CL-140658
Received: July 8, 2014 | Accepted: July 24, 2014 | Web Released: August 1, 2014
Synthesis of Glycidamide from Acrylonitrile Using Basic Hydrotalcite Catalyst
in the Presence of Aqueous Hydrogen Peroxide and Unsaturated Amide
Shinpei Fujiwara, Shun Nishimura, and Kohki Ebitani*
School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292
(E-mail: ebitani@jaist.ac.jp)
¹1
Glycidamide (GA) can be synthesized from acrylonitrile
(AN) by using hydrotalcite as a solid base catalyst and 25%
aqueous H2O2 as an oxidant, in the presence of acrylamide (AA)
as a cocatalyst in methanol solvent at 313 K for 18 h. The GA
yield and H2O2 utilization efficiency reached 74% and 60%,
respectively. The hydrotalcite catalyst could be easily separated
from the reaction mixture and reused at least once.
Ltd. Amberlyst A26 OH has 0.20 mmol g basic sites, which
could change the color of 2,4-dinitroaniline (pKa = 15), indicat-
ing that the base strength of Amberlyst A26 OH is stronger than
that of the HT.5 The reaction was performed in a 35-mL
cylindrical pressure glass-tube reactor. Methanol (Kanto Chem.
Co., Inc.) was used as the solvent. Products were analyzed by
using a GC (GC-2014, Shimadzu) equipped with a polar DB-
FFAP column (Agilent Technol. Inc.). 2-Butanol was used as an
internal standard. The actual concentration of H2O2, determined
by the iodometric titration method,6 was found to be 25.4%.
The reaction of AN generally gave both GA and AA
(Scheme 1) when using the catalysts listed in Table 1, with
methanol solvent. Table 1 shows the effect of various catalysts
on the AN conversion, GA yield, and selectivity. Basic catalysts4
such as HT, MgO, Amberlyst A26 OH, CaO, and SrO could
convert AN into AA and GA in methanol solvent. Among them,
HT-5.3 exhibited the highest GA yield and selectivity (Entry 1).
The moderate basicity of the HTs seems to be preferential for
the GA synthesis. The use of other alcoholic solvents such as
ethanol and 2-propanol also gave GA comparatively as with that
using methanol.7
Glycidamide (GA) has epoxide and amide moieties
(Scheme 1) and has the possibility for use as an industrial
starting material for resins, adhesive agents, and dyes.1 GA has
been synthesized from acrylonitrile (AN) by using NaOH and
aqueous (aq.) hydrogen peroxide (H2O2) via epoxidation of
the double bond to give glycidonitrile (GN) and subsequent
hydration of the nitrile moiety (Scheme 1, Route A).1a Because
of its high reactivity, however, it has not been industrialized till
now.
The use of a heterogeneous catalyst generally makes the
chemical process clean and simple because of the easy
separation of the catalyst after the reaction. Here, we aim at
the development of a heterogeneous catalytic system for GA
synthesis from AN using aq. H2O2 as a clean oxidant.2 We found
that the basic hydrotalcite, a layered Mg-Al double hydroxide,3
exhibited high catalytic activity for GA formation when using
aq. H2O2. The hydrotalcite is known to be a unique base catalyst
that can function in aqueous media.3k,4 It was also found that
α,β-unsaturated amides specifically facilitated the synthesis of
GA from AN via Route A, as outlined in Scheme 1.
The reactions of AA as a substrate using the same HT
catalyst under identical conditions at 313 and 373 K never give
GA; AA remains silent during the experiment. This reaction
system, therefore, cannot epoxidize AA to GA. In the present
case, GA is formed via Route A in Scheme 1, via the
epoxidation of AN to GN and subsequent hydration to GA
(vide infra).8 The basic sites of the HTs convert H2O2 to HOO
¹
to promote the first epoxidation of AN.3f,3j
Hydrotalcites (HTs) with Mg/Al = 3.0 and 5.3 or 5.4 were
supplied from Tomita Phamaceutical Co., Ltd. as AD500 (Lot.
S31064) and AD500PF (Lot. R20101 or R30104), respectively.
Accordingly, we tried to optimize the reaction conditions as
follows. Increasing the amount of aq. H2O2 over 0.75 mL
resulted in a drastic decrease in the GA yield. Increases in the
reaction temperature (373 K) also decreased the GA yield, due to
the decomposition of H2O2. The tentative maximum GA yield
was only 28% with 56% selectivity (HT-5.3 0.15 g, AN 2 mmol,
aq. H2O2 0.75 mL, methanol 3 mL, 313 K, and 13 h).9
¹1
The HT with Mg/Al = 3.0 (HT-3.0) has 0.21 mmol g basic
sites, which convert the color of brilliant cresyl blue (pKa = 11)
to a basic color.5 High-purity MgO (1000A) was purchased from
Ube Industries Ltd. Further, aq. H2O2 and CaO (99.9%) were
supplied from Wako Pure Chem. Co., Ltd. The Catalyst Society
of Japan supplied γ-Al2O3 as JRC-ALO-8. SrO (99.9%), and
Amberlyst A26 OH were purchased from Sigma Aldrich Co.,
Table 1. Effect of catalyst on formation of GA from ANa
Yield/%
AA GA
11 15
Selectivity
for GA/%
Entry Catalyst
AN conv./%
CN
Route A
O
1
2
3
4
5
6
7
8
HT (Mg/Al = 5.3)
HT (Mg/Al = 3.0)
MgO
Amberlyst A26 OH
CaO
SrO
γ-Al2O3
®
43
34
44
59
49
99
<1
0
35
32
14
12
4
3
0
0
[H2O]
17
21
5
11
6
7
[O]
O
NH2
CN
glycidonitrile (GN)
O
O
acrylonitrile (AN)
12
14
0
2
3
0
[H2O]
[O]
glycidamide (GA)
NH2
Route B
acrylamide (AA)
0
0
aReaction conditions: catalyst 0.15 g, AN 2 mmol, methanol 3 mL,
25.4% H2O2(aq.) 0.75 mL, 313 K, and 5 h.
Scheme 1. Synthetic routes for glycidamide (GA) from acrylonitrile
(AN).
© 2014 The Chemical Society of Japan