Preparation of PLA and PLGA nanoparticles by binary organic solvent diffusion method

The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the bi-nary organic solvent diffusion method. The yield, particle size and size distribution of these nanoparticles wereevaluated. The yield of nanoparticles prepared by this method is over 90%, and the average size of the nanoparticlesis between 130-180 nm. In order to clarify the effect of the organic solvent used in the system on nanoparticle yieldand size, the cloud points of PLA and PLGA were examined by cloud point titration. The results indicate that theyields of nanoparticles increase with the increase of ethanol in the acetone solution and attain the maximum at thecloud point of ethanol, while the size of nanoparticles decreases with the increase of ethanol in the acetone solutionand attains the minimum at the cloud point of ethanol. The optimal composition ratio of binary organic solvents coin-cides to that near the cloud point and the optimal condition of binary organic solvents can be predicted.

Synthesis and Characterization of Alumina-Zirconia Powders Obtained by Sol-Gel Method: Effect of Solvent and Water Addition Rate

The influence of solvent and the rate of addition of water on the characteristics of alumina-zirconia powders obtained by sol-gel method were investigated. The Al2O3-ZrO2 powders (1:1 molar ratio) were prepared using aluminum tri-sec-butoxide and zirconium n-propoxide as precursors. Ethanol (EtOH), isopropanol (iPrOH) and isobutanol (iBuOH) were used as solvents. The Al2O3-ZrO2 powders were characterized by nitrogen physisorption (SBET), Fourier transformed infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Prepared oxides calcined at 700℃ showed high specific surface area (200 - 240 m2/g). Obtained results suggest that the homogeneity of the mixed oxides is favored by using a water addition rate of 0.06 and 0.10 mL/min with ethanol as solvent.

STUDY ON SLOW-RELEASE CHARACTERISTICS OF MICROCAPSULES WITH EMULSION NON-SOLVENT ADDITION METHOD

An O / W emulsion non-solvent addition method was used to prepare ethyleellulose (EC) microcapsules of water soluble pharmaceutical (theophylline). The solvent and non-solvent reagents used in this work were toluene and cyclohexane. The effects of polymer concentration, core wall ratio and particle size on the kinetics as well as the dissolution rate of the drug were investigated. The results show that the dissolution rate increases with the increasing of polymer concentration and core wall ratio. The release of microcapsules prepared with different procedures can be selectively profiled with first order and Higuchi matrix kinetic models.

Stoichiometry and Stability Constant Values for Copper (II) Chelates with Ethylene Diamine in Deep Eutectic Solvents (DES) (Ethaline) Solutions

In this study we used the deep eutectic solvents (ionic liquids) to investigate the reaction between copper (II) with ethylene diamine (en). Two of the existing methods for analyzing spectrophotometric measurements have been applied for establishing, the stoichiometry and whenever possible, the stability constants of the chelates formed. The method of continuous variations was necessary to determine first whether, the metal ion and the ligand ethylene diamine form one or more than one chelate, when more than one chelate formed, the results obtained depend on the wavelength and for meaningful conclusions the wavelengths were carefully selected. The empirical formulae of the chelates were further substantiated by the molar ratio method. The effect of time and temperature on the formation and stability of these chelates in solution is also studied. The stability constants, K1 and K2 for the copper (II) chelates were calculated, though reliable, and are comparable to literature values.

Preparation and characteristic analysis of rice husk high boiling solvent lignin

Rice husk high boiling solvent lignin （RHL） was prepared by high boiling solvent method, and its characteristics was analyzed by using chemical composition analysis, infrared spectroscopy, and ^1H-NMR and ^13C-NMR spectroscopy. The optimum prepared condition was that the rice husk with 70%-90% aqueous solution of 1, 4-butanediol was mixed with autoclave, under a certain weight ratio of solid raw material and solvent, heated to 200-220℃ for 1.0-3.0 h, then water-insoluble RHL was separated from the liquor reaction mixture by water precipitation. Results suggested that the lower digestion temperature and concentration of 1,4-butanediol were both unfavorable for extracting lignin. Chemical weight-average molecular weight of RHL was 1939 g·mol^-1, and the residual polysaccharide content was 5.12%. The ^1H-NMR spectra of RHL showed the relative intensity ratio, aliphatic over aromatic methoxyl groups, situated at 3.5-3.8 and 3.8-4.0 ppm, respectively. The results from ^13C-NMR spectra showed that β-O-4 bond and β-5 carbon-carbon linkage were the major linkages between RHL units. The C9-formula of RHL was calculated by the experiment data.

Different surface modification methods and coating materials of zinc metal anode

Rechargeable aqueous Zn-ion batteries(AZIBs)are one of the most promising energy storage devices for large-scale energy storage owing to their high specific capacity,eco-friendliness,low cost and high safety.Nevertheless,zinc metal anodes suffer from severe dendrite growth and side reactions,resulting in the inferior electrochemical performance of AZIBs.To address these problems,surface modification of zinc metal anodes is a facile and effective method to regulate the interaction between the zinc anode and an electrolyte.In this review,the current challenges and strategies for zinc metal anodes are presented.Furthermore,recent advances in surface modification strategies to improve their electrochemical performance are concluded and discussed.Finally,challenges and prospects for future development of zinc metal anodes are proposed.We hope this review will be useful for designing and fabricating highperformance AZIBs and boosting their practical applications.

Solubilities of 1-Methyl-3-（3-sulfopropyl）-imidazolium Hydrogen Sulfate in Selected Solvents

Ionic liquid 1-methyl-3-(3-sulfopropyl) -imidazolium hydrogen sulfate([C3SO3HMIM][HSO4]) was synthesized and characterized by infrared spectroscopy(IR) ,nuclear magnetic resonance(1H and 13C NMR) and ultraviolet-visible(UV-Vis) spectra. Its thermal stability was also examined by thermogravimetric analysis(TGA) and a differential scanning calorimeter(DSC) . The mole fraction solubilities of [C3SO3HMIM][HSO4]) in 12 selected solvents(n-pentane,n-hexane,n-heptane,benzene,toluene,ethylbenzene,acetone,2-butanone,3-methyl-2-butanone,tetrahydrofuran,ethyl acetate and dichloromethane) in the temperature range from 289.15 to 363.15 K were meas-ured using a static analytical method and correlated with an empirical equation.

The Effects of Oxidation States, Spin States and Solvents on Molecular Structure, Stability and Spectroscopic Properties of Fe-Catechol Complexes: A Theoretical Study

In this study, in order to explain the solvent and spin state effects on the molecular structure of catechol-Fe complex [Fe(cat)3]n﹣?where n = 2 and 3, Hartree Fock (HF)-Density Functional Theory (DFT) hybrid calculations are performed at the B3LYP/6-311g(d,p) level of theory. The binding energies of Fe2+ and Fe3+ in high-spin state are higher than intermediate and low-spin states which show that the complex formation in a high spin state is more favorable. The calculated binding energies at different solvents indicate that the binding energies in polar solvents are lower than non-polar solvents. Furthermore, spectroscopic studies including FTIR and Raman spectrum in various solvents reveal that the formation of intermolecular bonds between the oxygen atom of carbonyl group and the hydrogen atom of solvent causes a spectral red shift. The calculated FTIR and geometry parameters are in good agreement with previous experimental data. Donor-acceptor interaction energies are evaluated due to the importance of the charge transfer in the complex formation. It is observed that the free electrons of oxygen atom interact with the antibonding orbitals of the iron. Finally, some correlations between the quantum chemical reactivity indices of the complexes and solvent polarity are considered. The study indicates a linear correlation between chemical hardness and binding energies of [Fe(cat)3]3﹣?complex.

Alcohol Solvent Effect on Fluorescence Properties in the Solvothermal Synthesis of Carbon Quantum Dots

Highly monodisperse carbon quantum dots(CQDs)were synthesized by a solvothermal method using L-ascorbic acid as carbon source and different simple alcohols(methanol,ethanol,ethylene glycol,and isopropanol)as reaction solvents at 180℃for 4 hours.The performance of CQDs was characterized by transmission electron microscope(TEM),Fourier infrared spectrometer(FTIR),UV-visible spectrophotometer,and fluorescence spectrophotometer.The results show that the prepared CQDs are wavelength-dependent,and have good hydrophilicity and similar surface compositions.However,there are more carbon and oxygen-containing functional groups on the surface of CQDs prepared with ethanol(CQDs-ET),and the type and number of functional groups will directly affect the fluorescence emission of CQDs.Also,it is found that the luminescence mechanisms of CQDs prepared by this solvothermal method are mainly based on the defect state of the oxygen group surface.And alcohol solvents do not directly participate in the formation of carbon nuclei during the reaction process,but it will affect the number and type of surface groups.Therefore,the influence of surface groups on the CQDs performance is greater than that of carbon nuclei in this experiment.

Application of the Electrochemical Method for Stripping Eu^（3＋） after Extraction with Benzo－15－crown－5 in Dichloromethane

Eu3+ is extracted at pH 6 with 5. 0×10-2 mol/L benzo-15-crown-5 in dichloromethane from 5. 0×10-2 mol/L aqueous solution of lithium picrate. The enriched extractability has been investigated. In a concentration range from 2. 4 ×10-4 to 1. 8 ×10-3 mol/L solution of europium nitrates, the enrichment coefficients are calculated with the phasc ratio (organic/aqueous) of 1: 5 or 4: 25. The ability of 0. 5 mol/L HNO3 as a back-extractant is discussed with the volume ratio [organic/(0. 5 mol/L HNO3)] of 1 : 3. Crown ether and picric acid exist in the back-extractivephase. Eu3+ is effectively separated from the organic phase by the electrochemical method. The separation efficiency is more than 84%. The optimum electrolysis time or cell voltage is obtained from the relation between the electrolysis current and the time or the voltage.

Analysis of Influence Factors for FCC Slurry Separation by Mixed Solvent Extraction

Daqing FCC slurry was treated using mixed solvent containing N,N-dimethylformamide(extraction solvent)and n-paraffin(stripping-agent).The influence of solvent formulation(ratio of DMF/stripping-agent),temperature,time and solvent-oil ratio on yield and aromatics content of the extract oil were analyzed by a four-factor and three-level orthogonal experimental design.The polynomial regression models between the extract oil yield and aromatics content with the four factors were established.Response surface analysis showed that solvent formulation,temperature and solvent-oil ratio have significant effects on extraction result and there is an interaction between temperature and solvent-oil ratio on aromatics content,when the FCC slurry is extracted by mixed solvent.However,the extraction time has no significant effect.The optimal conditions for FCC slurry extraction covered:a solvent mixed ratio of 2.3,a temperature of 62.8℃,a solvent-oil ratio of 3.2,and a time of 35 min.The result of verification experiment was in good agreement with the prediction of the model.

Solvent Synthesis,Growth Mechanism and Photocatalytic Properties of AgInS_2 Nanoplate and Nanoparticle

Orthorhombic AgInS2 nanoplate and nanoparticle were synthesized using pyridine and 1-dodecanethiol as the solvent.The obtained products were characterized by X-ray diffraction（XRD）,field-emission scanning electron microscope（FESEM）,field-emission transmission electron microscope（FETEM）,and the possible growth mechanism of AgInS2 was also proposed by the exploration of reaction temperature and time.Meanwhile,the bandgap of AgInS2 was calculated by the UV-Vis diffuse reflectance spectrum,and the photocatalytic activity was also investigated.Those experimental results indicate that the reaction temperature,reaction time and solvent have an influence on phase and morphology of AgInS2,and both AgInS2 nanoplate and nanoparticle have some ability on photocatalytic degradation of organic dyes under UV-Vis light irradiation.

超声有机溶剂法提取茶树花精油工艺优化及其成分分析

以茶树花为原料,采用超声有溶剂法提取茶树花精油。以茶树花精油得率为指标,在单因素试验的基础上通过响应面法优化提取工艺,并与索氏抽提法对比分析茶树花精油得率及其挥发性成分。结果表明:超声有机溶剂法提取茶树花精油的最佳工艺为超声功率240W、超声时间50min、石油醚添加量160mL、浸泡时间6h,在此条件下,茶树花精油得率为3.34%,而索氏抽提法的茶树花精油得率为1.59%。成分分析显示,在超声有溶剂法提取的茶树花精油中共检出23种挥发性成分,而在索氏抽提法提取的茶树花精油中只检出18种挥发性成分。

Effect of preparation method on halloysite supported cobalt catalysts for Fischer-Tropsch synthesis

Novel cobalt Fischer-Tropsch synthesis （FTS） catalysts were prepared from natural halloysite nanotubes （HNT） by double-solvent and wet- impregnation methods, and characterized by TEM, XRD, TPR and N2 adsorption-desorption. Comparing with the catalyst prepared by wet- impregnation method, the catalyst prepared by double-solvent method reduces Co3O4 particle migration and agglomeration due to size-induced effect, thus showing higher catalytic activity for Fischer-Tropsch synthesis.

响应面法优化有机溶剂提取虾青素的工艺研究

为确定有机溶剂提取虾青素的最佳条件,本研究选用破壁后的雨生红球藻,提取选用有机溶剂,以物料比、皂化液浓度、皂化时间、虾青素提取时间为指标,采用单因素和响应面法优化实验条件。结果表明,最佳工艺参数为:提取溶剂为乙酸乙酯-乙醇(1∶1)、料液比为1∶288(g∶mL)、皂化液浓度为0.05mol·L^(-1)、皂化时间为12h,虾青素平均提取率为3.32%。采用响应面法优化有机溶剂提取虾青素的工艺具有可行性,且提取的虾青素纯度较高,杂质少,可用于虾青素的提取。

金银花总黄酮低共熔溶剂提取工艺优化

目的优化金银花总黄酮低共熔溶剂提取工艺。方法在单因素试验基础上,以1,3-丁二醇与氯化胆碱比例、液料比、超声时间为影响因素,总黄酮得率为评价指标,响应面法和BP神经网络优化提取工艺。结果BP神经网络优化总黄酮得率高于响应面法优化。最优条件为1,3-丁二醇与氯化胆碱比例2.7∶1,液料比27∶1,超声时间29 min,总黄酮得率为7.85%。结论该方法稳定可靠,可用于低共熔溶剂提取金银花总黄酮。

Glycerol-Based Carbon-SO₃H Catalyzed Benign Synthetic Protocol for the Acetylation of Alcohols, Phenols and Amines under Solvent-Free Conditions

A simple and efficient solvent-free method was developed for the acetylation of alcohols, phenols and amines in excellent yields employing glycerol-based sulfonic acid (-SO3H) functionalized carbon catalyst under environmentally benign reaction conditions. The salient features of this protocol are the short reaction time, ease of product isolation and reusability of the carbon catalyst.

溶剂法提纯硫磺的工艺研究

为了解决天然气净化过程中副产物硫磺提纯难度大、提纯后硫磺纯度低的问题,结合溶剂萃取法操作简单、成本低等优势,利用相似相溶的原理,以CS2为溶剂设计了一种用溶剂法提纯硫磺的工艺。通过干燥时间考察了硫磺渣中的含水量,以硫磺产率为指标,考察了硫磺渣干燥时间、液固比、浸取时间、浸取温度和球磨粉碎对硫磺产率的影响,并通过XRD及ICP分析了纯化后硫磺的纯度。结果表明,硫磺渣干燥时间为60 min、液固比(体积质量比,m L/g)为8∶1、浸取时间为30 min、浸取温度为30℃及球磨成粉时,硫磺产率最佳。相较于传统的熔融法(85.7%)和气化法(85.37%)工艺,溶剂法工艺提纯硫磺后产率高达87.8%,提高了2.5%左右,且提纯后硫磺的纯度高达99.89%。该溶剂法提纯硫磺的工艺具有产率较高且纯度高、操作简单的优势,为有效处理硫磺提纯提供了技术路线,同时在硫磺纯化方面具有广阔的应用前景。

银耳多糖对麦醇溶蛋白纳米体系的影响及复合物的特性研究

该研究是以提高麦醇溶蛋白(gliadin,Gli)纳米颗粒(gliadin nanoparticles,GNPs)稳定性为目标,利用银耳多糖(Tremella fuciformis polysaccharides,TFPs)的乳化性能,探究TFPs添加量对GNPs稳定性的影响。采用反溶剂法制备银耳多糖和麦醇溶蛋白复合载体颗粒(gliadin-Tremella fuciformis polysaccharides composite nanoparticles,G/T NPs),并利用纳米粒度仪、傅里叶变换红外光谱仪、热场发射扫描电镜对G/T NPs的粒径和电位、相互作用、微观结构进行分析。结果表明,TFPs和Gli之间通过静电作用力和氢键作用力相结合,形成GNPs在内、TFPs外层附着的复合颗粒;TFPs的添加能够有效提高GNPs体系的稳定性,减少颗粒之间的聚集,制得的G/T_(4∶1)NPs的平均粒径、多分散指数(polydispersion index,PDI)、ζ-电位分别为(198.5±2.6)nm、0.269±0.005、(36.7±0.6)mV,且具有pH响应性。该研究为后续构建疏水营养成分的包埋和运载体系奠定了基础。

超声辅助低共熔溶剂法提取太白贝母总黄酮及其抗氧化活性研究

采用超声辅助低共熔溶剂法提取太白贝母总黄酮,以太白贝母总黄酮提取率为考察指标,通过单因素实验和响应面法对提取工艺进行了优化,并通过DPPH自由基清除实验和ABTS自由基清除实验研究了其抗氧化活性。结果表明,在超声功率为69 W、料液比为1∶18(g∶mL)、超声温度为79℃、超声时间为27 min的最优工艺条件下,太白贝母总黄酮提取率可以达到17.7004%,与预测值相差极小;太白贝母总黄酮是一种强抗氧化剂,对DPPH自由基、ABTS自由基具有较强的清除能力,在浓度为16 mg·mL^(-1)时,清除率分别达到82.15%、90.42%,与VC无明显差异。超声辅助低共熔溶剂法操作简便、提取率高,适用于太白贝母总黄酮的提取。该研究为太白贝母药材资源的开发利用提供了参考。