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.

CARBONYLATION OF ALLYL HALIDES CATALYZED BY POLY(N-VINYL-2-PYRROLIDONE) ANCHORED PALLADIUM CATALYST UNDER ATMOSPHERIC PRESSURE

Carbonylation of allyl halides catalyzed by poly(N-vinyl-2-pyrro- lidone) anchored palladium catalyst affords β,r-butonic acid under atmo- spheric pressure and at room temperature.The activity and efficiency of the catalyst are much higher than those of the reported catalysts for this reaction.

Ethylene absorption in N-methyl-2-pyrrolidone/silver nano-solvent:Thermodynamics and kinetics study

The effect of presence of silver nanoparticles in pure N-methyl-2-pyrrolidone(NMP)solvent for ethylene gas absorption in an experimental pressure decaying setup has been investigated.All experiments were performed at temperatures of 278.15 K,298.15 K and 328.15 K and different pressures(up to ethylene dew point)as well as different concentrations of silver nanoparticles(0.05 g·L^(-1) and 0.1 g·L^(-1)).The kinetic data of absorption,Henry’s law constants,and heat of absorption were calculated.Comparison of the pure solvent and the nanofluids absorption results revealed that the presence of small amounts of nanoparticles could improve the absorption performance between 1.5%-18%.Finally,the effect of temperature,pressure,and nanoparticle concentration on the equilibrium results were investigated.

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.

Effective N-methyl-2-pyrrolidone wet cleaning for fabricating highperformance monolayer MoS2 transistors

Two-dimensional semiconductors,such as MoS2 are known to be highly susceptible to diverse molecular adsorbates on the surface during fabrication,which could adversely affect device performance.To ensure high device yield,uniformity and performance,the semiconductor industry has long employed wet chemical cleaning strategies to remove undesirable surface contaminations,adsorbates,and native oxides from the surface of Si wafers.A similarly effective surface cleaning technique for two-dimensional materials has not yet been fully developed.In this study,we propose a wet chemical cleaning strategy for MoS2 by using N-methyl-2-pyrrolidone.The cleaning process not only preserves the intrinsic properties of monolayer MoS2,but also significantly improves the performance of monolayer MoS2 field-effect-transistors.Superior device on current of 12 μA·μm-1 for a channel length of 400 nm,contact resistance of 15 kΩ·μm,field-effect mobility of 15.5 cm^2·V^-1·s^-1,and the average on-off current ratio of 10^8 were successfully demonstrated.

SYNTHESIS OF POLYMER-STABILIZED RUTHENIUM COLLOIDS BY LOW BOILING POINT ALCOHOL REDUCTION

Stable and well-dispersed poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloidal clusters wereprepaxed via the reduction of ruthenium(III) chloride by refluxing with low boiling point alcohols. Investigation of the size ofRu colloids by transmission electron microscopy (TEM) indicated that the average diametes could be controlled in the rangeof 1.2-1.6 nm with relative standard deviations of less than 0.33 by changing the molar ratio of PVP to Ru. The X-rayphotoelectron spectroscopy (XPS) characterization verified the formation of elemental ruthenium colloids.

聚合物稳定的金簇合物上卤素吸附质:质谱检测及其对催化的影响（英文）

聚(N-乙烯基-2-吡咯烷酮)稳定的金簇合物(Au:PVP)的质谱结果表明,来源于合成前驱体的Cl吸附质主要存在于Au_(34)和Au_(43)簇合物上.金簇合物上Cl吸附质的数量不影响其催化有氧苯甲醇氧化性能,表明Cl原子与Au簇合物间存在较弱的键合作用.相反,用Br替代Au_(34)和Au_(43)簇合物上Cl显著抑制了其催化活性,但对其电子结构没有任何影响.这表明,Br原子与金簇合物的键合较强,在空间上堵塞了活性位.因Br吸附质而导致活性显著下降表明,Au_(34)和Au_(43)簇合物对Au:PVP催化活性起主要贡献.

Microwave-assisted synthesis of high aspect ratio ruthenium nanorods

Poly(N-vinyl-2-pyrrolidone)(PVP)-stabilized ruthenium nanorods with high aspect ratio by refluxing ruthenium(Ⅲ) chloride in n-propanol have been successfully prepared by means of a facile and rapid microwave heating for the first time.The structure and morphology of the obtained products were characterized by transmission electron microscopy(TEM),select area electron diffraction(SAED),ultraviolet-visible spectrophotometry(UV-vis),X-ray photoelectron spectroscopy(XPS) and Fourier transform spectroscopy(FT-IR).XPS analysis reveals that the nanorods were in the metallic state.TEM images showed that ruthenium nanorods had an obvious one-dimensional structure with the aspect ratio ranged from 5 to 40 nm and length up to 600 nm.SAED patterns indicated that the nanorods were single-crystalline with a hexagonal structure.

High-performance PVDF-HFP based gel polymer electrolyte with a safe solvent in Li metal polymer battery

Poly(vinylidenefluoride-co-hexafluoropropylene)(PVDF-HFP)based gel polymer electrolytes are widely studied owing to their electrochemical stability and high dielectric constant.However,most gel polymer electrolytes show unsatisfied safety and interface compatibility due to excessive absorption of volatile and flammable liquid solvents.Herein,by using a safe solvent(N-methyl-2-pyrrolidone)with higher boiling(203℃)and flash points(95℃),we initiatively fabricate a flexible PVDF-HFP based gel polymer electrolyte.The obtained gel polymer electrolyte demonstrates a high ionic conductivity of 7.24×10^−4 S cm−1,an electrochemical window of 5.2 V,and a high lithium transference number of 0.57.As a result,the synthesized polymer electrolyte exhibits a capacity retention of 70%after 500 cycles at 0.5 C,and a discharge capacity of 86 mAh g−1 even at a high current rate of 10 C for LiFePO4 based Li metal batteries.Moreover,a stable Li plating/stripping for more than 500 h is achieved under 0.1 mAh at both room temperature and 70℃.Our results indicate that the PVDF-HFP polymer electrolyte is promising for manufacturing safe and high-performance Li metal polymer batteries.

Physicochemical properties of β-cyclodextrin solutions and precipitates prepared from injectable vehicles

β-Cyclodextrin( β-CyD) is cyclic oligosaccharide of a glucopyranose, containing a relatively hydrophobic central cavity and hydrophilic outer surface. However, the usefulness of β-CyD is limited owing to its low aqueous solubility whereas we found that its apparent high solubility was evident in some injectable solvents including 2-pyrrolidone(PYR), Nmethyl pyrrolidone(NMP) and dimethyl sulfoxide(DMSO). Therefore, in the present study, the physicochemical properties of the 30–60% w/w β-CyD in PYR, NMP and DMSO were investigated such as viscosity, water resistant, matrix formation rate and syringeability. The higher the concentration of β-CyD resulted in the increased viscosity and the higher force and energy of syringeability. β-CyD in PYR gave the highest viscosity which contributed to the lowest syringeability while β-CyD in DMSO exhibited the highest syringeability. The β-CyD in DMSO and NMP exhibited the higher rate of matrix formation. β-CyD in PYR showed the highest water resistant for phase separation while β-CyD in NMP gave the faster de-mixing rate compared to that from PYR. The difference in physicochemical properties of β-CyD dried ppts studied by scanning electron microscope(SEM), differential scanning calorimetry(DSC), X-ray diffraction(XRD), Fourier-transform infrared spectroscopy(FT-IR) and thermogravimetric analysis(TGA) revealed that there was partial complexation of β-CyD with respective solvents. Both solution and precipitate characteristic properties will be useful for using β-CyD in further investigation as matrix material dissolved in the injectable vehicles as the in situ forming gel for periodontitis treatment.

A novel family of green ionic liquids with surface activities

Ionic liquids have many unique properties as a new and remarkable class of environmental benign solvents,which promises widespread applications in industry and other areas. However,the ionic liq-uids with surface activity are rarely reported. In this work,a series of novel ionic liquids was synthe-sized by using N-methyl-2-pyrrolidone and alkyl bromide. The physical properties of this family of ionic liquids have been characterized,which shows that these compounds have ionic liquids characteristics,surface activity and biocompatibility.

Biocompatible and Bioeliminable Hydrophilic Polymers

1 Introduction This presentation will report on some recent results obtained in Milan on two polymer families of biomedical interest, namely poly(N-vinyl-2-pyrrolidinone) and polyamidoamines. 2 Results and DiscussionPoly(N-vinyl-2-pyrrolidinone) (PVP) is a well known bioactive and biocompatible polymer. In its soluble form, it is largely used as excipient of oral pharmaceutical formulations, especially for its high water solubilising power.In its crosslinked form, it plays a relevant role as biomateria...