Electrochemical reduction of graphene oxide in organic solvents

Graphene oxide (GO) cast on conductive substrates was electrochemically reduced in some organic solvents. The amount of electricity required for the almost complete reduction of GO was 2.0 C for 1 mg GO, corresponding to attaching of a one-electron reducible species to each benzene ring in graphene. The electrochemically reduced GO film gave an electrical conductivity of about 3 S cm⁻¹ and exhibited a relatively high specific capacitance of 147.2 F g⁻¹ in propylene carbonate. The electrochemical reduction of GO was feasible on Al foils as well.     

Polymer-stabilized graphene dispersions at high concentrations in organic solvents for composite production

We demonstrate a simple and effective technique for dispersing pristine (unfunctionalized) graphene at high concentrations in a wide range of organic solvents by use of a stabilizing polymer (polyvinylpyrrolidone, PVP). These polymer-stabilized graphene dispersions are shown to be highly stable and readily redispersible even after freeze-drying. This technique yields significantly higher graphene concentrations compared to prior studies. An excellent increase in the thermal conductivity of the fluid by the addition of pristine graphene is also demonstrated. These well-dispersed pristine graphene sheets were then used as a strong and conductive nano-filler for polymer composites. Graphene/PVP composites were produced by the bulk polymerization of N-vinylpyrrolidone loaded with dispersed graphene, resulting in excellent load transfer and improved mechanical and electrical properties.     

Swelling of lignites in organic solvents

Data on the swelling of Turkish lignites can be summarized using linear multiparameter equations that take into account various properties of solvents. Factors responsible for the amounts of absorbed solvents are the basicity and cohesion energy density of the solvents.     

Synthesis of cobalt ferrite in organic solvents

The possibility of synthesizing the nanosized CoFe₂O₄ particles in organic solvents, such as glycerol and diphenyl oxide, at 250°C and atmospheric pressure under conditions of distillation of the formed water was studied. In the case of glycerol, we obtained the adduct of the latter with cobalt ferrite. The reaction in diphenyl oxide resulted in the formation of ferrite particles sized 8–10 nm.     

Diffusion of organic solvents in isobutylene-based polymers

Diffusion behavior of several organic solvents in polyisobutylene (PIB) and in poly(p-methylstyrene-co-iso-butylene) (PMS-BR) with different monomer ratios has been studied. The experiments have been conducted over a temperature range of 50 to 100°C using a conventional gravimetric Sorption technique. The PMS-BR copolymers contained 2, 7, and 15 weight percent p-methylstyrene, respectively. Although employing temperatures were far above the glass transition temperatures of polymers, the diffusion coefficients are correlated well with the Vrentas-Duda free-volume theory. For all the solvents, the PIB shows the highest diffusivity while the copolymer with the 15% p-methylstyrene gives the lowest value. This behavior can be explained by the amount of fractional free-volume present in a system.     

ZnTe electrodeposition from organic solvents

The electrodeposition of zinc telluride was investigated from various organic solvent baths such as methanol, acetonitrile, propylene carbonate. The potential window increases with increasing boiling point of the solvents. In particular, ZnTe with high crystallinity could be obtained in propylene carbonate by the under-potential deposition (UPD) of Zn. The current efficiency for ZnTe deposition in propylene carbonate was enhanced considerably compared to that in acidic aqueous solutions. A single-phase ZnTe film close to the ideal stoichiometric composition of ZnTe could be obtained at 423 K and −0.8 V versus Ag/AgCl in propylene carbonate with a molar ratio of Zn(II)/Te(IV) = 10 and a low Te(IV) concentration; the film had a smooth and dense granular crystal morphology.     

Debonding of photoresists by organic solvents

Chlorofluorocarbons (CFCs) have been widely used in the printed circuit board industry for many decades. However, the growing concern regarding their ozone depleting properties has demanded a ban on these solvents and consequently brought forth the search for environmentally friendly alternatives. In printed circuit board technology, methyl chloroform and methylene chloride have been widely utilized as solvents for developing and stripping, respectively, radiation sensitive materials useful in creating fine line circuitry patterns. The solubility of unexposed and exposed T168 resist in selected solvents or solvent mixtures at various temperatures is described here. Results addressing the ease of removal of such solvent based resists using environmentally friendly alternatives are presented. Debonding of the polymer layer from the underlying substrate was observed by monitoring the deflection of the composite strip immersed in the solvent using a Fotonic Sensor accessory. Debonding time, identified as the necessary time to remove the photoresist from such surfaces, can vary with temperature, solvent, photoresist type or thickness, and exposure energy. © 1996 John Wiley & Sons, Inc.     

The influence of organic solvents on transphosphatidylation by phospholipase D from peanut in anhydrous organic solvents

Phospholipase D (PLD) is widely used for the transphosphatidylation of phospholipids, which is conventionally performed in biphasic systems. The influence of organic solvents on transphosphatidylation by peanut PLD in anhydrous organic solvents was studied and, for the first time, compared to that of a biphasic system in this paper. The results demonstrated that PLD activity from peanut was influenced by solvents of different polarity in anhydrous organic solvents, and the influence tendency of organic solvents (diethyl ether, chloroform, methylenechloride) on transphosphatidylation by peanut PLD in anhydrous organic solvents was the same as that in a biphasic system consisting of water and a hydrophobic organic solvent.     

Self-assembly of block copolymer complexes in organic solvents

Micelles have been prepared by mixing poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP) copolymers and poly(acrylic acid) (PAA) homopolymers in organic solvents. Complexation via hydrogen bonding occurs between the P4VP and PAA blocks. Further aggregation of the accordingly formed complexes results in micelles stabilized by a corona of PS blocks. The influence of the relative lengths of the different blocks and of the quality of the solvent towards the complexes on the micellar characteristic features is studied. Soluble, non-aggregating, complexes have been observed in DMF, provided that the complexes are sufficiently small. In all other cases, the complexes were insoluble and aggregated in micelles. The size of those micelles depends strongly on the length of the P4VP blocks but only weakly on the PAA length.     

Highly soluble polyetheramine-functionalized graphene oxide and reduced graphene oxide both in aqueous and non-aqueous solvents

Among many methods to synthesize graphene, solution-based processing provides many advantages owing to its low cost, high productivity, chemical versatility, and scalability. In particular, graphene oxide (GO) is one of the most promising nanocarbons that enable the incorporation of graphene and related materials into bulk materials and nanocomposites. GO has hydrophilic nature that enables straightforward dispersion in aqueous solution by sonication, but GO show poor dispersibility in common organic solvents, which prevent much wider applications such as solution-mixing polymer nanocomposites. Here we prepared highly soluble, functionalized GO in both aqueous and non-aqueous solvents. This was achieved by reacting polyetheramine consisting of amphiphilic components, e.g., polypropylene oxide and polyethylene oxide, with carboxylic acid groups at GO edges. Moreover, the reduced GO (rGO) was also highly dispersible in aqueous solution as well as non-aqueous solutions. These functionalized GO and rGO can be used for many solution-processed graphene composites.     

氯化铷在有机溶剂中的溶解度

铷作为稀有碱金属常与钾共存,氯化铷在不同溶剂中的溶解度是对铷化合物结晶提纯的理论依据,因此,探究氯化铷在不同溶剂中的溶解规律对于实现铷钾分离具有指导意义。实验分别测定了常压条件下氯化铷在甲酸、冰乙酸、正丙醇和乙二醇中303.15—343.15 K条件下的溶解度。结果表明:氯化铷在上述4种有机溶剂中的溶解度均随温度的升高而增大,其中温度对氯化铷在甲酸中的溶解度影响最为明显;在4种溶剂中溶解度的排序为:甲酸乙二醇冰乙酸正丙醇,甲酸比较适合用于氯化铷的重结晶。同时对实验数据进行了拟合,实验数据与理论计算结果吻合,所得拟合方程可为氯化铷重结晶工艺路线的制定提供理论依据。     

On electrochemical behaviour of zinc in organic solvents

The electrochemical behaviour of Zn has been investigated in DMSO, DMF and AN by potentiostatic and voltammetric methods. The values of αn and βn equal to 0.5 and 1 show that the charge-discharge of Zn²⁺ in these solvents proceeds as a two-step reaction. The values of apparent exchange current densities depend on the employed measurement techniques. The assumption about the passivation of Zn electrode by the products of secondary chemical reaction has been formulated.     

Lipase-catalyzed monoesterification of 1-O-hexadecylglycerol in organic solvents

A simple method is presented to esterify 1-O-hexadecyl-rac-glycerol using lipases in different organic solvents. The following fatty acids were used: C_14∶0, C_16∶0, C_18∶0, C_18∶1, and C_18∶2. Monoesterification was achieved by using a limiting amount of the fatty acid. Both the 1-O-hexadecyl-3-O-acylglycerol and the 2-O-acylglycerol were obtained in a total yield of 75% and a ratio of 7∶1 in dichloromethane after 3 d. Chromatographic data for the monoesters, useful for the identification of the natural products, are given (gas-liquid chromatography, thin-layer chromatography, reverse-phase thin-layer chromatography). The structure was confirmed by a chemical synthesis of 1-O-hexadecyl-2-O-hexadecanoylglycerol. The 3-O-glyceride was also formed by acyl migration, as the minor component. The monoesters were separated by column chromatography and characterized by ¹H and ¹³C nuclear magnetic resonance spectra.     

Mixed organic solvents: A review

Research regarding the physicochemical properties and application of mixed organic solvents in extraction is reviewed.     

Diffusion of organic solvents into polycarbonate film

Diffusion rates of organic solvents and water into polycarbonate film were measured under saturated vapor, and the diffusion coefficients were determined by combining the finite element method and the least squares method. The logarithm of the diffusion coefficients decreased linearly with the increase of the molecular volumes of organic solvents and water. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 943–949, 1997     

L-丙交酯在不同有机溶剂中的溶解度测定

利用激光法测定了L-丙交酯在甲醇、乙醇、正丁醇、丙酮和乙酸乙酯中的溶解度,测试温度范围为293.15～313.15 K。L-丙交酯的溶解度大小顺序是:丙酮>乙酸乙酯>甲醇>乙醇>正丁醇。用Apelblat方程对测定的溶解度数据进行了拟合,通过计算得到在不同溶剂中的结晶热。