煤焦油沥青不同改性产物炭化性质的比较研究

比较研究了几种改性煤焦油沥青的炭化性质，并从原料结构上给出了解释。结果表明：在同一热处理条件下形成的各种中间相沥青的光学显微结构区域的大小顺序为：Ｓ－ＬＤＯＨＦ－ＭＣＴＰ＞Ｓ－ＭＣＴＰ＞ＭＣＴＰ－ＰＳ＞ＭＣＴＰ共炭化沥青分子中含有较多的短烷基侧链和环烷结构，炭化时能形成可溶性较好的广域型中间相体；超临界抽提能调整沥青的族组成和分子量分布，使分子更易于均匀聚合和取向，超临界抽提沥青的炭化性能优于抽提     

Methods of preparation and properties of mineral-carbon sorbents obtained from coal-tar pitch-polymer compositions

The purpose of this study was to determine the possibility of producing hydrophobic mesoporous mineral-carbon sorbents from aluminum hydroxide and coal-tar pitch-polymer compositions by carbonization at 600?°C in an nitrogen atmosphere. The method of homogenization was optimized using different solvents. Blends of aluminum hydroxide and coal-tar pitch with a definite composition or the products of co-precipitation of aluminum hydroxide in the coal-tar pitch-polymer medium were subjected to carbonization process. The hydrophilic?Chydrophobic properties were evaluated by adsorption of water vapors. The highest value of BET surface area about 370?m²/g, was achieved for the carbonization product obtained from co-precipitated raw components with 10?wt% coal-tar pitch-polymer compositions.     

Efficient preparation of mesocarbon microbeads by pyrolysis of coal-tar pitch in the presence of rosin

Mesocarbon microbeads (MCMB) were prepared by pyrolysis of coal-tar pitch in the presence of rosin, and characteristics of the pitch-rosin mixtures and the MCMB were studied. Pyrolysis behavior of the pitch-rosin mixtures was investigated by thermogravimetric analysis (TGA), and chemical structures of the pyrolysated pitch-rosin mixtures were studied using Fourier transform infrared spectroscopy (FTIR) technique. Optical textures of the pyrolysated pitch-rosin mixtures were characterized by polarized-light microscopy. In addition, morphologies and microstructures of the MCMB, extracted from the pyrolysated pitch-rosin mixtures, were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Results show that the rosin addition contributes to a notable increase of MCMB yield as well as a decrease in the aromaticity index of the pyrolysated pitch-rosin mixtures. Moreover, the pyrolysis conditions have great effect on the morphologies and yields of MCMB. When the pitch-rosin mixtures are pyrolysated at 450 °C for 1.5-2.5 h, the MCMB yields arrive at 33.8-54.6 wt.% of the pyrolysated pitch-rosin mixtures.     

Monitoring coal-tar pitch composition changes during air-blowing by gas chromatography

A series of air-blown coal-tar pitches was studied by GC and GC-MS in order to achieve a deeper understanding of the behaviour of the different pitch components during air-blowing. Compounds present in the parent pitch were identified and quantified and then compared to those present in the air-blown pitches. The compounds observed were identical before and after the treatments, but the concentration of each compound changed with the treatment to a different extent depending on its molecular structure and consequently its reactivity to oxygen. The most reactive compounds were those with a mehylene-bridge in a five member ring, followed by those with a methyl group in their structure.     

Preparation and carbonization behavior of cinnamaldehyde modified coal tar pitch

In this paper, coal tar pitch (CTP) was modified with cinnamaldehyde (CMA) in the presence of p-toluene sulfonic acid. The parent CTP and CMA modified CTP were characterized by ¹H nuclear magnetic resonance spectroscopy, elemental analysis and scanning electron microscopy. Carbonization behaviors of CMA modified CTPs were studied by thermogravimetric analysis, Fourier transform infrared spectroscopy and X-ray diffraction techniques. The results show that the carbonization behaviors of parent CTP and CMA modified CTPs are much different. The modification of CTP with CMA results in an increase in carbonization yield by 3.46–5.08% when 100 g CTP was modified with 5–15 ml of CMA. During the carbonization process, methyl and methylene groups of the CMA modified CTP gradually disappear while increasing temperature and its chemical structures change greatly when the temperature is higher than 400 °C. In addition, the modification with CMA is beneficial for increasing graphitizability of CTP.     

煤与废塑料共焦化基础研究Ⅳ. 煤种的影响

运用常压固定床及偏光显微镜研究了废塑料对不同煤种焦化产品分布的影响及焦炭光学性质的变化。实验结果表明：添加废塑料对不同煤种的焦化产物分布的影响各异,只有焦煤在添加废塑料后焦碳的光学织构得到改善;添加５％的混合废塑料与炼焦配煤共焦化有利于提高品的分布并能改善焦炭的光学织构;贫煤与沥青及废塑料三者的共焦化实验表明,沥青仅起到把不同的煤颗粒粘结在一起的作用。     

Coal-tar pitch characterization by thin-layer chromatography with flame ionization detection

Summary A rapid and quantitative method for compound class characterization of coal-tar pitches without previous fractionation, using an improved TLC method with an FID system, has been developed. Results show adequate accuracy and precision, including the sampling step.A fast calibration method, based on a variation of the internal normalization procedure, can be used for up to 18 g of whole sample application, avoiding the usually tedious absolute calibration in such analyses. This range is more than sufficient in view of the small amounts usually spotted in this technique.Speed of sample application by autospotter influences the shape of the peak nearest the point of application. For the coal tar pitch studied (9 wt.% non-eluted), slow application (0.5 L min^–1) gives a non-eluted Gaussianintegratable peak. A faster speed (10 L min^–1) is usable for analysing fossil products with lower non-eluted content. Total analysis time is less than 2 h, a considerably improvement on current methods.     

Water sorption properties of carbonized layers produced by controlled B<Superscript>+</Superscript> bombardment of thin polyimide and polysulfone films

Thin polyimide (PI) and polyethersulfone (PES) films are widely used as functional layers for microelectronic sensors. Ion implantation modifies the layer structure and morphology of these polymers and hence results in new mechanical and optical properties. However, ion-modified layers also show a change in sensitivity to moisture uptake under specific conditions. This is important for developing humidity sensors. Therefore, the water sorption ability of such modified polymer layers is studied by spectroscopic ellipsometry under definite relative humidity conditions (1–95%). Swelling data were obtained by fitting procedures based on changes of effective layer thickness and optical constants due to water uptake. Irradiation doses from 0.5 to 5×10¹⁵ B⁺ cm^–2 at an energy of 180 keV were used for polymer modification. At irradiation doses from 0.5 to 0.7×10¹⁵ B⁺ cm^–2, the maximum out-of-plane swelling is reached. At higher doses >2×10¹⁵ B⁺ cm^–2, the swelling decreases and corresponds to values of the pure polymer layers. The wetting properties of the layer surfaces determined by contact angle measurements are important to explain this behavior.     

Effect of oxidative stabilization on the electrochemical performance of carbon mesophases as electrode materials for lithium batteries

The effect of oxidative stabilization as a mean to modify the carbon texture was essayed in a group of mesophases previous to carbonization at 900 °C with the aim of evaluating the influence on electrochemical performance when used as electrode materials in lithium test cells. X-ray diffraction, optical microscopy and chemical analysis, Fourier-transform infrared spectroscopy have been used to describe the compositional and textural properties of the as-produced parent mesophases, the samples were further treated under air current to stabilize their microstructures and the corresponding carbonized samples at 900 °C. The electrochemical performance was determined by the galvanostatic method and further correlated to the physical–chemical properties and interface resistance of the materials. In all cases, the stabilization process has demonstrated a beneficial effect on the capacity retention in the measured range.     

Thermal curing of mesophase pitch: An alternative to oxidative stabilisation for the development of carbon–carbon composites

Thermal curing of mesophase pitch was studied as an alternative to oxidative stabilisation for the development of carbon–carbon composites, with the aim of avoiding several problems associated to the oxidative process such as thickness limitations or gradients in the properties of the resultant materials. Carbon fibre preforms densified with the mesophase were submitted to thermal treatments at temperatures between 400 and 475 °C for different periods in order to promote polymerisation and thus avoid exudation of the matrix precursor during carbonisation. Changes induced in the matrix precursor were monitored by thermogravimetric analysis and infrared spectroscopy. The effectiveness of the treatments was evaluated from the porosity of the resultant materials after carbonisation. The highest degree of polymerisation of the matrix precursor was achieved with treatments at 400 °C for 24 h or 475 °C for 5 h, the resultant materials having similar porosity values to those obtained by oxidative stabilisation.     

Electrochemical behavior of dopamine at a quercetin-SAM-modified gold electrode and analytical application

A stable quercetin–thioglycolic acid-modified gold electrode (Qu–TCA/Au) was prepared as a self-assembled monolayer (SAM) and its electrochemical behavior was investigated by electrochemical methods. In 0.05-M phosphate buffer solution (pH 7.0) quercetin exhibits quasi-reversible signals at the Qu–TCA/Au electrode. The stability of the quercetin-modified gold electrode is very good. The quercetin self-assembled monolayer is an effective mediator for the oxidation of dopamine, which was investigated by cyclic voltammetry and differential pulse voltammetry. Ascorbic acid does not interfere with determination of dopamine at an electrode modified with a mixture of quercetin–thioglycolic acid and quercetin–11-mercaptoundecanoic acid. This modification allows dopamine to be determined in the presence of ascorbic acid in the range from 3×10^–5 to 3×10^–4 M. The detection limit is 1×10^–6 M. Scanning electrochemical microscopy (SECM) was employed to study the electrochemical performances of the modified gold electrode indicating different feedback modes at differently modified surfaces.     

Effect of the nature of the iron salt on the hydrothermal modification of ferrosilica gel

The effect of iron(III) salts (chloride or nitrate) on the hydrothermal modification of the texture and phase composition of ferrosilica gel has been studied. Special features in the crystallization of prepared specimens as a function of the nature of the anion of the initial iron salt have been revealed by x-ray phase analysis and nuclear gamma-resonance spectroscopy.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 2, pp. 251–253, March–April 1988.     

烷基在针状焦形成中的作用

采用煤焦油沥青的甲苯可溶物和废聚苯乙烯共碳化制备针状焦,考察了中间相沥青中烷基含量对针状焦性能的影响。结果表明,通过添加废聚苯乙烯共碳化,中间相沥青中烷基的质量分数从12.0%增加到33.3%,可以制备出热膨胀系数更低、光学各向异性排列更好的针状焦。代表光学各向异性指数的两个量,在光学结构单元中,平行于热膨胀系数方向的轴向分矢量平均长度和光学结构单元的矢量平均长度,分别从20.8μm 和23.4μm增加到28.4μm和28.8μm,热膨胀系数从0.8×10^-6 /K降低到0.1×10^-6 /K。针状焦形成过程中中间相沥青的烷基含量增加使体系黏度降低,有利于光学各向异性相的融并和定向排列。烷基的增多在固化阶段产生足量的气体,在向外逸出过程中使融并中间相的芳香平面大分子沿轴向排列的更为规整。     

炭化温度对红柳林煤温和液化-炭化耦合转化产物的影响

在炭化温度为430-600℃研究了红柳林煤温和液化-炭化耦合转化过程的产物分布及理化性质。结果表明,半焦产率达40.64%-53.02%,有机液相产率达30.89%-36.98%,正己烷可溶物产率达29.74%-33.28%;在较低温度下炭化温度升高有利于正己烷可溶物产率提高,而在较高炭化温度下则相反;430℃炭化温度下半焦表现出较强黏结性,550℃炭化温度下半焦的黏结性消失,挥发分降至10%左右。通过调节炭化温度可使半焦定向用于配煤炼焦或无烟煤原料。     

Thermal dehydrochlorination of polyvinyl chloride in coal-tar pitch

Effect of coal-tar pitch and anthracene fraction on the pyrolysis of polyvinyl chloride was studied.     

High-yield Carbonization of Cellulose by Sulfuric Acid Impregnation

The carbonization of cellulose with sulfuric acid impregnation was studied by thermogravimetric analysis and scanning electron microscopy. The mass yield of carbon after 800°C treatment in nitrogen increased to 2–3 times by addition of small amounts of sulfuric acid. The sulfuric acid is considered to work as dehydration catalyst, thus suppressing the release of volatile organic substances. The shrinkage of the sample during carbonization was also significantly reduced by the addition of sulfuric acid.     

Spectroscopic and voltammetric studies of Pefloxacin bound to calf thymus double-stranded DNA

Spectral and electrochemical studies have been carried out on the interaction of pefloxacin with calf thymus double-stranded dsDNA. The voltammetric behavior of pefloxacin was investigated at glassy carbon, carbon paste and dsDNA-modified carbon paste electrodes using cyclic voltammetry. Pefloxacin was oxidized, yielding one irreversible oxidation peak. The modification of the carbon paste surface with dsDNA allowed an accumulation process to take place for pefloxacin such that higher sensitivity was achieved compared with the bare surface. The response was characterized with respect to ionic strength, accumulation time, pefloxacin concentration, and other variables. The stripping differential pulse voltammetric response showed a linear calibration curve in the range 1.0×10^–7–1.0×10^–5 mol l^–1 with a detection limit of 5.0×10^–8 mol l^–1 at the dsDNA modified electrode. The method was applied to the direct determination of pefloxacin in diluted urine samples.     

Thermal treatment of pitch-polymer blends

Coal-tar pitch was modified by addition of polystyrene, poly(ethylene terephthalate), unsaturated polyester and coumarone-indene resin. The optimum conditions for production of homogeneous binary pitch-polymer blends containing 10% w/w of the polymer were established. Softening points, contents of toluene and quinoline-insoluble matters and rheological properties of the blends were determined. The yield of solid fraction in semi-coking the blends was also found. The effect of polymers on the coal-tar pitch blend properties was evaluated. Some pitch-polymer blends were then carbonized to carbon sorbents used for purification of water and wastewater.     

煤沥青的电化学加氢──Ⅰ．原料煤沥青的预处理和组成结构分析

为选择适于作为碳纤维原料的煤沥青，对三种中低温煤沥青的预处理和组成结构进行了研究，同时对其中的太钢煤沥青进行了热缩聚制取中间相沥青的结构变化分析。研究分析结果表明，只要经过合适的工艺路线进行处理，这三种煤沥青都有可能作为沥青基碳纤维的原料。     

An Optical Chemical Sensor Based on Swellable Dicarboxylate Functionalized Polymer Microspheres for pH Copper and Calcium Determination

An optical chemical sensor based on polymer swelling and shrinking has been studied by way of optical transmission. Polyvinylbenzyl chloride cross-linked with divinylbenzene and derivatized as the dicarboxylate was dispersed as microspheres in a hydrogel membrane. The absorbance was measured vs. the wavelength upon exposing the modified membrane to solutions of varying pH (3.0–9.0). At low pH (3.0), the absorbance had the highest value (1.34), while the absorbance decreased significantly (1.10) when the pH was increased to 9.0, indicating polymer swelling.The modified membrane was also used for sensing metal ions, in particular calcium and copper. Complex formation with the dicarboxylate functionality caused the polymer to shrink. This resulted in an increase in absorbance for a concentration ranging from 1.0×10^–3 to 4.0×10^–3M.