Carbonization and liquid-crystal (mesophase) development. 17. Co-carbonization of a solvent-refined coal with petroleum pitches and hydrogenated coal-extract solution

This study characterizes the optical textures of cokes prepared by the carbonization of Ashland petroleum pitches, of non-hydrogenated and hydrogenated coal-extract solutions (CES) and of blends of non-hydrogenated CES materials with the petroleum pitches and hydrogenated CES materials. At an HTT of 823 K petroleum pitches produce cokes with large sized optical texture of flow-type anisotropy characteristic of needle-cokes. The non-hydrogenated CES materials produce cokes with optical textures of mozaics, 2–10 μm. However, following hydrogenation the CES materials carbonized to cokes all of which possess considerable large sized optical textures which for some materials resemble that of needle-cokes by possessing strong flow-type anisotropy, > 100 μm. Hydrogenation of the CES materials evidently facilitates the physical and chemical requirements for growth and coalescence of lamellar nematic liquid-crystals and mesophase from the fluid phase of carbonization leading to anisotropic carbon. Co-carbonizations of the non-hydrogenated and hydrogenated CES materials exhibit the dominant partner effect and are comparable in behaviour with Ashland petroleum pitches which are known to produce needle-cokes on carbonization.     

Mesophase formation in coal liquid solvent fractions

The single greatest influence on the mesophase microstructure is the chemical composition of the organic precursor. The effects of oxygen content and structural parameters of precursors from solvent fractions of coal liquefaction products on the microstructure and pyrolysis yields were determined. The fractions were analysed using the Brown-Ladner method to obtain average molecular structural parameters. It was found that pyrolysis yield increases with increased aromaticity and oxygen content and that mesophase microstructure is determined primarily by the oxygen content of the precursors.     

Co-carbonization of fractions of solvent-refined coal with a non-coking coal

Co-carbonizations of solubility fractions of a solvent-refined coal with a high-volatile, inertinite-rich non-coking coal are reported. Both chloroform-soluble and chloroform-insoluble fractions give rise to improved fusion in the cokes derived from the blends, but only the coke derived from the blend containing the chloroform-insoluble fraction contains areas of anisotropic microtexture.     

Carbonization and liquid-crystal (mesophase) development. 20. Co-carbonization of a high-volatile caking coal with several petroleum pitches

A high-volatile caking coal and five petroleum pitches were carbonized singly and coal/pitch systems were co-carbonized to 1273 K in the ratio of 75 wt% coal and 25 wt% pitch. Optical textures of cokes from the single carbonizations and co-carbonizations are assessed in terms of modification to the coalcoke by the pitch and unmodified pitch-coke using a point-counting technique. The pitches differ considerably in their carbonization behaviour. Each pitch can be placed into one of three groups defined in terms of their interaction with the high-volatile caking coal. A passive pitch does not modify the coalcoke but apparently carbonizes independently of the coal. An active pitch modifies some of the coalcoke. No pitch-coke can be detected. A super-active pitch modifies the coal-coke extensively beyond the extent expected from a 25% addition. No pitch-coke can be detected. The effects are related to the ability of the pitch to cause depolymerization of the coal. Quinoline-insoluble material in pitch may inhibit modification.     

Magnetic orientation studies of synthetic mesophase pitches

Previous studies have shown that mesophase spheres with Brooks-and-Taylor structure are nematic liquid crystals which oriënt with their molecular c-axes perpendicular to a magnetic field. Mesophase spheres in synthetic pitches made from anthracene and naphthalene with AlCl₃ show similar magnetic orientation behavior; however, they have a novel structure, which was elucidated with the use of sensitive tint microscopy and magnetic orientation experiments. In the proposed structure, the aromatic molecules within the bulk of the sphere, are stacked in parallel layers, similar to those in the Brooks-and-Taylor spheres. However, at the interface of the sphere with surrounding isotropic phase, the molecular planes are oriented parallel to the surface, unlike those observed in the Brooks-and-Taylor spheres.     

Relationship between chemical structure and secondary quinoline insoluble formation in electrode binder pitches

The relationship between the rate of secondary quinoline insoluble (QI) formation in coal-tar pitches and variations in their chemical composition is examined. Production of significant concentrations of secondary QI is shown to be accompanied by mesophase formation, the significance of which is discussed in terms of electrode binder performance.     

Gel formation in diimide‐hydrogenated polymers

The hydrogenation of diene‐based polymers via diimide is a very attractive alternative to the conventional catalytic hydrogenation route based on gaseous molecular hydrogen. However, serious crosslinking always accompanies it and limits the end‐use properties of the polymers. Gel formation in polymers that are hydrogenated via diimide has been investigated in detail through an inspection of all the chemical reactions involved in the process. The results indicate that hydrogen peroxide decomposition, some reactions related to oxygen, and the redox reaction between hydrogen peroxide and hydrazine are capable of generating radicals. However, radicals generated in the aqueous phase do not appear to initiate the crosslinking of diene‐based polymers in the latex form. It is proposed that the primary radicals giving rise to crosslinking are generated in the polymer phase in situ, and the step responsible for generating these organic radicals is possibly the diimide disproportionation reaction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1122–1125, 2005     

Evidence for formation of multi-quantum dots in hydrogenated graphene

ABSTRACT: We report the experimental evidence for the formation of multi-quantum dots in a hydrogenated single-layer graphene flake. The existence of multi-quantum dots is supported by the low-temperature measurements on a field effect transistor structure device. The resulting Coulomb blockade diamonds shown in the color scale plot together with the number of Coulomb peaks exhibit the characteristics of the so-called 'stochastic Coulomb blockade'. A possible explanation for the formation of the multi-quantum dots, which is not observed in pristine graphene to date, was attributed to the impurities and defects unintentionally decorated on a single-layer graphene flake which was not treated with the thermal annealing process. Graphene multi-quantum dots developed around impurities and defect sites during the hydrogen plasma exposure process.     

Nutritional studies of partially hydrogenated rapeseed oil

In three experiments rats were fed a purified basal diet with 20% by weight of partially hydrogenated rapeseed oil. One sample promoted, greater weight gains that the unhydrogenated oil. Another sample, containing a higher concentration of octadecadienoic acids other than 9,12-linoleic acid, produced the same response as the unhydrogenated material. With other samples of hydrogenated rapeseed oil, possessing less linoleic acid but other octadecadienoic acids, significantly lower weight gains were obtained. The alterations in the C₁₈ fatty acids resulting from hydrogenation of rapeseed oil appeared to be responsible for differing responses in weight gain.     

Coal liquefaction using a hydrogenated creosote oil solvent: H-atom transfer from hydrogen donor components in the solvent

The presence of hydroaromatic, hydrogen donor components in a coal-derived solvent is one of the more important factors in the successful operation of a non-catalytic coal liquefaction process. Various hydrogen donor species present in a hydrogenated creosote oil have been identified. Their rate of disappearance under conditions that are consistent with a short residence time coal liquefaction process has been used to rank the reactivities of the various hydrogen donors. 1,2,3,10b-Tetrahydrofluoranthene was found to be an exceptional donor while 4,5-dihydropyrene, the hexahydropyrenes and 9,10-dihydrophenanthrene were found to be quite active. Sym.-octahydrophenanthrene and 2a,3,4,5-tetrahydroacenaphthene exhibited moderate activity. Tetralin and the four methyltetralin isomers were found to be unreactive under the coal liquefaction conditions employed.     

Fractionation of menhaden oil and partially hydrogenated menhaden oil: Characterization of triacylglycerol fractions

Menhaden oil (MO) and partially hydrogenated menhaden oil (PHMO) were dry-fractionated and solvent-fractionated from acetone. After conversion to fatty acid methyl esters, the compositional distribution of saturated, monounsaturated, trans, and n−3 polyunsaturated fatty acids (PUFA) in the isolated fractions was determined by gas chromatography. Acetone fractionation of MO at −38°C significantly increased the n−3 PUFA content in the liquid fractions over that of starting MO (P<0.05). For PHMO, liquid fractions obtained by low-temperature crystallization (−38, −18, and 0°C) from acetone showed significant increases (P<0.05) in monounsaturated fatty acid (MUFA) content over that of the starting PHMO. For selected MUFA-enriched fractions, reversed-phase high-performance liquid chromatography (HPLC) was used to separate, isolate, and characterize the major triacylglycerol (TAG) molecular species present. Thermal crystallization patterns for these fractions also were determined by differential scanning calorimetry (DSC). The results demonstrated that under the appropriate conditions it is possible to dry-fractionate or solvent-fractionate MO and PHMO into various solid and liquid fractions that are enriched in either saturated, monounsaturated, polyunsaturated, or the n−3 classes of fatty acids. Moreover, characterization of these TAG fractions by reversed-phase HPLC gives insight into the compositional nature of the TAG that are concentrated into the various fractions produced by these fractionation processes. Finally, the DSC crystallization patterns for the fractions in conjunction with their fatty acid compositional data allow for the optimization of the fractionation schemes developed in this study. This information allows for the production of specific TAG fractions from MO and PHMO that are potentially useful as functional lipid products.     

Hydrogen bonding of the acid and base fractions separated from SRC II middle distillates

It has been demonstrated that hydrogen bonding is important in defining the high viscosity of coal-derived liquids. The aim of this study was to investigate the nature and strength of hydrogen bonding between the acid and base fractions of SRC II middle distillates. Amberlite IRA-904 and Amerlyst A-15 were used as anion- and cation-exchange resins respectively, to separate coal-derived products into various acid and base fractions. Formation constants of hydrogen bonding between the acid and base fractions were determined by i.r. spectroscopy. It appears that the acid-II and base-II fractions behave as hydrogen bond donors and acceptors, comparable to p-cresol (unhindered phenol) and quinoline-type nitrogen bases respectively.     

On the formation of blisters in annealed hydrogenated a-Si layers

Differently hydrogenated radio frequency-sputtered a-Si layers have been studied by infrared (IR) spectroscopy as a function of the annealing time at 350°C with the aim to get a deeper understanding of the origin of blisters previously observed by us in a-Si/a-Ge multilayers prepared under the same conditions as the ones applied to the present a-Si layers. The H content varied between 10.8 and 17.6 at.% as measured by elastic recoil detection analysis. IR spectroscopy showed that the concentration of the clustered (Si-H)_n groups and of the (Si-H₂)_n (n ≥ 1) polymers increased at the expense of the Si-H mono-hydrides with increasing annealing time, suggesting that there is a corresponding increase of the volume of micro-voids whose walls are assumed from literature to be decorated by the clustered mono-hydride groups and polymers. At the same time, an increase in the size of surface blisters was observed. Also, with increasing annealing time, the total concentration of bonded H of any type decreases, indicating that H is partially released from its bonds to Si. It is argued that the H released from the (Si-H)_n complexes and polymers at the microvoid surfaces form molecular H₂ inside the voids, whose size increases upon annealing because of the thermal expansion of the H₂ gas, eventually producing plastic surface deformation in the shape of blisters.     

Molecular distillation of a hydrogenated cottonseed oil and certain characteristics of the distilled fractions

Summary 1. A hydrogenated cottonseed oil has been molecularly distilled, and the distilled fractions examined. 2. Fractionation of a molecularly distilled oil occurs, as is to be expected, on the basis of variations in molecular weight of the glycerides. The composition of cottonseed oil is such that there is a considerable separation of the glycerides according to their degree of unsaturation. The composition of peanut oil is such that similar separation can only be slight. Soybean oil is in this respect intermediate between cottonseed oil and peanut oil. 3. Molecular distillation of hydrogenated cottonseed oil causes a segregation of tocopherols and related compounds similar to that observed in peanut oil. However, the fractions first distilled from the oil are relatively weak in antioxygenic properties. It appears probable that their lack of effectiveness is due to the presence of unknown substances capable of inhibiting or counteracting the action of tocopherols. However, the presence of substances other than tocopherols, which respond to or interfere with the Emmerie-Engel test is not to be excluded. The tocopherols in the potent fractions are more effective thana-tocopherol, but less effective than γ-tocopherol. This is one of four regional research laboratories operated by the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

煤与废塑料共焦化研究进展

介绍了煤与废塑料共焦化的机理,分析了影响煤与废塑料共焦化的主要因素:废塑料的种类、配入比例、粒径、预处理方式等,分别讨论了添加废塑料对膨胀压力和焦炭结构的影响。指出煤与废塑料共焦化技术在节约炼焦煤资源和环保方面具有较好的发展潜力。     

共炭化对热缩聚及炭化工艺过程的影响

采用煤沥青闪蒸油为原料,乙烯残油为添加剂,在实验室内进行热缩聚及炭化实验。结果表明:加入添加剂后,缩聚沥青的平均分子结构得到改善,从而显著改善了针状焦的显微组织结构,同时具有良好的脱氮效果。     

The effect of primary quinoline-insoluble material on the formation of secondary quinoline-insolubles in electrode binder pitches

The influence of primary quinoline-insoluble material (QI) on the subsequent formation of secondary QI has been investigated using two pitches derived from the same tar feedstock. One was prepared by heat treating the pitch without prior modification of the tar, and the other after nearly all the primary QI had been removed from the tar by filtration. No significant differences were observed between the two pitches in terms of the rate of secondary QI formation or softening point increase.