Catalysis Communications
Short communication
Facile one-pot synthesis of glycidol from glycerol and dimethyl carbonate
catalyzed by tetraethylammonium amino acid ionic liquids
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Yan Zhou, Fan Ouyang, Zhi-Bin Song , Zhen Yang, Duan-Jian Tao
Center of Analysis and Testing, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Four tetraethylammonium amino acid ionic liquids (TAAILs) were prepared and used as catalysts for facile one-
pot synthesis of glycidol from glycerol and dimethyl carbonate. The results indicate that tetraethylammonium
pipecolinate ([N2222][Pipe]) exhibits the best catalytic activity compared with other three TAAILs, and catalyzes
the reaction to reach a glycerol conversion of 96% and a glycidol yield of 79% under optimum conditions. More-
over, DFT calculated results further manifest that such excellent performance originates from the carboxyl group
in [N2222][Pipe], which enables [N2222][Pipe] to activate the substrates effectively.
Received 31 January 2015
Received in revised form 11 March 2015
Accepted 12 March 2015
Available online 13 March 2015
Keywords:
Ionic liquids
Glycidol
© 2015 Elsevier B.V. All rights reserved.
Glycerol
Dimethyl carbonate
One-pot synthesis
1. Introduction
of glycidol through glycerol and DMC is considered to be an attractive
green and sustainable chemical process.
Concerning about fossil fuel consumption and exhaustion, the
demand for the biomass-derived biodiesel is increasing globally in the
last decades, which makes by-product glycerol available in huge amounts
at decreasing prices. Therefore, the conversion of glycerol to various
commodity chemicals, such as dehydration to acrolein, hydrogenolysis
to 1,2-propanediol, and gasification to syngas has attracted considerable
attention recently [1–4]. Among various derivatives of glycerol, glycidol
is one of the most attractive and valuable chemical intermediates. Indeed,
glycidol can be widely used in the fields of pharmaceuticals, cosmetics,
detergents, demulsifiers, dye leveling agents, etc. [5,6].
Generally, the industrial production of glycidol involves two envi-
ronmentally unfriendly routes (Scheme 1a) [7]. One is the epoxidation
of allyl alcohol using hydrogen peroxide in the presence of tungsten or
vanadium homogeneous catalyst. Another method is through the reac-
tion of epichlorohydrin under alkaline conditions. However, both these
two processes have several inherent drawbacks, including high pro-
duction cost, a large amount of waste liquid and chloride salt, and
serious equipment corrosion. In order to overcome the above issues,
using dimethyl carbonate (DMC) as a raw material to produce glycidol
has recently attracted significant attention. As well known, DMC is an en-
vironmentally friendly chemical intermediate because of its low toxicity,
low bioaccumulation and high biodegradability [8]. Thus, the synthesis
As shown in Scheme 1b, the two-step protocol for the preparation of
glycidol includes the formation of glycerol carbonate followed by its
decarboxylation. So far, there are a few research groups concentrating
on glycerol carbonate and glycidol [9–16]. Malkemus et al. [9] were
the first to patent the synthesis of glycidol through decarboxylation of
glycerol carbonate using metal salts as catalysts. Later, Choi et al. [12]
and Bolívar-Diaz [13] obtained glycidol through glycerol carbonate
using [BMIm]-based ionic liquids and metallic oxide modified ZSM-5
zeolite as catalysts, respectively. Despite the excellent yields and selec-
tivities, there has been little attention paid to the one-pot synthesis of
glycidol directly from glycerol and DMC [17–20]. Kelkar et al. [17] re-
ported their pioneering work on the one-pot synthesis of glycidol
using tetramethylammonium hydroxide as catalyst. However, this cata-
lyst has some inherent drawbacks such as poor thermal ability and dif-
ficult reusability. Li et al. [18] investigated that NaAlO2 induced a
glycidol yield of 76% in the one-pot synthesis of glycidol. Unfortunately,
an inevitable disadvantage is that the utilization of NaAlO2 must be per-
formed under rigorously anhydrous conditions due to its nature of easy
hydrolysis. Therefore, there is still an urgent need to develop excellently
stable, highly efficient, and easily reusable catalysts for the facile one-
pot synthesis of glycidol.
In recent years, amino acid ionic liquids have attracted much atten-
tion owing to their cheap cost and environment-friendly characteristics
[21,22]. Because of their certain basicities, they could provide a potential
application in the one-pot synthesis of glycidol. Herein, we prepared a
series of tetraethylammonium amino acid ionic liquids (TAAILs). Their
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Corresponding authors.
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