carbonates under solvent-free
conditions is still an attractive topic. Encouraged by the advanta-
geous properties of PDA, herein, we conducted the reactions in
the presence of potassium halide and PDA under solvent-free con-
ditions for the first time, and found that the catalyst showed excel-
lent synergetic effect on the reactions, by which high yields could
be obtained for mono- and di-substituted epoxides. We believe
that this efficient, stable, and ecologically safe route to synthesize
cyclic carbonates has great potential in industrial application.
O
Cat.
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+
O
CO2
O
T, P
R
R
R=H, CH2,CH2Cl,C4H9,Ph, etc
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Corresponding authors. Tel.: +86 378 3881589 (Q.L.); tel./fax: +86 10 82627080
(S.Z.).
Scheme 1. Cyclic carbonates synthesis.
0040-4039/Ó 2014 Published by Elsevier Ltd.