Catalytic conversion of fructose to 1,3-dihydroxyacetone under mild conditions

Article abstract of DOI:10.1016/j.catcom.2020.106098

A novel zwitterionic catalyst containing imidazole, carboxyl and amino functional groups was synthesized to catalyze the retro-aldol condensation of fructose. The catalyst displayed efficiently catalytic activity for the conversion of fructose to 1,3-dihydroxyacetone (DHA). The yield of DHA and selectivity of DHA achieved 27.9percent and 46.5percent after reaction 2 h, respectively, at pH 9.5, 85 °C. A possible catalytic mechanism was suggested. The charged functional groups on the catalyst exhibited synergistic effect and played role in electron induction and proton transfer, which leaded to a good selectivity of DHA in the conversion of fructose under mild conditions.

Full text of DOI:10.1016/j.catcom.2020.106098

Journal Pre-proof
Catalytic conversion of fructose to 1,3-dihydroxyacetone under
mild conditions
Jing Lv, Xiang-Guang Meng, Hong Huang, Fei Wang, Wen-Wang
Yu, Yan-Yan Wu
PII:
S1566-7367(20)30174-6
DOI:
https://doi.org/10.1016/j.catcom.2020.106098
CATCOM 106098
Reference:
To appear in:
Catalysis Communications
Received date:
Revised date:
Accepted date:
7 March 2020
23 June 2020
24 June 2020
Please cite this article as: J. Lv, X.-G. Meng, H. Huang, et al., Catalytic conversion
of fructose to 1,3-dihydroxyacetone under mild conditions, Catalysis Communications
(2019), https://doi.org/10.1016/j.catcom.2020.106098
This is a PDF file of an article that has undergone enhancements after acceptance, such
as the addition of a cover page and metadata, and formatting for readability, but it is
not yet the definitive version of record. This version will undergo additional copyediting,
typesetting and review before it is published in its final form, but we are providing this
version to give early visibility of the article. Please note that, during the production
process, errors may be discovered which could affect the content, and all legal disclaimers
that apply to the journal pertain.
© 2019 Published by Elsevier.

Journal Pre-proof
Catalytic Conversion of Fructose to 1,3-Dihydroxyacetone
Under Mild Conditions
Jing Lv, Xiang-Guang Meng,* Hong Huang, Fei Wang, Wen-Wang Yu and Yan-Yan Wu
Key Laboratory of Green Chemistry and Technology, College of Chemistry, Sichuan
University, Chengdu 610064 (P.R. China)
*Corresponding author
E-mail address: mengxgchem@163.com
Abstract
A novel zwitterionic catalyst containing imidazole, carboxyl and amino
functional groups was synthesized to catalyze the retro-aldol condensation of fructose.
The catalyst displayed efficiently catalytic activity for the conversion of fructose to
1,3-dihydroxyacetone (DHA). The yield of DHA and selectivity of DHA achieved
27.9 % and 46.5 % after reaction 2 h, respectively, at pH 9.5, 85 °C. A possible
catalytic mechanism was suggested. The charged functional groups on the catalyst
exhibited synergistic effect and played role in electron induction and proton transfer,
which leaded to a good selectivity of DHA in the conversion of fructose under mild
conditions.
Keywords: fructose; 1,3-dihydroxyacetone; retro-aldol condensation reaction;
catalysis; aldolase; mechanism
1

Journal Pre-proof
1. Introduction
Biomass is considered as an alternative to fossil resources due to its renewable
and CO2 reutilization. Transforming renewable biomass into valuable chemical
[1,2]
feedstock is a promising path to a more sustainable chemical industry
.
1,3-Dihydroxyacetone is an important chemical and biochemical raw material. It is
widely used in medicine, pesticide synthesis intermediates and food additives. DHA is
also reported to produce lactic acid and alkyl lactates using Sn-Beta, Sn-MFI, and
Sn-MCM-41 catalysts [3,4]. Since the microbial formation of DHA from glycerol was
discovered by Bertrand [5], many investigators have reported the bioconversion of
glycerol to DHA by fermentation [6,7]. Despite microbial fermentation processes can
provide high selectivity to DHA, the fermentation route is limited by low reaction
rates, low productivity and high production cost. Catalytic oxidation of glycerol to
produce DHA is a common chemical method [8]. Xu et al reported the oxidation of
glycerol catalyzed by an Au/CuO nanoparticle and achieved 50-80 % DHA yields at
high O2 pressure (10-30 bar) [9]. Ning et al reported the oxidation of glycerol by O2 to
DHA catalyzed by Pt-Sb supported on N-doped carbon nanotubes with a selectivity of
38.1 % and 50.9 % conversion for reaction 6 h at 60 °C [10]. Wu et al reported a Cr (III)
[11]
complex catalyzed oxidation of glycerol to DHA and 50.7 % yield was obtained
.
Recently, Liu et al developed a photoelectrochemical nanoporous BiVO4 for the
oxidation of glycerol to DHA with 51 % selectivity [12]. The direct production of DHA
from fructose, a biomass product, is an important economic and practical alternative.
Retro-aldol condensation reaction has been considered as the limiting step in the
processes of converting fructose into DHA [13]. Unfortunately, it is relatively difficult
to perform the retro-aldol reaction effectively. By now, most reactions of the cleavage
2

Journal Pre-proof
of fructose involving the retro-aldol step were conducted at high temperature (≥
120 °C) owing to the lack of efficient catalyst [14,15]. However, low thermal stability of
DHA and inactivity of catalysts can cause a series of successive and parallel reactions
to form acids from fructose at high temperature [16-18]. And resulted in the chief
products lactic acid [19,20], levulinic acid [21,22], and esters [23,24], even only a minority of
DHA can be observed [25,26]. Therefore, to find a highly efficient catalyst on the
conversion of fructose to DHA is of fundamental and practical significance.
D-Fructose-1,6-bisphosphate aldolase (FBPA; EC 4.1.2.13) can catalyze the
reversible transformation of D-fructose 1,6-bisphosphate into dihydroxyacetone
phosphate and D-glyceraldehyde 3-phosphate under relatively mild conditions, thus
[27]
plays important role during glycolysis, gluconeogenesis, and the Calvin cycle
.
Glutamic acid, aspartic acid, histidine, tyrosine and arginine residues were commonly
found in the active site of aldolase [28,29], which play essential roles in proton transfer,
electrostatic interaction and the C-C bond rotation of fructose [30]. Despite of its high
activity and selectivity, natural enzyme is expensive and sensitive to environmental
conditions [31]
.
Here, we develop a new catalyst with carboxyl, amino, imidazole and phenol
groups, as illustrated in Fig. 1, which possesses positive and negative electrical sites
in aqueous solution and acts as a mimic aldolase. This catalyst exhibits efficiently
catalytic activity for the fragmentation of fructose to generate DHA. This is the first
example of converting fructose to DHA in good selectivity under mild conditions.
2. Experimental
2.1 Chemicals
Iminodiacetic acid, imidazole, pyruvaldehyde, glyceraldehyde, 4-imidazole
3

Journal Pre-proof
formaldehyde,
p-Cresol,
fructose,
glucose,
1,3-dihydroxyacetone
and
2,4-dimethylphenol were purchased from Adamas Company. Sodium hydroxide,
disodium hydrogen phosphate, trisodium phosphate and sodium dihydrogen
phosphate were purchased from Kelong reagent Company. All reagents used are
analytically pure.
2.2 Methods
The catalytic reaction was carried out in 20 ml thick-walled test tube heated in a
temperature-controlled water bath. In a typical experiment, 0.6485 g fructose and
0.0599 g catalyst were added into 18 ml 100 mM phosphate buffer solution. The
solution is filled with N2 for 30 minutes and then sealed at ambient temperature. The
reactor was placed in a water bath at desired temperature, and the solution was stirred
with a magnetic stirrer. After a certain reaction time, the reaction was stopped by
cooling the reactor in the cool water bath. A sample of 1ml was taken out from the
reaction solution and the concentrations of fructose and products were determined by
high-performance liquid chromatography using a sugar-D chromatographic column
equipped with RI and UV-vis detectors.
2.3 Synthesis of catalyst
The catalyst 2,2'-(((2-hydroxy-3,5-dimethylphenyl)-(1H-imidazol-4-yl)-methyl)
-azanediyl)-diacetic acid (HIDA) was synthesized as follows: 0.252 mol NaOH was
added to 140 ml H2O, subsequently 0.126 mol 2,4-dimethylphenol and 0.126 mol
2-imidazole formaldehyde were added to the solution and the mixture was stirred for
2 h at 40 ℃. Then 0.126 mol iminodiacetic acid was added into the solution and
stirred for 3h at 70 ℃. The solvent was acidized and removed by vacuum distillation,
and the product was obtained by recrystallizing in methanol. It was determined by
4

Journal Pre-proof
1
elemental analysis and H NMR. Elemental analysis: calcd for C16H18N3O5: C 57.65,
H 5.75, N 12.61 (%); found: C 56.76, H 5.66, N 12.02 (%). 1H NMR (400 MHz, D2O)
δ 9.49 (s, 1H), 7.32 (s, 1H), 6.94 (d, J = 3.6 Hz, 1H), 6.87 (d, J=1.2 Hz, 1H), 4.70 (s,
8H), 4.51 (s, 1H), 3.67 (s, 4H), 3.22 (s, 3H), 2.66 (s, 3H).
3. Results and Discussion
3.1 Comparison of Various Systems
The efficient cleavage of D-fructose-1,6-bisphosphate catalyzed by aldolase
provides us with an idea of selective transformation of fructose mildly. The functional
groups of the aldolase active site have become our focus. Herein, we synthesized a
catalyst with functional groups similar to those in the active site of aldolase, as
depicted in Fig. 1. Because of the existence of carboxyl, amine, imidazole and phenol,
the catalyst can donate and receive protons in aqueous solution. In this work, the
conditions of weak alkalinity and low temperature were focused on the conversion of
fructose. Many simple compounds with the above-mentioned functional groups were
concerned and their catalytic activities for the conversion of the retro-aldol reaction of
fructose to DHA were investigated and the results were listed in Table 1. From Table 1,
it can be found that only 12.3 % DHA formed after reacting 2 h at pH 9.5 and 85 °C in
the absence of any catalyst. In contrast, the simple functional compounds p-methyl
phenol, iminodiacetic acid and imidazole increased the conversion of fructose and
yield of DHA slightly, as well as yield of glucose. Interestingly, the multifunctional
compound HIDA consisting of carboxyl, amino, imidazole and phenol groups
displayed excellent catalytic performance for the retro-aldol condensation reaction of
fructose. The conversion of fructose was 60 % and the yield of DHA reached 27.9 %
in HIDA catalyzed system at pH 9.5 and 85°C for reaction 2 h. A good DHA
5

Journal Pre-proof
selectivity of 46.5 % was observed, which indicated good synergistic effect among
these functional groups. It can be further found that the conversion of fructose was
complex, the isomerization of fructose to glucose and dehydration of DHA to
pyruvaldehyde were also detected.
3.2 Effect of pH
In order to investigate the pH effect, the catalytic reaction was carried out in the
phosphate buffer solution at the pH range of 6.5-10, as illustrated in Fig. 2. From Fig.
2, it can be seen that in the presence of HIDA, the basicity of solution showed an
important effect on the reaction. The conversion of fructose raised rapidly with
increasing pH and reached 64.9 % at 85 °C for reaction 2 h. It can be further found
that the variations of products DHA, pyruvaldehyde and glucose, were different from
that of the conversion of fructose. We considered that DHA, pyruvaldehyde and
glucose may come from the products of retro-aldol reaction of fructose, dehydration
reaction of DHA and isomerization of fructose, respectively. For the retro-aldol
reaction of fructose, the yield of DHA increased slowly with increasing pH to 8.5.
Subsequently the yield increased rapidly in the range of pH 8.5 to 9.5 and up to a
maximum yield of 27.9 % with selectivity of 46.5 %. Then the yield decreased with
increasing pH. It was observed that the dehydration reaction of DHA increased
rapidly and the product pyruvaldehyde appeared in large quantity at pH > 9.5. As for
the isomerization of fructose to glucose, it was not obvious at pH < 8. Glucose
slightly increased at the pH range of 8 to 10, and the yield was between 10.1 % and
15.9 %. In the process of retro-aldol reaction of fructose, proton transfer, as well as
positive and negative electrical induction to fructose, is essential. In aqueous solution,
the groups imidazole, phenol and amino in catalyst can ionize proton and exist in two
6

Journal Pre-proof
forms of neutral and ionic. At pH > 9.5, the groups imidazole and phenol are in the
anionic forms and tertiary amine in the neutral form and hence it is difficult to supply
proton, which leads to the rate of formation of DHA lower than that of dehydration of
DHA.
3.3 Analysis of products in reaction process
In order to further explore the conversion of fructose, the concentrations of
fructose and products were detected at different reaction time, as shown in Fig. 3.
From Fig. 3, it can be seen that in the first 0.5 h, the catalytic reaction was rapid, the
conversion of fructose reached 37.2 % and yield of DHA reached 14.7 %, and then the
reaction proceeded smoothly. DHA was continuously generated with time, and
reached the maximum yield of 27.9 % after reaction 2 h, then dehydrated to
pyruvaldehyde. The yield of pyruvaldehyde increased slowly within 2 h and then
raised rapidly at 2-4 h, arrived 22.9 % after 4 hours. It can be also found that the
isomerization of fructose to glucose always accompanied, and the yield of glucose
raised steadily, reached 18.1 % after 4 hours. These observations indicated that in the
HIDA catalytic system, the conversion of fructose was complex, involving retro-aldol,
dehydration and isomerization.
3.4 Effect of Temperature
The energy of activation of the retro-aldol condensation reaction of fructose into
trioses was relatively large by the calculation [32], so the cleavage reactions of fructose
were usually carried out at high temperature (≥ 120 °C) [33,34]. In this work, the
temperature was in the range of 55 to 95 ℃, which was close to the optimum
temperature of natural Escherichia coli aldolase [35]. The effect of temperature on this
reaction was illustrated in Fig. 4. From Fig. 4, it can be seen that all reactions
7

Journal Pre-proof
accelerated with increasing temperature. High temperature promoted the conversion
of fructose and formation of products. In particular, the formation of DHA showed a
bell-shaped curve at 80-95 ℃, and a maximum yield of 27.9 % appeared at 85 ℃.
Further, it can be found that the dehydration reaction of DHA to pyruvaldehyde
obviously increased when the temperature was higher than 80 ℃, which resulted in no
further rises of DHA yield. Although further research is needed to get better results,
this is the first time we obtained high yield DHA in aqueous solution under mild
conditions.
3.5 Possible catalytic mechanism
In enzyme catalyzed retro-aldol reaction, the amino acid residues in the active
site play key roles in the electric effect, abstraction and transfer of proton in the
catalytic process [30]. In this work, the functional groups of the catalyst HIDA may
exhibit different role in retro-aldol reaction. The carboxyl exists in anionic form,
tertiary amine in cationic form, phenolic group and imidazole in both neutral and
anionic forms, respectively, in aqueous solution at pH 9.5. The proton abstraction is
facilitated by the anions phenoxy and imidazole, while cation tertiary amine may play
role in proton transfer. Acting as neutral phenolic and imidazole groups, the
abstraction and transfer of proton are closely related to the pKa of functional groups,
which was reflected in the pH effect of catalytic reaction, as shown in Fig. 2. The pKa
of phenol, imidazole and tertiary amino groups is in the range of 8.5 to 10.5, which
resulted in high yield of DHA at pH 8.5-10.
In addition, it is worth pointing out that electrical induction may play important
role in catalytic reaction. The electric field between the positive and negative groups
can induce the substrate atoms and promote the rotation of fructose chain, resulted in
8

Journal Pre-proof
the fragmentation of fructose to DHA or the isomerization of fructose to glucose. The
electrical effect can be also confirmed by the obvious decrease of the conversion of
fructose and the yields of products DHA and glucose through adding inorganic salts in
the aqueous solution as listed in Table S1. In order to further understand the catalytic
mechanism, the catalytic reaction was carried out in three buffer carbonate, tris
hydroxymethyl aminomethane (Tris) and phosphate, respectively. The yields of DHA
with reaction time were illustrated in Fig. 5. From Fig. 5, it can be seen that carbonate
and Tris buffer exhibit similar effect on the generation of DHA, while phosphate
buffer system can significantly improve the yield of DHA in 1-3 hours. The
promoting effect of phosphate may be derived from the electrical induction effect of
P+-O- and the convenient proton transfer due to the existence of four forms of
phosphate in aqueous solution. Based on the above analyses and experimental results,
a possible catalytic mechanism was proposed as shown in Scheme 1.
The catalytic mechanism of fructose to DHA may include the processes as
follows: ring-opening of fructose, rotation of C3-C4, cleavage of C3-C4 and the
formation of DHA. The ring-opening of fructose may be caused by the proton transfer
of the combining action of tertiary amine cation, neutral imidazole and phenoxy anion.
The electrostatically induced effect of positive and negative groups on fructose causes
the rotation of C3-C4. After this rotation, phenol anion is in a more favorable position
to abstract hydrogen proton from C3 to form intermediate 1. Proper rotation can
produce suitable spatial configuration, which seems to be very important for the
abstraction of proton. Consequently, the proton transfer takes place through the
exchange of the two N atoms of the imidazole group with the hydrogen proton, and to
generate the intermediate 2. The electrostatic induction of positive and negative
9

Journal Pre-proof
groups of the catalyst and the rearrangement of electrons further lead to the
fragmentation of fructose, which resulted in the formation of products DHA and
glyceraldehyde. It was noted that glyceraldehyde will easily isomerize to DHA under
this work’s conditions as showed in Table S2. This clarifies our observation that no
glyceraldehyde was detected in the reaction solution. It can be also found that
pyruvaldehyde, a highly valuable chemical, could also be obtained in high yield after
a long time.
Scheme 1. Proposed catalytic mechanism for the generation of DHA.
4. Conclusions
Aldolase is well known to have good activity for the fragmentation of D-fructose
1,6-bisphosphate into dihydroxyacetone phosphate and D-glyceraldehyde 3-phosphate.
In this study, a novel catalyst with key amino acid residues of aldolase was
synthesized as a mimic aldolase. The mimic aldolase system played efficiently
catalytic activity for the retro-aldol reaction of fructose into DHA in weakly alkaline
10

Journal Pre-proof
aqueous solution. The good selectivity 46.5 % of DHA was achieved after reacting 2
h. The functional groups phenoxy, carboxyl, imidazole and tertiary amino of HIDA
exhibited an obviously synergistic effect on the degradation of fructose into DHA.
The enhancement of catalytic efficiency in phosphate buffer and the reduction by
adding the inorganic salts were also observed. And glyceraldehyde will easily
isomerize to DHA under this work’s conditions. The electrical induction derives from
the positive and negative groups is an important promoting factor for the retro-aldol
reaction. The suitable pKa of groups phenol and imidazole on catalyst is beneficial to
the abstraction and transfer of protons under reaction conditions.
Acknowledgements
We gratefully acknowledge financial support from the Science&-Technology
Department of Sichuan Province Science Project (No. 2019YJ0104).
References
1. L. T. Mika, E. Csefalvay, A. Nemeth, Chem. Rev. 2017, 118, 505-613.
2. J. Zhang, Y. Wang, X. Du, Y. Qu, Bioresour. Technol. 2020, 122846.
3. C. M. Osmundsen, M. S. Holm, S. Dahl, E. Taarning, Proc. R. Soc. A. 2012, 468, 2000-2016.
4. K. D. Kim, Z. Wang, Y. Jiang, M. Hunger, J. Huang, Green Chem. 2019.
5. M. G. Bertrand, Bull. Soc. Chim. 1898, 3, 502-507.
6. P. K. Dikshit, G. J. Kharmawlong, V. S. Moholkar, Bioresour. Technol. 2018, 256, 302-311.
7. Z. C. Hu, Y. G. Zheng, Y. C. Shen, Bioresour. Technol. 2014, 102, 7177-7182.
8. Y. Wang, Y. Xiao, G. Xiao, Chin. J. Chem. Eng. 2019.
9. S. S. Liu, K. Q. Sun, B. Q. Xu, ACS Catal. 2014, 4, 2226-2230.
10. X. Ning, Y. Li, H. Yu, F. Peng, H. Wang, Y. Yang, J. Catal. 2016, 335, 95-104.
11. G. Wu, X. Wang, T. Jiang, Q. Lin, Catalysts. 2015, 5, 2039-2051.
12. D. Liu, J. C. Liu, W. Cai, J. Ma, H. B. Yang, H. Xiao, B. Liu, Nat. Commun. 2019, 101779.
11

Journal Pre-proof
13. M. Orazov, M. E. Davis, Proc. Natl. Acad. Sci. 2015, 112, 11777-11782.
14. F. H. Lyu, R. Bi, Y. H. Liu, W. S. Li, X. P. Zhou, Catal. Commun. 2014, 49, 78-81.
15. S. Tolborg, ChemSusChem. 2015, 8, 613-617.
16. W. Deng, P. Wang, B. Wang, Y. Wang, L. Yan, Y. Li, Y. Wang, Green Chem. 2018, 20,
735-744.
17. P. J. Deuss, K. Barta, J. G. De Vries, Catal. Sci. Technol. 2014, 4, 1174-1196.
18. Y. Wang, W. Deng, B. Wang, Q. Zhang, X. Wan, Z. Tang, Nat. Commun. 2013, 4, 2141.
19. F. De Clippel, J. Am. Chem. Soc. 2012, 134, 10089-10101.
20. J. B. Dos Santos, N. J. A. De Albuquerque, C. L. D. P. E Silva, M. R. Meneghetti, S. M.
P. Meneghetti, RSC Adv. 2015, 5, 90952-90959.
21. V. Choudhary, S. H. Mushrif, C. Ho, A. Anderko, V. Nikolakis, N. S. Marinkovic, D. G.
Vlachos, J. Am. Chem. Soc. 2013, 135, 3997-4006.
22. P. A. Son, S. Nishimura, K. Ebitani, React. Kinet. Mech. Catal. 2012, 106, 185-192.
23. X. Yang, B. Lyu, T. Lu, Y. Su, L. Zhou, Catal. Sci. Technol. 2020.
24. X. Lyu, L. Xu, J. Wang, X. Lu, Catal. Commun. 2019, 119, 46-50.
25. M. S. Holm, S. Saravanamurugan, E. Taarning, Science. 2010, 328, 602-605.
26. A. Bayu, A. Yoshida, S. Karnjanakom, K. Kusakabe, X. Hao, T. Prakoso, G. Guan, Green
Chem. 2018, 20, 4112-4119.
27. J. Du, R. F. Say, W. Lyu, G. Fuchs, O. Einsle, Nature. 2011, 478, 534.
28. S. Qamar, K. Marsh, A. Berry, Protein Sci. 1996, 5, 154-161.
29. S. M. Zgiby, G. J. Thomson, S. Qamar, A. Berry, Eur. J. Biochem. 2000, 267, 1858-1868.
30. B. Jacques, M. Coinçon, J. Sygusch, J. Biol. Chem. 2018, 293, 7737-7753.
31. K. Buchholz, J. Seibel, Carbohydr. Res. 2008, 343, 1966-1979.
32. R. S. Assary, L. A. Curtiss, Energy Fuels. 2012, 26, 1344-1352.
33. P. Wattanapaphawong, P. Reubroycharoen, A. Yamaguchi, RSC Adv. 2017, 7, 18561-18568.
34. S. Huang, K. L. Yang, X. F. Liu, H. Pan, H. Zhang, S. Yang, RSC Adv. 2017, 7, 5621-5627.
35. L. Zhang, Z. Guo, J. Huang, M. Liu, Y. Wang, C. Ji, Struct. Biol. Commun. 2014, 70,
1376-1379.
12

Journal Pre-proof
Figure captions
Fig. 1. The chemical structure of HIDA.
Fig. 2. Effects of pH on the fructose conversion reaction catalyzed by HIDA in
phosphate buffer solution. [fructose]0 = 0.196 mol L-1, [HIDA] = 0.01 mol L-1.
Fig. 3. Concentrations variation of fructose and products versus time at pH 9.5 and
85 ℃. [fructose]0 = 0.196 mol L-1, [HIDA] = 0.01 mol L-1.
Fig. 4. The effects of temperature on the conversion of fructose and yields of products
at pH 9.5, 2 h. [fructose]0 = 0.196 mol L-1, [HIDA] = 0.01 mol L-1.
Fig. 5. The yields of DHA with time in different buffer systems at pH 9.5 and 85 ℃.
[fructose]0 = 0.196 mol L-1, [DIDA] = 0.01 mol L-1.
13

Journal Pre-proof
Table 1 Conversion of fructose and yields of products in various systems*
Yield of
Selectivity of
DHA / %
Yield of
Yield of
Conversion
of fructose
/ %
Catalyst
DHA / %
glucose / %
pyruvaldehyde
/ %
7.1
Phosphate buffer
39.3
44.9
42.0
40.4
12.3
15.7
13.3
13.1
31.2
35.0
31.6
32.3
13.1
14.8
15.2
14.4
5.0
5.9
6.7
60.0
27.9
46.5
13.5
10.6
*[fructose] = 0.196 mol L-1, [catalyst] = 0.01 mol L-1,
9.5, 85 ℃, reaction 2 h.
pH
0
14

Journal Pre-proof
Fig. 1
68
51
34
17
0
33
22
11
0
Fructose
DHA
Glucose
Pyruvaldehyde
7
8
9
10
pH
Fig. 2
15

Journal Pre-proof
0.12
0.08
0.04
0.00
0.20
0.15
0.10
0.05
Fructose
DHA
Glucose
Pyruvaldehyde
0
1
2
3
4
Time / h
Fig. 3
70
56
42
28
14
0
35
28
21
14
7
Fructose
DHA
Glucose
Pyruvaldehyde
0
55 60 65 70 75 80 85 90 95
T / ℃
Fig. 4
16

Journal Pre-proof
30
20
10
0
Water
Tris-HCl
Na2CO3
Phosphate
0
1
2
3
Time / h
Fig. 5
17

Journal Pre-proof
Credit author statement
Jing Lv: Conceptualization, Investigation, Writing - Original Draft
Xiang-Guang Meng*:Resources, Project administration, Supervision
Hong Huang: Formal analysis
Fei Wang: Validation
Wen-Wang Yu: Writing - Review and Editing
Yan-Yan Wu: Formal analysis
18

Journal Pre-proof
Declaration of Interest Statement
This manuscript has not been published before and is not been considered for
publication elsewhere. All authors have contributed to the creation of this
manuscript and read and approved the final manuscript. We declare there is no
conflict of interest.
19

Journal Pre-proof
Catalytic Conversion of Fructose to 1,3-dihydroxyacetone
Under Mild Conditions
Jing Lv,[a] Xiang-Guang Meng,*[a] Hong Huang,[a] Fei Wang,[a] Wen-Wang Yu[a] and
Yan-Yan Wu[a]
Graphical Abstract
An amphoteric phenolic compound with carboxyl, imidazole, and amino functional
groups is synthesized as mimic aldolase to catalyze the retro-aldol reaction of fructose
into DHA. The mimic aldolase system displays excellent catalytic activity for the
fragmentation reaction of fructose to DHA under mild conditions.
20

Journal Pre-proof
Highlights
1. A novel zwitterionic catalyst with several functional groups was synthesized.
2. DHA was obtained in high yield by retro-aldol condensation reaction.
3. This is the first example of converting fructose to DHA in good selectivity.
21

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5