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doi.org/10.26434/chemrxiv.7751144.v1
NMR Elucidation of “NaCl Effect” in Carbohydrates Conversion Toward aRational PredictionGan Zhu, Hui Li, Yiqun Li, Liuqun Gu
Submitted date: 21/02/2019 • Posted date: 21/02/2019Licence: CC BY-NC-ND 4.0Citation information: Zhu, Gan; Li, Hui; Li, Yiqun; Gu, Liuqun (2019): NMR Elucidation of “NaCl Effect” inCarbohydrates Conversion Toward a Rational Prediction. ChemRxiv. Preprint.
“NaCl Effect” was well known in biomass chemical degradation including carbohydrate transformations, inwhich NaCl had significant positive effect in promoting/catalyzing particular transformation. However, directevidence was very rare in proposed mechanisms to elucidate “NaCl Effect”, here we reported 1H NMRevidences of “NaCl Effect” on different saccharides and at once non-selective bonding of Cl-H was proposedinstead of sequence bonding during deconstruction of hydrogen bonding network based on evidences. Ageneral recommending NaCl usage based on total hydroxyls on saccharides could well explain the best effectof hydrogen bonding destruction in most reported literatures.
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1
NMR Elucidation of “NaCl Effect” in Carbohydrates
Conversion Toward a Rational Prediction
Gan Zhu♀b, Hui Li♀a, Yiqun Li b* and Liuqun Gua*
a Department of Biomedical Engineering, Jinan University; #601, Huangpudadaoxi,
Guangzhou, China
b Department of Chemistry, Jinan University; #601, Huangpudadaoxi, Guangzhou,
China
KEYWORDS. NaCl effect; 1H NMR elucidation; carbohydrate; hydrogen bonding; biomass
depolymerization.
Abstract:
“NaCl Effect” was well known in biomass chemical degradation including carbohydrate
transformations, in which NaCl had significant positive effect in promoting/catalyzing
particular transformation. However, direct evidence was very rare in proposed mechanisms
to elucidate “NaCl Effect”, here we reported 1H NMR evidences of “NaCl Effect” on different
saccharides and at once non-selective bonding of Cl-H was proposed instead of sequence
bonding during deconstruction of hydrogen bonding network based on evidences. A general
recommending NaCl usage based on total hydroxyls on saccharides could well explain the
best effect of hydrogen bonding destruction in most reported literatures.
Alkali chlorides including sodium chloride (NaCl) and potassium chloride (KCl) et. al played
important roles in extracellular fluid of many multicellular organisms; the former is well known
as a condiment and food preservative, and the latter is one of most frequent used fertilizer in
agriculture. In recent decade, research on their use as additives1-6
or promoters7-9
for biomass
chemical degradation including carbohydrate transformations into valuable chemicals were
increasingly popular because they are abundant in nature and are very cheap in cost;
particularly for sodium chloride and “NaCl Effect” (or “salt effect”) was well known in biomass
conversion and carbohydrate chemistry. However, the mechanism of “NaCl Effect” was very
less explored10. No direct evidence mapping interaction between carbohydrates (or cellulose
2
and so on) and NaCl was reported to our best of knowledge probably because of the complex
nature of biomass components and carbohydrates. Here we reported 1H NMR evidences of
“NaCl Effect” on different saccharides and a relatively stable bonding of O(N)-H-Cl was
observed with all hydroxyls of saccharides.
Chloride ion on ionic liquid along with the anion part have been reported being able to break
hydrogen bond in cellulose11,12
by measuring the crystal Root Mean Square Deviation (RMSD)
values in atomic positions of the cellulose bunch and using molecular dynamics simulations.
Very recently C. Hu and J. H. Clark reported a comprehensive mechanistic study10 on “NaCl
effect” on the thermochemical depolymerization of cellulose and further demonstrated the
strong potential of a cheap and readily available mineral (NaCl) can be used to help improve
the resource efficiencies of lignocellulosic biorefineries. However, mechanism detail on how
NaCl molecular interact with proton of hydroxyl on sugar moiety in cellulose and the
minimum of NaCl required for the best effect of disrupting hydrogen bonding are largely
unknown. Inspired by a sharp difference of 1H NMR shifts of glucosamine in deionized water
and saturated NaCl solution, we envisaged an NMR angle by measuring 1H NMR shifts of
monosaccharides and oligosaccharides might be helpful to understand the mechanism of
“NaCl Effect”.
It was known that solid state NMR and IR spectra both showed no obvious change, especially
in spectral regions characteristic of the ordered and disordered regions of cellulose in the
presence of NaCl10,13
, probably because of cellulose’s poor solubility in water. Hence, water
soluble monosaccharides including D-glucose, D-glucosamine hydrogen chloride, N-acetyl-
D-glucosamine and D-fructose were initially chosen in order to gain some insights on “NaCl
effect” on the intramolecular/intermolecular hydrogen bonding in water via regular 1H NMR
analysis. Variant concentration of 4.8%, 9.1%, 13.0%, 16.7% (all in wt%) and saturated NaCl
solutions were made for comparison study.
Figure 1. 1H NMR Spectra of N-Acetyl-D-glucosamine and Five Peaks Marked for
Tracking.
3
Initially 0.5 mmol of N-acetyl-D-glucosamine was dissolved into 6 mL of NaCl solution with
different concentration and the mixtures continued to stir for 6 hours at room temperature
before one portion was taken out for 1H NMR analysis. Five peaks including hydrogens on 1-
position carbon of both α-anomer and β-anomer14 were marked (Figure 1) in order to track
their changes in different concentration of NaCl solution. After a solution of 0.5 mmol of N-
acetyl-D-glucosamine was stirred in deionized water, protons on 1-position carbon of α-
anomer and β-anomer displayed at δ 5.18 and 4.67 respectively on 1H NMR spectra in D2O,
the former was at left side of D2O peak while the latter was at right side. Significant deshielding
effect was observed for all protons of N-acetyl-D-glucosamine (△δ = 0.26 ppm) in the
presence of 4.8% NaCl solution, which was likely induced by newly formed H-Cl bond (Figures
2 and 3). A remarkable downfield shifting (△δ = 0.18 ppm) on 1H NMR shift between spectra
obtained in 4.8% NaCl solution and that obtained in 9.1% NaCl solution continued. Shift
changes became intangible when further increase of concentration (13.0% from 9.1% or to
16.7% from 13.0% or to saturated NaCl solution from 16.7%) (△δ <= 0.02 ppm). Based on
these data (Figures 2 and 3), it could be concluded that almost completed deconstruction of
intramolecular/intermolecular hydrogen bonding within N-acetyl-D-glucosamine molecular
was achievable in 9.1% NaCl solution and in which relatively stable H-Cl bonding formed.
Figure 2. 1H NMR Spectra of N-Acetyl-D-glucosamine after Mixing with Different
Concentration of NaCl Solutions.
4
Figure 3. 1H NMR Shift Changes of N-Acetyl-D-glucosamine, D-Glucose, D-Fructose and
D-Glucosamine Hydrogen Chloride Correlating with Concentration of NaCl by Tracking
Marked Five/Six Peaks.
In order to gain more clues, similar 1H NMR tracking analysis in different concentration of
NaCl solutions was also performed with other three abundant monosaccharides (D-glucose,
D-fructose and D-glucosamine hydrogen chloride) in nature (Figure 3). Trends of 1H NMR
shift changes of D-glucose in marked six peaks were pretty similar with those observed from
N-acetyl-D-glucosamine; Significant changes were observed upon increase of concentration
of NaCl solution (4.8% from 0% or to 9.1% from 4.8%). No change at all for all marked peaks
occurred in the presence of higher concentration of NaCl solution (13.0%, 16.7% and saturated
solution). For D-fructose, obvious 1H NMR shifting could still be observed for all protons of
six marked peaks when further increase of concentration to 13.0% from 9.1% (△δ = 0.07 ppm).
Continued increase of NaCl concentration led to intangible change on 1H NMR spectra (△δ
<= 0.02 ppm). Interestingly, with D-glucosamine hydrogen chloride stable complex could
only be obtained till NaCl concentration was increased to 16.7% although the shifting of the
marked six peaks was small (△δ = 0.03 - 0.05 ppm) when increase of concentration to 16.7%
from 13.0%. The significant delay to a stable H-Cl bonding was likely due to the increase of
free protons by amine ion moiety of D-glucosamine hydrogen chloride. It worth being noted
that shifting trends of all marked peaks were almost same in all four monosaccharides which
indicated that deconstruction process of hydrogen bonding and generating new hydrogen
chloride bonding occurred at once and were non-selective.
Figure 4. 1H NMR Shift Changes of Sucrose, Trehalose and Stachyose Correlating with
Concentration of NaCl by Tracking Marked Four Peaks.
5
Next two disaccharides (sucrose and trehalose) and one tetrasaccharide (stachyose) were also
selected as targets for 1H NMR comparison study in variant concentration of NaCl solutions
(Figure 4), in order to provide more viable references for NaCl promoted deconstruction of
hydrogen bonding of polysaccharides such as cellulose. The correlation of 1H NMR shifts with
concentration of NaCl solution for sucrose was pretty much similar with that of fructose, in
which an obvious shifting on 1H NMR spectra disappeared after concentration of NaCl was
increased to 13.0%. It was easy to be understand because one molecule sucrose composed of
two monosaccharides (glucose and fructose) and the moiety (fructose) in slow rate
determined the rate of sucrose in deconstruction of hydrogen bonding. An increase of mixing
temperature to 60℃ had positive effect (△δ = 0.11 ppm) on deconstruction of hydrogen
bonding of sucrose in low concentration of NaCl solution (4.8%); however, influence was
intangible in relatively high concentration of NaCl solution (>9.1%) (see supporting
information). As a disaccharide formed by a 1,1-glycosidic bond between two α-glucose units,
trehalose has a stronger hydrogen bonding network than that by D-glucose. Trends of 1H
NMR shift for four marked peaks of trehalose correlating with concentration of NaCl solution
was more like that of sucrose rather than that of D-glucose, and almost a same 1H NMR
spectra was obtained in case that concentration of NaCl solution was over 13.0%. Increase of
disaccharide to tetrasaccharide (stachyose) led to small effect on the correlation between 1H
NMR shift and concentration of NaCl solution. Small shifting for marked four peaks of
stachyose was observed upon increase of concentration of NaCl solution to 16.7% from 13.0%,
meanwhile the change vanished when increase of temperature to 60℃ (see supporting
information).
With all clues in hand, we combed through three main factors including temperature,
6
concentration (NaCl solution) and absolute volume (NaCl solution) which might have effect
on deconstruction of hydrogen bonding network and generation of H-Cl bonds. The
significant shifting difference for all marked peaks of sucrose in the presence of 4.8% NaCl
solution at room temperature and 60℃ indicated the important role of temperature,
particularly an expected more important role for polysaccharides that have poor solubility in
water due to large molecular weight. NaCl concentration was well known to have strong effect
on hydrogen bonding in water due to solvation15-17
; here it was also found to influent
deconstruction of hydrogen bonding network and generation of H-Cl bonds remarkably for
all selected monosaccharides and oligosaccharides. The higher concentration of NaCl solution,
the better effect on deconstruction of hydrogen bonding network based on 1H NMR shifting.
Effect of volume of was also investigated with N-acetyl-D-glucosamine (0.5 mmol) in 9.1 wt%
NaCl solution (Figure 5). Downfield shifting was observed along with increase of volume till
6 mL, and after then bonding network became steady and no change was observed on 1H
NMR spectra. The total usage of NaCl was 10 mmol under the turning point condition (6 mL).
Figure 5. 1H NMR Spectra of N-Acetyl-D-glucosamine after Mixing with Different
Volume of 9.1 wt% NaCl Solution at Room Temperature.
Concerning frequent optimization on NaCl usage in literatures, we tentatively to propose a
calculation model recommending the best usage of NaCl for deconstruction of hydrogen
bonding network of polysaccharides including starch, chitin and cellulose. Recommended
concentration of NaCl solution ranged from 9% to 15% (wt%) since too high concentration led
to little difference (Figure 4). Recommended absolute amount of NaCl in solution is 3.5 – 4.0
7
equivalent to total hydroxyl of saccharides (including protons on amine moiety if
glucosamine-based saccharides were used) since all the turning points for our selected four
monosaccharides and three oligosaccharides are within this range. For temperature, room
temperature is usually sufficient for monosaccharides and oligosaccharides which are soluble
in water; however, typically increase of temperature was pretty necessary for cellulose
depolymerization according to a recent report10 that “NaCl effect” was only be obvious at
above 210℃.
Stable complexes illustrating interaction of saccharides (D-glucose and N-acetyl-D-
glucosamine) and chloride ions in water were proposed as shown in Figure 6. In which five
chloride ions (here ignoring solvation with water molecular along with sodium anion) bond
with hydrogens on hydroxyls (and acetyl amide) respectively at one time in a non-selective
manner. In another word, the bonding structure of complex in NaCl solution should be same
regardless parameters of concentration, volume and temperature and the only change is
bonding length, according to our observance that all marked peaks changed in a similar trend.
Figure 6. Complexes of D-Glucose and N-Acetyl-D-glucosamine Coordinating with
Chloride Ion in NaCl Solution.
A further exploration on 1H NMR shifting of D-glucose in saline solution showed clear shift
on spectrum (Figure 7) for all six marked peaks (△δ = 0.10 – 0.11 ppm). Such observance
might be of much value to understand carbohydrates in human body via NMR analysis
techniques18.
Figure 7. 1H NMR Spectra of D-glucose after Mixing with Saline Solution (0.9 wt% NaCl)
at Room Temperature.
8
In summary, 1H NMR elucidation of “NaCl effect” of monosaccharides and oligosaccharides
at room temperature was investigated, which provided evidences of prevailing “NaCl effect”
in molecular level. With clues in hand, non-selective hydrogen-chloride bonds formed at
once instead of sequence mechanism was proposed during deconstruction of hydrogen
bonding network of carbohydrates. A general recommending NaCl usage of 3.5 – 4.0
equivalent mole of hydroxyls (including amines or amides) on saccharides in a solution of
concentration ranging from 9.0-15 wt% was proposed based on achieved data; which might
be a reference for deconstruction of hydrogen bonding in polysaccharides (including cellulose
and starch) depolymerization. A clear observance of “NaCl effect” on D-glucose in saline
solution might contribute to understanding of carbohydrates in human body.
ASSOCIATED CONTENT
Supporting Information.
The following files are available free of charge.
AUTHOR INFORMATION
Corresponding Author
*(L. Gu) E-mail: guliuqun@jnu.edu.cn or guliuqun@yahoo.com;
* (Y. Li). E-mail: tlyq@jnu.edu.cn
9
Author Contributions
The manuscript was written through contributions of all authors. All authors have
given approval to the final version of the manuscript.
♀These authors contributed equally.
ACKNOWLEDGMENT
We acknowledge a startup funding from Jinan University to L. Gu (No: 88015155 and
88016607) and a funding of the National Natural Science Foundation of China (No.
21372099) to Y. Li.
References:
[1] Chen, X.; Chew, S. L.; Kerton, F. M.; Yan, N., Direct conversion of chitin into a N-containing furan
derivative. Green Chem. 2014, 16 (4), 2204-2212.
[2] Omari, K. W.; Dodot, L.; Kerton, F. M., A simple one-pot dehydration process to convert N-
acetyl-D-glucosamine into a nitrogen-containing compound, 3-acetamido-5-acetylfuran.
ChemSusChem 2012, 5 (9), 1767-72.
[3] Hansen, T. S.; Mielby, J.; Riisager, A., Synergy of boric acid and added salts in the catalytic
dehydration of hexoses to 5-hydroxymethylfurfural in water. Green Chem. 2011, 13 (1), 109-114.
[4] Wang, C.; Zhang, Q.; Chen, Y.; Zhang, X.; Xu, F., Highly Efficient Conversion of Xylose Residues
to Levulinic Acid over FeCl3 Catalyst in Green Salt Solutions. ACS Sustainable Chemistry &
Engineering 2018, 6 (3), 3154-3161.
[5] Yang, H.; Wang, L.; Jia, L.; Qiu, C.; Pang, Q.; Pan, X., Selective Decomposition of Cellulose into
Glucose and Levulinic Acid over Fe-Resin Catalyst in NaCl Solution under Hydrothermal Conditions.
Industrial & Engineering Chemistry Research 2014, 53 (15), 6562-6568.
[6] Potvin, J.; Sorlien, E.; Hegner, J.; DeBoef, B.; Lucht, B. L., Effect of NaCl on the conversion of
cellulose to glucose and levulinic acid via solid supported acid catalysis. Tetrahedron Letters 2011,
52 (44), 5891-5893.
[7] Li, M.; Li, W.; Lu, Y.; Jameel, H.; Chang, H.-m.; Ma, L., High conversion of glucose to 5-
hydroxymethylfurfural using hydrochloric acid as a catalyst and sodium chloride as a promoter in
a water/γ-valerolactone system. RSC Advances 2017, 7 (24), 14330-14336.
[8] Jiang, Z.; Budarin, V. L.; Fan, J.; Remón, J.; Li, T.; Hu, C.; Clark, J. H., Sodium Chloride-Assisted
Depolymerization of Xylo-oligomers to Xylose. ACS Sustainable Chemistry & Engineering 2018, 6
(3), 4098-4104.
10
[9] Amoah, J.; Hasunuma, T.; Ogino, C.; Kondo, A., 5-Hydroxymethylfurfural production from salt-
induced photoautotrophically cultivated Chlorella sorokiniana. Biochemical Engineering Journal
2019, 142, 117-123.
[10] Jiang, Z.; Fan, J.; Budarin, V. L.; Macquarrie, D. J.; Gao, Y.; Li, T.; Hu, C.; Clark, J. H., Mechanistic
understanding of salt-assisted autocatalytic hydrolysis of cellulose. Sustainable Energy & Fuels
2018, 2 (5), 936-940.
[11] Y. Li, X. Liu, S. Zhang, Y. Yao, X. Yao, J. Xu and X. Lu, Dissolving process of a cellulose bunch
in ionic liquids: a molecular dynamics study. Phys. Chem. Chem. Phys., 2015, 17, 17894-17905.
[12] B. D. Rabideau and A. E. Ismail, Mechanisms of hydrogen bond formation between ionic
liquids and cellulose and the influence of water content. Phys. Chem. Chem. Phys., 2015, 17, 5767-
5775.
[13] Fan, J.; Bruyn, M. D.; Zhu, Z.; Budarin, V.; Gronnow, M.; Gomez, L. D.; Macquarrie, D.; Clark, J.
H. Microwave-enhanced formation of glucose from cellulosic waste. Chem. Eng. Process., 2013,
71, 37-42.
[14] Usually a mixture of α-anomer and β-anomer both exist due to dissociated equivalent.
[15] Dedonder-Lardeux, C.; Gregoire, G.; Jouvet, C.; Martrenchard, S.; and Solgadi, D. Charge
separation in molecular clusters: dissolution of a salt in a salt-(solvent)n cluster. Chem. Rev., 2000,
100, 4023 – 4037.
[16] Beladjine, S.; Amrani, M.; Zanoun, A.; Belaidi, A,; Vergoten, G. Structure and hydrogen bonding
in aqueous sodium chloride solutions using theoretical water model AB4: effects of concentration.
Comput. Theor. Chem. 2011, 977, 97 – 102.
[17] Shalit, A.; Ahamed, S.; Savolainen, J. and Hamm, P. Terahertz echos reveal the inhomogeneity
of aqueous salt solutions. Nat. Chem., 2017, 9, 273-278.
[18] Duus, J.; Gotfredsen, C. H.; and Bock, K. Carbohydrate Structural Determination by NMR
Spectroscopy: Modern Methods and Limitations. Chem. Rev., 2000, 100, 4589 – 4614.
download fileview on ChemRxivNMR Elucidation of.pdf (0.92 MiB)
S1
Supporting Information For NMR Elucidation of “NaCl Effect” in Carbohydrates
Conversion Toward a Rational Prediction
Gan Zhu♀b, Hui Li♀a, Yiqun Li b* and Liuqun Gua*
a Department of Biomedical Engineering, Jinan University; #601, Huangpudadaoxi, Guangzhou, China
E-mail: guliuqun@jnu.edu.cn or guliuqun@yahoo.com;
b Department of Chemistry, Jinan University; #601, Huangpudadaoxi, Guangzhou, China
E-mail: tlyq@jnu.edu.cn
♀These authors contributed equally.
Table of Content
General information ----------------------------------------------------------------------------------S2
Preparation for different concentration of NaCl solutions ---------------------------------S2
General procedure for investigation of “NaCl effect” on monosaccharides via 1H NMR
analysis --------------------------------------------------------------------------------------------------S2
General procedure for investigation of “NaCl effect” on oligosaccharides via 1H NMR
analysis---------------------------------------------------------------------------------------------------S3
General procedure for investigation volume impact (9.1% NaCl solution) of “NaCl
effect” on N-acetyl-D-glucosamine via 1H NMR analysis -----------------------------------S3
General procedure for investigation of “NaCl effect” on D-glucose in saline solution
(0.9% NaCl) via 1H NMR analysis ------------------------------------------------------------------S4
1H NMR shifts for marked peaks of monosaccharides and oligosaccharides in
different concentration of NaCl solutions ------------------------------------------------------S4
Marked peaks on 1H NMR spectrum -------------------------------------------------------------S8
1H NMR spectra of monosaccharides and oligosaccharides in different concentration
of NaCl solutions -------------------------------------------------------------------------------------S12
S2
General Information:
D(+)-Glucosamine hydrochloride was purchased from Shanghai Macklin
Biochemical Co., Ltd. Ethanol was purchased from Guangdong Test Agent
Technology Co., Ltd. N-Acetyl-D-glucosamine, glucose, D2O and NaCl were
purchased from Aladdin Industrial Corporation. Fructose was purchased
form Shanghai TCI Chemical Industry Development Co., Ltd. Sucrose and
trehalose were both purchased from Guangzhou Asegene Co., Ltd.
Stachyose(80%) was purchased from Macklin Co., Ltd. All reagents were
used without further purification. Saline solution (medical, 0.9%) was
purchased from Hebei Tiancheng Pharmaceutical Co. Ltd. Deionized water
was used in all experiments. All reagents were used without further
purification. 1H NMR spectra was recorded on Bruker AV-300 (300 MHz)
instrument.
Preparation for different concentration of NaCl solutions:
1. 4.8% NaCl solution: 1 g NaCl was dissolved in 20 mL deionized water.
2. 9.1% NaCl solution: 2 g NaCl was dissolved in 20 mL deionized water.
3. 13.0% NaCl solution: 3 g NaCl was dissolved in 20 mL deionized water.
4. 16.7% NaCl solution: 4 g NaCl was dissolved in 20 mL deionized water.
General procedure for investigation of “NaCl effect” on
monosaccharides via 1H NMR analysis
S3
Monosaccharide (0.5 mmol) was added into different concentration of
NaCl solution (6 mL) and the mixture was stirred for 6 h at room
temperature. After then, 1 mL of the reaction mixture was taken out and
was mixed with some ethanol (for fast evaporation); and the solvent
mixture was evaporated under reduced pressure at 37℃. Removal of
residual solvent in vaccum gave a crude product for 1H NMR to determine
chemical shift.
General procedure for investigation of “NaCl effect” on oligosaccharides
via 1H NMR analysis
Sucrose (107.0 mg, 0.31 mmol, Mw: 342.3 g/mol, 8 OHs/molecular) or
trehalose (107.0 mg, 0.31 mmol, Mw: 342.3 g/mol, 8 OHs/molecular) or
stachyose (148.8 mg, 0.18 mmol, 80%, Mw: 666.6 g/mol, 14
OHs/molecular) was added into different concentration of NaCl solution
(6 mL) and the mixture was stirred for 6 h at room temperature or 60℃;
After then, 1 mL of the reaction mixture was taken out and was mixed with
some ethanol (for fast evaporation); and the solvent mixture was
evaporated under reduced pressure below 50℃ . Removal of residual
solvent in vaccum gave a crude product for 1H NMR to determine chemical
shift.
General procedure for investigation volume impact (9.1% NaCl solution)
S4
of “NaCl effect” on N-acetyl-D-glucosamine via 1H NMR analysis
N-Acetyl-D-glucosamine (0.5 mmol) was added into 9.1 wt% NaCl solution
(1.5 mL, or 3 mL or 6 mL or 12 mL) and the mixture was stirred for 6 h at
room temperature. After then, 1 mL of the reaction mixture was taken out
and was mixed with some ethanol (for fast evaporation); and the solvent
mixture was evaporated under reduced pressure at 37℃. Removal of
residual solvent in vaccum gave a crude product for 1H NMR to determine
chemical shift.
General procedure for investigation of “NaCl effect” on D-glucose in
saline solution (0.9% NaCl) via 1H NMR analysis
D-glucose (0.5 mmol) was added into 9.1 wt% NaCl solution (1.5 mL, or 3
mL or 6 mL or 12 mL) and the mixture was stirred for 6 h at room
temperature. After then, 1 mL of the reaction mixture was taken out and
was mixed with some ethanol (for fast evaporation); and the solvent
mixture was evaporated under reduced pressure at 37℃. Removal of
residual solvent in vaccum gave a crude product for 1H NMR to determine
chemical shift.
1H NMR shifts for marked peaks of monosaccharides and
oligosaccharides in different concentration of NaCl solutions
S5
D-Glucose
Concentration 1 2 3 4 5 6
0.0% 5.143 4.551 3.841 3.665 3.408 3.161
4.8% 5.341 4.757 4.017 3.845 3.616 3.355
9.1% 5.633 5.061 4.276 4.129 3.926 3.664
13.0% 5.647 5.075 4.287 4.14 3.939 3.677
16.7% 5.644 5.071 4.283 4.136 3.936 3.674
saturated 5.647 5.075 4.287 4.14 3.939 3.676
Glucosamine hydrochloride
Concentration 1 2 3 4 5 6
0.50% 5.431 4.924 3.913 3.474 3.312 3.997
1.90% 5.519 5.022 3.992 3.555 3.395 3.093
N-acetyl-glucosamine
Concentration 1 2 3 4 5
0 5.18 4.67 3.84 3.65 3.46
4.8% 5.42 4.96 4.08 3.87 3.71
9.1% 5.6 5.14 4.26 4.05 3.89
13% 5.62 5.17 4.29 4.06 3.92
16.7% 5.62 5.17 4.28 4.06 3.92
saturated 5.64 5.18 4.30 4.07 3.93
Concentration 1 2 3 4 5 6
0.50% 5.17 4.579 3.865 3.69 3.437 3.187
2.40% 5.311 4.726 3.99 3.816 3.584 3.325
Concentration 1 2 3 4 5 6
0 5.45 4.93 3.89 3.52 3.31 3.01
4.8% 5.64 5.15 4.05 3.71 3.53 3.23
9.1% 5.8 5.31 4.23 3.86 3.70 3.41
13% 5.89 5.41 4.32 3.95 3.82 3.52
16.7% 5.94 5.44 4.35 3.98 3.86 3.56
saturated 5.93 5.45 4.35 3.99 3.85 3.57
Concentration 1 2 3 4 5
0.50% 5.162 4.672 3.831 3.649 3.439
S6
N-acetyl-glucosamine in 9.1 wt%
volume 1 2 3 4 5
1.5ml 5.314 4.857 4.006 3.775 3.601
3ml 5.364 4.911 4.054 3.823 3.659
6ml 5.6 5.14 4.26 4.05 3.89
12ml 5.583 5.137 4.257 4.05 3.886
Fructose
Concentration 1 2 3 4 5 6
0 4.091 4.025 3.895 3.784 3.706 3.555
4.8% 4.204 4.133 4.011 3.892 3.818 3.666
9.1% 4.467 4.382 4.278 4.143 4.089 3.928
13% 4.543 4.453 4.355 4.216 4.16 4.002
16.7% 4.543 4.456 4.354 4.216 4.159 4.002
saturated 4.543 4.461 4.359 4.22 4.167 4.006
Sucrose (room temperature)
Concentration 1 2 3 4
0 5.362 4.176 3.994 3.412
4.8% 5.515 4.325 4.145 3.569
9.1% 5.756 4.562 4.377 3.813
13% 5.823 4.63 4.441 3.88
16.7% 5.826 4.633 4.445 3.884
saturated 5.827 4.634 4.446 3.885
60℃
1 2 3 4
0 5.351 4.166 3.984 3.401
4.8% 5.624 4.432 4.251 3.68
9.1% 5.725 4.532 4.348 3.781
13% 5.823 4.63 4.442 3.881
16.7% 5.82 4.627 4.439 3.878
1.90% 5.227 —— 3.889 3.684 3.498
Concentration 1 2 3 4 5 6
0.50% 4.081 4.017 3.883 3.77 3.693 3.538
2.40% 4.2 4.127 4.007 3.886 3.813 3.66
S7
saturated 5.822 4.629 4.44 3.88
Trehalose (room temperature)
Concentration 1 2 3 4
0 5.145 3.828 3.613 3.39
4.8% 5.416 4.119 3.909 3.684
9.1% 5.538 4.253 4.043 3.817
13% 5.601 4.323 4.112 3.886
16.7% 5.597 4.319 4.108 3.882
saturated 5.6 4.322 4.111 3.885
60℃
Concentration 1 2 3 4
0 5.139 3.822 3.607 3.384
4.8% 5.287 3.98 3.769 3.545
9.1% 5.543 4.259 4.049 3.823
13% 5.592 4.314 4.103 3.877
16.7% 5.595 4.317 4.106 3.88
saturated 5.598 4.32 4.109 3.883
Stachyose (room temperature)
Concentration 1 2 3 4
0 5.371 4.931 4.175 3.607
4.8% 5.568 5.144 4.369 3.815
9.1% 5.721 5.314 4.52 3.982
13% 5.822 5.425 4.621 4.094
16.7% 5.842 5.437 4.642 4.115
saturated 5.848 5.451 4.648 4.122
60℃
Concentration 1 2 3 4
0 5.393 4.951 4.197 3.627
4.8% 5.586 5.163 4.387 3.834
9.1% 5.721 5.313 4.52 3.98
13% 5.843 5.446 4.642 4.114
16.7% 5.843 5.446 4.641 4.114
saturated 5.848 5.452 4.648 4.121
S8
Marked peaks on 1H NMR spectrum
S9
S10
S11
S12
1H NMR spectra of D-(+)-Glucose
S13
1H NMR spectra of D-(+)-Glucosamine hydrochloride
S14
1H NMR spectra of Frucrose
S15
1H NMR spectra of sucrose
S16
S17
1H NMR spectra of trehalose
S18
S19
1H NMR spectra of stachyose
S20
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