低共熔溶剂在储能与传热方面的研究进展

低共熔溶剂（deep eutectic solvents,DESs）通常是由一定化学计量比的氢键受体和氢键给体以氢键缔合的形式组成。因其具有低成本、无毒、饱和蒸气压低、热稳定性好、导电性好等优点,现已在有机合成、材料化学、电化学、生物质降解、催化等多个领域得到广泛应用。近年来,随着现代社会对高效能量存储和换热方面需求不断增加,低共熔溶剂在储能与传热等领域的应用受到研究人员的广泛关注。从“储与传”的角度详细综述了近年来低共熔溶剂在储能与传热方面的研究进展,从不同能量传递形式的角度出发主要分为以下两个部分：作为低共熔相变储能材料满足对潜热、相变温度及稳定性等方面的要求;作为传热工质满足对高效传热的需求。     

New Carvone-Based Deep Eutectic Solvents for Siloxanes Capture from Biogas

During biogas combustion, siloxanes form deposits of SiO₂ on engine components, thus shortening the lifespan of the installation. Therefore, the development of new methods for the purification of biogas is receiving increasing attention. One of the most effective methods is physical absorption with the use of appropriate solvents. According to the principles of green engineering, solvents should be biodegradable, non-toxic, and have a high absorption capacity. Deep eutectic solvents (DES) possess such characteristics. In the literature, due to the very large number of DES combinations, conductor-like screening models for real solvents (COSMO-RS), based on the comparison of siloxane activity coefficient of 90 DESs of various types, were studied. DESs, which have the highest affinity to siloxanes, were synthesized. The most important physicochemical properties of DESs were carefully studied. In order to explain of the mechanism of DES formation, and the interaction between DES and siloxanes, the theoretical studies based on σ-profiles, and experimental studies including the ¹H NMR, ¹³C NMR, and FT-IR spectra, were applied. The obtained results indicated that the new DESs, which were composed of carvone and carboxylic acids, were characterized by the highest affinity to siloxanes. It was shown that the hydrogen bonds between the active ketone group (=O) and the carboxyl group (-COOH) determined the formation of stable DESs with a melting point much lower than those of the individual components. On the other hand, non-bonded interactions mainly determined the effective capture of siloxanes with DES.     

VIS absorption spectrophotometry of disperse dyes

In the investigations of the dyeing processes, the low solubility of disperse dyes in water represents a practical problem for the determination of dye concentration in dyebaths and waste waters. Therefore the use of an organic solvent which, dissolves disperse dyes, is recommended in visible spectrophotometry of disperse dyes. Three organic solvents (ethanol, N,N-dimethylformamide, acetone) and two disperse dyes, the disazo dye C.I. Disperse Orange 29 and the anthraquinone dye C.I. Disperse Blue 56, were used for spectroscopic analysis in this present work. The absorbance of aqueous dye dispersions and various organic solvent dye solutions was measured to evaluate the effect of the solvent on the shape and intensity of the absorption spectra and on the wavelength shift of maximum absorption. The validity of Beer–Lambert’s law in each system was ascertained. A suggestion is made how VIS absorption spectrophotometry can be used to determine the dye concentration in disperse dyebaths. The addition of organic solvent to the dyebath leads to dye dissolution, and the Beer-Lambert’s law is then fulfilled. The optimum ratio between the dyebath dispersion and the organic solvents for the dyes investigated is also determined.     

The Optimization of Mixing Amine Solvents for CO2 Absorption Based on Aqueous MDEA/DETA and MDEA/TETA

Mixed amine solvents have gained increasing attention in recent years. The absorption and desorption performance of mixed amine solvents for CO₂ were analyzed by experiments. The absorption rate, absorption load, and desorption rate were used as the evaluating index. The experiment results show that the smaller proportion of MDEA/DETA solvents is the higher absorption load and absorption rate are, but the final desorption degree does not rise. When the rate of TETA is high, it is helpful to improve absorption rate and reduce desorption time of MDEA + TETA, but it is not necessary to add excessive TETA into mixed amine solvents.     

The Solubility of Asphaltenes in Different Hydrocarbon Liquids

Abstract

Bitumen miscibility in low-molecular-weight hydrocarbon liquids was evaluated. The presence of toluene in bitumen–solvent blends improved bitumen miscibility and led to the delay in onset of asphaltenes precipitation due to the dipole–dipole and heteromolecular interactions. For heavy naphtha, the results showed reduced asphaltenes precipitation and enthalpy of mixing due to strong hydrogen bonding and moderate homomolecular interactions. Hexane and light naphtha systems showed higher heats of mixing and higher asphaltenes precipitation due to homomolecular interactions. The best miscibility characteristics of heavy petroleum were obtained with aromatic solvents and solvent mixtures that contained increasing composition of toluene.     

Partitioning of Printing Ink Solvents on Chocolate

Partitioning (Kp) of printing ink solvents was studied in three types of chocolate with different fat content and degrees of crystallinity. At 25°C, chocolate liquor (48% fat and medium crystallinity) showed a higher Kp than chips (25% fat and higher crystallinity), but cream (29% fat and lowest crystallinity) showed the highest Kp. Order appeared to depend on degree of crystallinity. At 35°C and 45°C as samples became increasingly molten, effect of crystallinity diminished and order of increasing Kp depended on fat content. Kp order of solvents was the same in all chocolates and temperatures: toluene > isopropanol > methyl ethyl ketone > ethyl acetate > hexane in accord with Hildebrand solubility parameter differences.     

CL-20转晶废剂的处理研究

采用烃油及正辛醇对六硝基六氮杂异伍兹烷(CL-20)转晶废剂进行预处理,回收CL-20固体,再利用废剂中各溶剂的沸点不同,通过共沸蒸馏分离出乙酸乙酯和氯仿等溶剂。利用高效液相色谱(HPLC)、傅里叶变换红外光谱(FTIR)、扫描电镜(SEM)对转晶废剂组分和析出的固体进行了表征。结果表明,转晶废剂主要含有氯仿、乙酸乙酯、α-CL-20;用烃油处理废剂回收到的α-CL-20的纯度为99.1%,回收率为79.5%。     

Utilization of coordinating green solvents for high quality methylammonium bismuth iodide thin films for photovoltaic applications

Photovoltaic performances of the bismuth-based solar cells are profoundly affected by the thin film quality of the photoactive layer. Herein, we report on various green solvent system to obtain the highly crystalline, pinhole free and homogeneously methylammonium bismuth iodide (MBI) active layer. The MBI structure prepared with tetrahydrofuran:2-ethoxy-ethanol (THF-2ETO) solvent system was found to have the best film quality. Adding 0.05 M 2ETO as the co-solvent is sufficient to produce high quality BiI₃ and MBI thin films. According to the X-ray photoelectron spectroscopy (XPS) analyzes, we have demonstrated that there is an interaction between BiI₃ and 2ETO according to the concentration of 2ETO added to the main THF. Our study clarifies the importance of THF-2ETO solvent system that can accelerate the evolution of the Bi-based solar cells by creating high-quality BiI₃ or MBI thin films.     

Non-Halogenated-Solvent Processed and Additive-Free Tandem Organic Solar Cell with Efficiency Reaching 16.67%

Organic solar cells (OSCs) have recently reached a remarkably high efficiency and become a promising technology for commercial application. However, OSCs with top efficiency are mostly processed by halogenated solvents and with additives that are not environmentally friendly, which hinders large-scale manufacture. In this study, high-performance tandem OSCs, based on polymer donors and two small-molecule acceptors with different bandgaps, are fabricated by solution processing with non-halogenated solvents without additive. Importantly, the two active layers developed from non-halogenated solvents show better phase segregation and charge transport properties, leading to superior performance than halogenated ones. As a result, a tandem OSC with high efficiency of up to 16.67% is obtained, showing unique advantages in future massive production.     

High Resolution Optical Interference Measurements of Changes in Bond-Line Thickness—A Review

A novel moire optical interference method, originally developed¹ to measure the swelling displacement normal to the plane of a simple butt joint during water uptake at the joint edge, was subsequently used to investigate the unexpected occurrence of shrinkage and, at the same time, swelling during exposure to organic solvents. In later experiments, synergistic displacement fields generated during simultaneous exposure to water and organic solvents were studied. The same method has also been used to investigate the origin of adhesion failures at copper plated-through holes in thermally cycled multi-layer circuit boards.

The method employs a thin glass cover slip as one adherend. Changes in bondline thickness flex the cover slip thereby changing the gap between the latter and a nearby optical flat. By using monochromatic light to illuminate the specimen, interference between incident and reflected light is achieved. The small displacements of individual fringes associated with changes in gap size are used to generate moire patterns which bear a 1:1 relationship to the local changes in bondline thickness. Application of thin plate elasticity theory to the flexing of the cover slip yields the stress acting normal to the joint. The magnitude of this normal stress is strongly inhomogeneous, oscillating in sign and reaching compressive values as high as 50MNm^?2 for water uptake by a simple butt joint, and exceeding the yield strength of oxygen-free high conductivity copper (1MNm^?2) for the thermal expansion that accompanies simulated soldering of a multi-layer circuit board.

Attention is drawn to the high resolution achievable with the method. Changes in bond-line thickness of the order of Δ/10, where Δ is the wavelength of the light giving rise to the interference pattern, are readily resolved. It is pointed out that the method may well be sufficiently sensitive to detect the effects of different physical properties (thermal conductivity, specific heat capacity) of adherend surface on the nature of the cured adhesive and hence on the mechanical behaviour of the bond-line.