Transesterification of dimethyl carbonate and phenol to diphenyl carbonate with the bismuth compounds

Article abstract of DOI:10.1007/s11696-018-0467-x

Bismuth oxide was first employed for the transesterification of dimethyl carbonate with phenol to diphenyl carbonate, which has excellent catalytic activity. With 0.4?g Bi₂O₃, the phenol conversion of 46.4% and transesterification selectivity of 99.9% were attained. The characterization of the used sample by XRD, FTIR and solid-state ¹³C-NMR indicate that a new compound of bismuth phenoxide was formed with the disappearance of bismuth oxide. It was evidenced that the bismuth phenoxide act as the role of active phase in the transesterification, which was generated facilely in situ by the reaction of bismuth oxide added with the raw material of phenol. The bismuth phenoxide presents excellent reusability, after four consecutive runs, the phenol conversion remained above 45%, and the transesterification selectivity was maintained at 99.9%.

Full text of DOI:10.1007/s11696-018-0467-x

Chemical Papers
https://doi.org/10.1007/s11696-018-0467-x
ORIGINAL PAPER
Transesterifcation of dimethyl carbonate and phenol to diphenyl
carbonate with the bismuth compounds
Zhongliang Xiao1,2 · Hao Yang1,2 · Hua Zhang1 · Tong Chen1 · Gongying Wang1
Received: 14 November 2017 / Accepted: 3 April 2018
© Institute of Chemistry, Slovak Academy of Sciences 2018
Abstract
Bismuth oxide was frst employed for the transesterifcation of dimethyl carbonate with phenol to diphenyl carbonate, which
has excellent catalytic activity. With 0.4 g Bi2O3, the phenol conversion of 46.4% and transesterifcation selectivity of 99.9%
were attained. The characterization of the used sample by XRD, FTIR and solid-state 13C-NMR indicate that a new compound
of bismuth phenoxide was formed with the disappearance of bismuth oxide. It was evidenced that the bismuth phenoxide
act as the role of active phase in the transesterifcation, which was generated facilely in situ by the reaction of bismuth oxide
added with the raw material of phenol. The bismuth phenoxide presents excellent reusability, after four consecutive runs,
the phenol conversion remained above 45%, and the transesterifcation selectivity was maintained at 99.9%.
Keywords Bismuth oxide · Transesterifcation · Diphenyl carbonate · Heterogeneous catalyst · Phenol
Introduction
unstable and difcult to be separated from the products. So
heterogeneous catalyst was developed (Chen et al. 2007; Li
et al. 2012; Tang et al. 2014; Zhou et al. 2014; Wang et al.
2015b; Zhang et al. 2016; Deshmukh et al. 2010). In recent
years, numerous metal oxides had been explored as hetero-
geneous catalysts for transesterifcation of DMC and phenol,
such as TiO2 (Zhou et al. 2014; Gao et al. 2016), V2O5 (Tong
et al. 2007), MoO3 (Li et al. 2008; Kim and Park 2009a),
Pb3O4 (Zhou et al. 2004). Among them, V2O5, MoO3 and
Pb3O4 showed high catalytic activity, the phenol conversion
exceeds 40%, but the transesterifcation selectivity is less
than 95%, and it is not satisfactory. Consequently, the devel-
opment of more efcient catalysts is desirable.
Diphenyl carbonate (DPC) is an important chemical inter-
mediate, which was extensively employed in the syntheses
of various organic compounds, especially utilized as the
key raw material for the non-phosgene preparation of PC
by a melt polymerization process (Gong et al. 2007; Muray-
ama et al. 2012; Kim and Lee 2002). Transesterifcation of
DMC with phenol has been regarded as an attractive non-
phosgene route for the synthesis of diphenyl carbonate (Park
et al. 2014). This route is a two-step process, which involves
the transesterifcation of DMC and phenol to methyl phenyl
carbonate (MPC) (Eq. 1) and the further transesterifcation
of MPC and phenol (Eq. 2) or disproportion of MPC to DPC
(Eq. 3) as shown in Scheme 1.
Diferently from many heavy meatal, bismuth compounds
are remarkably nontoxic, inexpensive, tolerant of small
amounts of moisture and noncorrosive. All of these proper-
ties make bismuth compounds especially attractive from a
green chemistry perspective (Bothwell et al. 2011). Also,
bismuth compounds present from moderate to strong Lewis
acidity due to defcient nucleus shielding by the f electron
shell (Bi=[Xe] 4f14,5d10,6 s2,6p3) (da Silva et al. 2013). As
a result, the catalytic behavior of bismuth compounds has
been investigated in diferent chemical reactions (Bothwell
et al. 2011; da Silva et al. 2013; Dai et al. 2008; Kwie et al.
2010), but their application in the transesterifcation of DMC
and phenol is still unknown.
The frst step is rate-controlling step because the reac-
tion rate is far slower than the disproportionation (Mei et al.
2004; Wang et al. 2015a). This reaction is usually carried out
in the liquid phase, with homogenous catalyst of organo-tin
and organo-titanium, but these homogeneous catalysts are
* Tong Chen
chentongw@sina.com.cn
1
Chengdu Institute of Organic Chemistry, Chinese Academy
of Science, Chengdu 610041, Sichuan, China
2
University of Chinese Academy of Sciences, Beijing 10049,
China
Vol.:(0123456789)
1 3

Chemical Papers
Scheme 1 Transesterifcation of
DMC with phenol to DPC
In the present work, bismuth oxide was used to synthe-
size DPC via the transesterifcation of DMC and phenol,
the fresh and used Bi2O3 were characterized by XRD and
FT-IR. According to the characterization result, it is found
that the active phase in the transesterifcation is bismuth
phenoxide, bismuth phenoxide is formed facilely in situ
with the reaction of Bi2O3 and phenol, and the reusability
of bismuth phenoxide was also investigated.
Transesterifcation reaction of phenol and DMC
The transesterifcation reaction was carried out in a three-
neck round-bottom fask (150 mL), equipped with nitrogen
inlet, magnetic stirring bar, dropping funnel and fractionat-
ing column connected to a liquid dividing head. Typically,
under nitrogen atmosphere, phenol and catalyst were added
into the fask. When the mixture was heated to 175 °C, DMC
was added dropwise and the reaction temperature was kept at
160–180 °C under refuxing condition. During the reaction
procedure, an azeotrope of DMC and methanol were collected
in receiver fask. After the reaction, the mixture was cooled to
room temperature, the catalyst was centrifugalized and then
the fltrate was analyzed.
Experimental
Catalyst preparation
Identifcation analysis of the products was detected by
GC–MS on a HP-6890/5973 system. The products were
quantitatively analyzed by gas chromatograph (Agilent Tech-
nologies 7820A) equipped with a DB-35 capillary column
(30 m×320 μm×0.25 μm) and a fame ionization detector
(FID). The conversion and selectivity were calculated based
on the phenol.
All chemicals were obtained from local manufactures
and were used as received. Bismuth oxide was obtained
by calcining bismuth nitrate in air at 500 °C for 4 h.
(NH4)8Mo10O34 was prepared using a reported procedure
at 150 °C in He for 1 h (Kim and Park 2009b). The catalyst
used was recovered through centrifugation, washed with
DMC and following by dried under vacuum at 120 °C.
Results and discussions
Catalyst characterization
Catalytic performance of Bi2O3
Fourier transform infrared (FT-IR) spectra were recorded
on a Nicolet 400 spectrophotometer using the KBr wafer
technique in the range of 4000–400 cm−1 and the resolu-
tion was 4 cm−1. Powder X-ray difraction (XRD) pattern
was recorded in the 3°–80° 2θ range in the scan mode
(step size 0.06°, counting 1 s per step) using a DX-1000
difractometer (λ= 1.542 Å). Thermal analysis (TGA) was
carried out using a METTLER TG1 model. Samples were
heated from room temperature to 800 °C at a heating rate
The catalytic performance of Bi2O3 for the transesterifcation
of DMC and phenol was tested; for comparison, the catalytic
activities of some reported catalysts were tested in the same
reaction conditions. The results are listed in Table 1. It could
be seen in Table 1 that pure TiO2 and SnO2 were inactive for
this reaction, and Bi2O3 had the highest activity of the tested
catalysts in the same conditions.
Efect of catalyst amount on the transesterifcation
of 10 °C min−1 under a nitrogen fow of 50 mL min−1
.
Solid-state 13C-NMR spectra were recorded on a Bruker
Avance III 500 MHz solid-state spectrometer operating at
frequencies of 125 MHz.
The efect of the Bi2O3 amount on the transesterifcation of
DMC with phenol was frst studied and the results are listed
1 3

Chemical Papers
Table 1 The activity comparison among various catalysts
Catalyst
Conversion Yield (%)
Transesterifca-
tion selectivity
(%)
of phenol
MPC DPC AN
(%)
TiO2
MoO3
V2O5
SnO2
PbO
Bi2O3
(NH4)8Mo10O34 29.8
4.6
2.8
15.7 18.9 Trace 99.9
13.5 14.1 0.1 99.8
4.9 5.2 Trace 99.9
17.6 10.4 1.2 95.9
20.2 26.6 Trace 99.9
15.3 14.3 0.2 99.3
1.8 Trace 99.9
34.6
27.7
10.1
29.2
46.8
Reaction conditions: DMC 0.16 mol, phenol 0.16 mol, catalyst 0.4 g,
temperature 150–180 °C, reaction time 9 h
Table 2 The efect of Bi2O3 amount on the transesterifcation of
Fig. 1 Reusability of the bismuth phenoxide for DMC transesterifca-
tion. Reaction conditions: DMC 0.16 mol, phenol 0.16 mol, catalyst
0.4 g, temperature 150–180 °C, reaction time 9 h
DMC with phenol
Catalyst
Phenol con-
version (%)
Yield (%)
MPC
Transesterifca-
tion selectivity
(%)
amount (g)
DPC
0.1
0.2
0.3
0.4
0.5
0.6
29.4
36.3
40.7
46.2
45.9
45.4
11.8
15.6
17.8
18.7
20.9
17.7
17.5
20.7
22.9
27.5
25.0
27.7
99.9
99.9
99.9
99.9
99.9
99.9
Reaction conditions: DMC 0.16 mol, phenol 0.16 mol, catalyst 0.6 g,
temperature 150–180 °C, reaction time 9 h
in Table 2. From the Table 2, it can be seen that the products
are MPC and DPC, no byproduct of anisole was detected,
and the transesterifcation selectivity was 99.9%. With the
amount of Bi2O3 from 0.1 g increase to 0.4 g, the conversion
of phenol from 29.4% increases to 46.2%. Further adding the
amount of Bi2O3, the phenol conversion was unchanged. An
excess amount of Bi2O3 did not further promote the reaction
to form more products. This might be attributed to the efect
of mass transfer. Therefore, the optimal catalyst amount
should be 0.4 g.
Fig. 2 XRD patterns of catalyst for transesterifcation of DMC with
phenol. a Bismuth oxide, b sample used, c synthesized compound A
the sample used, no difraction peak of Bi2O3 was observed.
Meanwhile, the new peaks at 2θ values of 5°, 6°, 23°, 30°,
32° were found, which could be attributed to the character-
istic peak of metal aryloxides (Bradley et al. 2001).
Reusability of bismuth phenoxide
The activity of recovered catalyst was tested by fve consecu-
tive runs and the results are shown in Fig. 1. The results
show that there is no obvious loss of phenol conversion after
fve cycles, the transesterifcation selectivity maintained at
99.9%.
Furthermore, the FT-IR spectrum of fresh and used sam-
ple is also distinct diferent, as displayed in Fig. 3. For the
fresh sample, only the bands at 503 and 432 cm−1 attrib-
uted to the Bi–O stretching mode were observed (Dai et al.
2008). For the sample used, these bands of Bi2O3 disap-
pear, and new bands of 523, 692, 759, 820, 1021, 1070,
1167, 1253, 1385, 1478 and 1589 cm−1 were found. The
bands at 523 cm−1 can be assigned to ν(Bi–O) stretching
vibrations. The bands at 1589 and 1478 cm−1 corresponded
The structure of the fresh and the used sample was char-
acterized by XRD and the result was shown as Fig. 2. The
XRD pattern of the fresh sample shows the difraction peak
at 2θ values of 25°, 27°, 33°, 46°, which attributes to the
characteristic peak of Bi2O3 (PDF 41–1449). However, for
1 3

Chemical Papers
Fig. 4 Spectra of solid-state 13C-NMR for the sample used
Fig. 3 FTIR spectra of catalyst for transesterifcation of DMC with
phenol. a Bismuth oxide, b sample used, c synthesized compound A
of DMC with phenol, Bi2O3 was converted in suit into a
typical metal aryloxide compound, we named as bismuth
phenoxide.
to the skeletal vibration of benzene ring. These bands of
820, 759, and 692 cm−1 were attributed to the out-of-plane
bending vibration of single displacement of benzene ring.
It could surmise the existence of single displacement of
benzene ring at the sample used. The literature (Bradley
et al. 2001; Kaur and Singh 2012) reveals that two types
of bands in metal aryloxides due to ν(C–O)M appear in
the region of 1180–1010 cm−1, among them, the bands of
1180–1060 cm−1 were attributed to the terminal ν(C–O)
M stretching vibrations, and the bands of 1060–1010 cm−1
were attributed to the bridged ν(C–O)M stretching vibra-
tions. In the present product, bands of 1167 and 1070 cm−1
may be assigned to terminal ν(C–O)Bi phenoxy groups and
the bands in the 1021 cm−1 may be attributed to bridged
ν(C–O)Bi phenoxy groups.
Identifcation of the active phase
Although the structure of sample used is diferent from the
fresh Bi2O3, the catalytic activity of sample used was still
maintained, so we deduce that the sample used is the active
phase. To identify the assumption, two experiments were
designed. For the frst one, the compound A was synthesized
by the reaction of phenol and bismuth oxide at 160 °C for
5 min under atmospheric pressure, then the solid was cen-
trifugalized, washed with DMC and vacuum dried for 2 h at
120 °C. The XRD and FT-IR of compound A were displayed
in Figs. 2 and 3. It can be seen that the XRD and FT-IR of
the used sample are as same as the compound A. For the
second experiment, the synthesized compound A was used
From the result of XRD and FT-IR, it is known that the
structure of sample used is remarkably diferent from the
fresh Bi2O3. The sample used contains phenyl group, C–O
bond and Bi–O bond. So, we speculate the Bi2O3 converted
to a new compound by reaction with phenol in the transes-
terifcation process. The presence of phenyl group in the
sample used is evident from the solid-state 13C NMR charac-
terization. From the spectra of solid-state 13C NMR in Fig. 4,
it can be seen that three types of phenyl carbon can be iden-
tifed at chemical shift of 159.23, 130.99 and 121.09 ppm.
Compared with the standard chemical shifts, diference
occurred for all the carbon of the Bi–O–phenyl, which is
caused by heteronuclear interaction of bonding between Bi
and phenyl. This is the results of fast spin–spin relaxation
of carbon close to metal core (Aini et al. 2014). The weak
peak at chemical shift of 67.82 and 56.18 ppm are assigned
carbon of the –OCH3 and –OCH2, respectively, which come
from the little adsorbed MPC (Kouzu et al. 2008).
Fig. 5 Catalytic activity of the sample used and synthesized com-
pound A. Reaction conditions: DMC 0.16 mol, phenol 0.16 mol, cat-
alyst 0.4 g, temperature 150–180 °C, reaction time 9 h
From the characterization result of XRD, FTIR and 13C-
NMR, we can deduce that in the transesterifcation reaction
1 3

Chemical Papers
Fig. 6 TG-DTG curve of cata-
lyst samples. a Used catalyst, b
synthesized compound A
as catalyst for the transesterifcation and the activity result
is illustrated in Fig. 5. The compound A shows excellent
activity, with phenol conversion of 46.4% and transesteri-
fcation of 99.9%, and this activity result of compound A
is as active as the sample used in the transesterifcation of
DMC and phenol.
in situ by Bi2O3 react with phenol, and it has excellent
catalytic activity and reusability, after fve successive runs,
the phenol conversion remained above 45%.
Acknowledgements Financial support for this work from the National
High Technology Research and Development Program of China (863
program, No. 2013AA031703), and the Science and Technology Sup-
port Program of Sichuan Province (No. 2013GZX0135) are greatly
acknowledged.
Figure 6 shows TG-DTG curve measured for the used
sample (Fig. 6a) and the synthesized compound A (Fig. 6b).
They all have two exothermal peaks at around 231 and
380 °C. The weight loss of used sample and compound A
was 21.6 and 21.2%, respectively; the result of TG date con-
frmed the structure of two sample were similar.
References
From the result of IR and XRD, it can be confrmed that
the active phase is bismuth phenoxide, which is obtained
in situ by react with Bi2O3 and phenol in the transesterifca-
tion process.
Aini S, Efendi J, Lintang HO, Chandren S, Nur H (2014) Ti–phenyl
nanoparticles encapsulated in mesoporous silica as active and
selective catalyst for the oxidation of alkenes. Catal Commun
46:150–155. https://doi.org/10.1016/j.catcom.2013.12.012
Bothwell JM, Krabbe SW, Mohan RS (2011) Applications of
bismuth(III) compounds in organic synthesis. Chem Soc Rev
40(9):4649–4707. https://doi.org/10.1039/c0cs00206b
Bradley DC, Mehrotra RC, Rothwell IP, Singh A (2001) Alkoxo and
aryloxo derivatives of metals, 1st edn. Academic Press, Salt Lake
City
On the basis of these fndings, it was clear that, when
Bi2O3 was used to catalyze the transesterifcation of DMC
and phenol, Bi2O3 was reacted with phenol to form a new
compound. The structure and activity of the used sample
are same as the synthesized compound A, such observation
suggested that bismuth phenoxide was the active phase in
the transesterifcation of DMC with phenol.
Chen T, Han HJ, Yao J, Wang GY (2007) The transesterifcation of
dimethyl carbonate and phenol catalyzed by 12-molybdophos-
phoric salts. Catal Commun 8(9):1361–1365. https://doi.
org/10.1016/j.catcom.2006.11.032
da Silva FR, Luciano Silveira MH, Cordeiro CS, Nakagaki S, Wypych
F, Ramos LP (2013) Esterifcation of fatty acids using a bismuth-
containing solid acid catalyst. Energy Fuels 27(4):2218–2225.
https://doi.org/10.1021/ef400001r
Conclusions
Bi2O3 was frst used for the transesterifcation of DMC and
phenol to DPC. With the amount of Bi2O3 was 0.4 g, the
phenol conversion and transesterifcation selectivity were
46.4 and 99.9%, respectively. According to the characteri-
zation of XRD, FTIR and solid-state 13C-NMR, it can be
known that the Bi2O3 converted to a new compound of bis-
muth phenoxide after react with the raw material phenol.
The XRD and FTIR spectrum of compound A is consistent
with those samples of bismuth oxide used, which have the
structure of bismuth phenoxide. Simultaneously, the cata-
lytic performance of compound A is as well as the fresh
Bi2O3, which could guess the bismuth phenoxide is the
active phase for the transesterifcation of phenol and DMC
to DPC. The bismuth phenoxide can be generated facilely
Dai YS, Wang Y, Yao J, Wang QY, Liu LM, Chu W, Wang GY
(2008) Phosgene-free synthesis of phenyl isocyanate by catalytic
decomposition of methyl N-phenyl carbamate over Bi2O3 cata-
lyst. Catal Lett 123(3–4):307–316. https://doi.org/10.1007/s1056
2-008-9424-6
Deshmukh KM, Qureshi ZS, Dhake KP, Bhanage BM (2010) Transes-
terifcation of dimethyl carbonate with phenol using Bronsted and
Lewis acidic ionic liquids. Catal Commun 12(3):207–211. https
://doi.org/10.1016/j.catcom.2010.09.017
Gao Y, Li ZH, Su KM, Cheng BW (2016) Excellent performance
of TiO2(B) nanotubes in selective transesterifcation of DMC
with phenol derivatives. Chem Eng J 301:12–18. https://doi.
org/10.1016/j.cej.2016.04.036
Gong JL, Ma XB, Wang SP (2007) Phosgene-free approaches to
catalytic synthesis of diphenyl carbonate and its intermediates.
Appl Catal A Gen 316(1):1–21. https://doi.org/10.1016/j.apcat
a.2006.09.006
1 3

Chemical Papers
Kaur H, Singh B (2012) Direct electrochemical synthesis of
bismuth(III) phenoxides and their coordination compounds. Eur
J Chem 9(1):381–388
Park SJ, Hwang IC, Shin SH (2014) Liquid–liquid equilibria for ter-
nary mixtures of methylphenyl carbonate, dimethyl carbonate,
diphenyl carbonate, anisole, methanol, phenol, and water at sev-
eral temperatures. J Chem Eng Data 59(2):323–328. https://doi.
org/10.1021/je400776b
Kim WB, Lee JS (2002) Comparison of polycarbonate precursors syn-
thesized from catalytic reactions of bisphenol-A with diphenyl
carbonate, dimethyl carbonate, or carbon monoxide. J Appl Polym
Sci 86(4):937–947. https://doi.org/10.1002/app.11026
Tang RZ, Chen T, Chen Y, Zhang YZ, Wang GY (2014) Core-shell
TiO2@SiO2 catalyst for transesterifcation of dimethyl carbonate
and phenol to diphenyl carbonate. Chin J Catal 35(4):457–461.
https://doi.org/10.1016/s1872-2067(14)60059-0
Kim YT, Park ED (2009a) Transesterifcation between dimethyl car-
bonate and phenol in the presence of (NH4)8Mo10O34 as a cata-
lyst precursor. Appl Catal A Gen 361(1–2):26–31. https://doi.
org/10.1016/j.apcata.2009.03.029
Tong DS, Yao J, Wang Y, Niu HY, Wang GY (2007) Transesterifca-
tion of dimethyl carbonate with phenol to diphenyl carbonate over
V2O5 catalyst. J Mol Catal A Chem 268(1–2):120–126. https://
doi.org/10.1016/j.molcata.2006.12.013
Kim YT, Park ED (2009b) Deactivation phenomena of MoO3/SiO2
and TiO2/SiO2 during transesterifcation between dimethyl car-
bonate and phenol. Appl Catal A Gen 356(2):211–215. https://
doi.org/10.1016/j.apcata.2009.01.008
Wang SL, Tang RZ, Zhang YZ, Chen T, Wang GY (2015a) 12-Molyb-
dophosphoric acid supported on titania: a highly active and selec-
tive heterogeneous catalyst for the transesterifcation of dimethyl
carbonate and phenol. Chem Eng Sci 138:93–98. https://doi.
org/10.1016/j.ces.2015.08.005
Kouzu M, Kasuno T, Tajika M, Yamanaka S, Hidaka J (2008) Active
phase of calcium oxide used as solid base catalyst for transesteri-
fcation of soybean oil with refuxing methanol. Appl Catal A Gen
334(1–2):357–365. https://doi.org/10.1016/j.apcata.2007.10.023
Kwie FHA, Baudoin-Dehoux C, Blonski C, Lherbet C (2010)
Bismuth(III) trifate: a safe and easily handled precursor for tri-
fic acid: application to the esterifcation reaction. Synth Commun
40(7):1082–1087. https://doi.org/10.1080/00397910903046846
Li ZH, Cheng B, Su K, Gu Y, Xi P, Guo ML (2008) The synthesis
of diphenyl carbonate from dimethyl carbonate and phenol over
mesoporous MoO3/SiMCM-41. J Mol Catal A Chem 289(1–
2):100–105. https://doi.org/10.1016/j.molcata.2008.04.018
Li BJ, Tang RZ, Chen T, Wang GY (2012) Transesterifcation of phenol
and dimethyl carbonate catalyzed by titanium oxide acetylaceto-
nate catalyst. Chin J Catal 33(4):601–604. https://doi.org/10.1016/
s1872-2067(11)60381-1
Wang SL, Zhang YZ, Chen T, Wang GY (2015b) Preparation and cat-
alytic property of MoO3/SiO2 for disproportionation of methyl
phenyl carbonate to diphenyl carbonate. J Mol Catal A Chem
398:248–254. https://doi.org/10.1016/j.molcata.2014.11.014
Zhang YZ, Wang SL, Xiao ZL, Chen T, Wang GY (2016) Mesoporous
silica-anchored organotin as heterogeneous catalyst for the trans-
esterification of dimethyl carbonate with phenol. Res Chem
Intermed 42(9):7213–7222. https://doi.org/10.1007/s1116
4-016-2530-y
Zhou WQ, Zhao XQ, Wang YJ, Zhang JY (2004) Synthesis of diphe-
nyl carbonate by transesterifcation over lead and zinc double
oxide catalyst. Appl Catal A Gen 260(1):19–24. https://doi.
org/10.1016/j.apcata.2003.10.024
Mei FM, Pei Z, Li GX (2004) The transesterifcation of dimethyl car-
bonate with phenol over Mg–Al-hydrotalcite catalyst. Org Process
Res Dev 8(3):372–375. https://doi.org/10.1021/op0302098
Murayama T, Hayashi T, Kanega R, Yamanaka I (2012) Phosgene-
free method for diphenyl carbonate synthesis at the Pd-0/Ketjen-
black anode. J Phys Chem C 116(19):10607–10616. https://doi.
org/10.1021/jp300809s
Zhou X, Ge X, Tang RZ, Chen T, Wang GY (2014) Preparation and
catalytic property of modifed multi-walled carbon nanotube-
supported TiO2 for the transesterifcation of dimethyl carbonate
with phenol. Chin J Catal 35(4):481–489. https://doi.org/10.1016/
s1872-2067(14)60010-3
1 3