Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites
An important product of biomass carbohydrate conversion is 5-hydroxymethylfurfural as a potential raw material component of a wide range of important chemicals. The aim of the work was to study the conversion of glucose into 5-hydroxymethylfurfural in the presence of modified clinoptilolite and mord...
Gespeichert in:
| Datum: | 2025 |
|---|---|
| Автори та афіліації: |
|
| Ключові слова: | keywords |
| Hauptverfasser: | , , , , , |
| Format: | Artikel |
| Sprache: | Englisch |
| Veröffentlicht: |
V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the National Academy of Sciences of Ukraine
2025
|
| Schlagworte: | |
| Online Zugang: | https://kataliz.org.ua/index.php/journal/article/view/126 |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| Назва журналу: | Catalysis and petrochemistry |
| Завантажити файл: |  |
Institution
Catalysis and petrochemistry| _version_ | 1872009066091380736 |
|---|---|
| author | Patrylak, Lyubov K. Konovalov, Serhiy V. Zubenko, Stepan O. Yakovenko, Anzhela V. Voloshyna, Yuliya G. Pertko, Olexandra P. |
| author_facet | Patrylak, Lyubov K. Konovalov, Serhiy V. Zubenko, Stepan O. Yakovenko, Anzhela V. Voloshyna, Yuliya G. Pertko, Olexandra P. |
| author_institution_txt_mv | [
{
"author": "Lyubov K. Patrylak",
"institution": "V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Sciences of Ukraine 1 Academician Kukhar Str., Kyiv, 02094, Ukraine"
},
{
"author": "Serhiy V. Konovalov",
"institution": "V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Sciences of Ukraine 1 Academician Kukhar Str., Kyiv, 02094, Ukraine"
},
{
"author": "Stepan O. Zubenko",
"institution": "V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Sciences of Ukraine 1 Academician Kukhar Str., Kyiv, 02094, Ukraine"
},
{
"author": "Anzhela V. Yakovenko",
"institution": "V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Sciences of Ukraine 1 Academician Kukhar Str., Kyiv, 02094, Ukraine"
},
{
"author": "Yuliya G. Voloshyna",
"institution": "V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Sciences of Ukraine 1 Academician Kukhar Str., Kyiv, 02094, Ukraine"
},
{
"author": "Olexandra P. Pertko",
"institution": "V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Sciences of Ukraine 1 Academician Kukhar Str., Kyiv, 02094, Ukraine"
}
] |
| author_sort | Patrylak, Lyubov K. |
| baseUrl_str | https://kataliz.org.ua/index.php/journal/oai |
| collection | OJS |
| datestamp_date | 2025-12-28T17:23:30Z |
| description | An important product of biomass carbohydrate conversion is 5-hydroxymethylfurfural as a potential raw material component of a wide range of important chemicals. The aim of the work was to study the conversion of glucose into 5-hydroxymethylfurfural in the presence of modified clinoptilolite and mordenite-clinoptilolite zeolite rocks from Transcarpathia. A number of acid catalysts have been synthesized by liquid-phase ion exchange of native cations with calcium, lanthanum, and ammonium cations, as well as by dealumination with hydrochloric and ethylenediaminetetraacetic acid. Their properties were characterized using XRD and XRF analysis, low-temperature nitrogen adsorption/desorption, and FTIR spectroscopy. The acidity of the samples was determined by reverse n-butylamine titration. Acid treatment of the samples contributed to an increase in the specific surface area of the samples by an order of magnitude. The samples were tested in the conversion of 9% aqueous glucose solution into 5-hydroxymethylfurfural. The composition of the reaction products was analyzed by gas chromatography. The glucose conversions and the yields of 5-hydroxymethylfurfural, levulinic acid, and fructose were calculated. The glucose conversions ranged from 30 to 70 %. The results were analyzed in accordance with the characteristics of the nature of the active sites of the catalysts and the porous structure of the latter. It was found that the samples with the presence of Lewis acid sites in the form of extra-framework aluminum and multiply charged cations are characterized by the highest 5-hydroxymethylfurfural yields. Due to glucose conversion occurs mainly on the outer surface of zeolite crystals and at the entrances to the cavities, the polycationic form of clinoptilolite, despite its low porous characteristics, demonstrates the highest yield of            5-hydroxymethylfurfural. |
| doi_str_mv | 10.15407/kataliz2025.36.033 |
| first_indexed | 2026-03-12T15:50:23Z |
| format | Article |
| fulltext |
Каталіз та нафтохімія, 2025, №36 33
Catalysis and Petrochemistry, 2025, 36
UDC 544.473
https://doi.org/10.15407/kataliz2025.36.033
Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites
Lyubov K. Patrylak, Serhiy V. Konovalov, Stepan O. Zubenko, Anzhela V. Yakovenko,
Yuliya G. Voloshyna, Olexandra P. Pertko
V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Sciences of Ukraine
1 Academician Kukhar Str., Kyiv, 02094, Ukraine, e-mail: lkpg@ukr.net
An important product of biomass carbohydrate conversion is 5-hydroxymethylfurfural as a potential raw
material component of a wide range of important chemicals. The aim of the work was to study the conversion of
glucose into 5-hydroxymethylfurfural in the presence of modified clinoptilolite and mordenite-clinoptilolite
zeolite rocks from Transcarpathia. A number of acid catalysts have been synthesized by liquid-phase ion
exchange of native cations with calcium, lanthanum, and ammonium cations, as well as by dealumination with
hydrochloric and ethylenediaminetetraacetic acid. Their properties were characterized using XRD and XRF
analysis, low-temperature nitrogen adsorption/desorption, and FTIR spectroscopy. The acidity of the samples was
determined by reverse n-butylamine titration. Acid treatment of the samples contributed to an increase in the
specific surface area of the samples by an order of magnitude. The samples were tested in the conversion of 9%
aqueous glucose solution into 5-hydroxymethylfurfural. The composition of the reaction products was analyzed
by gas chromatography. The glucose conversions and the yields of 5-hydroxymethylfurfural, levulinic acid, and
fructose were calculated. The glucose conversions ranged from 30 to 70 %. The results were analyzed in
accordance with the characteristics of the nature of the active sites of the catalysts and the porous structure of the
latter. It was found that the samples with the presence of Lewis acid sites in the form of extra-framework
aluminum and multiply charged cations are characterized by the highest 5-hydroxymethylfurfural yields. Due to
glucose conversion occurs mainly on the outer surface of zeolite crystals and at the entrances to the cavities, the
polycationic form of clinoptilolite, despite its low porous characteristics, demonstrates the highest yield of
5-hydroxymethylfurfural.
Keywords: natural zeolites, acid sites, 5-hydroxymethylfurfural, glucose conversion
Introduction
Carbohydrates of biomass are important natural sources of energy. However, the bulk of the
biomass carbohydrates is in the form of cellulose, which, despite its abundance, is little used in the
chemical industry due to its low solubility and low reactivity. This natural biopolymer can be hydrolyzed
to simple carbohydrates, and the latter can be dehydrated to furan derivatives, in particular, furfural,
5-hydroxymethylfurfural (5-HMF), levulinic, and lactic acids [1-4].
Biomass-derived 5-HMF is a potential feedstock for a wide range of chemicals and biofuels. Its
production from monosaccharides involves the isomerization of glucose into fructose, which converts
into 5-HMF by losing three water molecules (Scheme 1). Therefore, fructose is considered as a key
precursor of 5-HMF.
Scheme 1. Scheme of glucose transformation into 5-HMF
It is believed [5, 6] that in the first stage, Lewis acid sites (LAS) catalyze the isomerization of
glucose into fructose by the 1,2-hydride transfer mechanism, while Brønsted acid sites (BAS) contribute
34 Каталіз та нафтохімія, 2025, №36
Catalysis and Petrochemistry, 2025, 36
to the second stage - the dehydration of fructose into 5-HMF. There is another approach [7], according
to which the dehydration of glucose into 5-HMF is possible through the formation of the intermediate
1,2-enediol without involving fructose as an intermediate product.
It is natural that the use of heterogeneous catalysis in the conversion of hexoses is a progressive
and promising direction that will contribute to the development of technologically advantageous
processes for obtaining platform substances from sugars. Today, the conversion of glucose and fructose
is intensively studied in aqueous, alcoholic, or other solvent environments with the involvement of a
significant range of solid catalysts. However, cheap natural zeolites have not yet found proper
application in this area [8-12].
Therefore, the aim of the work was to study the conversion of glucose into 5-HMF in the
presence of modified natural clinoptilolite and mordenite-clinoptilolite zeolite rocks of Transcarpathia.
Experiment
Synthesis of catalysts
As the starting materials, the samples of natural Transcarpathian zeolite rocks of mordenite-
clinoptilolite (MC) and clinoptilolite (C) origin were used. The SiO2/Al2O3 ratio for C rock was 8.4, and
for MC rock – 9.5. The content of clinoptilolite in the C rock is about 80 % by mass, and the content of
mordenite and clinoptilolite in MC rock is 75 % and 25 % by mass. The main impurities are mica and
quartz. Sodium, calcium, potassium, and magnesium cations compensate negative charge of aluminum
tetrahedrals. Their content was CaO (3 wt. %), Na2O (1 wt. %), K2O (2 wt. %) [13] and CaO
(5.5 wt. %), Na2O (0.6 wt. %), MgO (1.0 wt. %), K2O (8.1 wt. %) [14] for MC and C rocks respectively.
As a result of acid treatment of the corresponding rock with hydrochloric acid (1.5 mol/l and
4 mol/l) at the boiling temperature of a water bath, samples of hydrogen forms C-1 and MC-1 were
obtained.
The polycationic form of clinoptilolite (C-3) was obtained by sequential exchange at 90-150 °C
for calcium ions (4 exchanges), lanthanum (2 exchanges), and ammonium (1 exchange) from aqueous
solutions of the corresponding nitrates with intermediate calcinations at 550 °C for 2 h.
By “soft” dealumination of sample C-3 using ethylenediaminetetraacetic acid (EDTA) in an
aqueous medium in three stages, sample C-4 was obtained. The procedure of obtaining these samples is
described in more detail in [14, 15].
To obtain the MC-2 sample, silicon atoms in the MC framework were subjected to partial
isomorphic substitution with aluminum atoms by high-temperature treatment (600 °C) in SiCl4 vapors,
followed by conversion to the hydrogen form by ion exchange with 3 mol/L ammonium nitrate solution
and subsequent calcination at 500 °C for 3 h.
Characterization of the catalysts
To determine the total concentration of acid centers in zeolite samples, a reverse titration with n-
butylamine was performed. To start with, 0.3 g of a natural rock-based sample was placed in a vial of
100 cm3, weighed with analytical accuracy, and 10 cm3 of a 0.1 M solution of n-butylamine in
cyclohexane was added. The vial was sealed, shaken vigorously, and left for 24 hours. After that, the
entire liquid phase was collected, transferred to a titration flask, weighed, and titrated with a 0.1 M HCl
solution in i-propyl alcohol. The concentration of acid sites was determined from the calculated change
in n-butylamine concentration based on the titration results and the known weight of the sample. This
Каталіз та нафтохімія, 2025, №36 35
Catalysis and Petrochemistry, 2025, 36
procedure was repeated three times for each studied sample. The results were statistically processed.
Confidence level of 95 % was used for calculating confidence intervals.
XRD patterns were recorded using DRON 4-07 equipment. FTIR spectrum was recorded using
Affinity-1S spectrometer (Shimadzu Corp.). All samples were also examined by low-temperature
nitrogen adsorption/desorption methods (Nova 1200, Quantachrome Instr.). The specific surface areas
(SBET) have been calculated according to the standard Brunauer–Emmet–Teller (BET) method utilizing
the nitrogen adsorption data at P/P0 values between 0.06 and 0.2. The micropores volumes (Vt
micro) and
micropores surface areas (St
miсro) have been estimated using the de Boer t-plot method. External surface
(St) was calculated as the difference between SBET and St
miсro. Silica to alumina ratio in the samples were
determined using XRF analysis (X-Supreme8000, Oxford Instruments).
Glucose dehydration
The conversion of glucose on zeolite-based catalysts was carried out in an aqueous medium
using glass autoclave reactors of 35 cm3 with a screw Teflon top. The loading volume of the aqueous
reagent solution was 5.0 cm3, the mass ratio of solid to liquid (S:L) phase was 1:9. The catalyst sample
of 0.50 g was poured into the flask, 0.50 g of glucose and 5.00 g of distilled water were added. A
magnetic stirrer was placed in the autoclave, then it was sealed and placed in a preheated oil bath. The
process was carried out for 4 h with intensive stirring (1000 rpm) at 160 °C. The products were cooled in
air and in a stream of cold water. The catalyst and precipitate of insoluble humins as by-products were
separated by centrifugation (10 min, 3000 rpm).
Reaction products were analyzed by using an Agilent 7890A gas chromatograph (FID detector,
split/splitless inlet, the capillary column J&W HP-5 (5 %-phenyl)-methylsiloxane, 30 m, inner diameter
0.32 mm, film thickness 0.25 µm). For the analysis, about 0.2 cm3 of liquid products weighed with an
accuracy of 0.0001 g were diluted with 2.0 cm3 of distilled water. The brown sediment of water-
insoluble humins was separated using centrifugation (15 min, 4000 min–1). The following conditions
were used for the analysis: inlet temperature – 200 °C; split ratio – 20:1; chromatographic column heater
temperature – 100 °C, then 5 °C/min to 175 °C and 30 °С/min to 320 °C; carrier gas (N2) flow rate –
3 cm3/min; detector temperature – 260 °C; injection volume – 1 µl. The concentrations of 5-HMF and
levulinic acid were calculated using calibration curves in range 0.1 to 0.5 wt. % for 5-HMF and 0.05 to
0.2 wt. % for levulinic acid obtained with analytical standards of corresponding pure substances. The
analysis was repeated 3–5 times and the results were averaged.
To determine the concentration of glucose in liquid products of catalytic transformation, gas
chromatography analysis with D-sorbitol as internal standard (≥ 98.0 %,) was carried out with
preliminary derivatization of hydroxyl groups by means of trimethylsilytatation with
trimethylchlorosilane (Sigma Aldrich, ≥ 99.0 %, for GC derivatization) and hexamethyldisilazane
(Sigma Aldrich, ≥ 99.0 %, for GC derivatization). About 0.04-0.05 g of the liquid products were placed
in a glass vial (10 cm3). The vial with the sample was weighed with an accuracy of 0.0001 g and then
evacuated (< 1 kPa) for 3 h at 20 °C and for 1 h at 70-80 °C to remove water and volatile products. The
residue was dissolved in 2 cm3 of D-sorbitol standard solution in pyridine (0.315 wt. %), pyridine, and
then 60 µl trimethylchlorosilane and 120 µl of hexamethyldisilazane were added. The vial was closed
and shaken intensively followed by centrifugation (10 min, 3000 min–1) in order to remove the sediment
of ammonium chloride. The sample for chromatographic analysis was taken from the liquid phase, not
disturbing the formed sediment. Varying amounts (about 0.04-0.08 g) of D-glucose (pharmaceutical
purity FS 42U-52/37 709 00, Ukraine) standard solution in pyridine (10.00 wt. %) were treated in the
36 Каталіз та нафтохімія, 2025, №36
Catalysis and Petrochemistry, 2025, 36
same manner in order to calibrate the ratio of FID sensitivity to derivatized forms of D-glucose and
D-sorbitol. The conditions of analysis were the same as for 5-HMF and levulinic acid analysis.
D-glucose concentration was calculated from chromatographic peaks areas of both anomers of its
six-member cyclic form (α- and β-D-glucopyranose).
The conversion of glucose as well as the yields of 5-HMF, levulinic acid, and fructose were
calculated from the chromatographic data.
Results and discussion
Starting raw rocks were investigated by using XRD analysis. The diffraction pattern of the MC
rock is characterized by 12 lines (2Ѳ = 6.5; 9.76; 13.44; 13.82; 14.58; 19.6; 22.18; 23.14; 25.6; 26.22;
27.66; 33.12; 35.58), which reflect the presence of mordenite and clinoptilolite phases (Fig. 1). For the C
rock, in addition to clinoptilolite lines, intensive lines of impurity quartz have been observed (Fig. 2).
0 10 20 30 40 50 60 70 80 90
Cl
M
M
M
M
M M+Cl
M
M
M
M
2Q
MCl
Cl
Cl M
Fig. 1. XRD pattern of MC rock: M – mordenite, Cl - clinoptilolite
0 10 20 30 40 50 60 70 80 90
Cl
Cl
2q
Q
Q
Cl
Fig. 2. XRD pattern of C rock: Cl – clinoptilolite, Q – quartz
It is known that ion-exchange cations in the Transcarpatian zeolite rocks are represented
predominantly by potassium, sodium, calcium, and magnesium [14, 16]. As a result of modification of
the rocks, the silica to alumina ratio of zeolites was changed. Table 1 shows the corresponding values
established by using XRF analysis.
Table 2 shows the porous characteristics of the catalyst samples calculated from low-temperature
nitrogen adsorption/desorption isotherms. It should be noted that the application of this method for
narrow-porous zeolites, such as clinoptilolite (0.31×0.75 nm, 0.36×0.46 nm, and 0.28×0.47 nm) and
Каталіз та нафтохімія, 2025, №36 37
Catalysis and Petrochemistry, 2025, 36
mordenite (0.67×0.70 nm, 0.29×0.57 nm) [17], is quite limited due to the slow diffusion of nitrogen in
their narrow channels.
Table 1. Silica to alumina ratio in the samples
Sample SiO2/Al2O3 Sample SiO2/Al2O3
C 8.4 MC 9.5
C1 8.8 MC1 18
C3 10.9 MC2 12
C4 13.1
Table 2. Adsorption characteristics of the catalysts
Sample SBET, m2/g St, m2/g St
miсro, m2/g VΣ, cm3/g Vt
micro, cm3/g Vmicro/VΣ, %
C 9.6 3.7 5.8 0.016 0.002 13
C-1 131 9.9 121 0.075 0.049 65
C-3 9.2 2.3 6.9 0.013 0.003 24
C-4 89 16.6 72.1 0.031 0.071 42
МC 62 22 40 0.075 0.019 25
МC-1 264 21 243 0.157 0.096 62
МC-2 31 13 18 0.067 0.006 8.8
As can be seen from the data in the table, the specific surface area of the C zeolite and its
polycationic form C-3 is quite low (~ 9 m2/g). Moreover, for C-3 it is even slightly smaller than the
value for the original rock, which may be due to an increase in the radius of cations in the polycationic
form, in particular, the presence of lanthanum cations. After acid treatments (samples C-1 and C-4), the
specific surface area increases by an order of magnitude due to unlocking access to micropores after
partial destruction of the zeolite structure, leaching of impurities, and ion exchange of divalent cations
for a proton. A similar trend of significant increase in BET surface area is observed after acid treatment
of mordenite-clinoptilolite rock. The specific surface area increased from 62 to 264 m2/g, which is close
to the values for synthetic mordenite-type zeolite [18]. At the same time, the content of micropores
increases approximately 5 times. The latter can be caused not only by the removal of structural
aluminum, but also by the replacement of the original cations of sodium, potassium, calcium with a
cation with a smaller radius - a proton [19]. The volume of mesopores also increases.
In the case of modification of MC by isomorphic substitution of framework aluminum atoms
with silicon (sample MC-2), the opposite situation is observed - the specific surface area decreases by
half, and the volume of meso- and micropores also decreases. This occurs, apparently, as a result of the
well-known phenomenon of the formation of extra-framework aluminum structures that remain in the
pores of the zeolite [20].
The mesopore content in the samples, calculated using DFT theory, is summarized in Table 3.
Dealumination with hydrochloric acid contributed to a slight increase in the mesopore volume in the
case of samples MC-1 and C-1, while EDTA treatment (sample C-4) caused a 15-fold increase in the
mesopore volume. Obviously during the treatment of the polycationic form of C-3 with EDTA, partial
dealumination and decationization of the rock with pore expansion occurs. It is interesting that the use of
EDTA contributes to both an increase in microporosity and mesoporosity of the sample, while treatment
with mineral acid only leads to an increase in microporosity (Tables 1 and 3).
38 Каталіз та нафтохімія, 2025, №36
Catalysis and Petrochemistry, 2025, 36
Table 3. Volume of pores (V) with a diameter bigger than 2 nm for unmodified and modified samples
calculated using DFT approaches
Sample V, cm3/g Sample V, cm3/g
C 0.003 MC 0.062
C1 0.015 MC1 0.073
C3 0.008 MC2 0.051
C4 0.045
Table 4 shows the concentration of acid centers in the zeolite catalyst samples, measured by
reverse titration with n-butylamine. Obviously, the molecules of the latter (kinetic diameter ~ 0.5 nm)
cannot access the acid sites inside the zeolite micropores of clinoptilolite. Therefore, the values given
refer only to the centers on the outer surface of the catalysts. One can be absolutely sure that glucose
molecules (kinetic diameter about 1 nm [21]) cannot access the centers located deep in the clinoptilolite
structure, to which n-butylamine does not have access. As might be seen from the data in Table 4, the
concentration of acid sites available for the latter in the original C rock and its polycationic form, C-3, is
extremely low. A noticeable increase in the number of acid sites in the C-4 sample is observed after
EDTA treatment. As shown above, the surface area of the sample also increased significantly (Table 2).
The start MC rock contains slightly more acid centers than the C rock. The acid treatment resulted in a
threefold increase in their concentration (sample MC-1), while dealumination by isomorphic substitution
of aluminum (sample MC-2) for silicon reduced it, which is apparently due to the removal of aluminum
necessary for the formation of bridged BAS. But when treating the sample with silicon tetrachloride
under static conditions, aluminum compounds are not removed, and therefore they can be LAS.
However, access to them is difficult, which is confirmed by a decrease in the BET specific surface area
of the sample.
Table 4. Experimental (Cac) and reduced cconcentration (CRac) of acid sites in zeolite samples according
to the results of titration with n-butylamine
Catalyst Cac, mmol/g CRac, mmol/m2 Potential LAS Potential BAS
C 0.07±0.06 0.0184* Na+, K+, Ca2+ Weak BAS
C-1 - - Bridge OH-groups
C-3 0.04±0.04 0.0173* Ca2+, La3+
Weak BAS
Bridge OH-groups
C-4 0.28±0.04 0.031** Ca2+, La3+
Weak BAS
Bridge OH-groups
MC 0.18±0.1 0.0082* Na+, K+, Ca2+ Weak BAS
МC-1 0.53±0.02 0.002** - Bridge OH-groups
МC-2 0.11±0.04 0.085*
Ca2+, La3+,
extraframework Al
species
Weak BAS
Bridge OH-groups
* experimental number of sites divided by external surface area, which is accessible for glucose molecules
** experimental number of sites divided by BET surface area, which is accessible for n-butylamine molecules
In the third column of Table 4, the reduced concentration of acid sites of the samples and lists of
potential sources of LAS and BAS were also indicated. The initial forms contain calcium, sodium, and
potassium cations, which compensate the negative charges on the aluminum-oxide tetrahedra. In the
field of polyvalent cations, in this case calcium, the decomposition of a water molecule is possible with
Каталіз та нафтохімія, 2025, №36 39
Catalysis and Petrochemistry, 2025, 36
the formation of a cation (CaOH)+ and an acid-bridging OH-group - BAS. Therefore, the original form
uniquely contains both Brønsted acid sites and weak Lewis acid sites in the form of mono- and divalent
cations of sodium, potassium, and calcium.
During acid treatment with 4 mol/L hydrochloric acid (sample MC-1), partial dealumination of
the rock and simultaneous decationization with the formation of new BAS occur. Aluminum was mainly
removed from the sample in this case. When treating the C rock with 1.5 mol/l hydrochloric acid, no
significant dealumination occurred. This is confirmed by the small change in silica to alumina ratio
(Table 1), which is apparently caused by the low acid concentration.
When performing isomorphic substitution of aluminum for silicon, the silica to alumina ratio
increases, which, as is known, contributes to an increase in the acidity strength of Brønsted sites, which
are formed during ion exchange of native cations for ammonium and followed by thermal decomposition
of the latter. However, further thermal treatment of ammonium forms is accompanied by partial
dehydroxylation and destruction of the zeolite lattice with the formation of extra-framework aluminum,
which acts as a Lewis acid site. In addition, extra-framework aluminum compounds are formed during
the isomorphic substitution procedure itself [20]. This is confirmed by the presence of an absorption
band at 3650 cm–1 in the FTIR spectrum (Fig. 3), which is associated with the formation of Al-OH-Al
groups [22].
Fig. 3. FTIR spectrum of MC-2 sample in the region of valence vibration of OH-groups
Therefore, when determining the acidity in MC-1 sample by titration with n-butylamine, it is quite
natural that the number of acid sites is significantly greater than in the original rock. And these centers,
which are located in the mesopores, can be partly accessible for glucose molecules, which are bigger than
n-buthylamine molecules. Whereas in the raw rock MC and in MC-2 sample, only the centers of the
external surface of the zeolite and the entrances to the channels are available for glucose conversion.
The polycationic form of C-3 contains about 80 % of the exchange capacity of lanthanum.
However, the significant kinetic radius of the lanthanum cation allows it to enter into the narrow pores of
clinoptilolite-type zeolites only upon destruction of the hydration shell at high temperatures of
hydrothermal ion exchange. At the same time, the entrances to the channels become even narrower, and
the BET surface becomes even smaller (Table 2).
The results of glucose catalytic transformations are presented in Table 5. It is quite natural that
the process of glucose transformation in aqueous medium proceeds worse than, for example, in DMSO
[23], and the obtained yields of 5-HMF are significantly lower.
In relation to the number of acid centers and their nature, the obtained data can be interpreted as
follows. In the raw MC rock, there are weaker LAS (sodium, potassium, calcium, and magnesium
cations) than BAS, since the latter are formed only in the interaction with divalent cations.
3500 3550 3600 3650 3700 3750 3800
1
П
о
гл
и
н
ан
н
я
а б
в г
д е
є ж
3500 3550 3600 3650 3700 3750 3800
1
П
о
гл
и
н
ан
н
я
3500 3550 3600 3650 3700 3750 3800
1
П
о
гл
и
н
ан
н
я
3500 3550 3600 3650 3700 3750 3800
1
П
о
гл
и
н
ан
н
я
1450 1500 1550
3
2
1
v, см
-1
v, см
-1
v, см
-1
v, см
-1
1450 1500 1550
3
2
1
1450 1500 1550
3
2
1
1450 1500 1550
3
2
1
A
b
so
rb
an
ce
, cm
-1
40 Каталіз та нафтохімія, 2025, №36
Catalysis and Petrochemistry, 2025, 36
Table 5. Glucose conversion (X), 5-HMF yield (YHMF), levulinic acid yield (YLA), and fructose yield
(YFR) on the zeolite samples
Catalyst X, % YHMF,% mol YLA, % mol YFR, % mol
MC 30 10.5 4.4 10.6
MC-1 51 12.0 4.1 4.4
MC-2 60 14.7 4.2 11.9
C 68 13.3 4.0 8.0
C-1 50 11.0 4.1 3.3
C-3 70 18.7 4.3 3.4
C-4 39 13.4 <3.2 9.3
Therefore, part of fructose as an intermediate product of the conversion of glucose into 5-HMF
remains in the products. Weak BAS predominantly convert glucose into humins, as was found in [23].
The MC-1 sample has a lot of BAS, while the number of LAS has decreased because the cations
have been replaced by protons using mineral acid. The extra-framework aluminum is simultaneously
mainly removed from the sample in the form of aluminum chloride. As a result, the degree of glucose
conversion has increased, but the yield of 5-HMF has increased insignificantly (only by 2 %). Therefore,
the main contribution to increase in glucose conversion was made by the formation of humins as by-
products.
On the MC-2 sample, the increase in the BAS strength contributed to an increase in the yield of
HMF by 4 %. However, in this case, the hydrogen form was obtained through the decomposition of the
ammonium form, which caused the formation of extra-framework aluminum, which acts as LAS. In
addition, strong LAS in the form of extra-framework aluminum structures were formed during the
isomorphic substitution procedure itself. Therefore, the fructose yield increased again compared to the
previous sample. However, the contribution of humins is still significant in this case.
The degrees of glucose conversion on the C and C-3 samples are close. However, in the second
sample, the presence of lanthanum increases the contribution of LAS and weak BAS, which are formed
during the decomposition of a water molecule in the La3+ force field. As a result, the yield of 5-HMF
increases up to 19 %. On the other hand, in C-1 sample treated with hydrochloric acid, almost all metal
cations were removed, which leads to the depletion of the sample in the LAS. While dealumination
occurred to a small extent, the acidity strength did not change significantly. As a result, it naturally
demonstrates both lower conversion and lower selectivity for 5-HMF.
In the case of C-4 sample with a higher total acidity according to butylamine titration, the same
fructose yield is observed as on the original rock form, which may be due to the potentially larger
number of LAS compared to BAS. However, glucose access to them is limited, so the overall conversion
is low.
Taking into account the approximately comparable yields of levulinic acid on all catalysts, strong
BAS are represented to a negligible extent in the above samples [23].
Therefore, in general, there is a certain correlation between the reduced number of acid sites
titrated with n-butylamine and the activity of the samples in glucose conversion. There is a clear
agreement with the nature of the acid sites caused by different stages of sample modification. The
clearly higher content of 5-HMF yields in samples with the presence of lanthanum and extra-framework
aluminum as strong LAS indicates the implementation of a two-stage scheme of glucose conversion
through its initial isomerization into fructose. The highest yield of humins is observed on samples
Каталіз та нафтохімія, 2025, №36 41
Catalysis and Petrochemistry, 2025, 36
modified with hydrochloric acid with a minimum amount of LAS. It is 85 and 86.4 wt. % for MC-1 and
C-1 samples respectively.
The glucose conversions obtained in this work are not very high (30-70 %). They are lower than
fructose conversions on natural clinoptilolite samples [14] obtained in DMSO medium. However, the
obtained yields of 5-HMF are comparable and even slightly higher than the yields of 5-HMF on
synthetic hydrogen and nickel-containing forms of zeolites Y, M, and ZSM-5 [23], which did not exceed
10-12 %.
Conclusions
Thus, in view of the large size of the glucose molecule compared to the pore size of narrow-pore
natural zeolites, the transformations are realized mainly on the outer surface of the zeolites and at the
entrances to the channels. The degree of glucose conversion and the yield of 5-HMF correlate with the
acidity of the samples, determined by n-butylamine titration, referred to the sample surface area
accessible to glucose molecules. The features of the catalytic conversion of glucose into 5-HMF are in
accordance with the nature of the active sites of the samples and their porous structure. The efficiency of
glucose conversion is significantly influenced by the nature of Lewis acidity, which is represented in the
samples by metal cations and extra-framework aluminum species. The presence of multiply charged
cations, in particular, lanthanum, contributes to a more efficient course of glucose conversion compared
to the raw rocks, in which Lewis acidity is provided by singly and doubly charged cations. The highest
yield of 5-HMF of about 19 % was obtained on the polycationic form of the clinoptilolite with high
lanthanum content. The obtained data confirm the two-stage conversion scheme of glucose on natural
zeolites with the intermediate formation of fructose.
Acknowledgements
The authors would like to thank the organizers of the II European Chemical School for Ukrainians
(https://acmin.agh.edu.pl/en/detail/s/ii-european-chemistry-school-for-ukrainians) for their support and helpful
educational information.
References
1. Esteban J., Yustos P., Ladero M. Catalytic processes from biomass-derived hexoses and pentoses: a recent
literature overview. Catalysts., 2018, 8, 637–678.
2. Chen N., Zhu Z., Ma H., Liao W., Lü H. Catalytic upgrading of biomass-derived 5-hydroxymethylfurfural to
biofuel 2,5-dimethylfuran over Beta zeolite supported non-noble Co catalyst. Mol. Catal., 2020, 486, 110882.
3. Xu H., Wang Z., Huang J., Jiang Y. Thermal Catalytic Conversion of Biomass-Derived Glucose to Fine
Chemicals. Energy Fuels, 2021, 35(10), 8602–8616.
4. Tomishige K., Yabushita M., Cao J., Nakagawa Y. Hydrodeoxygenation of potential platform chemicals
derived from biomass to fuels and chemicals. Green Chem., 2022, 24, 5652–5690.
5. Choudhary V., Mushrif S.H., Ho C., Anderko A., Nikolakis V. et al. Insights into the interplay of Lewis and
Brønsted acid catalysts in glucose and fructose conversion to 5-(hydroxymethyl)furfural and levulinic acid in
aqueous media. J. Am. Soc., 2013, 135, 3997–4006.
6. Bhaumik P., Dhepe P.L. Solid Acid Catalyzed Synthesis of Furans from Carbohydrates. Catal. Rev., 2016,
58(1), 36–112.
7. Li J., Li J., Zhang D., Liu C. Theoretical elucidation of glucose dehydration to 5-hydroxymethylfurfural
catalyzed by a SO3H-functionalized ionic liquid. J. Phys. Chem. B, 2015, 119, 13398–13406.
https://www.sciencedirect.com/science/article/abs/pii/S2468823120301346#!
https://www.sciencedirect.com/science/article/abs/pii/S2468823120301346#!
https://doi.org/10.1039/1463-9270/1999
42 Каталіз та нафтохімія, 2025, №36
Catalysis and Petrochemistry, 2025, 36
8. Barbosa S.L., de S. Freitas M., dos Santos W.T.P. et al. Dehydration of d-fructose to 5-hydroxymethyl-2-
furfural in DMSO using a hydrophilic sulfonated silica catalyst in a process promoted by microwave
irradiation. Sci. Rep., 2021, 11, 1919.
9. Pande A., Niphadkar P., Pandare K., Bokade V. Acid modified H‑USY zeolite for efficient catalytic
transformation of fructose to 5‑hydroxymethylfurfural (biofuel precursor) in methyl isobutyl ketone−water
biphasic system. Energy Fuels., 2018, 32(3), 3783–3791.
10. Levytska S.I. Investigation of glucose isomerization into fructose on MgO-ZrO2 catalyst in flow mode.
Catalysis and Petrochemistry, 2017, 26, 46–52. [in Ukrainian].
11. Huang F., Jiang T., Dai H., Xu X., Jiang S., Xhen L., Fei Z., Dyson P.J. Transformation of glucose to
5-hydroxymethylfurfural over regenerated cellulose supported Nb2O5 center dot nH2O in aqueous solution.
Catal. Letters., 2020, 10, 13489–13495.
12. Wei W.Q., Wu S.B. Experimental and kinetic study of glucose conversion to levulinic acid in aqueous
medium over Cr/HZSM-5 catalyst. Fuel, 2018, 225, 311–321.
13. Patrylak K., Bobonych F., Voloshyna Yu. et al. Ukrainian mordenite-clinoptilolite rocks as a base for linear
hexane isomerization catalyst. Appl. Catal. A Gen., 1998, 174(1–2), 187–198.
14. Patrylak L., Konovalov S., Yakovenko A., Pertko O., Povazhnyi V. et al. Fructose transformation into
5-hydroxymethylfurfural over natural transcarpathian zeolites. Сhem. Chem. Technol., 2022, 16(4), 521–531.
15. Patrylak L., Konovalov S., Zubenko S., Yakovenko A. Transformation of hexoses on natural and synthetic
zeolites. Сhem. Chem. Technol., 2023, 17(2), 287–293.
16. Vasylechko V., Sydorchuk V., Manko N., Kostiv O., Klyuchivska O., Ilkov O., Bagday S., Zelinskiy A.,
Gromyko A., Stoika R., Kalychak Ya. Effect of physico-chemical modification of clinoptilolite composites
on their antimicrobial activity. Chem. Chem. Technol., 2025, 19(2), 183–195.
17. Breck D.W. Zeolite molecular sieves: structure, chemistry and use. – John Wiley, New York, 1974.
18. Ahmed A.M., Jarullah A.T., Hussein H.M., Ahmed A.N. Mordenite-Type Zeolite from Iraq Sand: Synthesis
and Characterization. J. Petrol. Research and Studies, 2023, 13(3), 126–142.
19. Voloshyna Yu., Pertko O., Pavazhnyi V., Yakovenko A. Effect of modifying the clinoptilolite-containing
rocks of Transcarpathia on their porous characteristicss and catalytic properties in the conversation of
C6-hydrocarbons. Chem. Chem. Technol., 2023, 17(2), 373–385.
20. Anderson M.W., Klinowski J. Zeolites treated with silicon tetrachloride vapour. Part 1 – Preparation and
characterization. J. Chem. Soc., Faraday Trans.1, 1986, 82, 1449–1496.
21. Mahala S., Arumugam S.M., Kumar S., Devi B., Elumalai S. Tuning of MgO's base characteristics by
blending it with amphoteric ZnO facilitating the selective glucose isomerization to fructose for bioenergy
development. Nanoscale Adv., 2023, 5(9), 2470–2486.
22. Khivantsev K., Jaegers N.R., Kovarik L., Derewinski M.A., Kwak J.-H., Szanyi J. On the nature of extra-
framework aluminum species and improved catalytic properties in steamed zeolites. Molecules, 2022, 27(7),
2352.
23. Patrylak L.K., Konovalov S.V., Yakovenko A.V., Pertko O.P., Povazhnyi V.A., Voloshyna Yu.G.,
Melnychuk O.V., Filonenko M.M. Micro–mesoporous kaolin-based zeolites as catalysts for glucose
transformation into 5-hydroxymethylfurfural. Appl. Nanosci., 2023, 13(7), 4795–4808.
24. Patrylak L.K., Pertko O.P., Povazhnyi V.A., Yakovenko A.V., Konovalov S.V. Evaluation of nickel-
contaning zeolites in the catalytic transformation of glucose in an aqueous medium. Appl. Nanosci., 2022,
12(4), 869–882.
Надійшла до редакції 11.09.2025
Каталіз та нафтохімія, 2025, №36 43
Catalysis and Petrochemistry, 2025, 36
Перетворення глюкози до 5-гідроксиметилфурфуролу
на українських природних цеолітах
Любов К. Патриляк, Сергій В. Коновалов, Степан О. Зубенко,
Анжела В. Яковенко, Юлія Г. Волошина, Олександра П. Пертко
Інститут біоорганічної хімії та нафтохімії ім. В.П.Кухаря Національної академії наук України
вул. Академіка Кухаря, 1, Київ, 02094, Україна, e-mail: lkpg@ukr.net
Важливим продуктом перетворення вуглеводів біомаси є 5-гідроксиметилфурфурол як
потенційний сировинний компонент широкого ряду важливих хімічних речовин. Метою роботи було
дослідження конверсії глюкози до 5-гідроксиметилфурфуролу в присутності модифікованих
клиноптилолітової та морденіт-клиноптилолітової цеолітових порід Закарпаття. Синтезовано ряд
кислотних каталізаторів шляхом рідкофазного іонного обміну нативних катіонів на катіони кальцію,
лантану та амонію, а також шляхом деалюмінування хлоридною та етилендіамінтетраоцтвою кислотою.
Охарактеризовано їх властивості за допомогою рентгено-фазового та рентгенофлуорисцентного аналізу,
низькотемпературної адсорбції/десорбції азоту та ІЧ-спектроскопії. Здійснено оцінку кислотності зразків
за титруванням з н-бутиламіном. Кислотна обробка зразків сприяла зростанню питомої поверхні зразків
на порядок. Зразки випробувано у перетворенні 9 % водного розчину глюкози до
5-гідроксиметилфурфуролу. Склад продуктів реакції аналізували за допомогою газової хроматографії.
Було розраховано конверсії глюкози та виходи 5-гідроксиметилфурфуролу, левуліновї кислоти та
фруктози. Конверсії глюкози склали від 30 до 70 %. Результати проаналізовано у відповідності до
особливостей природи активних центрів та пористої структури каталізаторів. Встановлено, що найкращі
виходи 5-гідроксиметилфурфуролу характерні для зразків із наявністю льюїсових кислотних центрів у
вигляді позакаркасного алюмінію та багатозарядних катіонів. Оскільки перетворення глюкози перебігає
переважно на зовнішній поверхні цеолітних кристалів та у входах у порожнини, то полікатіонна форма
клиноптилоліту, незважаючи на її низьку пористість, демонструє найвищий вихід
5-гідроксиметилфурфуролу.
Ключові слова: природні цеоліти, кислотні центри, 5-гідроксиметилфурфурол, конверсія глюкози
|
| id | oai:katalizorgua:article-126 |
| institution | Catalysis and petrochemistry |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-03-12T15:50:23Z |
| publishDate | 2025 |
| publisher | V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the National Academy of Sciences of Ukraine |
| record_format | ojs |
| resource_txt_mv | katalizorgua/20/5d3c16af6eb6d344333960128838b520.pdf |
| spelling | oai:katalizorgua:article-1262025-12-28T17:23:30Z Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites Patrylak, Lyubov K. Konovalov, Serhiy V. Zubenko, Stepan O. Yakovenko, Anzhela V. Voloshyna, Yuliya G. Pertko, Olexandra P. natural zeolites, acid sites, 5-hydroxymethylfurfural, glucose conversion природні цеоліти, кислотні центри, 5-гідроксиметилфурфурол, конверсія глюкози An important product of biomass carbohydrate conversion is 5-hydroxymethylfurfural as a potential raw material component of a wide range of important chemicals. The aim of the work was to study the conversion of glucose into 5-hydroxymethylfurfural in the presence of modified clinoptilolite and mordenite-clinoptilolite zeolite rocks from Transcarpathia.&nbsp;A number of acid catalysts have been synthesized by liquid-phase ion exchange of native cations with calcium, lanthanum, and ammonium cations, as well as by dealumination with hydrochloric and ethylenediaminetetraacetic acid. Their properties were characterized using XRD and XRF analysis, low-temperature nitrogen adsorption/desorption, and FTIR spectroscopy. The acidity of the samples was determined by reverse n-butylamine titration. Acid treatment of the samples contributed to an increase in the specific surface area of the samples by an order of magnitude. The samples were tested in the conversion of 9% aqueous glucose solution into 5-hydroxymethylfurfural. The composition of the reaction products was analyzed by gas chromatography. The glucose conversions and the yields of 5-hydroxymethylfurfural, levulinic acid, and fructose were calculated. The glucose conversions ranged from 30 to 70&nbsp;%. The results were analyzed in accordance with the characteristics of the nature of the active sites of the catalysts and the porous structure of the latter. It was found that the samples with the presence of Lewis acid sites in the form of extra-framework aluminum and multiply charged cations are characterized by the highest 5-hydroxymethylfurfural yields. Due to glucose conversion occurs mainly on the outer surface of zeolite crystals and at the entrances to the cavities, the polycationic form of clinoptilolite, despite its low porous characteristics, demonstrates the highest yield of &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5-hydroxymethylfurfural. Важливим продуктом перетворення вуглеводів біомаси є 5-гідроксиметилфурфурол як потенційний сировинний компонент широкого ряду важливих хімічних речовин. Метою роботи було дослідження конверсії глюкози до 5-гідроксиметилфурфуролу в присутності модифікованих клиноптилолітової та морденіт-клиноптилолітової цеолітових порід Закарпаття. Синтезовано ряд кислотних каталізаторів шляхом рідкофазного іонного обміну нативних катіонів на катіони кальцію, лантану та амонію, а також шляхом деалюмінування хлоридною та етилендіамінтетраоцтвою кислотою. Охарактеризовано їх властивості за допомогою рентгено-фазового та рентгенофлуорисцентного аналізу, низькотемпературної адсорбції/десорбції азоту та ІЧ-спектроскопії. Здійснено оцінку кислотності зразків за титруванням з н-бутиламіном. Кислотна обробка зразків сприяла зростанню питомої поверхні зразків на порядок. Зразки випробувано у перетворенні 9&nbsp;% водного розчину глюкози до &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5-гідроксиметилфурфуролу. Склад продуктів реакції аналізували за допомогою газової хроматографії. Було розраховано конверсії глюкози та виходи 5-гідроксиметилфурфуролу, левуліновї кислоти та фруктози. Конверсії глюкози склали від 30 до 70&nbsp;%. Результати проаналізовано у відповідності до особливостей природи активних центрів та пористої структури каталізаторів. Встановлено, що найкращі виходи 5-гідроксиметилфурфуролу характерні для зразків із наявністю льюїсових кислотних центрів у вигляді позакаркасного алюмінію та багатозарядних катіонів. Оскільки перетворення глюкози перебігає переважно на зовнішній поверхні цеолітних кристалів та у входах у порожнини, то полікатіонна форма клиноптилоліту, незважаючи на її низьку пористість, демонструє найвищий вихід &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5-гідроксиметилфурфуролу. V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the National Academy of Sciences of Ukraine 2025-12-08 Article Article application/pdf https://kataliz.org.ua/index.php/journal/article/view/126 10.15407/kataliz2025.36.033 Catalysis and petrochemistry; No. 36 (2025): Catalysis and petrochemistry; 33-43 Каталіз та нафтохімія; № 36 (2025): Каталіз та нафтохімія; 33-43 2707-5796 2412-4176 10.15407/kataliz2025.36 en https://kataliz.org.ua/index.php/journal/article/view/126/110 Copyright (c) 2025 Catalysis and petrochemistry |
| spellingShingle | природні цеоліти кислотні центри 5-гідроксиметилфурфурол конверсія глюкози Patrylak, Lyubov K. Konovalov, Serhiy V. Zubenko, Stepan O. Yakovenko, Anzhela V. Voloshyna, Yuliya G. Pertko, Olexandra P. Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites |
| title | Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites |
| title_alt | Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites |
| title_full | Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites |
| title_fullStr | Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites |
| title_full_unstemmed | Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites |
| title_short | Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites |
| title_sort | conversion of glucose into 5-hydroxymethylfurfural on ukrainian natural zeolites |
| topic | природні цеоліти кислотні центри 5-гідроксиметилфурфурол конверсія глюкози |
| topic_facet | natural zeolites acid sites 5-hydroxymethylfurfural glucose conversion природні цеоліти кислотні центри 5-гідроксиметилфурфурол конверсія глюкози |
| url | https://kataliz.org.ua/index.php/journal/article/view/126 |
| work_keys_str_mv | AT patrylaklyubovk conversionofglucoseinto5hydroxymethylfurfuralonukrainiannaturalzeolites AT konovalovserhiyv conversionofglucoseinto5hydroxymethylfurfuralonukrainiannaturalzeolites AT zubenkostepano conversionofglucoseinto5hydroxymethylfurfuralonukrainiannaturalzeolites AT yakovenkoanzhelav conversionofglucoseinto5hydroxymethylfurfuralonukrainiannaturalzeolites AT voloshynayuliyag conversionofglucoseinto5hydroxymethylfurfuralonukrainiannaturalzeolites AT pertkoolexandrap conversionofglucoseinto5hydroxymethylfurfuralonukrainiannaturalzeolites |