Volume 10, Issue 4, 2020, 5760 - 5764 ISSN 2069-5837 … · 2020. 4. 1. · acid (LA, AR), ethanol...
Transcript of Volume 10, Issue 4, 2020, 5760 - 5764 ISSN 2069-5837 … · 2020. 4. 1. · acid (LA, AR), ethanol...
Page | 5760
Catalytic production of biodiesel from esterification of lauric acid over a solid acid hybrid
Qiuyun Zhang 1,*
, Li Zhao 1, Taoli Deng
1, , Yutao Zhang
2, , Hu Li
3,4*
1 School of Chemistry and Chemical Engineering, Anshun University, Anshun, Guizhou, China 2 School of Resource and Environmental Engineering, Anshun University, Anshun, Guizhou, China 3 College of Engineering, Nanjing Agricultural University, Nanjing 210031, China 4 State-Local Joint Engineering Lab for Comprehensive Utilization of Biomass, Guizhou University, Guiyang 550025, China
*corresponding author e-mail addresses: [email protected] | Scopus ID 57203621185
[email protected] | Scopus ID 35933455300
ABSTRACT
In this study, an acidic heterogeneous hybrid (H4SiW/MIL-100(Fe)) was synthesized by incorporation of 12-silicotungstic acid (H4SiW)
into a porous metal-organic framework MIL-100(Fe) via a simple hydrothermal method. The hybrid was characterized by XRD, FT-IR,
SEM, and TGA, and those characterization analyses showed the H4SiW/MIL-100(Fe) hybrid was successfully synthesized and exhibited
good structural stability. The catalytic activity of H4SiW/MIL-100(Fe) was determined by esterification of lauric acid (LA) to produce
biodiesel. Optimum LA conversion of 80.3% was achieved over the H4SiW/MIL-100(Fe) hybrid under the reaction conditions of lauric
acid/methanol mole ratio of 1/12, 0.3 g catalyst dosage at 160°C for 3 h. After being repeatedly used for eleven cycles, the lauric acid
conversion of the catalyst could still maintain with >60%, which indicates potential cost-saving and affordable biodiesel synthesis
possibilities.
Keywords: 12-Silicotungstic acid; MIL-100(Fe); Immobilized; Lauric acid; Esterification; Biodiesel.
1. INTRODUCTION
In recent years, decreasing fossils fuels and increasing
greenhouse gas emissions led to global warming, which has
encouraged scientists to devote a search for alternative fuels that
can create less pollution and are more eco-friendly [1-3].
Biodiesel, as a promising eco-friendly alternative fuel, has high
potential to be a substitute for fossils fuels, and it can be produced
by either esterification of free fatty acids or transesterification of
triglycerides with short-chain alcohols in the presence of an acidic
catalyst [4]. In general, liquid acid (sulfuric acid, hydrochloric
acid, and phosphoric acid, etc.), which is relatively cheap, exhibits
high catalytic activity. However, it will lead to catalyst recycling
difficulties, corrosion of the equipment, and a large amount of
acidity wastewater [5]. To avoid the above problems, varieties of
solid acid catalysts can be used as more promising substitutes [6-
10].
Recently, due to its strong Brønsted acidity properties and
high catalytic activity, heteropolyacids with Keggin-type structure
have been widely studied for acid catalysis and catalytic synthesis
[11-13]. However, the heteropolyacids are unsuitable for
esterification due to their high solubility in a polar solvent, and
they also suffer from the drawback of the low specific surface area
[14]. Thus, great efforts have made to the development of
supported heteropolyacids, such as mesoporous H4SiW12O40-SiO2
[15], H3PW12O40/K10 [16], and (PW11)3/MCM-41 [17].
Currently, the heteropolyacids have been introduced to
metal-organic frameworks (MOFs), due to the extremely large
surface areas and appropriate porous pores of MOFs. Wee et al.
[18] reported that an original synthesis approach to prepare
Cu3(BTC)2 encapsulated Keggin HPW, which showed higher
catalytic activity in the esterification. Xie et al. [19] also
demonstrated that the encapsulation of Cs2.5H0.5PW12O40 in the
cages of UiO-66, and the catalyst demonstrate excellent catalytic
activities for the production of low-calorie structured lipids. Our
group has also studied the production of biodiesel over HPMo/Cu-
BTC and HSiW/UiO-66 hybrids, and the obtained results revealed
these hybrids exhibited good catalytic activity [20-21].
However, no work has been done so far for the production
of methyl laurate over a heterogeneous and stable acidic
H4SiW/MIL-100(Fe) hybrid catalyst in the literature.
In the present investigation, the encapsulation of H4SiW in
the cages of MIL-100(Fe) was developed and its catalytic ability
was tested for the esterification of lauric acid to methyl laurate,
biodiesel component. The characterization of the synthesized
hybrid was done using XRD, FTIR, SEM, and TGA. Further, the
stability of the catalyst had also been studied by reutilization tests.
2. MATERIALS AND METHODS
2.1. Materials.
Iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O, AR), lauric
acid (LA, AR), ethanol (AR), and methanol (AR) were obtained
from Sinopharm Chemical Reagent Co., Ltd. Silicotungstic acid
(H4SiW12O40·nH2O, H4SiW, AR), and 1,3,5-benzene tricarboxylic
acid (H3-BTC, AR) were obtained from Shanghai Aladdin
Industrial Inc. All the purchased chemicals were used without
further purification.
2.2. Synthesis of samples.
H4SiW/MIL-100(Fe) was synthesized by a hydrothermal
technique according to the following steps [21]: Fe(NO3)3·9H2O
(1.21 g) and H4SiW (1.0 g) were dissolved into 18 mL distilled
water, and H3-BTC (0.63 g) was then added into the above
mixture with stirring magnetically at room temperature for 1 h.
Volume 10, Issue 4, 2020, 5760 - 5764 ISSN 2069-5837
Open Access Journal Received: 10.03.2020 / Revised: 26.03.2020 / Accepted: 28.03.2020 / Published on-line: 01.04.2020
Original Research Article
Biointerface Research in Applied Chemistry www.BiointerfaceResearch.com
https://doi.org/10.33263/BRIAC104.760764
Catalytic production of biodiesel from esterification of lauric acid over a solid acid hybrid
Page | 5761
The mixture solution was put in 50 mL Teflon liner
autoclave, closed in an autoclave and heated in an oven for 6 h at
120 °C. After cooling, the resulting solid was centrifuged, and
washed with ethanol many times. Then, the solid was further
stirred for 3 h several times in a hot ethanol bath, and dried for 24
h in an oven at 120 °C. MIL-100(Fe) was also synthesized to
follow the same method in the absence of H4SiW.
2.3. Characterizations.
The X-ray powder diffraction (XRD) patterns of the
samples were recorded by a D8 ADVANCE (Germany) using
CuKĮ (1.5406 Å) radiation. Infrared spectra were recorded on a
PerkinElmer spectrum100 Fourier-transform infrared (FTIR)
spectrometer in the range of 400-4000 cm-1. The morphologies of
as-synthesized catalysts were observed by a Hitachi S-4800 field
emission scanning electron microscopy (SEM) with an
acceleration voltage of 2.0 kV. Thermogravimetric (TG) analysis
was carried out in a NETZSCH/STA 409 PC Luxx simultaneous
thermal analyzer.
2.4. Esterification experiment.
LA, methanol, and required amount of as-prepared
catalysts were loaded into the stainless steel autoclave.
Subsequently, the reaction system was heated to the specified
temperature. After reaction for the designated period, the catalysts
were centrifuged, and the liquid mixture was vaporized to remove
the excess methanol combined with the water produced. The
conversion of LA was calculated by titration according to the acid
value before and after the reaction, and the acid value was
calculated by ISO 660-2009 standard method.
3. RESULTS
3.1 Characterization.
The powder XRD patterns of the H4SiW, MIL-100(Fe),
and H4SiW/MIL-100(Fe) samples are presented in Figure 1. The
XRD pattern of the MIL-100(Fe) shows a broad diffraction peak
within 10° to 40° was attributed to a low level of crystallinity, and
the trend was the same as those reported in the literature [22].
Moreover, Keggin H4SiW anion diffraction peaks were
observed in a halo between 5° and 60° (2 theta) [23]. When the
synthesis was performed in the presence of H4SiW, a similar
phenomenon was also observed between MIL-100(Fe) and
H4SiW/MIL-100(Fe). More specifically, the XRD pattern of
H4SiW could not be detected from that of H4SiW/MIL-100(Fe),
this probably because of the H4SiW was uniformly distributed into
the MIL-100(Fe) framework. Thus, it can be seen that the
H4SiW/MIL-100(Fe) hybrid was successfully synthesized.
Figure 1. XRD patterns of H4SiW, MIL-100(Fe), and H4SiW/MIL-
100(Fe) catalysts.
The FT-IR spectra of the H4SiW, MIL-100(Fe), and
H4SiW/MIL-100(Fe) catalysts are shown in Figure 2. For the pure
H4SiW, The peaks at 804, 884, 927, and 980 cm-1 represent the
Keggin structure of H4SiW [24]. For MIL-100(Fe), the FTIR
spectrum observed in the region of 1636 and 1585 cm-1 is due to
the splitting of the coordinated -CO2- vibrations, FT-IR bands at
around 759 cm-1 and 710 cm-1 are due to the presence of C-CO2
bond. The FTIR peaks detected at 1454 cm-1 and 1383 cm-1
represent the existence of -COOFe metallic esters, and a similar
result was observed by other authors [25]. In strong contrast to
H4SiW and MIL-100(Fe) sample, the absorption peaks for
H4SiW/MIL-100(Fe) hybrids are also seen at 804, 884, 927, and
980 cm-1, which correspond to the W-Oe-W, W-Oc-W, Si-O,
W=O, respectively, suggesting that the pristine H4SiW were well
maintained in the materials synthesis process. These results
indicated that the pristine H4SiW molecules were introduced into
the MIL-100(Fe) matrix successfully.
Figure 2. FTIR spectra of H4SiW, MIL-100(Fe), H4SiW/MIL-100(Fe),
and H4SiW/MIL-100(Fe) after 11 reaction cycles.
SEM was recorded to observe the morphology of the
prepared hybrids; Hence, the morphology of the prepared
H4SiW/MIL-100(Fe) hybrids is studied using SEM and the results
are shown in Figure 3a-c.
The SEM image of MIL-100(Fe) shows many nearly-cube
and nearly-spherical particles with an average size of about 400-
500 nm can be found (Figure 3b). In accordance with previous
reports, similar morphologies have also been observed [26]. As
shown in Figure 3c, the SEM image of the H4SiW/MIL-100(Fe)
sample also demonstrates that a cube-like structure with the size of
about 300 nm, and the surface of these particles are relatively
smooth, suggesting that the H4SiW molecules are pretty uniformly
distributed on the MIL-100(Fe) crystals.
Meanwhile, no morphology difference was observed after
the introduction of the H4SiW species, which fits the XRD
Qiuyun Zhang, Li Zhao, Taoli Deng, Yutao Zhang, Hu Li
Page | 5762
analysis well, and it could be also seen that the frame structure of
MIL-100(Fe) was stable in the synthesis process.
Figure 3. SEM images of (a) H4SiW, (b) MIL-100(Fe), and (c)
H4SiW/MIL-100(Fe) catalysts.
Figure 4 shows the result of TGA analysis of H4SiW/MIL-
100(Fe) hybrid. In the temperature range of 40-300 °C, a 15%
weight loss was observed, which was due to the loss of water
molecules and solvent molecules solvent inner/outer the surfaces
of the catalyst. The second mass loss (20%) occurred in the range
of 300-700°C, which may be related to the decomposition of the
frameworks. Thus, the synthesized H4SiW/MIL-100(Fe) hybrid
shows greater stability up to 300 °C, and can be employed as a
solid acid catalyst for LA esterification.
Figure 4. TGA thermogram of H4SiW/MIL-100(Fe) hybrid.
3.2. Material performance.
Figure 5a shows the time effect on the esterification
reaction of biodiesel production from LA in the range of 0.5-5 h.
The reaction was performed at 160°C, 0.3 g of catalyst, and LA-
methanol mole ratio 1:12. In half an hour of reaction, the
H4SiW/MIL-100(Fe) hybrid was not effective because the LA
conversion was only 22.6%. With increasing reaction time in the
range of 0.5 to 3 h, LA conversion was also increased from 22.6%
to 80.3%, respectively. However, further increasing reaction time
resulted in the decrease of LA conversion, which may be probably
due to the addition of time causing the esterification reaction
reversion back by hydrolysis of methyl laurate to LA. Shuit et al.
[27] also reported a similar trend in their study. Hence, in the
present study, 3 h was set as the optimum reaction time.
Different LA to methanol molar ratios were used in
studying the influence of methanol content in the esterification of
LA, as presented in Figure 5b. The reaction was performed at
160°C, 0.3 g of catalyst after 3 h reaction. It was observed that the
conversion of LA increased gradually from 1:4 to 1:12. The
maximum LA conversion (80.3%) was obtained for the LA to
methanol ratio of 1:12. However, a significant change in LA
conversion was observed with the excess amount of methanol.
When the LA to methanol ratio was 1:16, the LA conversion was
decreased to 71.0%. This result may be due to the dissolution of
LA, intermediates and methyl laurate product, and the reduced
hybrid catalyst effect by filling its porous structure. Similar work
was performed by Sanger et al. [28] Thus, 1:12 LA to methanol
molar ratio was determined as the optimum for esterification of
LA.
The effect of reaction temperature from 100 to 180°C on
the conversion of LA was investigated and shown in Figure 5c.
The impact of reaction temperature was investigated between 100
and 180°C for 0.3 g of catalyst and LA-methanol mole ratio 1:12
after 3 h reaction. As the reaction temperature raising from 100 to
160°C resulted in an increase in LA conversion from 40.2% to
80.3%, respectively.
Figure. 5 Effect of (a) reaction time, (b) LA-methanol mole ratio, (c)
reaction temperature, and catalyst dosage (d) on LA conversion using
H4SiW/MIL-100(Fe) hybrids.
However, with a further increment of temperature from 160
to 180 °C, there was no major change in LA conversion,
indicating that the reaction had reached equilibrium [29].
Catalytic production of biodiesel from esterification of lauric acid over a solid acid hybrid
Page | 5763
Therefore, in this work, 160°C was the optimal reaction
temperature for the reaction.
The effect of H4SiW/MIL-100(Fe) catalyst weight on the
esterification reaction also was examined. The catalyst weight was
varied from 0.03 to 0.36 g by LA-methanol mole ratio 1:12 and
the reaction was carried out at a temperature of 160°C for 3 h. The
obtained results are shown in Figure 5d.
It was observed that the LA conversion increased as the
catalyst amount was increased. When the catalyst weight was 0.3
g, the LA conversion of 80.3% was obtained. However, it must be
noted that the excess amount of the catalyst can result in the
increased viscosity of the mixture and increased separation cost
[30]. 0.3 g is thus selected as the appropriate catalyst weight for
the present esterification reaction over H4SiW/MIL-100(Fe)
hybrids.
On the basis of the above experimental observation,
optimum conditions for esterification of LA were determined as
LA-methanol mole ratio of 1:12, 4 h for completion of the
reaction, temperature at 160°C, and catalyst weight of 0.3 g.
3.3. Stability and reusability.
An eleven-times recycling ability experiment was
performed to probe the reusability of H4SiW/MIL-100(Fe) hybrid.
The used catalyst was treated by centrifugation, washed two times
using methanol, and subsequently used for the next turn of methyl
laurate production. The results are presented in Figure 6. About
17% reduction was observed in the activity of the H4SiW/MIL-
100(Fe) catalyst compared to the fresh catalyst after eleven cycles,
and founded that the LA conversion maintained with >60%. It
may be the reason for the deposition of the LA and products onto
the surface of catalyst, and the loss of catalyst during each
separation process resulted in reduction of active sites. To
examine the structure of catalyst, FT-IR analyses of fresh and used
catalysts were investigated (Figure 2).
It was seen that a series of characteristic peaks were
observed in the range of 980-904 cm-1 and 1636-1383 cm-1 for the
fresh and eleventh cycle catalysts, respectively. These
characteristic peaks were assigned to the Keggin structure and
MIL-100(Fe) framework structure. It can be deduced that the
structure of the H4SiW/MIL-100(Fe) hybrid had essentially
retained after eleven reaction cycles.
Figure 6. H4SiW/MIL-100(Fe) hybrid reusability versus LA conversi on
of biodiesel synthesis. (Reaction conditions: LA-methanol molar ratio of
1:12, catalyst weight of 0.3 g, 160 °C, and 3 h).
4. CONCLUSIONS
In summary, a highly catalytically active H4SiW/MIL-
100(Fe) hybrid was prepared by wrapping H4SiW molecules onto
MIL-100(Fe) through a simple hydrothermal method. The
H4SiW/MIL-100(Fe) catalyst displayed excellent catalytic activity
for biodiesel production, which could be attributed to its strong
acidic sites and good stability. Meanwhile, H4SiW/MIL-100(Fe)
had a long lifetime and maintained activity at >60% LA
conversion even after being repeatedly used for 11 times, offering
the efficient encapsulated heteropolyacid catalyst for the
production of biodiesel.
5. REFERENCES
1. Abukhadra, M.R.; Salam, M.A.; Ibrahim, S.M. Insight into the
catalytic conversion of palm oil into biodiesel using Na+/K+ trapped
muscovite/phillipsite composite as a novel catalyst: Effect of ultrasonic
irradiation and mechanism. Renewable and Sustainable Energy Reviews
2019, 115, https://doi.org/10.1016/j.rser.2019.109346.
2. Chua, S.Y.; Periasamy, L.A.P.; Goh, C.M.H.; Tan, Y.H.; Mubarak,
N.M.; Kansedo, J.; Khalid, M.; Walvekar, R.; Abdullah, E.C. Biodiesel
synthesis using natural solid catalyst derived from biomass waste-A
review. Journal of Industrial and Engineering Chemistry 2020, 81, 41-
60, https://doi.org/10.1016/j.jiec.2019.09.022.
3. Li. X.X.; Zhang, L.L.; Wang, S.S.; Wu, Y.L. Recent advances in
aqueous-phase catalytic conversions of biomass platform chemicals
over heterogeneous catalysts. Frontiers in Chemistry 2020, 7, 948,
https://doi.org/10.3389/fchem.2019.00948.
4. Rashid, U.; Ahmad, J.; Ibrahim, M. L.; Nisar, J.; Hanif, M.A.; Shean,
T.Y.C. Single-pot synthess of biodiesel using efficient sulfonated-
derived tea waste-heterogeneous catalyst. Materials 2019, 12, 2293,
https://doi.org/10.3390/ma12142293.
5. Gomes, G.J.; Dal Pozzo, D.M.; Zalazar, M.F.; Costa, M.B.; Arroyo,
P.A.; Bittencourt, P.R.S. Oleic acid esterification catalyzed by zeolite Y
‑model of the biomass conversion. Topics in Catalysis 2019, 62, 874-
883, https://doi.org/10.1007/s11244-019-01172-3.
6. Li, H.; Yang, S. Catalytic transformation of fructose and sucrose to
HMF with proline-derived ionic liquids under mild conditions.
International Journal of Chemical Engineering 2014, 2014, 1-7,
https://doi.org/10.1155/2014/978708.
7. Xu, Y.F.; Long, J.X.; Zhao, W.F.; Li, H.; Yang, S. Efficient transfer
hydrogenation of nitro compounds to amines enabled by mesoporous N-
stabilized Co-Zn/C. Frontiers in Chemistry 2019, 7, 590,
https://doi.org/10.3389/fchem.2019.00590.
8. Zhang, Q.Y.; Ling, D.; Lei, D.D.; Wang, J.L.; Liu, X.F.; Zhang, Y.
T.; Ma, P.H. Green and facile synthesis of metal-organic framework
Cu-BTC-supported Sn (II)-substituted Keggin heteropoly composites as
an esterification nanocatalyst for biodiesel production. Frontiers in
Chemistry 2020, 8, 129, https://doi.org/10.3389/fchem.2020.00129.
9. Xie, W.L.; Wan, F. Immobilization of polyoxometalate-based
sulfonated ionic liquids on UiO-66-2COOH metal-organic frameworks
for biodiesel production via one-pot transesterification-esterification of
acidic vegetable oils. Chemical Engineering Journal 2019, 365, 40-50,
https://doi.org/10.1016/j.cej.2019.02.016.
10. Li, H.; Li, Y.; Fang, Z.; Smith, R.L. Efficient catalytic transfer
hydrogenation of biomass-based furfural to furfuryl alcohol with
recycable Hf-phenylphosphonate nanohybrids. Catalysis Today 2019,
319, 84-92, https://doi.org/10.1016/j.cattod.2018.04.056.
11. da Conceiçao, L.R.V.; Carneiro, L.M.; Giordani, D.S.; de Castro,
H.F. Synthesis of biodiesel from macaw palm oil using mesoporous
solid catalyst comprising 12-molybdophosphoric acid and niobia.
Renewable Energy 2017, 113, 119-128,
https://doi.org/10.1016/j.renene.2017.05.080.
12. Ghubayra, R.; Nuttall, C.; Hodgkiss, S.; Craven, M.; Kozhevnikova,
E.F.; Kozhevnikov, I.V. Oxidative desulfurization of model diesel fuel
catalyzed by carbon-supported heteropoly acids. Applied Catalysis
B: Environmental 2019, 253, 309-316,
https://doi.org/10.1016/j.apcatb.2019.04.063.
13. Zhang, Q.Y.; Yue, C.Y.; Pu, Q.L.; Yang, T.T.; Wu, Z.F.; Zhang,
Y.T. Facile synthesis of ferric-modified phosphomolybdic acid
composite catalysts for biodiesel production with response surface
Qiuyun Zhang, Li Zhao, Taoli Deng, Yutao Zhang, Hu Li
Page | 5764
optimization. ACS Omega 2019, 4, 9041-9048,
https://doi.org/10.1021/acsomega.9b01037.
14. Ekinci, E.K.; Oktar, N. Production of value-added chemicals from
esterification of waste glycerol over MCM-41 supported catalysts.
Green Processing and Synthesis 2019, 8, 128-134,
https://doi.org/10.1515/gps-2018-0034.
15. Yan, K.; Wu, G.S.; Wen, J.L.; Chen, A.C. One-step synthesis of
mesoporous H4SiW12O40-SiO2 catalysts for the production of methyl
and ethyl levulinate biodiesel. Catalysis Communications 2013, 34, 58-
63, https://doi.org/10.1016/j.catcom.2013.01.010.
16. Nandiwale, K.Y.; Bokade, V.V. Process optimization by response
surface methodology and kinetic modeling for synthesis of methyl
oleate biodiesel over H3PW12O40 anchored montmorillonite K10.
Industrial and Engineering Chemistry Research 2014, 53, 18690-
18698, https://doi.org/10.1021/ie500672v.
17. Singh, S.; Patel, A. Mono lacunary phosphotungstate anchored to
MCM-41 as recyclable catalyst for biodiesel production via
transesterification of waste cooking oil. Fuel 2015, 159, 720-727,
https://doi.org/10.1016/j.fuel.2015.07.004.
18. Wee, L.H.; Janssens, N.; Bajpe, S.R.; Kirschhock, C.E.A.; Martens,
J.A. Heteropolyacid encapsulated in Cu3(BTC)2 nanocrystals: An
effective esterification catalyst. Catalysis Today 2011, 171, 275-280,
https://doi.org/10.1016/j.cattod.2011.03.017.
19. Xie, W.L.; Yang, X.L.; Hu, P.T. Cs2.5H0.5PW12O40 encapsulated in
metal-organic framework UiO-66 as heterogeneous catalysts for
acidolysis of soybean oil. Catalysis Letters 2017, 147, 2772-2782,
https://doi.org/10.1007/s10562-017-2189-z.
20. Zhang, Q.Y.; Yue, C.Y.; Ao, L.F.; Lei, D.D.; Ling, D.; Yang, D.;
Zhang, Y.T. Facile one-pot synthesis of Cu-BTC metal-organic
frameworks supported Keggin phosphomolybdic acid for esterification
reactions. Energy Sources, Part A: Recovery, Utilization, and
Environmental Effects 2019, 1-12,
https://doi.org/10.1080/15567036.2019.1651794.
21. Zhang, Q.Y.; Yang, T.T.; Liu, X.F.; Yue, C.Y.; Ao, L.F.; Deng, T.
L.; Zhang, Y.T. Heteropoly acid-encapsulated metal-organic framework
as a stable and highly efficient nanocatalyst for esterification reaction.
RSC Advances 2019, 9, 16357-16365,
https://doi.org/10.1039/C9RA03209F.
22. Yang, X.P.; Guo, X.X.; Zhang, C.H.; Yang, Y.; Li, Y.W. Large
scale halogen-free synthesis of metal-organic framework material Fe-
MIL-100. Chinese Journal of Materials Research 2017, 31, 569-575,
https://doi.org/10.11901/1005.3093.2016.563.
23. Chaves, D.M.; Ferreira, S.O.; da Silva, R.C.; Natalino, R.; da Silva,
M.J. Glycerol esterification over Sn(II)-exchanged Keggin heteropoly
salt catalysts: Effect of thermal treatment temperature.
Energy and Fuels 2019, 33, 7705-7716,
https://doi.org/10.1021/acs.energyfuels.9b01583.
24. da Silva, M.J.; de Andrade Leles, L.C.; Ferreira, S.O.; da Silva,
R.C.; de Viveiros, V.K.; Chaves, D.M.; Pinheiro, P.F. A rare carbon
skeletal oxidative rearrangement of camphene catalyzed by Al-
exchanged Keggin heteropolyacid salts. ChemistrySelect 2019, 4, 7665-
7672, https://doi.org/10.1002/slct.201901025.
25. Yang, Y.J.; Bai, Y.; Zhao, F.Q.; Yao, E.G.; Yi, J.H.; Xuan, C.L.;
Chen, S.P. Effects of metal organic framework Fe-BTC on the thermal
decomposition of ammonium perchlorate. RSC Advances 2016, 6,
67308-67314, https://doi.org/10.1039/C6RA12634K.
26. Hu, P.F.; Chen, C.C.; Wang, Y.F.; Pan, L.; Lu, C.H. Room-
temperature self-assembled preparation of porous ZnFe2O4/MIL-
100(Fe) nanocomposites and their visible-light derived photocatalytic
properties. ChemistrySelect 2019, 4, 9703-9709,
https://doi.org/10.1002/slct.201902246.
27. Shuit, S.H.; Tan, S.H. Biodiesel production via esterification of
palm fatty acid distillate using sulphonated multi-walled carbon
nanotubes as a solid acid catalyst: process study, catalyst reusability and
kinetic study. BioEnergy Research 2015, 8, 605-617,
https://doi.org/10.1007/s12155-014-9545-2.
28. Sanger, S.K.; Syazwani, O.N.; Ahmad Farabi, M.S.; Razali, S.M.;
Shobhana, G.; Teo, S.H.; Taufiq-Yap, Y.H. Effective biodiesel
synthesis from palm fatty acid distillate (PFAD) using carbon-based
solid acid catalyst derived glycerol. Renewable Energy 2019, 142, 658-
667, https://doi.org/10.1016/j.renene.2019.04.118.
29. Teo, S.H.; Islam, A.; Chan, E.S.; Thomas Choong, S.Y.; Alharthi,
N.H.; Taufiq-Yap, Y.H.; Awual, M.R. Efficient biodiesel production
from Jatropha curcus using CaSO4/Fe2O3-SiO2 core-shell magnetic
nanoparticles. Journal of Cleaner Production 2019, 208, 816-826,
https://doi.org/10.1016/j.jclepro.2018.10.107.
30. Peng, Y.P.; Amesho, K.; Chen, C.E.; Jhang, S.R.; Chou, F.C.; Lin,
Y.C. Optimization of biodiesel production from waste cooking oil using
waste eggshell as a base catalyst under a microwave heating system.
Catalysts 2018, 8, 81, https://doi.org/10.3390/catal8020081.
6. ACKNOWLEDGEMENTS
This research was supported by the Guizhou Science and Technology Foundation ([2020]1Y054), the Academician Workstation
of Guizhou Science and Technology Plan (Guizhou S&T Cooperation Platform Talents [2016]5602), the Science and Technology
Cooperation Project of Guizhou Province (LH [2017]7059), the Key Support Discipline in Agricultural Resources and Environment of
Anshun University, and the Creative Research Groups Support Program of Guizhou Education Department (KY [2017]049).
© 2020 by the authors. This article is an open access article distributed under the terms and conditions of the
Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).