The Influence of Tartaric Acid in the Silver Nanoparticle Synthesis Using Response Surface Methodology

Silver nanoparticles(AgNPs)synthesized using tartaric acid as a capping agent have a great impact on the reaction kinetics and contribute significantly to the stability of AgNPs.The protective layer formed by tartaric acid is an important factor that protects the silver surface and reduces potential cytotoxicity problems.These attributes are critical for assessing the compatibility of AgNPs with biological systems and making them suitable for drug delivery applications.The aim of this research is to conduct a comprehensive study of the effect of tartaric acid concentration,sonication time and temperature on the formation of silver nanoparticles.Using Response Surface Methodology(RSM)with Face-Centered Central Composite Design(FCCD),the optimization process identifies the most favorable synthesis conditions.UV-Vis spectrum regression analysis shows that AgNPs stabilized with tartaric acid are more stable than AgNPs without tartaric acid.This highlights the increased stability that tartaric acid provides in AgNP ssssynthesis.Particle size distribution analysis showed a multimodal distribution for AgNPs with tartaric acid and showed the smallest size peak with an average size of 20.53 nm.The second peak with increasing intensity shows a dominant average size of 108.8 nm accompanied by one standard deviation of 4.225 nm and a zeta potential of−11.08 mV.In contrast,AgNPs synthesized with polyvinylpyrrolidone(PVP)showed a unimodal particle distribution with an average particle size of 81.62 nm and a zeta potential of−2.96 mV.The more negative zeta potential of AgNP-tartaric acid indicates its increased stability.Evaluation of antibacterial activity showed that AgNPs stabilized with tartaric acid showed better performance against E.coli and B.subtilis bacteria compared with AgNPs-PVP.In summary,this study highlights the potential of tartaric acid in AgNP synthesis and suggests an avenue for the development of stable AgNPs with versatile applications.

离子液体催化合成巯基丙酸甲酯的性能分析及表征

采用一步法合成吡咯烷酮-硫酸离子液体催化剂,利用红外光谱仪、液相色谱仪、热重分析仪、核磁共振氢谱等对其进行表征。研究了该离子液体对甲醇与巯基丙酸酯化反应的催化性能,并与传统浓硫酸催化剂的催化性能进行比较。结果表明,合成物质为[Hnhp]HSO_(4)离子液体且纯度为96%;与传统浓硫酸催化剂相比,以[Hnhp]HSO_(4)离子液体为催化剂时反应时间短,产品的收率高于浓硫酸催化剂产品收率约5%;[Hnhp]HSO_(4)离子液体重复10次试验后,催化剂性能没有降低,且产品收率在85%左右。

N-甲基吡咯烷酮法丁二烯抽提装置技术探讨

结合N-甲基吡咯烷酮(NMP)法丁二烯抽提装置的生产工艺特点,对装置的综合能耗、控制理念、设备布置以及环保指标等进行研究。试验结果表明,采用三级能量回收技术方案及抽余C_(4)产品规格的调整方案,可有效降低NMP法丁二烯抽提装置的综合能耗;以气相稀释剂与液相稀释剂相结合的方式稀释高含量C_(4)炔烃,可控制C_(4)炔烃含量小于40%(w);以顺-2-丁烯作为中间塔的关键组分,可控制粗1,3-丁二烯的产品质量;在高含量气相1,3-丁二烯换热器中采用倾斜3%角度布置及纵向立式布置两种方式,可降低1,3-丁二烯聚合物堵塞换热器的风险;废气、废水的排放量较少,处理效果整体满足国内相关标准要求;在装置内设置的烃类密闭排放系统及NMP溶剂储罐废气水洗系统等环保措施可有效提高装置的安全性。

Rational Synthesis of Cylindrical Silver Single-crystalline Nanowires via Poly(vinyl pyrrolidone) Reduction of AgCl

We presented a simple yet convenient hydrothermal approach for the large-scale synthesis of uniform cylindrical silver (Ag) single-crystalline nanowires with diameters of about 25 nm and lengths of 1-4 μm. Poly(vinyl pyrrolidone) (PVP) was used as a reducing agent, and AgCl was used as a precursor to deliberately control [Ag^+] at a low degree in the overall reaction process through its dynamic equilibrium by directly reducing AgCl with PVP at a quasi-equilibrium growth condition. The as-obtained products were characterized by powder X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), infrared spectra (IR) and Raman spectra. Factors such as [PVP], reaction temperature, time, and species of reducing agents and precursors were investigated to have strong influences on the morphologies and structures of the resultant Ag nanostructures. The wire diameter can conveniently be adjusted between 25 and 50 nm by simply adjusting [PVP], reaction temperature and reducing agent species. The as-synthesized silver nanowires can be self-assembled into perfect order arrays after being dried on tin foil due to the PVP coating on the surface, the circular cross-section and the uniform diameter of the Ag nanowires. These special silver nanowires with a core-shell structure as well as their spontaneous self-assembly of order arrays are expected to provide potential applications in flexible conductors, dielectric materials, electromagnetic shielding materials and nano-devices.

The ion balance of Shotokuseki extract promotes filaggrin fragmentation and increases amino acid production and pyrrolidone carboxylic acid content in three-dimensional cultured human epidermis

Natural moisturizing factor(NMF)in the stratum corneum contributes to the retention of moisture there.The purpose of this study was to determine the penetration of ions in Shotokuseki extract(SE)into the three-dimensional cultured epidermis and the effect of NMF on the biosynthesis of amino acids and pyrrolidone carboxylic acid formation.Vari-ous ions,amino acids and pyrrolidone carboxylic acid were quantified by inductively coupled plasma mass spectrom-etry,fully automatic amino acid analyzer or high-performance liquid chromatography(HPLC)in three-dimensional cultured epidermis after application of SE.Gene expression levels of profilaggrin,calpain1,caspase14,and bleomycin hydrolase,which are involved in NMF production,were determined by reverse-transcription qPCR and bleomycin hydrolase activity was determined by aminopeptidase assay.The application of SE increased Na,K,Mg,Ca,Al,and Fe levels in three-dimensional cultured epidermis.The mRNA levels of the starting material of amino acid synthesis profilaggrin,and calpain1 and bleomycin hydrolase,which are involved in its fragmentation,increased.The activity of bleomycin hydrolase also increased.Furthermore,the levels of amino acids and pyrrolidone carboxylic acid increased in the three-dimensional cultured epidermis.This suggests that the ionic composition of SE may be involved in its moisturizing effect on the stratum corneum.

Thermo-Responsive Electrospun Nanofibers from Poly( N-isopropylacrylamide )/Polyvinyl Pyrrolidone Blends

A novel nanofiber composite poly(N-isopropylacrylamide)(PNIPAAm)/polyvinyl pyrrolidone(PVP)was successfully prepared by electrospinning.Analogous medicated fibers loaded with ketoprofen(KET)as a model drug were prepared.X-ray diffraction(XRD)demonstrated that the drug was presented in the fibers with an amorphous form.Both scanning and transmission electron microscopy showed that the fibers had an even diameter and smooth surface,and no phase separation was observed.The KET loaded nanofibers did not affect the morphology of the fibers,and no drug aggregation was separated from the polymer fibers.Water contact angle measurements proved that the PNIPAAm/PVP fibers switched from hydrophilic to hydrophobic when the temperature increased the lower critical solution temperature of 32℃.In vitro drug release studies were also undertaken and the result indicated that the PNIPAAm/PVP blend nanofiber presented the properties of the two polymers,having temperature-sensitive systems with sustained release properties.In addition,MTT assay demonstrated that the nanofiber film was non-toxic and suitable for cell growth.Thus,the nanofiber can be used as thermoresponsive carriers for sustained release of poor water soluble drugs.

Kinetic hydrate inhibitor performance of new copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s with TBAB

In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s (HGs) is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran (THF) hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.

Dissolution Properties of 2-(Dinitromethylene)-5-methyl-1,3-diazacyclopentane in Dimethyl Sulfoxide and N-Methyl Pyrrolidone

The molar enthalpies of dissolution for 2-(dinitromethylene)-5-methyl-1,3-diazacyclopentane(DNMDZ) in dimethyl sulfoxide(DMSO) and N-methyl pyrrolidone(NMP) were measured using an RD496-2000 Calvet microcalorimeter at 298.15 K under atmospheric pressure.Empirical formulae for the calculation of the molar enthalpies of dissolution(Δ diss H) were obtained from the experimental data of the dissolution processes of DNMDZ in DMSO or NMP.The relationships between the rate constant(k) and the molality(b) and between the reaction order(n) and the molality(b) were determined.The corresponding kinetic equations describing the two dissolution processes were dα/dt=10-2.16(1-α) 1.01 for the dissolution of DNMDZ in DMSO,and dα/dt=10-2.02(1-α) 0.85 for the dissolution of DNMDZ in NMP,respectively.

A new pyrrolidone derivative from Pistacia chinensis

新 N-phenyl-pyrrolidone 衍生物从 Pistacia 脊骨被孤立是 Bunge。它的结构作为 4-hydroxy-5-(2-oxo-1-pyrrolidinyl ) 被阐明安息香的酸的、命名 pistaciamide 根据 1D-NMR，系， HMQC 和 HMBC 分光镜的技术。

Effect of Added Poly (vinyl pyrrolidone) during Condensation on Properties of Poly(p-phenylene terephthalamide)Pulp

Poly(p-phenylene terephthalamide)(PPTA)pulp was prepared by polycondensation of the p-phenylene diamine(PPDA)with terephthaloyl chloride(TPC)in the completely anhydrous solvent system of N-methyl pyrrolidone(NMP)having calcium chloride,in the presence of poly(vinyl pyrrolidone)(PVP)having a viscosity average molecular weight lower than 40 000.It was confirmed that the polycondensation could be accelerated,the inherent viscosity of the polymer could be increased,and the polymers could be fibrillated more easily by the addition of the PVP.FTIR and X-ray spectra proved that PVP had not combined into molecular chains of the resultant PPTA pulps.The morphology of the resultant pulps,the effect of viscosity average molecular weight,amount and adding mode of PVP on inherent viscosity,specific surface area,and mean length of the resultant pulps were discussed in detail.And the friction and wear properties of the compound reinforced by the resultant pulps were simply investigated.

Separation Performance of Sodium Alginate/Poly(Vinyl Pyrrolidone)Membranes for Aqueous/Dimethylformamide Mixtures by Vapor Permeation and Vapor Permeation with Temperature Difference Methods

In this study sodium alginate (NaAlg)/poly (vinyl pyrrolidone) (PVP) blend membranes were prepared and crosslinked with CaCl2 (0.1 Molarity (M)) for the separation of aqueous/dimethylformamide (DMF) mixtures. Membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and their performance was examined by varying experimental parameters such as feed composition (0 - 100 wt%), operating temperature (30℃ - 50℃) and membrane thickness (30 - 90 micrometer (μm)). Blending NaAlg with PVP, decreased separation factor whereas increased the permeation rate as the permeation temperature was increased in Vapor Permeation (VP) and Vapor Permeation with Temperature Difference (TDVP) methods. In the TDVP method, the separation factors increased and the permeation rates decreased as the temperature of the membrane surrounding is decreased. The highest separation factor of 60 was obtained in TDVP method for 90 wt% DMF concentration in the feed.

Excess Molar Volumes and Viscosities of Binary Mixtures of p-Xylene with Cyclohexane, n-Heptane, n-Octane, Sulfolane, N-Methyl-2-pyrrolidone and Acetic Acid at 303.15 K and 323.15 K and Atmospheric Pressure

Experimental data on density and viscosity at 303.15K and 323.15K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-2-pyrrolidone and acetic acid.From these data, the excess molar volume and deviations in viscosity have been calculated. The computed quantities have been fitted to the Redlich-Kister Equation to derive coefficients and estimate the standard error values. Results are discussed in terms of intermolecular interactions.

Measurement and correlation of solid–liquid phase equilibria for binary and ternary systems consisting of N-vinylpyrrolidone, 2-pyrrolidone and water

The solid–liquid equilibria(SLE)for binary and ternary systems consisting of N-Vinylpyrrolidone(NVP),2-Pyrrolidone(2-P)and water are measured.The phase diagrams of NVP(1)+2-P(2),NVP(1)+water(2),NVP(1)+2-P(2)+1 wt%water(3)and NVP(1)+2-P(2)+2 wt%water(3)are identified as simple eutectic type with the eutectic points at 263.75 K(x_(1E)=0.5427),251.65 K(x_(1E)=0.3722),260.25 K(x_(1E)=0.5031)and256.55 K(x_(1E)=0.4684),respectively.The phase diagram of 2-P(1)+water(2)has two eutectic points(x_(1E)=0.1236,T_E=259.15 K and x_(1E)=0.7831,T_E=286.15 K)and one congruent melting point(x_(1C)=0.4997,T_C=303.55 K)because of the generation of a congruently melting addition compound:2-P·H_2O.The ideal solubility and the UNIFAC models were applied to predict the SLE,while the Wilson and NRTL models were employed in correlating the experimental data.The best correlation of the SLE data has been obtained by the Wilson model for the binary system of NVP+2-P.The UNIFAC model gives more satisfactory predictions than the ideal solubility model.

Synthesis and Crystal Structure of Bis(nitrate)bis(N-n-octyl-α-pyrrolidone)uranyl (II)

The crystal structure of the title compound UO2(NO3)2[CH2(CH2)2CONC8H17] was determined by single-crystal X-ray diffraction. Crystal data: triclinic, space group P , a = 7.456(2), b = 8.371(2), c = 13.470(3) ? ?= 95.66(1), ?= 94.64(2), ?= 102.67(2), C24H46N4O10U, Mr = 788.68, V = 811.7(3) ?, Dc = 1.613 g/cm3, Z = 1, F(000) = 390, ?= 5.052 mm-1, the final R = 0.0256 and wR = 0.0568 for 2826 observed reflections (I > 2(I)). The central uranyl ions are coordinated by six oxygen atoms. Two of them are from the carbonyl groups of N-octyl-a-pyrrolidone molecules, and the other four from two nitrate groups.

Preparation and characterization of the antifouling porous membranes from poly(vinylidene fluoride)-graft-poly(N-vinyl pyrrolidone) powders

Porous membranes were prepared using the phase inversion method from poly(vinylidene fluoride)-graftpoly(N-vinyl pyrrolidone)(PVDF-g-PVP) powders, which were synthesized via γ-ray induced graft polymerization(pre-irradiation). Chemical compositions, thermal behavior, morphology and hydrophilicity of the membranes were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, element analysis, thermalgravimetric analysis, differential scanning calorimetry, scanning electron microscopy and contact angle measurements, respectively. Permeation experiments were conducted to evaluate the water flux,and the dynamic BSA fouling resistance performances were investigated, too. All the experimental results indicate that the PVDF-g-PVP membranes demonstrate better separation performances over the pristine PVDF membrane.

Synthesis and Characterization of Poly(N-Vinyl-2-Pyrrolidone/Itaconic Acid) Hydrogel

With N-vinyl-2-pyrrolidone (NVP) and itaconic acid(IA), poly(N-vinyl-2-pyrrolidone/itaconic acid)[P(NVP/IA)] hydrogel was synthesized by free radical solution polymerization. The structure of this (P(NVP/IA)) was characterized by IR. Effects of concentration of itaconic acid, amount of cross-link agent, N,N′-methylene-bis-acrylamide, reaction temperature, and time on properties of swelling ratio(SR) of the hydrogel were investigated.The results show that the best swelling property of the hydrogel is obtained at 50 ℃ and 1.5 h. pH sensitivity increases as the concentration of itaconic acid in the hydrogel system increases. Swelling ratio of the hydrogel decreases as the amount of cross-link agent increases.

Dissolution and recrystallization of perovskite induced by N-methyl-2-pyrrolidone in a closed steam annealing method

High quality perovskite films with large columnar grains are greatly desired for efficient perovskite solar cells. Here, low volatility N-methyl-2-pyrrolidone(NMP) was added in MAI/IPA solution in a two-step spin-coating method, which promoted the conversion of lead iodide to perovskite. The perovskite films were annealed by a closed-steam annealing method to prolong the recrystallization process of perovskite films assisted by the residual NMP. It leaded to high quality CH_3NH_3PbI_3 perovskite films with large columnar grains due to its enhancement of the Oswald ripening. The large grain perovskite film leaded to efficient carrier transformation and injection, and low recombination. The photovoltaic performance of the perovskite solar cells was improved significantly.

布洛芬光固化模印片的制备及释药行为

目的制备具有定制个性化形状的缓释布洛芬光固化模印片,满足不同人群的需求。方法利用3D打印技术制备不同形状的模具。将布洛芬粉末和N-乙烯基吡咯烷酮(N-vinyl-2-pyrrolidone,NVP)制成软材,填充于模具,成型并推出。将预制片在紫外光下固化制得模印片。考察不同模印片的性质及释放行为。结果布洛芬光固化模印片硬度较高,约4 kg力;光固化模印片具有缓释特征,而传统工艺制备的布洛芬模印片仅能快速释放。结论基于NVP光聚合和3D打印模具的光固化模印片制备工艺简单、质量稳定,是一种可定制的缓释口服剂型。

利用NVP组分调控亲水增强型温敏性PNIPAAm共聚物

聚N-异丙基丙烯酰胺(PNIPAAm)是目前在生物医药领域研究和应用最为广泛的一种温敏性聚合物。但PNIPAAm均聚物的温敏性能相对单一,且由其构建的终产物难以在较宽温度范围内通过改变温度发生整体体积或表面润湿性能转变,因此限制了其应用范围。为了扩展PNIPAAm的应用领域,设计可以调控特别是提升PNIPAAm基材最低临界溶液温度(LCST)的温敏性聚合物十分必要。鉴于此,本研究将亲水性N-乙烯基吡咯烷酮(NVP)引入温敏性聚合物分子骨架,同时利用共聚物的反应基团将P(NIPAAm-co-NVP)共聚物聚合接枝于铂片表面从而形成共聚物膜。衰减全反射-傅里叶变换红外光谱(ATR-FTIR)、核磁共振氢谱(1H-NMR)和凝胶渗透色谱(GPC)的鉴定结果表明各单体间的共聚反应均按预定方案进行,且可显著提升NVP在聚合过程的参与率;动态光散射(DLS)和静态接触角数据、扫描电子显微镜(SEM)图像均证明可以利用NVP组分提升P(NIPAAm-co-NVP)共聚物的LCST,从而获得亲水增强型的温敏性共聚物膜,该膜可用于药物控制释放和非侵害性细胞收获等。