Table of Content

10 May 2019, Volume 40 Issue 5

Previous Issue    Next Issue

Content

Cover and Content of Chemical Journal of Chinese Universities Vol.40 No.5(2019)

2019, 40(5):  0-0. 

Asbtract ( )   PDF (18277KB) ( )  

Related Articles | Metrics

Review

MOFs-Based Materials for Photocatalytic CO₂ Reduction^†

HE Pengchen,ZHOU Jian,ZHOU Awu,DOU Yibo,LI Jianrong

2019, 40(5):  855-866.  doi:10.7503/cjcu20180688

Asbtract ( )   HTML ( )   PDF (6262KB) ( )  

Figures and Tables | References | Related Articles | Metrics

We summarize the recent progress of metal-organic frameworks(MOFs) used for photocatalytic CO₂ reduction, including MOFs employed directly as the photocatalysts for CO₂ reduction and as components in hybrid photocatalytic systems for CO₂ reduction. Meanwhile, the fascinating features of MOFs-based photocatalysts in CO₂ reduction are presented. Finally, the challenges and perspectives regarding of MOFs-based photocatalyst are also discussed.



Inorganic Chemistry

Synthesis of STW-zeotype Germanosilicate via Steam-assisted Crystallization^†

FANG Xijie,LIU Ruiyun,LIN Sen,SHI Lei,WANG Runwei,LI Yi,LI Junying

2019, 40(5):  867-872.  doi:10.7503/cjcu20180859

Asbtract ( )   HTML ( )   PDF (1964KB) ( )  

Figures and Tables | References | Related Articles | Metrics

STW-zeotype germanosilicate was synthesized via the steam-assisted conversion(SAC) approach with N,N'-diethylethylenediamine(DEEDA) as an organic template. The effect of additional water on the resultant materials was systematically investigated by powder X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive spectrometer(EDS) and thermogravimetric(TG) analyses. In comparison with the conventional hydrothermal synthesis, the SAC method needs significantly less organic templates, through which the synthesized germanosilicate exhibits a high crystallinity and much more Si element content, as well as the high structural stability. The framework of STW-zeotype germanosilicate prepared by the SAC method remains stable even after undergoing a high temperature calcination(600 ℃).



Syntheses, Structures and Properties of Homochiral Metal-organic Frameworks with Helices and Trinuclear Cluster Units Based on Semirigid Proline Derivatives^†

XU Zhongxuan,HUANG Lina,DENG Yuhua,MENG Qin

2019, 40(5):  873-879.  doi:10.7503/cjcu20180827

Asbtract ( )   HTML ( )   PDF (3379KB) ( )  

Figures and Tables | References | Related Articles | Metrics

With the help of nitrogen heterocycle auxiliary ligand 1,4-di(pyridin-4-yl)benzene)(1,4-DPB), a pair of homochiral metal-organic frameworks named [Cd_1.5((R)-PIA)(1,4-DPB)_1.5]·0.75H₂O·xGuest(1-D) and [Cd_1.5((S)-PIA)(1,4-DPB)_1.5]·0.75 H₂O·xGuest(1-L)[H₃PIA=5-(2-carboxypyrrolidine-1-carbonyl)isophthalic acid] have been prepared from proline derivative ligands (R)-H₃PIA and (S)-H₃PIA and cadmium ions. Crystallographic analysis indicates that complexes 1-D and 1-L feature three-dimensional open pore structure, containing wavy metal-carboxylate layers and almost linear trinuclear cadmium cluster units. In complexes 1-D and 1-L, the wavy metal-carboxylate layers consists of two types of homochiral helical chains, which are constructed by PIA fragments and cadmium ions. Moreover, powder X-ray diffraction patterns(PXRD), thermogravimetric analysis(TGA), circular dichroism(CD) spectra, and photoluminescent spectra of complexes 1-D and 1-L were also investigated. The results show all the peak positions of simulated and experimental PXRD patterns match well with each other, indicating that the complexes were obtained as a single phase. Furthermore, TGA curves of complexes 1-D and 1-L are very similar to each other and their CD spectrum have obviously positive or negative signal, which accord with their enantiomeric properties.



Analytical Chemistry

Derivation and Application of Signal-to-background-to-concentration Ratio for Atomic Emission Spectrometry^†

YU Bingwen,JIN Wei,JIN Qinhan,LIU Xu

2019, 40(5):  880-886.  doi:10.7503/cjcu20180801

Asbtract ( )   HTML ( )   PDF (2236KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The concept of signal-to-background-concentration ratio(SBCR) was derived and proposed to be a useful tool for judgement of the excitation power of an atomic excitation source(e.g., MPT) for atomic spectrometry based on the linear relationship between signal intensity, CCD integration period and sample concentration. The relationship between detection limit and SBCR was derived according to the definition of detection limit. The predicted expressions of maximum integration period, maximum signal-to-background ratio, and maximum SBCR were derived based on reasonable assumptions. The above model was verified by experiments. Finally, the excitation capability of low-power ArMPT for copper was characterized by this SBCR method, and the detection limit of Cu was improved from 13.1 ng/mL to 2.8 ng/mL.



Bimetallic Multi-core Nanoparticles with Dual SiO₂ Layer Au@SiO₂@Ag@SiO₂ for the Detection of Glucose^†

QI Qi,LU Bingxin,CHE Yuping,WANG Yang,ZHAI Jin

2019, 40(5):  887-894.  doi:10.7503/cjcu20180722

Asbtract ( )   HTML ( )   PDF (3700KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Surface-enhanced Raman scattering(SERS) was demonstrated as a highly efficient approach for the amplification of extremely low signals due to the strong electromagnetic field enhancement that occurs near closely-packed metallic nanostructures, which was dependent on the unique localized surface plasmon resonance(LSPR). To develop sensitive SERS probes, different geometric configurations as approaches are focusing on the synthesis of advanced nanostructures, or efficient Raman label compounds that are resonant with excitation light. These geometric factors affect the polarization direction and magnitude of plasmonic coupling and the SERS signal intensity. As we know, plasmonic properties of Au and Ag NPs are highly sensitive to their shapes. In order to improve the performance of metal nanoparticles in SERS detection, we prepared a highly sensitive and stable bimetallic double silicon core-shell nanostructured material of Au@SiO₂@Ag@SiO₂. The nanoparticles have good Raman scattering properties and excellent stability, since the silicon layer between the bimetals promotes remote plasma excitation transfer. The main component of human urine can be directly detected by using this SERS active material, and the material exhibits the ability to detect highly effectiveness 10^-6 mol/L glucose with label-free Au@SiO₂@Ag@SiO₂ nanoparticles. In addition, simultaneous detection of medium concentrations of 10^-3 mol/L glucose and urea molecules in artificial urine and detection of 10^-3 mol/L glucose in actual urine were also achieved. The Au@SiO₂@Ag@SiO₂ nanoparticles show the potential for detection glucose in the presence of multiple biomolecules.



Preparation and Sensing Application of Graphene/SU-8 Composite Conductive Photoresist^†

WU Qian,XU Mengyi,XU Sheng,WEI Wei,LI Xiaojie,LIU Xiaoya

2019, 40(5):  895-900.  doi:10.7503/cjcu20180816

Asbtract ( )   HTML ( )   PDF (3748KB) ( )  

Figures and Tables | References | Related Articles | Metrics

It was proposed to introduce graphene(GR) with electrical and thermal conductivity into the photoresist SU-8 to prepare a conductive composite photoresist. The ultra-depth microscope and multimeter were used to investigate the dispersion and the conductivity of the composite photoresist, respectively. The results show that the composite photoresist is conductive when the mass fraction of graphene reaches 3%, and the dispersion of graphene is relatively uniform. Subsequently, a novel GR/SU-8 patterned electrode(GR/SU-8/ITO) with the designed pattern was prepared by photolithography on ITO glass surface. The composite conductive photoresist with 4%GR forms a conductive path with the ITO electrode, which increases the specific surface area of the electrode. After 40 cycles of cyclic voltammetry scanning, the redox current of the composite electrode was increased and the electrode performance was further improved. Finally, a hydrogen peroxide-free enzyme sensor was prepared on the surface of composite GR/SU-8/ITO electrode by electrochemical in situ reduction of copper nanoparticles. The excellent electron transfer ability of the electrode was verified by this simple enzyme-free sensing system. The prepared sensor has good linearity detection for hydrogen peroxide in the range of 1—20 mmol/L(R²=0.999). The stability of the obtained biosensor is excellent because the current response can still be maintained above 90% after 15 d. At the same time, the obtained sensor also has good selectivity and anti-interference which reflected in the nearly same current response to hydrogen peroxide in the presence of various interferents. In conclusion, the above results prove the application of the conductive photoresist in the field of electrochemistry. It is believed that the composite non-enzymatic electrochemical sensor has great application in point of care in the future.



Preparation of SiW₁₁ Incorporated SiO₂ Nanofibers(SiW₁₁/SiO₂) and Its Application in the Analysis of Polyamines in Arabidopsis^†

CAI Jiao,YU Qiongwei,HE Xiaomei,XU Jing,DING Qiong,FENG Yuqi

2019, 40(5):  901-908.  doi:10.7503/cjcu20180531

Asbtract ( )   HTML ( )   PDF (2731KB) ( )  

Figures and Tables | References | Related Articles | Metrics

SiW₁₁ incorporated SiO₂ nanofibers(SiW₁₁/SiO₂) was prepared by electrospinning technology. The mass of incorporated SiW₁₁ accounted for 7.83% of nanofibers. SiW₁₁/SiO₂ nanofiber possessed uniform structure with the diameter about 450 nm, and was negative charged in the pH range of 1.0—11.0. Compared with SiO₂ nanofibers, the SiW₁₁/SiO₂ nanofiber exhibited stronger cation-exchange interactions to extract PUT and CAD. Under the optimized condition, an in-syringe dSPE-UHPLC-MS/MS method for rapid and selective detection of polyamines from plants was established. The limits of detection(LODs) for the target CAD and PUT ranged from 0.5 ng/mL to 0.9 ng/mL, and the linear range was 10—1000 ng/mL and 20—1000 ng/mL with determination coefficients(R²) higher than 0.9950. The recoveries ranged from 87.5% to 111.3% with relative standard deviations(RSDs) of 1.9%—7.2%. The proposed method can be used to detect the trace CAD and PUT in Arabidopsis.



Organic Chemistry

Synthesis and Biological Activities of Myricetin Derivatives Containing Quinoxaline^†

LI Pu,CHEN Ying,XIA Rongjiao,GUO Tao,ZHANG Min,JIANG Shichun,ANG Xu,HE Ming,XUE Wei

2019, 40(5):  909-917.  doi:10.7503/cjcu20180828

Asbtract ( )   HTML ( )   PDF (771KB) ( )  

Figures and Tables | References | Related Articles | Metrics

According to the active substructure combination theory, a series of novel myricetin derivatives containing quinoxaline moieties was synthesized by introducing the quinoxaline blocks into the structures of myricetins. The antibacterial activities of the target compounds were evaluated via turbidimeter test in vitro. The preliminary bioassay results indicated that all of the title compounds exhibited certain antibacterial activities in vitro against Xanthomonas axonopodis pv. Citri(X. citri) and Xanthomonas oryzae pv. Oryzae(X. oryzae). The compounds were also tested to evaluate the half maximal effective concentration(EC₅₀) of phytopathogenic bacteria. The results showed that all the X. citri EC₅₀ of the target compounds were superior to those of the control drugs of bismerthiazol and thiodiazole copper(54.85 and 61.13 μg/mL, respectively). Compound 4o(EC₅₀=11.17 μg/mL) exhibited the best activity. All of the X. oryzae EC₅₀ of the target compounds were superior to the control drugs of bismerthiazol and thiodiazole copper(148.20 and 175.47 μg/mL, respectively). Compound 4f(EC₅₀=34.49 μg/mL) exhibited the best activity. The in vivo efficacies against tobacco mosaic virus(TMV) of the target compounds were tested through half-leaf method. The results of bioassay showed that the target compounds exhibited certain anti-TMV activities at the concentration of 500 mg/L.



Simultaneous Extraction of Salidroside and Tyrosol from Rhodiolarosea L. Using Tailor-made Deep Eutectic Solvents^†

WU Rong,WANG Huimin,CAO Jun,CHEN Luyao,SU Erzheng

2019, 40(5):  918-926.  doi:10.7503/cjcu20180669

Asbtract ( )   HTML ( )   PDF (2697KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A method for simultaneously extracting the salidroside and tyrosol from Rhodiolarosea L. using deep eutectic solvents(DESs) as the extraction solvents was developed in this work. Firstly, the hydrogen bond donor(HBD), hydrogen bond acceptor(HBA), molar ratio of HBA to HBD, and water content were optimized. The optimal DES for the simultaneous extraction was obtained as ethylene glycol-levulinic acid at the molar ratio of 1∶1 and water content of mass fraction of 40%, which was recorded as LAEG-40. Then, taking the LAEG-40 as the extraction solvent, the extraction conditions such as extraction method, solid to solvent ratio, extraction temperature and extraction time were further optimized. The optimal conditions were obtained as follows: stirring extraction at the solid to solvent ratio of 1∶12.5(g/mL) and 60 ℃ for 65 min. Under these conditions, the extraction yields of salidroside and tyrosol reached (18.1268±0.1667) and (1.5608±0.0240) mg/g, respectively. However, under the same conditions, taking water or ethanol as the extraction solvents, the extraction yields of salidroside and tyrosol were (15.1221±0.1342) and (1.1120±0.0389) mg/g, or (16.3425±0.0897) and (1.1923±0.0423) mg/g, respectively. It could be seen that the extraction efficiency of LAEG-40 was obviously higher than those of traditional solvents. The results showed that LAEG-40 was a green and efficient solvent for simultaneous extraction of salidroside and tyrosol, which could be used as a substitute for traditional solvents.



High Efficiency Catalytic Synthesis of N-Sulfonyltriazole in Aqueous Phase by Copper Sulfate/Substituted Thiourea^†

DONG Lirong,WANG Siyu,ZHANG Xiaomei,CHENG Jiajia,YUAN Yaofeng

2019, 40(5):  927-931.  doi:10.7503/cjcu20180540

Asbtract ( )   HTML ( )   PDF (633KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The reaction of a series of sulfonyl-containing azides and terminal alkynes indicated that the combination of copper sulfate/substituted thiourea was more suitable for general copper-catalyzed azide-end alkyne ring addition[Cu(Ⅰ) catalyzed azide-alkyne cycloaddition, CuAAC] reaction. The type of reaction was also possible to efficiently catalyze the synthesis of N-sulfonyl-1,2,3-triazole in the aqueous phase. The type of reaction was not sensitive to water and the yield was up to 99% in the aqueous phase. The reaction mixture was stirred in the air under room temperature(25 ℃). The novel system showed high atom-economy and functional-group tolurance. It provided a simple and efficient synthesis method for the synthesis of a series of N-sulfonyltriazoles.



Physical Chemistry

Study on Raman Spectroscopy Non-coincidence Effect of Propionic Anhydride C=O Vibration Mode^†

LIU Qiuna,XU Wenwen,LIU Maozhu,WANG Huigang,ZHENG Xuming

2019, 40(5):  932-939.  doi:10.7503/cjcu20180648

Asbtract ( )   HTML ( )   PDF (2750KB) ( )  

Figures and Tables | References | Related Articles | Metrics

According to the isotropic and anisotropic Raman spectroscopy of C=O vibration and the characteristics of infrared spectroscopy, the local ordered vibration and coupling mechanism of propionic anhydride molecules were studied. The isotropic and anisotropic Raman spectra of different concentrations of propionic anhydride were determined by three-stage confocal Raman microspectroscopy. The spectra of propionic anhydride in carbon tetrachloride and methanol and the spectra in other solvents were collected. Concentration effects, solvent effects, and Raman spectroscopy non-coincidence effects(NCE) of propionic anhydride were analyzed in detail. The results show that the NCE effect of propionic anhydride decreases with decreasing concentration; the NCE value increases with the decreasing of solvent polarity. The geometrically stable configuration of propionic anhydride monomer and dimer was calculated by the density functional theory B3LYP-D3/31-311G(d, p) basis set. The NCE effect, concentration effect and solvent effect of propionic anhydride molecule were explained by the aggregation state theory model. The theoretical calculation results are in agreement with the experimental results.



Influence of Surface Reactivity of Lanthanum Oxide on the Activation of Methane and Oxygen^†

CHENG Wenmin,XIA Wensheng,WAN Huilin

2019, 40(5):  940-949.  doi:10.7503/cjcu20190063

Asbtract ( )   HTML ( )   PDF (6727KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The properties of lanthanum oxide facets[(001),(110) and (100)] and the adsorption, activation and dissociation of methane and oxygen on them were studied by means of periodical density functional theory(DFT), based on the previous experimental investigation upon structure sensitivity of lanthanum oxide in Oxidative coupling of methane(OCM). The result shows that surface energy of lanthanum oxide facets decreases in the order of (110)>(100)>(001), and the energy gap between valence and conduction bands follows the order of (110)<(100)<(001), meaning that the facet (001) is most stable and (110) is most reactive among the three facets. The associative adsorption of methane on lanthanum oxide is very weak(ca. 0.03 eV), and the barriers for H—CH₃ on lanthanum oxide (001), (110) and (100) surfaces are 2.16, 0.68 and 0.90 eV, respectively, showing the reactivity of the facets is matched with the dissociation of methane. On the other hand, the associative adsorption energy of oxygen on lanthanum oxide (001), (110) and (100) surfaces is -0.04, -0.31 and -0.12 eV, respectively, and the dissociation barrier is 1.22, 0.53 and 1.52 eV, respectively. The oxygen adsorption is greatly influenced by the varied structures of lanthanum oxide. The interaction of oxygen with the facet (001) is the weakest, but the strongest with the facet (110) among the three facets of lanthanum oxide, which promotes O—O bond cleavage at lower barrier(0.53 eV) on the facet (110) to lead to the formation of electrophilic peroxide species. As oxygen adsorption on lanthanum oxide is stronger than methane, the structure sensitivity of lanthanum oxide in OCM should be closely associated with oxygen adsorption and activation. In addition, the mechanism of methane and oxygen activation on lanthanum oxide can be ascribed to the transfer of electrons from the surface to their antibonding orbitals, which implies that varied structures of the lanthanum oxide surfaces can change the driving forces on the electron transfer.



Rapid Calculation of the Three-body Interaction Energies in Water Clusters^†

LI Xiaolei,WANG Changsheng

2019, 40(5):  950-958.  doi:10.7503/cjcu20190038

Asbtract ( )   HTML ( )   PDF (3078KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A method was proposed to calculate the three-body interaction energies in water clusters. The O—H bond of a water molecule was regarded as a bond-dipole, and the three-body interaction energy were expressed as the sum of long-range induction and short-range correction. The long-range induction was treated by using Thole model, and the short-range correction was derived by considering both permutations among different water molecules and permutations between the two dipoles within each molecule. The parameters needed in the method were determined by fitting to the CCSD(T)/aug-cc-pVTZ three-body interaction energies of 12347 water trimers taken from the reference. The accuracy of the method is validated through comparing the three-body interaction energies of 67 water clusters ranging from trimer to 30-mer obtained by CCSD(T) method, MP2 method, and M06-2X method. The method can reproduce the CCSD(T)/aug-cc-pVDZ total three-body interaction energies, with the RMSD of 3.32 kJ/mol and the MRD of 2.43%, slightly better than the MP2 method, and outperforms the M06-2X method for large water clusters. The method is helpful in simulating the dynamic properties of water and other biomolecules.



Facet and Temperature Effects on Dissolution Thermodynamic Functions of Ag₃PO₄ Microcrystals^†

HE Zijun,XIAO Ming,MA Xiangying,QIU Jiangyuan,XIAO Biyuan,QIN Fanghong,HUANG Zaiyin

2019, 40(5):  959-964.  doi:10.7503/cjcu20190036

Asbtract ( )   HTML ( )   PDF (2837KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Ag₃PO₄ microcrystals with different facets, such as {100}(cubic), {111}(tetrahedron), {110}(rhombohedral dodecahedron), and bulk Ag₃PO₄ microcrystals were synthesized at room temperature. Based on the difference of the conductivity between Ag₃PO₄ microcrystals with different facets, the dissolution thermodynamic function of Ag₃PO₄ microcrystals were derived via combining the theoretical formula of strong electrolyte solution and dissolution thermodynamics. According to this method, the dissolution thermodynamic functions such as standard dissolution Gibbs free energy, standard dissolution enthalpy and standard dissolution entropy of the prepared Ag₃PO₄ microcrystals were gained. Moreover, the facet effect and temperature effect on these obtained dissolution thermodynamic functions were discussed. The results revealed that the dissolution thermodynamic function of rhombohedral dodecahedron Ag₃PO₄ were maximum, followed by cubic and tetrahedron Ag₃PO₄ . Along with the increase of the temperature, dissolution equilibrium constant and standard dissolution Gibbs free energy increased.



Theoretical Study on the Second-order Nonlinear Optical Properties of a Porphyrin-o-Carborane-Boron-dipyrromethene Triad Compound^†

KANG Huimin,WANG Hongqiang,WANG Huiying,WU Lixin,QIU Yongqing

2019, 40(5):  965-972.  doi:10.7503/cjcu20180851

Asbtract ( )   HTML ( )   PDF (2584KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The calculations of geometric structures, electronic absorption spectra, second-order nonlinear optical(NLO) properties of porphyrin-o-carborane-boron-dipyrromethene(BODIPY) triad were carried out by density functional theory(DFT). The results show that the static first hyperpolarizability(β_tot) of the V-shaped compound is larger than that of the linear-shaped compound, and the β_tot values can be enhanced by extending π-conjugate bridge. The analysis of electron density difference maps can be seen that the charge transfer pattern of the oxidized/reduced species have changed, which lead to the second-order NLO properties have significantly varied. The investigation of the frequency-dependent first hyperpolarizability shown that less dispersion effect at restrictive frequency region for all of the compounds. Therefore, second-order NLO properties can be effectively modulated by extending π-conjugate bridge and oxidized/reduced reactions.



Ion Transfer Behavior of Protonated Phenazopyridine at the Liquid/Liquid Interface Modified by Functionalized Hybrid Mesoporous Silica Membrane^†

LIU Shufeng,QIU Haiyan,JIANG Tao,ZHANG Yehua,ZHAO Yun,CHENG Hanwen,CHEN Yong

2019, 40(5):  973-979.  doi:10.7503/cjcu20180811

Asbtract ( )   HTML ( )   PDF (2204KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The transfer behavior of a clinical drug, phenazopyridine hydrochloride, at the water/1,6-dichlorhexane(W/DCH) interface modified by functionalized mesoporous silica membrane was studied by cyclic voltammetry and differential pulse voltammetry. It was found that the phenazopyridine(PAP) can be protonated to form phenazopyridine cation(HPAP⁺) under acidic condition, which can transfer at such a membrane-modified W/DCH interface. According to the relationship between the transfer peak current and the scan rate, as well as the equation of Randles-Sev$\check{c}$ik, the diffusion coefficient of HPAP⁺ in the functionalized hybrid mesoporous silica membrane was calculated to be 5.14×10^-8 cm²/s. In addition, the electrochemical response of ion-transfer of HPAP⁺ at the W/DCH interface modified by functionalized hybrid mesoporous silica membrane is much higher than bare PET membrane, which can improve the electrochemical detection performance of phenazopyridine cation. Moreover, the ionic partition diagram of HPAP⁺ at the W/DCH interface modified by functionalized hybrid mesoporous silica membrane was obtained by differential pulse voltammetry, which can not only understand the distribution of HPAP⁺ under different conditions(pH value and interfacial potential), but also obtain the distribution coefficient and ion-transfer Gibbs free energy of HPAP⁺, which helps to understand the transmembrane process of HPAP⁺ across biological membrane and provide a new electrochemical method to detect phenazopyridine hydrochloride.



Electron Transport of Metal String Complexes of [MM'M″(dpa)₄(Cl)₂](M=Co, Ni; M',M″=Co, Rh)^†

ZHI Shasha,BAN Ying,XU Zhiguang,XU Xuan

2019, 40(5):  980-987.  doi:10.7503/cjcu20180804

Asbtract ( )   HTML ( )   PDF (5960KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The electronic structures and transmission properties of metal string complexes [MM'M″(dpa)₄·(Cl)₂][MM'M″=CoCoCo(1); CoCoRh(2); CoRhRh(3); NiCoRh(4)] were investigated by density functional theory BP86 method. The results show that there is a delocalized 3-center-3-lectron σ bond of (MM'M″)⁶⁺ among complexes 1, 2 and 4, while there are one delocalized 3-center-4-electron σ bond of (MM'M″)⁶⁺ and two 3-center-5-electron π bonds in complex 3. The Rh—Rh bond of complex 3 is the strongest among complexes 1—4 and the Co—Rh bond is second on account of above-mentioned information. The substitution of Rh enhanced the M—M bond, and the replace of Ni weakened the M—M bond. In conclusion, the order of bond is Rh—Rh>Co—Rh>Co—Co>Ni—Co. The transport channels of complexes 1—4 contain π-type and σ-type orbitals. Under positive bias, the currents in complexes 2 and 3 are greater than complexes 1 and 4. Under negative bias, there is a negative differential resistance effect in complex 4. The energy splitting of σ_nbα/β and π^*α/β orbit as transport channels in complex 3 are the most obvious among complexes 1—4. Moreover, the contribution of (MM'M″)⁶⁺ to the π^* orbit of β spin(up to 88%) is larger than that of α (up to 74%). Thus, the electronic transmission of β spin channel is stronger than α spin. To sum up, the complex 3 has significant spin filter effect (up to 70%—80%).



Fabrication of 3D Porous Core-shell PdNi@Au Nanocatalyst for Formic Acid Electro-oxidation^†

LI Jiahui,QIN Menghan,ZHANG Jie,DU Yi,SUN Dongmei,TANG Yawen

2019, 40(5):  988-994.  doi:10.7503/cjcu20180776

Asbtract ( )   HTML ( )   PDF (4667KB) ( )  

Figures and Tables | References | Related Articles | Metrics

K₂PdCl₄ and K₂Ni(CN)₄ were employed as precursors to fabricate cyanogel, which was then reduced by NaBH₄ to prepare 3D porous coral-like PdNi alloy. On the basis of the synthesized PdNi alloy, 3D porous PdNi@Au catalysts with PdNi alloy as inner core and Au layers of different thickness on the surface were synthesized by in situ Galvanic replacement between PdNi alloy and HAuCl₄ aqueous solution. X-Ray diffraction(XRD) and transmission electron microscopy(TEM) indicated that the 3D network structure was composed of interconnected nanoparticles with diameter of 7 nm. Energy dispersive X-ray(EDX) line scanning and mapping could declare its typical core-shell structure. Electrochemical measurements demonstrated that the electro-catalytic performance of PdNi@Au catalysts could be affected by the thickness of Au layer. When the content of Au reached a value of 5.6%(molar fraction), PdNi@Au catalyst exhibited the best catalytic performance for formic acid electro-oxidation. In this case, the peak current density of PdNi@Au catalyst was 7.2 times that of commercial Pd black.



Effects of Gas Adsorption on Two Dimensional Metal-hexaiminobenzene Frameworks^†

SUN Guodong,WANG Xue,JIANG Guoliang,XU Zhiyong,LIU Hongmei

2019, 40(5):  995-1004.  doi:10.7503/cjcu20180768

Asbtract ( )   HTML ( )   PDF (4684KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The effects of gas molecules(NH₃, H₂O, H₂S, and NO₂) adsorption on two-dimensional M₃(HIB)₂(M=Ni, Cu; HIB=hexaiminobenzene) surfaces on the geometric structure and electronic structure were studied via the first-principles theory. The results show that there are different responses of two thin films to four gas molecules. The adsorptions of NH₃, H₂O and H₂S on the surface of M₃(HIB)₂ thin films are weak and the gas molecules tend to form hydrogen bond with the imino group of the film with an adsorption energy that is less than -0.36 eV. These weak adsorptions just slightly affect the electronic properties of the adsorbed films. In contrast, NO₂ molecules are strongly chemisorbed on the two films with adsorption energy in the region of -0.65—-1.72 eV. The adsorption of NO₂ molecules evidently changes the electronic structures of the film. For instance, there is a band gap opening at the Fermi level for Cu₃(HIB)₂ film and it changes from metal to semiconductor. This feature originates from the strong orbital hybridization between NO₂ p_z and metal $d_{z}^{2}$ orbitals. Furthermore, when NO₂ molecules with a high concentration are adsorbed on M₃(HIB)₂ surface, the Ni₃(HIB)₂ film transits from nonmagnetic to magnetic states and changes from metallic to half-metallic property, while the Cu₃(HIB)₂ film converts to semiconductor, suggesting a potential application of M₃(HIB)₂ films in gas sensing.



Effect of Structure and Properties of CuO-WO₃-ZrO₂ on Hydrogenation Catalytic of Benzaldehyde^†

HUANG Rui,YAO Zhilong,SUN Peiyong,ZHANG Shenghong

2019, 40(5):  1005-1012.  doi:10.7503/cjcu20180757

Asbtract ( )   HTML ( )   PDF (2358KB) ( )  

Figures and Tables | References | Related Articles | Metrics

CuO-WO₃-ZrO₂ catalysts were prepared by co-precipitation method. Structures and surface properties of the catalysts were characterized by X-ray powder diffraction(XRD), scanning electron microscope(SEM), X-ray fluorescence(XRF), N₂ physisorption, temperature programmed hydrogen reduction(H₂-TPR), X-ray photoelectron spectroscopy(XPS) and temperature programmed desorption(TPD). Addition of WO₃ into CuO-ZrO₂ induced the transformation of ZrO₂ from monoclinic to tetragonal phases, improved the dispersion of CuO species, changed the acid-base properties of the catalysts as well as the catalyst textural features such as surface area and the average pore diameter. As a consequence, the catalytic performance for the hydrogenation of benzaldehyde to benzyl alcohol was greatly promoted by the introduction of WO₃. For the optimal catalyst containing 10%(mass fraction) CuO and 18%(mass fraction) WO₃, the conversion of benzaldehyde and the selectivity to benzyl alcohol reached 94.76% and 92.03%, respectively.



Fabrication and Electrocatalytic Performance of Graphene-fullerene Ammonium Iodide Composite Supported Pd Nanocatalyst for Ethanol Oxidation^†

LIN Zhouchen,HUANG Qiaoxi,LEI Ming

2019, 40(5):  1013-1018.  doi:10.7503/cjcu20180708

Asbtract ( )   HTML ( )   PDF (3748KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Reduced graphene oxide/[6,6]-phenyl-C61-butyric acid trimethylaminoethyl ester iodide hybrid composites(RGO-PCBANI) were used to support Pd nanoparticle to fabricate Pd/RGO-PCBANI electrocatalysts on electrode. The morphology and structure of the RGO-PCBANI and Pd/RGO-PCBANI were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS). Furthermore, the electrocatalytic performance of Pd/RGO-PCBANI towards ethanol oxidation was evaluated by using electrochemical methods such as cyclic voltammetry and chronoamperometry. The results showed that the prepared RGO-PCBANI(6∶1) support displayed good dispersibility and could immobilize Pd nanoparticle with 5.2 nm average size. Moreover, the fabricated Pd/RGO-PCBANI(6∶1) catalyst exhibited best catalyst activity and stability. The mass current density reached 1288. 8 mA/mg. The good catalytic performance is attributed to highly conductive PCBANI’s spacer function in the RGO-PCBANI composite support.



Fabrication and Rectification Studies of Serial/Parallel Composite Nanofluidic Diode Based on Hierarchically Branched Alumina Nanochannels^†

ZHANG Dan,HOU Shengnan,LIU You,FAN Xia

2019, 40(5):  1019-1028.  doi:10.7503/cjcu20180701

Asbtract ( )   HTML ( )   PDF (6229KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Based on hierarchically branched alumina nanochannels, a serial/parallel composite nanofluidic diode system with experimentally adjustable ion rectification characteristics was fabricated. Using a simple anodization method, we fabricated four two-generation branched alumina nanochannels with 1-2-2, 1-2-3, 1-3-2 and 1-3-3 geometric structures. Among them, if we view each branch node as a diode, its first branch node will be equivalent to one series diode, and its second branch node will be equivalent to multiple parallel diodes. In this case, the circuits of the branched alumina nanochannels with 1-2-2 and 1-2-3 geometric structures are regarded as two parallel diodes and then the third diode in series. Similarly, the ones with 1-3-2 and 1-3-3 geometric structures are considered as three parallel diodes and then connected in series with the fourth diode. However, considering different structures and numbers of the secondary branches of the 1-2-2 and 1-2-3 alumina nanochannels as well as the 1-3-2 and 1-3-3 alumina nanochannels, the four branched alumina nanochannels will ultimately be classified into four nanofluidic diodes with serial/parallel composite characteristic. Accordingly, benefiting from cooperative asymmetry of the first-branched and the second-branched geometries, which affects the surface-charge distribution on inner walls, the branched alumina nanochannels with 1-2-2, 1-2-3, 1-3-2 and 1-3-3 structures exhibit gradually enhanced ionic rectification properties. Further, the rectification ratios of the representative 1-1-2 branched alumina nanochannels increase as the length of the branch channel increases. This indicates that the branch part with stronger ion selectivity plays a decisive role in the rectification characteristics of the entire series/parallel composite nanofluidic diode system. Compared with the previous single ion diode system, this serial/parallel composite nanofluidic diode with geometry-tailorable hierarchically branched alumina nanochannels could not only provide a basic platform to build ionic diode circuitry and more complex nanofluidic devices, but also spark further efforts to simulate the smart ion transport processes of multiple-channel with sparallel/serial mode in living bodies.



Functional Specific Heteropoly Acid Ionic Liquid Catalyzed Direct Esterification of Aqueous Succinate Solution^†

DING Zhongxie,LIANG Jinhua,LIU Zhen,SHEN Jiecan,ZHANG Feng,REN Xiaoqian,JIANG Min

2019, 40(5):  1029-1036.  doi:10.7503/cjcu20180668

Asbtract ( )   HTML ( )   PDF (3605KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A series of functionally specific acid ionic liquid catalysts([HMT-4PS][HPA]) was synthesized by combining sulfonated hexamethylenetetramine[HMT-4PS] with heteropoly acid anions, and then used for catalyzing the direct esterification of methanol with aqueous succinic acid(SA) solution. The results indicated that the series of ionic liquids were uniformly dispersed in the system as “emulsion” during the reaction. After the reaction was completed, the rapid separation of the catalyst could be accomplished by reducing the polarity of the system. [HMT-4PS]₃[PW]₄ exhibited the best catalytic activity during the series of synthesized catalysts. The effects of temperature, amount of catalyst, molar ratio of acid to alcohol and reaction time were fully investigated. The optimal reaction conditions were determined: reaction temperature 80 ℃, catalyst mass fraction of 5%(based on SA aqueous solution), n(SA)∶n(MeOH) = 1∶30, reaction time 8 h. The conversion of succinic acid could reach 79.3%, the diester selectivity could reach 92.9%. After 5 times reused, the conversion of succinic acid and the selectivity of the diester still reached above 77% and 90%.



Polymer Chemistry

Simulation Study on the Self-assembly of Softtriblock Janus Particles^†

WANG Yanhui,ZOU Qingzhi,ZHU Youliang,FU Cuiliu,HUANG Yineng,LI Zhanwei,SUN Zhaoyan

2019, 40(5):  1037-1042.  doi:10.7503/cjcu20190062

Asbtract ( )   HTML ( )   PDF (4102KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The self-assembly of soft triblock Janus particles in dilute solutions were simulated by the soft patchy particle model and coarse-grained molecular dynamics. By properly tuning the patch size and the attraction strength between the patches, we obtained various ordered self-assembly structures, including string-like structures, hexagonal columnar structures, fibre-like body-centered tetragonal structures, and three-dimensional networks. Furthermore, the formation process of the fibre-like body-centered tetragonal structures was analyzed in detail. These soft triblock Janus particles in our model are well within the reach of today’s experimental capabilities. Therefore, our results provide conceptual and practical guidance towards the experimental realization of novel nanostructures.



Preparation and Properties Characterization of Biobased Dihydrocoumarin Toughened Epoxy Resin^†

HAN Tao,CAI Xiaoxia,LI Cong,QIAO Congde,ZHAO Hui

2019, 40(5):  1043-1050.  doi:10.7503/cjcu20190007

Asbtract ( )   HTML ( )   PDF (3448KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A kind of 3D polymeric network, obtained through alternating copolymerization of dihydrocoumarin(DHC) and epoxides with the aid of chromium(Ⅲ) complexes and bis(triphenylphosp-hosphoranylidene) ammonium chloride(PPNCl) catalysts, was introduced into the diglycidyl ether of bisphenol A(DGEBA) matrix to build a double network structure. This structure can achieve an effective stress transfer and energy absorption for the DGEBA toughness. The gel permeation chromatography(GPC) results showed that the molecular weight of DHC-net increased with the react time. DHC-based network(DHC-net) structure was confirmed via the ¹H NMR spectrum. Moreover, the chemical structures of epoxy resin(EP), DHC-net and EP/DHC-net double networks were confirmed via the FTIR spectra. DMA, DSC and TGA tests indicated that a good compability between the DHC-based network and the DGEBA matrix. Mechanical test showed that an obvious increase in the elongation at break was achieved after the DHC-based network was introduced into the DGEBA matrix. Furthermore, compared to the neat DGEGA resin, remarkable improvements in tensile and impact strength were found after the introduction of DHC-based network with content no higher than 30%(mass fraction) into the DGEBA matrix.



Preparation and Properties of Filling-type Sulfonated Poly(arylene ether sulfone)/Poly(ether sulfone) Composite Membranes with Microporous Structures^†

ZHU Yuxin,HARAGIRIMANA Alphonse,LU Yao,BUREGEYA Ingabire Providence,NING Cong,LI Na,HU Zhaoxia,CHEN Shouwen

2019, 40(5):  1051-1057.  doi:10.7503/cjcu20180785

Asbtract ( )   HTML ( )   PDF (2342KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A series of filling-type composite polymer exchange membranes was prepared based on sulfonated poly(arylene ether sulfones)(SPAES) and poly(ether sulfone)s(PES), and the properties including water uptake, dimensional change, thermal-mechanical properties, proton conductivity, methanol permeability and chemical stability were evaluated. Firstly, a series of microporous composite proton exchange membranes(Sx-y, x refers to the sulfonation degree of the SPAES copolymers, y refers to the mass ratio(20%—40%) of SPAES copolymers) was fabricated via immersion phase inversion method from PES and SPAES copolymers with sulfonation degree of 30%(S30), 40%(S40) and 50%(S50). Then, the corresponding filling-type composite polymer exchange membranes(Sx-y+F50) were prepared by filling S50 in the Sx-y micropores by vacuum filtration. The results indicate that the Sx-y membranes, despite of the rather low ion exchange capacity(IEC), all display fairly high proton conductivity, fine mechanical strength, excellent chemical stability and rather low methanol permeability. After filling with S50, the corresponding Sx-y+F50 membranes exhibit improved IEC and proton conductivity, lowered methanol permeability, and maintain high mechanical strength and chemical stability. The S30-40+F50 membrane(IEC=0.69 mmol/g) shows the best comprehensive properties: proton conductivity of 50.4 mS/cm at 90 ℃ in water; mass loss of 8.2% and proton conductivity loss of 9% by aging in water at 140 ℃ for 24 h, and mass loss of 0.66% by soaking in Fenton reagent(3% H₂O₂, 20 mg/L FeSO₄) at 80 ℃ for 1 h; methanol permeability of 6.8×10^-8 cm²/s. The filling-type composite proton exchange membranes are promising candidates for fuel cell applications.



Lignin Impacts on the Lignin-urea-formaldehyde Copolymer Resin and the Reaction Mechanism^†

DUAN Yajun,CHENG Yanyan,SUI Guanghui,ZHU Yanchao,WANG Xiaofeng,GUO Yupeng,WANG Zichen

2019, 40(5):  1058-1064.  doi:10.7503/cjcu20180778

Asbtract ( )   HTML ( )   PDF (2962KB) ( )  

Figures and Tables | References | Related Articles | Metrics

By regulating the molar ratio of formaldehyde and urea to reduce the content of free formaldehyde in urea-formaldehyde resin adhesive, using biomass corn cob as raw material to extract lignin with alkali solution, the alkali lignin solution was gradually copolymerized with formaldehyde and urea to compensate for the problem of rapid decrease in the bonding strength caused by the reduction of aldehyde urea ratio. With reducing the free formaldehyde content and taking into account the bonding strength as a principle to explore, the best experimental conditions were obtained: formaldehyde to urea molar ratio of F/U is 0.91∶1, the amount of lignin added is 20%(mass fraction), under these conditions, the lignin-urea-formaldehyde(LUF) copolymer resin has a bonding strength of 0.99 MPa and a free formaldehyde content of 0.26%. The characterization results of the copolymer resin using HR-MS, XPS, FTIR and TG show that lignin can participate in the reaction and improve the thermal stability and water resistance of the resin. At the same time, the mechanism of the reaction was discussed.



Preparation of Dendrimer-gold Nanoparticle Composites for pH Responsive Drug Delivery^†

ZHU Qinfu,HU Kezhen,LI Xiaojie,CHEN Mingqing

2019, 40(5):  1065-1070.  doi:10.7503/cjcu20180764

Asbtract ( )   HTML ( )   PDF (2447KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Dendrimer-gold nanoparticle composites were prepared based on poly(ethylene glycol) modified dendrimer(PEG-PAMAM). Gold nanoparticles internal provided an efficient platform for lipoic acid functionalized DoxorubicinLA-DOX linking, leading to the high loading efficiency of anticancer drugs DOX. Meanwhile the hydrazine linker in LA-DOX realized pH sensitive release for nanocarrier. Verified by UV-Vis spectra, the loading efficiency of LA-DOX in dendrimer-gold nanoparticle nanocomposite was improved. Cell Experiment indicated excellent cytotoxicity of dendrimer-gold nanoparticle composite against Hela cells.



Synthesis and Properties of a Novel Bio-based Benzoxazine^†

YIN Ping,YAN Hongqiang,CHENG Jie,FANG Zhengping

2019, 40(5):  1071-1079.  doi:10.7503/cjcu20180751

Asbtract ( )   HTML ( )   PDF (4790KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A novel bio-based benzoxazine resin(phenolphthalein-furfuramine-benzoxazine, PTL-F-BOZ), used bio-based furfurylamine, phenolphthalein, and paraformaldehyde as raw materials, was synthesized and characterized by Fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance(¹H NMR and ¹³C NMR). The curing, thermal and flame retardant properties were analyzed by differential scanning calorimetric(DSC), thermogravimetric analyzer(TG), limiting oxygen index(LOI), vertical burning test, microscale combustion calorimetry(MCC), cone calorimeter(Cone) and scanning electron microscope(SEM). The DSC curve of PTL-F-BOZ showed a two-stage curing with two maxima at 224 and 251 ℃ respectively, and had lower curing temperature than that of the traditional fossil-based bisphenol benzoxazine bisphenol A-aniline benzoxazine(bisphenol A-aniline-benzoxazine, BPA-A-BOZ). The presence of the furan ring in the furfurylamine increased the cross-linking density of polymer, retarded the rearrangement reaction from the phenoxy structure to the phenol structure, and resulted in two curing peaks in the DSC curve of PTL-F-BOZ. Under nitrogen and air atmospheres, the temperatures of 5% mass loss(T_5%) for PPTL-F-BOZ resin were 380 and 370 ℃, respectively and the residual chars at 800 ℃ were 63.0% and 10.5%, respectively. Compared with PBPA-A-BOZ resin, PPTL-F-BOZ resin both possessed higher T_5% and residual char of 800 ℃. From the DTG curve, the maximum mass loss rates of two decomposition stage(Peak 1 and Peak 2 values) of PPTL-F-BOZ resin were 0.67%/min and 3.28%/min, which were only 7.38% and 63.44% of PBPA-A-BOZ(9.07%/min and 5.17%/min) under nitrogen atmosphere, and those were also the same under air atmosphere. LOI of PPTL-F-BOZ resin was 36.2%, which was higher than that of PBPA-A-BOZ resin. Meanwhile, in the UL-94 test, PPTL-F-BOZ resin extinguished quickly and released less smoke during combustion process, and the original morphology was kept well and a stable carbon layer was formed after burning. Its first ignition time(t₁) and second ignition time(t₂) were 1.4 and 8.5 s, respectively, far smaller than the maximum permissible values of 10 s, and a UL94 V-0 rating was also achieved. Hence, PPTL-F-BOZ resin showed excellent thermal and flame retardant properties.



Preparation and Properties of CS/nHA Porous Composite Scaffold Based on In-situ Precipitation Method^†

WANG Ruanfeng,YAN Shifeng,HU Zhen,YIN Jingbo

2019, 40(5):  1080-1088.  doi:10.7503/cjcu20180724

Asbtract ( )   HTML ( )   PDF (7901KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The initial porous scaffold containing calcium phosphate precursors(CaP) was obtained by in situ precipitation and freezing phase separation techniques. The chitosan(CS) membranes generated in situ on the outer layer of porous scaffolds were used to slow down the penetration rate of OH^- ions in NaOH solution, so as to achieve the purpose of slow formation of nano-hydroxyapatite(nHA), and thus to prepare CS/nHA porous composite scaffolds with uniform distribution of nHA. The scanning electron microscopy(SEM) and universal testing machine were used to study the structure and properties of the composite scaffold. It was found that the nHA was acicular structure, with a length of 80―200 nm and a width of 20―50 nm. With the increase of nHA content, the porosity of the composite scaffold decreased from (93.8±3.3)% to (87.7±3.8)%, and the compressive strength gradually increased from (0.5±0.09) MPa to (1.5±0.06) MPa. No obvious agglomeration of nHA was found, and nHA was evenly distributed in the CS matrix when the content of nHA in the composite scaffold was 25%. It is concluded by infrared spectrometer(FTIR), X-ray diffractometer(XRD) and X-ray photoelectron spectrometer(XPS) analysis that there may be coordination and hydrogen bonding between nHA and CS. The results of cell experiments showed that the nHA/CS porous composite scaffold has good biocompatibility, and the cells adhered to the scaffold. It is expected that the CS/nHA porous composite scaffold has a good application prospect in the field of bone tissue engineering.



Siloxane Crosslinked Imidazolium PPO/PTFE Membranes for High Temperature Proton Exchange Membranes^†

REN Xiaorui,LIU Chao,LI Huanhuan,YANG Jingshuai,HE Ronghuan

2019, 40(5):  1089-1095.  doi:10.7503/cjcu20180721

Asbtract ( )   HTML ( )   PDF (3623KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Based on poly(2,6-dimethyl-1,4-phenylene oxide)(PPO), novel high temperature proton exchange membranes were prepared with high phosphoric acid content, superior proton conductivity and excellent mechanical properties. Both methylimidazole(MeIm) and triethoxysilylpropyldihydroimidazole(SiIm) were used as functional reagents to graft the imidazolium groups onto the PPO polymer, in which the imidazolium group provided the phosphoric acid interaction sites. Meanwhile crosslinking of the modified PPO was achieved by forming a crosslinked silane network via the hydrolysis reaction of SiIm in an acidmedium. Moreover, porous poly(tetrafluoroethylene)(PTFE) was used as the membrane matrix toenhance the dimensional stabilities and mechanical strength of the fabricated membranes. Physicochemical properties of composite membranes with various crosslinking degrees were investigated accordingly. The results showed that the PPO-SiIm-MeIm/PTFE composite membranes possessed dense structure, superior thermal stability, improved chemical stability, high conductivity and suitable mechanical strength simultaneously. As an example, the PPO-50%SiIm-50%MeIm/PTFE membrane with a phosphoric acid doping content of 242.5% exhibited a conductivity of 0.09 S/cm at 160 ℃ under no humidification conditions, and a tensile strength of 3.6 MPa at room temperature. The results indicate that PPO-x%SiIm-y%MeIm/PTFE membranes have the potential to be used as HT-PEMs.



Preparation and Controlled Release of Multifunctional Avermectin Nano-pesticide^†

GUAN Wenxun,TANG Liming

2019, 40(5):  1096-1102.  doi:10.7503/cjcu20180702

Asbtract ( )   HTML ( )   PDF (1722KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Based on the two active hydroxyl groups, avermectin reacted with acryloyl chloride, tetraethylenepentamine and succinic anhydride consecutively to obtain a new kind of emulsifier precursor with ester bonds and drug affinity. The structure of the emulsifier precursor was characterized by various techniques. After neutralization, the emulsifier and avermectin could form a stable nanoemulsion in water spontaneously. The particle size of the nanoemulsion could be adjusted by drug loading and neutralization extent. The nanoemulsion exhibited a series of good properties, including high drug loading, high stability, photolysis resistance, low surface tension and high leaf affinity. The ester bonds in the emulsifier could be hydrolyzed in presence of esterase or under strong alkaline, so that the hydrophilic part of the emulsifier could be separated from the lipophilic part, promoting the releasing of avermectin from the particles. Therefore, this nano pesticide exhibited a better insecticidal effect than the commercial avermectin emulsifiable concentrate(EC).