Synthesis and Properties of Alkoxyethyl β-d-Xylopyranoside

Article abstract of DOI:10.1002/jsde.12013

In order to improve the water solubility of sugar-based surfactants, alkyl β-d-xylopyranosides, novel sugar-based surfactants, 1,2-trans alkoxyethyl β-d-xylopyranosides, with alkyl chain length n = 6–12 were stereoselectively prepared by the trichloroacetimidate method. Their properties including hydrophilic–lipophilic balance (HLB) number, water solubility, surface tension, emulsification, foamability, thermotropic liquid crystal, and hygroscopicity were investigated. The results indicated that their HLB number decreased with increase of alkyl chain, the water solubility improved since the hydrophilic oxyethene (─OCH₂CH₂─) fragment was introduced. The dissolution process was entropy driven at 25–45 °C for alkyl chain length n = 6–10. Octyloxyethyl β-d-xylopyranoside had the best foaming ability. Nonyloxyethyl β-d-xylopyranoside had the best foam stability and the emulsifying ability was better in toluene/water system than in rapeseed oil/water system. The surface tension of in aqueous solution dropped to 27.8 mN m^?1 at the critical micelle concentration, and it also showed the most distinct thermotropic liquid phases with cross pattern texture upon heating and the fan schlieren texture on cooling. Hexyloxyethyl β-d-xylopyranoside possessed the strongest hygroscopicity. Based on the effective improvement of water solubility, the prepared alkoxyethyl β-d-xylopyranosides showed excellent surface activity and are expected to develop their practical application as a class of novel sugar-based surfactants.

Full text of DOI:10.1002/jsde.12013

J Surfact Deterg (2018)
DOI 10.1002/jsde.12013
ORIGINAL ARTICLE
Synthesis and Properties of Alkoxyethyl β-D-Xylopyranoside
Wangzhen Shen1 · Shanwei Ji1 · Langqiu Chen1 · Yanhua Zhang1 · Xiubing Wu1
Received: 7 May 2017 / Revised: 13 August 2017 / Accepted: 26 October 2017
© 2018 AOCS
Abstract In order to improve the water solubility of
sugar-based surfactants, alkyl β-D-xylopyranosides, novel
sugar-based surfactants, 1,2-trans alkoxyethyl β-D-xylopyr-
anosides, with alkyl chain length n = 6–12 were stereose-
lectively prepared by the trichloroacetimidate method.
Their properties including hydrophilic–lipophilic balance
(HLB) number, water solubility, surface tension, emulsifi-
cation, foamability, thermotropic liquid crystal, and hygro-
scopicity were investigated. The results indicated that their
HLB number decreased with increase of alkyl chain, the
water solubility improved since the hydrophilic oxyethene
(─OCH2CH2─) fragment was introduced. The dissolution
alkoxyethyl β-D-xylopyranosides showed excellent surface
activity and are expected to develop their practical applica-
tion as a class of novel sugar-based surfactants.
Keywords Surface activity ꢁ Synthesis ꢁ Non-ionic
surfactants ꢁ Interfacial science
J Surfact Deterg (2018).
Introduction
ꢀ
process was entropy driven at 25–45 C for alkyl chain
From a long-term point of view, shortage of petroleum
resources will become more and more serious. Fortunately for
our planet, there are solutions involving utilization of renew-
able materials and/or effective access to biodegradable prod-
ucts. A few surfactants are prepared from renewable materials
and have excellent biodegradable properties. Alkyl polygly-
cosides (APGs) are safe and environmentally friendly sugar-
based nonionic surfactants. APG is synthesized from carbo-
hydrates and fatty alcohols that are naturally occurring and
renewable raw materials (Ríos, Fernández-Arteaga, Lechuga,
Jurado, & Fernández-Serrano, 2016). They have been
employed in industrial and consumer application fields, such
as detergents, food products, pharmaceuticals, agrochemicals,
protein science, and personal care products, because they pos-
sess the excellent properties including low surface tension,
efficient decontamination ability, exquisite and stable foam,
low toxicity, and so on (Ardolino, Meloni, Brugali, Corsini, &
Galli, 2016; Du, Wang, Tai, Wang, & Liu, 2016; Lukic, Pan-
telic, & Savic, 2016; Reading et al., 2015).
length n = 6–10. Octyloxyethyl β-D-xylopyranoside had the
best foaming ability. Nonyloxyethyl β-D-xylopyranoside
had the best foam stability and the emulsifying ability was
better in toluene/water system than in rapeseed oil/water
system. The surface tension of in aqueous solution dropped
to 27.8 mN m−1 at the critical micelle concentration, and it
also showed the most distinct thermotropic liquid phases
with cross pattern texture upon heating and the fan schlie-
ren texture on cooling. Hexyloxyethyl β-D-xylopyranoside
possessed the strongest hygroscopicity. Based on the effec-
tive improvement of water solubility, the prepared
Electronic supplementary material The online version of this article
(doi:10.1002/jsde.12013) contains supplementary material including
syntheses, characterization and 1H NMR spectra of target compounds
(6a-6f), which is available to authorized users.
* Langqiu Chen
chengood2003@263.net
APG has a hydrophilic head group portion and a hydro-
phobic tail portion. The hydrophilic head group could be
designated as glucosyl, galactosyl, maltosyl, xylosyl, and
other glycosyl fragments (Baâzaoui et al., 2016; Bayach,
1
College of Chemistry, Key Laboratory of Environmentally
Friendly Chemistry and Application of Ministry of Education,
Xiangtan University, Xiangtan, 411105, Hunan, China
Published online:
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decrease gradually with the increase of its alkyl chain for
same hydrophilic glycosyl head (Kuang et al., 2016). The
water solubility is high when the HLB number is large.
However, if the alkyl chain is too short (hydrophilic group
is relatively large), the ideal directional arrangement on the
surface of the solvent is affected leading to low surface
activity (Kuang et al., 2016). If the alkyl chain is too long,
the corresponding HLB number is rather small, there is
weak water solubility and it is not easy to form micelles in
water and reduce the surface tension.
Meanwhile, the water solubility of any sugar-based sur-
factants also decreases gradually with the decrease in the
volume of the glycosyl head group for same alkyl chain
length. As shown in Fig. 1, alkyl glycoside changes from
alkyl glucoside, alkyl galactoside, and alkyl maltoside with
bigger hydrophilic head to alkyl xyloside with smaller
hydrophilic head. Despite the low toxicity toward human
cells and good performance in diverse applications, alkyl
xyloside has the weakest water solubility as it lacks a
hydrophilic hydroxymethyl group (Bálint, J., Egri, G., Kol-
bert, A., Dianóczky, C., Fogassy, E., Novák, L., & Poppe,
L., 1999; Renciuk, D., Blacque, O., Vorlickova, M., &
Spingler, B., 2013; Tardy-Planechaud, S., Fujimoto, J.,
Lin, S. S., & Sowers, L. C., 1997) on the C5 carbon. This
difficult technical issue should be considered carefully in
order to take full advantage of the cheap, economic, and
renewable resource material xylose (Bayach et al., 2016).
In order to improve the water solubility of alkyl β-D-xylo-
pyranoside, based on the research of predecessors (Bayach
et al., 2016; Chen, Li, et al., 2016), we introduced an oxy-
ethene fragment (─OCH2CH2─) as a hydrophilic spacer to
design an array of novel alkoxyethyl β-D-xylopyranosides
(6) as shown in Fig. 2. The alkoxyethyl β-D-xylopyranosides
were prepared by the trichloroacetimidate method (Fig. 3),
and their physicochemical properties including water solu-
bility, emulsifying property, foaming property, surface ten-
sion, thermotropic liquid crystalline (LC) property, and
moisture–absorption property were investigated. By system-
atically varying the length of the hydrophobic tail, water
solubility and structure–property relationships were investi-
gated. Compared with the same alkyl-chain-length alkyl
xylopyranoside (Kuang et al., 2016), the new designed
alkoxyethyl β-D-xylopyranoside should be a value-added
sugar-based nonionic surfactant since longer alkyl chain
Fig. 1 Water solubility of alkyl glyocoside
Manickam-Achari, Iskandar, Sugimura, & Hashim, 2016;
Charoensapyanan, Ito, Rudeekulthamrong, & Kaulpiboon,
2016; Chen, Li, Chen, Ji, & Shen, 2016; Guo, Xu, Kang,
Han, & Zheng, 2016; Xu et al., 2012). The hydrophobic
hydrocarbon tail group is usually composed of different
chain lengths of saturated, fluorinated, or unsaturated alco-
hol (Chen, Li, et al., 2016; Xu et al., 2012). The most read-
ily available monosaccharide raw materials are glucose and
xylose (Oldham et al., 2013). For some time, sugar-based
surfactants have been prepared by glycochemical methods
with glucose (anhydrous or monohydrate), dextrose, and
starch as the starting materials (El-Sukkary, Syed, Aiad, &
El-Azab, 2008; Rather & Mishra, 2013; Turner, Svensson,
Adlercreutz, & Karlsson, 2007; von Rybinski & Hill, 1998;
Weuthen, Kawa, Hill, & Ansmann, 1995).
Xylose is the second most abundant sugar in the cell walls
of angiosperms and can be readily obtained from raw corn
stover and other agricultural wastes (Chatron-Colliet et al.,
2017; Chen, Shen, Kuang, & Ji, 2016; Hong et al., 2016;
Liew, Salim, Zahid, & Hashim, 2015; Qian et al., 2016;
Yuan, Teng, Zhong, & Ye, 2015). Accordingly, APG based
on xylose or xylan instead of glucose, maltose, and starch as
raw material will be a potential hot research topic. Indeed,
enzymatic/microbial, Koenigs–Knorr reaction or Fischer gly-
cosylation reactions can be used to synthesis xylose-based
surfactants that could be a useful class of xylose derivatives
(Bouxin, Marinkovic, Bras, & Estrine, 2010; Chatron-Colliet
et al., 2017; Damez et al., 2007; Das et al., 2017; Ochs,
Muzard, Plantier-Royon, Estrine, & Rémond, 2011; Satgé,
Bras, Hénin, & Muzart, 2005). Surface activity has been
reported such as the surface tension of octyl β-D-xyloside and
octyl α/β-D-xyloside was 30 and 27 mN m−1, at their critical
micelle concentration (CMC) (5.72 × 10−2 and 3.63 × 10−3 mol
L−1), respectively (Kuang et al., 2016; Liew et al., 2015).
It is generally known that both of the hydrophilic–
lipophilic balance (HLB) number and the water solubility
of any sugar-based surfactant alkyl glycoside should
Fig. 2 A hydrophilic spacer is inserted into alkyl β-D-xylopyranoside
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readily prepared by three reaction steps including acetyla-
tion, selective deprotection of protecting groups at the C-1
position, and reaction with trichloroacetonitrile. The donor
4 was coupled with a monoalkyl ethers of ethylene glycol
to afford selectively 1,2-trans alkoxyethyl 2,3,4-tri-O-ace-
tyl-β-D-xylopyranoside (5). The intermediate was then
deacetylated to obtain the target product alkoxyethyl
β-D-xylopyranoside (6). The detailed synthetic procedure
was compiled in Appendix S1 (Supporting Information).
HLB Number
The HLB of alkoxyethyl β-D-xylopyranosides (6a–6f) was
calculated from Eq. 1 using Griffin’s method (Abeyrathne,
Perera, & Karunaratne, 2013).
Fig. 3 Synthesis of alkoxyethyl β-D-xylopyranoside
length can be employed to achieve appropriate water solubil-
ity and surface activity for the xylopyranoside due to the
introduction of the hydrophilic oxyethene spacer.
20X
HLB =
ð1Þ
X + A
where X and A are the MS of the hydrophilic and lipophilic
portion of the β-D-xylopyranoside (6a–6f), respectively.
Experimental Section
Solubility Properties
Instrumental Analysis
The solubility of xylopyranoside (6a–6f) was measured in dif-
ferent solvents (water, ethanol, and ethyl acetate) at room tem-
perature (25 C) according to the literature (Chen, Li, Chen,
The chemical structures of the synthesized alkoxyethyl β-D-
xylopyranoside were confirmed using H NMR spectroscopy
ꢀ
1
Ji, & Shen, 2017; Li, 2007). The xylopyranoside (6a–6f) was
weighed in the test cup and a certain amount of solvent was
accurately introduced into the same cup and placed on the bed
and waved for 1 h. Extra solvent was carefully added dropwise
until the substance completely dissolved. The solubility can be
calculated according to the total consumption of the solvent.
using a Bruker Avance 400 spectrometer (Bruker Daltonics
Inc., Fällanden, Switzerland) for solutions in CDCl3, D2O, or
DMSO-d6. Molecular mass (MS) was measured using a Bruker
Autoflex III smartbean MALDI-TOF spectrometer (Bruker
Daltonics Inc., Breman, Germany). High-resolution mass spec-
trum (HRMS) was measured using a Thermo Scientific LTQ
Orbitrap XL (Thermo Fisher Scientific, 168 Third Avenue
Waltham, USA). Melting point (mp) was obtained with an X-4
digital mp apparatus. Liquid crystal properties were observed
with a DM-LM-P polarization microscope (Leica, Ernst-Leitz-
Strasse 17-37 Wetzlar, 35578, Germany). Crystallinity was
assessed by differential scanning calorimetry (DSC) on a TA
Q10 instrument (TA Instruments, 159 Lukens Drive, New Cas-
tle, USA) under a nitrogen atmosphere at a heating or cooling
rate of 5 ꢀC min over 0–100 C temperature range. Surface
tension was measured by the maximum bubble pressure
method (MBPM) using a DP-A precision digital pressure
gauge (Nanjing Sangli electronic equipment factory, Nanjing,
China). Thin-layer chromatography (TLC) was carried out on
preactivated silica gel HF254 by charring detection with a
H2SO4/MeOH solution.
Dissolution Enthalpy and Entropy
According to the literature (Chen, Li, et al., 2016), the
water solubility of the xylopyranoside (6a–6e) was mea-
sured as a function of temperature (25, 30, 35, 40, and
ꢀ
45 C), and Eq. 2 was used to fit the solubility (xA):
B
−1
ꢀ
lnxA = A +
ð2Þ
T
where the A and B values were achieved with least squares
fitting of the experimental data and the T represented the
temperature in Kelvin. Equations 3 and 4 were obtained
based on Gibbs–Duhem equation (Kuang et al., 2016).
ꢀ
ꢁ
dlnxA
dT
ΔsolH = RT2
ð3Þ
P
Synthesis
ꢀ
ꢁ
All raw materials were chemical or analytical grade. As
shown in Fig. 3, with D-xylose (1) as raw material, 2,3,4-
tri-O-acetyl-D-xylopyranosyl trichloroacetimidate (4) was
dlnxA
dT
ΔsolS = RT
ð4Þ
P
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Equations 5 and 6 were deduced to obtain the dissolution
enthalpy and entropy from Eqs. 2–4.
and 10, the saturated adsorption amount (Γmax) and the
average molecular area (Amin) were achieved, respectively.
ΔsolH = −RB
ð5Þ
ð6Þ
γ = kΔp
ð8Þ
ꢀ
ꢁ
RB
ΔsolS = −
T
1
dγ
Γ
max = −
ꢁ
ð9Þ
nRT dlnC
Emulsification Properties
1
Amin
=
ð10Þ
NAΓmax
According to the literature (Han, Yang, Liu, Wang, & Gao,
2015), a 20.0 mL aqueous solution of alkoxyethyl β-D-xylopyr-
anoside (6a–6e) (0.25%) and 20.0 mL toluene were accurately
addꢀed into a 100-mL measuring cylinder with stopper at
25 C. The cylinder was covered and shaken; the mixture was
then allowed to stand for 1.0 h; and the volume of the water
layer, the emulsion layer, and the oil layer were recorded,
respectively. Similarly, the emulsification of alkoxyethyl β-D-
xylopyranoside in rapeseed oil/water system was also tested;
the corresponding volumes of the water layer, the emulsion
layer, and the oil layer were also recorded, respectively.
Since xylopyranoside (6a–6d) is classified as a nonionic
surfactant, n = 1; R = 8.314 KJ mol−1 K−1; T stands for
thermodynamic temperature (K); dγ/lnC represented the
slope of the fitted curve before the inflection point and NA
is Avogadro constant. The effectiveness (πCMC) was
obtained from Eq. 11.
πCMC = γ0 −γCMC
ð11Þ
In Eq. 11, γ0 is the surface tension of distilled water and
γCMC was the surface tension at the CMC. The efficiency
and the ability to reduce surface tension (pC20) were calcu-
lated by Eq. 12.
Foaming Properties
pC20 = − logC20
ð12Þ
According to the literature (Chen, Li, et al., 2016; Gao,
Yang, Bai, & Zhang, 2014), a 100 mL aqueous solution of
the alkoxyethylꢀβ-D-xylopyranoside (6a–6d) (0.25%) was
prepared at 25 C, and 10 mL of the solution was taken
into a 100 mL measuring cylinder with stopper. The mea-
suring cylinder was covered and shaken vigorously up and
down for 1 min and the volume of foam at the moment
(H0) was recorded. After the mixed solution was kept static
state for 5 min, the volume of foam (H5) was recorded.
According to Eq. 7, the rate (υ) of bubble disappearance
was calculated, which was used to estimate the foaming
stability.
In Eq. 12, C20 is the concentration when the solution sur-
face tension was (γ0) 20) mN m−1.
The standard micellization and adsorption free energies
(ΔGmic and ΔGads) of alkoxyethyl β-D-xylopyranoside were
calculated from Eqs. 13 and 14, respectively.
ΔGmic = RT lnðCMCÞ
ð13Þ
πCMC
ΔGads = ΔGmic
−
ð14Þ
Γmax
ꢀ
ꢁ
V0 −V5 cm3
ν =
ð7Þ
Thermotropic Phase Behavior
t
s
According to the known literature (Hashim et al., 2011; Liew
et al., 2015), the thermotropic phase behavior of alkoxyethyl
β-D-xylopyranoside (6a–6f) was evaluated by polarized
Interfacial Properties
−1
ꢀ
microscopy (POM) with a heating rate of 3 C min . Both
the mp and clearing point (Cp) were recorded. Crystallinity
was assessed by DSC method on a TA Q10 instrument under
According to the MBPM (Chen, Li, et al., 2016; Eastoe &
Dalton, 2000; Fainerman, Kazakov, Lylyk, Makievski, &
Miller, 2004), a series of different concentrations of aque-
ousꢀ solution of xylopyranoside (6a–6d) were prepared at
25 C to record the corresponding maximum additional
stress (Δp); with secondary distilled water as a reference,
the surface tension (γ) of different concentrations was fur-
ther calculated according to the Laplace formula (Eq. 8).
The surface tension (γ) and the concentration (C) were
drawn out from all the obtained data. According to Eqs. 9
ꢀ
a nitrogen atmosphere at a heating and cooling rate of 5 C
min−1 over the temperature range of 0–100 C.
ꢀ
Hygroscopicity
According to the literature method (Ying, Yang, Yi, & Xu,
2007), the hygroscopicity of alkoxyethyl β-D-xylopyranoside
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Table 1 HLB number of alkoxyethyl β-D-xylopyranoside
and coupling constant (J1,2) of H-1 were δ 4.57 (d,
J = 6.8 Hz) to affirm a 1,2-trans structure. For deprotected
target compounds alkoxyethyl β-D-xylopyranosides (6a–
6f), their chemical shifts (δ) (ppm) and coupling constants
(J1,2) of H-1 for the xylopyranosides (6a–6f) were δ 4.41
(d, J = 7.8 Hz) (6a), 4.33 (d, J = 7.8 Hz) (6b), and 4.40 (d,
J = 7.4 Hz) (6c) with D2O as the solvent, δ 4.11 (d,
J = 7.6 Hz) (6d), 4.11 (d, J = 7.6 Hz) (6e) with DMSO-d6
as the solvent, 4.13 (d, J = 7.6 Hz) (6f) with DMSO-d6/
D2O as the solvent, all of the prepared β-D-xylopyranosides
(6a–6f, n = 6–12) were further approved to possess 1,2-
trans β-glycosyl bond since their coupling constant J1,2 of
H-1 is in the range of 4.0–8.0 Hz by the 1H NMR spectros-
copy (Bouxin et al., 2010; Chen & Kong, 2002; Kuang
et al., 2016; Xu et al., 2012).
Glycoside
6a
6b
6c
6d
6e
6f
HLB number
13.9
13.2
12.6
12.1
11.6
10.7
(6a–6f) was determined by the weighing method. The dried
xylosides were accurately weighted (1.00 g) and placed into
bottles of the same size, the bottles with the samples was
placed into a desiccator, and kept with the constant tempera-
ture and constant relative humidity (RH) for a period of time.
The additional weight gain was measured to estimate the
hygroscopic ability from its surroundings by Eq. 15.
Wt −W0
W% =
× 100%
ð15Þ
W0
In Eq. 15, W0 is the weight of dried sample before test-
ing, and Wt is the weight of sample after testing for t hours.
HLB Number and Solubility
According to Eq. 1, the calculated HLB numbers of alkoxy-
ethyl β-D-xylopyranosides (6a–6f, n = 6–12) are shown in
Table 1. In Table 1, the HLB numbers decrease with
increasing alkyl chain length. All HLB numbers are at the
range of 10.7–13.9, which illustrates that all of them are
hydrophilicity since HLB > 10. By comparison, three alkyl
polyglucosides (APG) had HLB numbers of 13 (capryl glu-
coside, APG-R8–10DP1.4), 11.9 (coco glucoside, APG-
R8–14DP1.3), and 11.2 (lauryl glucoside, APG-R12-14DP1.5),
respectively (Ríos et al., 2016). Therefore, our prepared
alkoxyethyl β-D-xylopyranosides (6a–6f) also achieved
around the APG HLB values by introducing a hydrophilic
spacer (─OCH2CH2─) instead of increasing DP.
Results and Discussion
Preparation and Structure Characterization
Alkoxyethyl β-D-xylopyranosides (6a–6f, n = 6–12) may
be obtained by a glycosidase enzyme that is able to catalyze
the formation of glycosides in a green and highly selective
process, but the operating conditions such as water activity,
temperature, time of incubation, pH value, nature of the
substrate, resource, and activity of enzyme will affect their
process, yield, and cost. Nevertheless, the technique is
mainly in the experimental stage (Chatron-Colliet et al.,
2017; Ochs et al., 2011).
Fischer glycosylation reaction does not afford 1,2-trans
alkoxyethyl β-D-xylopyranoside, but an inseparable mixture
of α/β anomers (Bouxin et al., 2010; Damez et al., 2007).
Koenigs–Knorr method can achieve 1,2-trans β-D-xylopyra-
noside, but there are some disadvantages such as high-cost
catalyst, environmentally unfriendly, unsuitable for indus-
trial production (Geetha & Tyagi, 2012; Satgé et al., 2005;
Xu et al., 2012). In spite of this, the Schmidt method was
selected to prepare a series of 1,2-trans alkoxyethyl β-D-
xylopyranosides (6a–6f, n = 6–12) by the neighboring group
participation as shown in Fig. 3. The detailed synthetic
procedure is described in Appendix S1. The characterization
data of alkoxyethyl 2,3,4-tri-O-acetyl-β-D-xylopyranosides
(5a, n = 6) and alkoxyethyl β-D-xylopyranosides (6a–6f,
n = 6–12) are also shown in Appendix S1.
The solubilities of alkoxyethyl β-D-xylopyranosides (6a–
ꢀ
6f, n = 6–12) in H2O, EtOH, and AcOEt at 25 C are
shown in Fig. 4. The solubilities in H2O, EtOH, and AcOEt
For some glycosides including xylopyranoside, gluco-
pyranoside, 2-acetamido-2-deoxy-β-glucopyranoside, and
galactopyranoside, their anomers can be handily confirmed
1
from their coupling constant J1,2 of H-1 at H NMR spec-
trum. For a coupling compound hexyloxyethyl 2,3,4-tri-O-
acetyl-β-D-xylopyranoside (5a), its chemical shift (δ) (ppm)
Fig. 4 Solubility of alkoxyethyl β-D-xylopyranoside in different
solvent
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all decrease with increasing alkyl chain length. The solubil-
ity in EtOH was greater than the solubility in
H2O. Dodecyloxyethyl β-D-xylopyranoside (6f) still dis-
solved in EtOH in spite of the carbon number (n) of its
alkyl chain reaching as high as 12; however, decyloxyethyl
β-D-xylopyranoside (6e) (n = 10) had poor solubility in
H2O, only as low as 0.2 g per 100 g, and 6f (n = 12) did
not dissolve in H2O. Other alkoxyethyl β-D-xylopyrano-
sides (6a–6d) (n = 6–9) were observed to have excellent
solubility in H2O, EtOH, and AcOEt, and their calculated
HLB numbers were all larger than 12.0.
In the literature (Chen, Li, et al., 2016; Kuang et al.,
2016), with the six-membered C5O ring, there is a proton
instead of the strong hydrophilic hydroxymethyl group at
the C5 position on the xylosyl headgroup; hence, the water
solubility of alkyl β-D-xylopyranoside decreased gradually
with the increase of alkyl chain as it has a smaller head-
group volume that naturally renders its less hydrophilic
compared to other glycoside such as alkyl β-D-glucopyra-
noside and alkyl β-D-maltoside. Hexyl β-D-xylopyranoside
(n = 6) has poor solubility in water. To our delight, the oxy-
ethene fragment (─OCH2CH2─) as a hydrophilic spacer
was introduced to obtain a series of xylopyranosides,
i.e., alkoxyethyl β-D-xylopyranosides (6a–6f), and they
have novelty and better solubility in water with comparison
of the same alkyl chain length of alkyl β-D-xylopyrano-
sides. There are totally similar improving trends of the
solubilities in ethanol for comparing alkoxyethyl β-D-xylo-
pyranosides (6a–6f) and alkyl β-D-xylopyranosides with
the same alkyl chain length as well.
and alkyl galactoside, e.g., octyl β-D-glucoside, octyl α-D-
glucoside, octyl β-D-galactoside, and octyl α-D-galactoside
have same HLB number (12.3), and their water solubilities
were 0.60 (Liu et al., 2013), 0.05 (Li, Chen, Chen, Shen, &
Ji, 2016), 1.07, and 10.02 g/100 mL (water) at room tem-
perature (Chen et al., 2017; Chen, Li, et al., 2016). They
are different from each other, indicating that the glycosyl
head and anomeric configuration affect the water solubility
in spite of identical HLB numbers. APG with DP from 1 to
5 containing alkyl chains from 6 to 14 carbons are soluble
in water, such as C8/C10 polyglucosides, C9–11 polyglu-
cosides, and C12/C14 polyglucosides, they are considered
as water solubility; but these molecules with 16–22 carbon
atoms are oil-soluble. Their water solubility increases
with increasing DP (Sułek, Ogorzałek, Wasilewski, &
Klimaszewska, 2013). Of course, cloud point can also be
used to evaluate water solubility to some extent (von
Rybinski & Hill, 1998).
As foundational research, alkyl glycoside such as alkyl
β-D-xylopyranoside or its derivative alkoxyethyl β-D-xylo-
pyranoside and other pure compounds are easy to obtain
exact data on water solubility, but mixtures of alkyl (poly)
glycosides, such as APG, alkyl α/β-glycoside, or alkyl
furanoside/pyranoside, are difficult to achieve exact data
for water solubility.
Dissolution Enthalpy and Entropy
The heat of solution can be defined as the change in
enthalpy when a given solute is dissolved in a solvent to
form a solution at a certain temperature and pressure. More-
over, the dissolution enthalpy of the solution can reflect the
influence of temperature on the solute’s solubility. The dis-
solution behavior is an endothermic process while the dis-
solution enthalpy has a positive value and vice versa.
As disclosed in the literature (Ochs et al., 2011), parti-
tioning of octyl oligoxyloside between aqueous and octanol
phase depends on the average degree of polymerization
(DP), octyl β-D-xyloside (95%), octyl β-D-xylobioside
(88%), and octyl β-D-xylotrioside (62%) were mainly local-
ized in the octanol phase. The result could be considered as
octyl β-D-xylopyranoside (HLB = 11.4 < 12.0) had very
small water solubility (0.05 g per 100 g [water]) (Kuang
et al., 2016), octyl β-D-xylobioside (HLB = 14.3) and octyl
β-D-xylotrioside (HLB = 15.7) should have higher water
solubility though the data were not found in literature, but
the two anomeric pure alkyl oligoxylosides are more diffi-
cult to prepare than alkoxyethyl β-D-xyloside with glyco-
chemistry. For the alkyl polyxylosides, Krafft point was
also used to evaluate the water solubility, the Krafft points
of octyl polyxyloside (DP = 1.2), decyl polyxyloside
(DP = 1.1), and dodecyl polyxyloside (DP = 1.2) were
In order to determine the dissolution enthalpy (ΔsolH)
and dissolution entropy (ΔsolS) of alkoxyethyl β-D-xylopyr-
anoside, we selected some alkoxyethyl β-D-xylopyrano-
sides (6a–6e, n = 6–10) that were soluble in water at room
temperature as described previously,ꢀand measured their
solubility at 25, 30, 35, 40, and 45 C. The relationship
between solubility (lnxA) and temperature (1/T) is shown in
Fig. 5. In Fig. 5, the solubility (lnxA) increased obviously
as the temperature increased gradually. Moreover, for hexy-
loxyethyl, heptyloxyethyl, and octyloxyethyl β-D-xylopyra-
noside (6a–6b, n = 6–8), the variation magnitudes of their
solubilities (lnxA) were smaller with increasing tempera-
ture; for decyloxyethyl β-D-xylopyranoside (6e, n = 10), its
variation was obviously larger with increase in temperature
as there is a relatively steep straight line, far away from
other lines of β-D-xylopyranosides (6a–6d). The values of
A and B were obtained from the straight line in Fig. 1 and
Eq. 2 are given in Table 2. According to Eq. 5, the values
ꢀ
21, 36.2, and 44.9 C, respectively, indicating that octyl
polyxyloside (DP = 1.2, HLB = 12.2) had rather low water
solubility, decyl polyxyloside (DP = 1.1, HLB = 10.7), and
dodecyl polyxyloside (DP = 1.2, HLB = 10.2) have low
water solubility as they have low DP (near 1) (Renault,
Portella, Marinkovic, & Estrine, 2012). For alkyl glucoside
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Fig. 6 Dissolution entropy of xylopyranosides at different
temperature
Fig. 5 Solubility of alkoxyethyl xylopyranoside in water at different
temperature
Foaming Properties
of dissolution enthalpy (ΔsolH) of β-D-xylopyranosides
(6a–6e) were calculated and given in Table 2 and ΔsolH > 0,
which indicated that the dissolution process of β-D-xylopyr-
anosides (6a–6e) is an endothermic process and that ΔsolH
increases with increasing alkyl chain length.
APG generally have rich and delicate foam. In this study, the
foaming property of alkoxyethyl β-D-xylopyranosides (6a–
6d, n = 6–9) including foaming characteristics and foam sta-
bility was investigated. In Fig. 7, the foaming ability,
i.e., initial volume (H0), of alkoxyethyl β-D-xylopyranosides
(6a–6d) first increased and then decreased with increasing
alkyl chain length, final volume (H5) also changed in the
same manner; however, rate (ν) of bubble disappearance
shows slight differences. In addition, octyloxyethyl β-D-xylo-
pyranoside (6c, n = 8) and nonyloxyethyl β-D-xylopyrano-
side (6d, n = 9) had excellent foaming ability, and
octyloxyethyl β-D-xylopyranoside (6c, n = 8) has the stron-
gest foaming ability, and its H5 was as high as 35 mL, but
the nonyloxyethyl β-D-xylopyranoside (6d) had best foam
stability as its ν was as low as 0.01 mL s−1.
In addition, the value of dissolution entropy (ΔsolS) was
calculated by Eq. 6. The relationship between temperature
and dissolution entropy is shown in Fig. 6, and the dissolu-
tion entropy of β-D-xylopyranoside (6a–6e) decreased grad-
ually with increasing temperature. The value of dissolution
entropy of hexyloxyethyl β-D-xylopyranoside (6a) was the
smallest, and that of decyloxyethyl β-D-xylopyranoside (6e)
was maximal and far away other β-D-xylopyranosides (6a,
6b), and ΔsolS > 0. In the literature (Kuang et al., 2016),
both ΔsolH and ΔsolS values of alkyl β-D-xylopyranosides
(n = 4–9) also decreased with increasing temperature. The
ΔsolS values increased with the increase of alkyl chain. The
oxyethene fragment (─OCH2CH2─) as a hydrophilic spacer
was introduced to obtain novel alkoxyethyl β-D-xylopyra-
noside, with increased HLB number and improved water
solubility, but did not change the trend in the dissolution
process. Hence, both should have the same endothermic
and entropic driving force because both of ΔsolH > 0 and
ΔsolS > 0 during the dissolution process of alkyl β-D-xylo-
pyranosides (n = 4–9) and alkoxyethyl β-D-xylopyranosides
(6a–6e, n = 6–10) in water.
Emulsification Properties
The emulsification of alkoxyethyl β-D-xylopyranoside (6a–
6e, n = 6–10) in rapeseed oil/water system and in toluene/
water system was investigated. In Figs. 8 and 9, the volume
of the oil-in-water (O/W) emulsion layer first increased and
then decreased in the same way in both systems with
increasing alkyl chain length. In both systems, emulsifying
ability of nonyloxyethyl β-D-xylopyranoside (6d, n = 9)
Table 2 Parameter of Eq. 2 and dissolution enthalpy for different solution
Glycoside
6a
6b
6c
6d
6e
A
B
13.96
−1999.29
16.62
16.48
−2844.24
23.65
16.91
−3022.05
25.13
20.57
−4338.55
36.07
28.36
−7919.63
65.85
Δ
solH (kJ mol−1
)
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Fig. 7 Foaming ability of alkoxyethyl β-D-xylopyranoside (6a–6d)
was the strongest, the emulsified layer had as high as
30 mL in rapeseed oil/water system and 40 mL in toluene/
water system, respectively. In spite of its weak water solu-
bility, the possible reasons may be that the nonyl group
was the most excellent by its weak hydrophobic bonds and
fine flexible chain in making the strongest emulsifying abil-
ity as its calculated HLB was 12.1.
For the rapeseed oil/water system, hexyloxyethyl xylo-
pyranoside (6a, n = 6) had poor emulsifying ability; hepty-
loxyethyl and octyloxyethyl xylopyranoside (6b, 6c, n = 7,
8) had only weak emulsifying ability; and formed Winsor
type III systems (water layer, emulsifying layer and oil
layer), nonyloxyethyl, and decyloxyethyl xylopyranosides
(6d, 6e, n = 9, 10) shows the formation of Winsor II sys-
tems (Ruckenstein, 1996). Moreover, for the toluene/water
system, both of hexyloxyethyl and heptyloxyethyl xylopyr-
anosides (6a, 6b, n = 6, 7) show weak O/W emulsifying
ability, and three xylopyranosides (6a–6c, n = 6–8) partici-
pated in the formation of the Winsor type III systems,
Fig. 9 Emulsifying of ability of xylopyranoside (6a–6e) in toluene/
water system
nonyloxyethyl xylopyranoside (6d, n = 9) had the strongest
emulsifying ability and participated in the formation of sin-
gle layer, i.e., an emulsifying layer, decyloxyethyl xylopyr-
anoside (6e, n = 10) participated in the formation of a
Winsor type II system. The xylopyranoside (6a–6e) were
observed to have slightly stronger emulsifying ability in
toluene/water system than that in rapeseed oil/water system
because there were higher emulsion layer volumes in tolu-
ene/water system than in rapeseed oil/water system.
Interfacial Properties
The relationship between the concentration of alkoxyethyl
β-D-xylopyranosides (6a–6d, n = 6–9) and the surface ten-
ꢀ
sion in their aqueous solution was investigated at 25 C
and the results are shown in Fig. 10 and Table 3. In Fig. 10,
Fig. 8 Emulsifying ability of xylopyranoside (6a–6e) in rapeseed oil/-
Fig. 10 Relationship between surface tension and concentration of
water system
xylopyranoside
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Table 3 Adsorption parameter of β-D-xylopyranoside at 25 C
ꢀ
Glycoside
6a
6b
6c
6d
−1
CMC (mol L
)
9.00 × 10−2
30.96
3.81 × 10−2
29.41
2.42 × 10−2
29.26
7.96 × 10−2
27.80
γCMC (mN m−1
)
dγ/dlnC
−8.79
−9.45
−10.36
4.18
−11.59
4.68
Γ
max (10−6 mol m−2
Amn (Å2)
)
3.55
3.81
46.79
43.60
39.74
35.50
πCMC (mN m−1
)
41.01
42.56
42.71
44.17
pC20
2.08
2.48
2.59
3.04
ΔGmic (kJ m−1
ΔGads (kJ m−1
)
−5.97
−8.10
−9.23
−11.98
−21.42
)
−17.52
−19.27
−19.45
there is an inflection point for each curve and the concen-
tration at the inflection point is considered as the CMC.
The surface tension (γ) of the aqueous solution of the β-D-
xylopyranoside (6a–6d) gradually decreased with increas-
above the CMC, the surface tension (γ) of the β-D-xylopyr-
anoside (6a–6d) solution is a constant straight line because
the surface concentration remains constant and the extra
β-D-xylopyranoside is incorporated into micelles. There-
fore, the spontaneous self-assembled micellization is driven
by the hydrophobic effect owing to the minimization of the
Gibbs free energy.
The CMC value of octyl β-D-glucoside (HLB = 12.3) is
2.5 × 10−2 mol L−1 (Chen & Kong, 2002). APG, C8APG,
C9APG, C10APG, and C12APG have CMC (γCMC) values
of 1.71 × 10−3 (29), 1.23 × 10−3 (33), 7.81 × 10−4 (31),
and 2.97 × 10−4 mol L−1 (32 mN m−1) (El-Sukkary et al.,
2008). Two representative commercial APG had CMC
ing concentration and reached a specific low value (γCMC
)
at the CMC. The surface tension of the aqueous solution of
nonyloxyethyl β-D-xylopyranoside (6d, n = 9) was as low
as 27.80 mN m−1 at its CMC. Different alkoxyethyl β-D-
xylopyranoside had different CMC value and the value
depends on the length of alkyl chain, the longer the alkyl
chain, the lower the CMC value, which indicated that there
was higher surface activity for alkoxyethyl β-D-xylopyrano-
side with longer chain in the range of n = 6–9. In Table 3,
the average molecular area (Amin) of alkoxyethyl β-D-xylo-
pyranoside (6a–6d, n = 6–9) is also shown to decrease with
increasing alkyl chain length.
In Table 3, the effectiveness (πCMC) increased for β-D-
xylopyranoside (6a–6d) with increasing alkyl chain length,
the higher the effectiveness of surface tension reduction at
the CMC, the stronger the surface activity. As shown in
Table 3, the efficiency (pC20) increased also for β-D-xylo-
pyranoside (6a–6d) with increasing alkyl chain length, the
larger pC20 value, the greater the tendency of the surfactant
to adsorb at the air/water interface (Chen, Li, et al., 2016).
Hence, nonyloxyethyl β-D-xylopyranoside (6d) had the
values of 1.01 (capryl glucoside, APG-R8–10DP1.4
HLB = 13) and 0.15 (coco glucoside, APG-R8–14DP1.3
,
,
HLB = 11.9), respectively (Ríos et al., 2016). For the alkyl
polyxylosides, the CMC (γCMC) values of octyl α/β-D-xylo-
side (DP = 1, HLB = 11.4) and octyl β-D-oligoxylosides
(DP > 2) were 0.953 gꢁL−1 (i.e., 3.66 × 10−6 mol L−1)
(27 mN m−1) and 4.23 g L−1 (27.0 mN m−1), respectively
(Ochs et al., 2011). The data show that lower CMC value
regardless of the alkoxyethyl β-D-xylopyranosides com-
pared to other alkyl (poly)glycosides.
In the literature (Kuang et al., 2016), the surface tensions
of octyl and nonyl β-D-xylopyranoside (n = 8, 9) were
30.08 and 35.72 mN m−1 in their aqueous solution under
the CMC, respectively. And the surface tensions of octy-
loxyethyl and nonyloxyethyl β-D-xylopyranose (6c, 6d,
n = 8, 9) were 29.26 and 27.80 mN m−1 in their aqueous
solution under the CMC in this work, respectively. There-
fore, compared with the alkyl β-D-xylopyranoside, our syn-
thesized alkoxyethyl β-D-xylopyranosides had better
surface activity at the same carbon chain length.
strongest surface activity because its effectiveness (πCMC
)
and efficiency (pC20) were largest.
In addition, the micellization free energy (ΔGmic) in the
solution and the adsorption free energy (ΔGads) in the sur-
face layer of alkoxyethyl β-D-xylopyranosides (6a–6d,
n = 6–9) in aqueous solution were negative as shown in
Table 3, and their values became more negative with
increasing alky chain length, indicating that the micelle and
surface adsorption in solution is a spontaneous process
involving the hydrophobic effect (Chen, Li, et al., 2016).
The ΔGads value is more negative than the ΔGmic value,
which indicated that alkoxyethyl β-D-xylopyranoside (6a–
6d) was easier to adsorb at the interface to form a mono-
layer rather than to form micelles in solution when the con-
centration is below the CMC. When the concentration is
Thermotropic LC Properties
LC phase structures are often found in living organisms.
Cellular membranes are the result of lyotropic LC phases
resulting from the dissolution of phopholipids in water
(de Souza et al., 2017; Lagerwall & Scalia, 2012). There
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Fig. 11 Texture of alkoxyethyl β-D-xylopyranoside characterized by OPM upon heating (a) and cooling (b) (magnification 200×)
should be value in studying sugar-based amphiprotic non-
ionic surfactants such as alkyl glycosides with many advan-
tages (Hashim, Sugimura, Minamikawa, & Heidelberg,
2012) as some of them possess the LC performance. The
lyotropic LC behavior and/or thermotropic LC behavior are
related to its structure and other physicochemical proper-
ties, thereby the specific research results are able to provide
a lot of useful information in drug delivery, gene delivery,
self-organization, self-assembly and supermolecule forma-
tion, functional biomembrane, LC biological sensors, and
LC-based immunodetection to some extent (Hashim et al.,
2012; Lagerwall & Scalia, 2012; de Souza et al., 2017).
We used a polarizing microscope (OPM) to observe the
thermotropic LC behavior of the alkoxyethyl β-D-xylopyra-
nosides (6a–6f, n = 6–12) in the heating process to learn
more about the relations between their alkyl chain length
and the thermotropic LC performance, and the results are
shown in Fig. 11.
texture in the heating process, weakened obviously their
fan schlieren texture to some extent and even remained
obscure in cooling process.
Table 4 summarizes their mp and the Cp, both mp and
Cp increase gradually with increasing alkyl chain length,
and the phase transformation temperature (ΔT) were in the
range of 9.38–15.65. Meanwhile, Fig. 12 shows the DSC
thermogram of alkoxyethyl β-D-xylopyranoside (6a–6f,
n = 6–12). In Fig. 12, hexyloxyethyl β-D-xylopyranoside
(6a) and heptyloxyethyl β-D-xylopyranoside (6b) show
lower mp and Cp than other β-D-xylopyranosides (6c–6f,
n = 6–12) from their heat flow curves. Alkoxyethyl β-D-
xylopyranosides (6c–6f, n = 8–12) show weaker heat flow
of phase transition from solid to liquid crystal; conversely,
they showed stronger heat flow of phase transition from liq-
uid crystal to isotropic liquid.
In Fig. 11, the thermotropic liquid crystal texture was
observed in the process of heating (A) under the polarizing
microscope. Nonyloxyethyl β-D-xylopyranoside (6d, n = 9)
presented clear Maltese cross pattern texture in the process
of heating, conversely, it showed fan schlieren texture in
the process of cooling, the texture belonging to crystal
Smetic A (Hashim et al., 2012). However, other alkox-
yethyl β-D-xylopyranoside (6a–6c, n = 6–8; 6e, n = 10; 6f,
n = 12) performed indistinct, even shapeless, cross pattern
Table 4 Phase transition temperature of alkoxyethyl β-D-
xylopyranoside
Glycoside
6a
6b
6c
6d
6e
6f
mp (ꢀC)
Cp (ꢀC)
ΔT (ꢀC)
26.38
42.03
15.65
34.79
48.25
13.46
43.12
52.50
9.38
43.48
53.82
10.34
45.29
57.55
12.26
59.24
69.46
10.22
Fig. 12 DSC curve for xylopyranoside during the heating process
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Fig. 13 DSC thermogram of dodecyloxyethyl β-D-xylopyrano-
side (6f)
Fig. 15 Hygroscopicity of alkoxyethyl β-D-xylopyranoside
on RH = 81%
DSC thermogram of dodecyloxyethyl β-D-xylopyranose
(6f, n = 12) is shown in Fig. 13. At first, the transition pro-
cesses from crystal state to isotropic liquid state via liquid
Hygroscopicity
Under the same humidity, the more moisture the compound
absorbs, the higher the hygroscopicity. We investigated the
hygroscopicity of alkoxyethyl β-D-xylopyranosides (6a–6f,
n = 6–12) according to references (Chen et al., 2017; Ying
et al., 2007). The dried samples were measured under the
environments of RH (RH = 43% [saturated Na2CO3 aque-
ous solution] and RH = 81% [saturated (NH4)2SO4 aqueous
ꢀ
crystal formation upon heating at a rate of 20 C per min.
Next, an LC phase was formed on cooling at a rate of 5 ꢀC
min–1. Finally, the melting peak was not observed by the
second heating at a rate of 5 ꢀC min–1. The possible reason
is that dodecyloxyethyl β-D-xylopyranose (6f) does not
form a fine crystal state with lower symmetry under cooling
from thermally induced isotropic liquid state with high
symmetry by the spontaneous symmetry breaking mecha-
nism by the change of the order parameter of Landau’s
phase-transition theory, and it was possible to turn into an
aggregate state at the cooling; therefore, such aggregate
state was observed to merge into a diffuse broad peak rather
than two sharp peaks (melting peak and clearing peak).
ꢀ
solution] at 25 C, respectively). The additional weights
were recorded at the time of 2, 4, 6, 8, 10, 24, 48, and 72 h,
respectively, and the results are shown in Figs. 14
(RH = 43%) and 15 (RH = 81%) according to Eq. 15.
In Figs. 14 (RH = 43%) and 15 (RH = 81%), the hygro-
scopicity (W%) increased with the increase of time, con-
versely, the hygroscopicity (W%) decreased with the
increase of alkyl chain length. There was fine hygroscopic-
ity for alkoxyethyl β-D-xylopyranoside (6a–6d, n = 6–9)
due to its shorter alkyl chain, hexyloxyethyl β-D-xylopyra-
nose (6a) possessed the strongest hygroscopicity (W
% = 29.16% [RH 43%] and 24.68% [RH 81%]).
Conclusion
In this study, alkyl β-D-xylopyranosides were upgraded to
design rationally and prepare readily six alkoxyethyl β-D-
xylopyranosides (6a–6f) with an oxyethene spacer by the
glycochemistry method, and their 1,2-trans configurations
were confirmed by 1H NMR spectroscopy.
An introduction of the hydrophilic space was of a benefit
to the glycosides (6a–6e) in higher HLB number and
higher water solubility than the original alkyl β-D-xylopyra-
nosides with the same alkyl chain (Kuang et al., 2016);
Fig. 14 Hygroscopicity of alkoxyethyl β-D-xylopyranoside
on RH = 43%
J Surfact Deterg (2018)

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and their application as emulsifying and antibacterial agents. Bio-
technology and Bioprocess Engineering, 21:389–401.
however, dodecyloxyethyl glycoside (6f) did not dissolve
in water because the alkyl chain is too long. By compari-
son, octyloxyethyl glycoside (6c) had the best foaming
ability and better foam stability; nonyloxyethyl glycoside
(6d) had better foaming ability, the best foam stability, and
the strongest emulsifying ability. The glycosides (6a–6d)
decreased surface tension of the aqueous solution. All gly-
cosides (6a–6f) had thermotropic LC behavior, their mp
and the Cp increased gradually with increasing alkyl chain,
nonyloxyethyl glycoside (6d) showed the most distinct
thermotropic liquid phase, and there was a cross pattern
texture at heating and the fan schlieren texture in cooling.
Their hygroscopicity (6a–6f) decreased with increasing
alkyl chain length.
A series of anomerically pure alkoxyethyl β-D-xylopyra-
nosides (6a–6f) were successfully obtained with a hydro-
philic spacer (─OCH2CH2─), and their water solubility
was improved, and they had higher surface activity than the
original alkyl β-D-xylopyranosides (Kuang et al., 2016).
The foundational research should broaden their potential
applications as a class of novel mild nonionic sugar-based
amphiphilic surfactants with favorable ecological and toxi-
cological properties.
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Chen, G., Li, Z., Chen, L., Ji, S., & Shen, W. (2016) Synthesis and
properties of alkyl β-D-galactopyranoside. Journal of Surfactants
and Detergents, 19:1095–1105.
Chen, G., Li, Z., Chen, L., Ji, S., & Shen, W. (2017) Synthesis and
properties of alkyl α-D-galactopyranoside. Journal of Dispersion
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Chen, L., Shen, W. Z., Kuang, N., & Ji, S. W. (2016) Synthesis of
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Hausen, M., & Chaud, M. (2017) Spotlight on biomimetic systems
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Acknowledgements This work was supported by the National Nat-
ural Science Foundation of China (grant no. 21643010) and Hunan
2011 Collaborative Innovation Center of Chemical Engineering &
Technology with Environmental Benignity and Effective Resource
Utilization
Du, Z., Wang, C., Tai, X., Wang, G., & Liu, X. (2016) Optimization
and characterization of biocompatible oil-in-water nanoemulsion
for pesticide delivery. ACS Sustainable Chemistry & Engineering,
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(2008) Synthesis and characterization of some alkyl polyglycosides
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Wangzhen Shen is a postgraduate student in college of chemistry at
Xiangtan University. She obtained her B.E. in food quality and safety
from Jishou University in 2014. Her studies involve the synthesis and
application of sugar-based surfactants.
Shanwei Ji is a postgraduate student in college of chemistry at Xiang-
tan University. He obtained his B.Sc. in materials chemistry from
Yulin Normal University in 2014. His studies involve the synthesis
and application of alkyl glycoside.
Langqiu Chen received his B.Sc. in chemistry from Xiangtan Uni-
versity in 1984, his M.E. in food Engineering from Light Industry
Institute of Tianjing in 1990, and his Ph.D. from the Graduate School
of Chinese Academy of Sciences (Research Center for Eco-Environ-
mental Science, Academia Sinica) in 2003. He worked as a guest
researcher in Ryukoku University which was supported by JSPS for
ten months and as a postdoctoral position in department of chemistry
at Oxford University for one year. He is a professor in college of
chemistry at Xiangtan University. His studies involve the research of
carbohydrate chemistry, sugar-based surfactants, organic synthesis,
pharmaceutical synthesis and food additives.
Yanhua Zhang is a postgraduate student in college of chemistry at
Xiangtan University. She obtained his B.Sc. in chemistry from Heng-
yang Normal University in 2015. Her studies involve the synthesis
and application of alkyl glycoside.
Ríos, F., Fernández-Arteaga, A., Lechuga, M., Jurado, E.,
&
Fernández-Serrano, M. (2016) Kinetic study of the anaerobic bio-
degradation of alkyl polyglucosides and the influence of their struc-
tural parameters. Environmental Science and Pollution Research,
23:8286–8293.
Ruckenstein, E. (1996) Microemulsions, macroemulsions, and the
Bancroft rule. Langmuir, 12:6351–6353.
Xiubing Wu is a postgraduate student in college of chemistry at
Xiangtan University. He obtained his B.E. in chemical engineering
and technology from Hunan Institute of Engineering in 2016. His
studies involve the synthesis and application of alkyl glycoside.
J Surfact Deterg (2018)