Benzene Insoluble Fraction Research Articles

Thermodynamic study of phase transition behavior between the isotropic phase and mesophase using benzene-soluble and benzene-insoluble as phase indicators

Preparing carbonaceous mesophase pitch precursor by thermal treatment of isotropic pitch is a feasible and effective method for fabricating various high-performance carbon materials including high-modulus carbon fiber, needle coke, graphite, etc. However, the industrial production of qualified mesophase with desirable properties needs to be further improved in many regions. Especially, during pitch preparation, the transformation from isotropic phase to mesophase is difficult to be controlled since it significantly depends on reaction conditions, raw material and preparation parameters. While the optimization of the production conditions of mesophase with special properties requires time-consuming and costly exploratory experiments due to the lack of the fundamental understanding in the transformation behavior from isotropic phase to mesophase. This paper elaborates a fundamental work seeking a more suitable and accurate thermodynamic model and a parameter estimation method to describe phase transition behavior using benzene-soluble (BS) and benzene-insoluble (BI) fractions of coal tar-based pitch as indicators of isotropic phase and mesophase, respectively. The combined equation of simplified statistical associating fluid theory with anisotropic pseudopotential (SSAFT-APP) is used to describe phase transition, and the related parameters of each equation are estimated based on average molecular weight and carbon aromaticity of BS and BI fractions, respectively. The mesophase content of various samples prepared by annealing the mixtures of BS and BI fractions under different mixing ratios are used to calibrate the computed data. The results show that BS fraction has a restraining effect on the formation of mesophase when BI fraction is lower than 60 wt%, while this effect becomes weak with a higher content of BI fraction. A phase diagram is proposed by substituting the estimated parameters in SSAFT-APP equation with experimental data. Mesophase is able to be generated when the adding amount of BI fraction is increased to 12 wt%, and 100% mesophase could be obtained when the ratio of BI fraction is higher than 94 wt%. This work is expected to shed light on the phase transition behavior between isotropic phase and mesophase during pitch preparation from coal tar. In addition, based on the thermodynamic study optimizing preparation conditions and a novel method for obtaining the products with an optimal proportion between isotropic phase and mesophase is proposed.

Wound healing activity of extracts derived from Shorea robusta resin

Context: Shorea robusta Gaertn.f. (Dipterocarpaceae) resin is used for treating infected wounds and burns by tribals in India.Objectives: The objective of this study was to investigate wound-healing activity of S. robusta resin extracts and essential oil in rats.Materials and methods: Methanol extract (SRME), petroleum ether, benzene insoluble fraction of methanol extract (SRPEBIME), and essential oil (SREO) of S. robusta resin were incorporated in soft yellow paraffin (10% w/w) and applied once daily on incision and excision wounds of Wistar rats. Framycetin ointment (1.0% w/w) was applied to the standard group. Tensile strength (on the 10th day), wound contraction, and scar area (on the 14th day) were recorded. On the 15th day, granulation tissues of excision wounds were analyzed for total protein, hydroxyproline, and hexosamine contents and activities of lipid peroxidation and super oxide dismutase (SOD). Histopathology of the wounds was also studied.Results and discussion: SRPEBIME and SREO healed incision and excision wounds faster than plain ointment base and framycetin. Tensile strength of SRPEBIME-treated incision wounds was 53% higher than that of control animals. In excision wounds, wound contraction and scar areas were found to be 99% and 7.7 mm2 (SRPEBIME) and 71.7% and 21 mm2 (control). Protein and hydroxyproline contents were higher in SRPEBIME (20.8 and 3.5% w/w) and SREO (17.4 and 2.8% w/w) groups as against 9.95 and 1.48% w/w in control groups. Histopathology revealed complete epithelization and new blood vessel formation in SRPEBIME groups.Discussion and conclusion: SRPEBIME and SREO have significant wound-healing activities on incision and excision wounds.

Mathematical analysis of physicochemical phenomena in the catalyst during hydrogenating depolymerization of coal extract benzene insoluble fraction

Efficiency and selectivity of hydrogenating depolymerization of the coal extract benzene-insoluble part over the heterogeneous Co–Mo/Al2O3 catalyst were assessed using a mathematical model. The analytical equations of the mathematical model were generated based on material balance incorporating the physico-chemical phenomena (reaction and diffusion) both in the autoclave and the catalyst grain. The equations offer the possibility for predicting changes of the reactants in the autoclave during the process and for determining the distribution of reactant concentrations in the grain as a function of its radius. The analytical equations of the model serve as the basis of the algorithm for assessing the influence of restrictive diffusion on the effectiveness and selectivity of the catalyst, and also for defining the optimal radii of the catalyst's pores to enable free transport of reactants in the grain interior.

Evaluation of Azadirachta indica Leaf Fractions for in Vitro Antioxidant Potential and Protective Effects against H2O2-Induced Oxidative Damage to pBR322 DNA and Red Blood Cells

We evaluated the protective effects of subfractions of the ethyl acetate fraction (EAF) and the methanolic fraction (MF) from the crude ethanolic extract (CEE) of Azadirachta indica A. Juss (neem) leaves against various free radicals and hydrogen peroxide (H2O2)-induced oxidative damage to red blood cells (RBCs) and pBR322 DNA. Neem leaf fractions reduced DPPH(*), ABTS(*+), superoxide (O(*-)), hydroxyl (OH(*)), and nitric oxide radicals to nonradical forms in a concentration-dependent manner. Treatment with the benzene insoluble fraction from EAF (EBIF), the chloroform insoluble fraction from EAF (ECIF), the chloroform insoluble fraction from MF (MCIF), and the ethyl acetate insoluble fraction from MF (MEIF) significantly mitigated H2O2-induced oxidative damage to RBCs and pBR322 DNA. Although we found low in vitro free radical scavenging activity for the benzene insoluble fraction from EAF (EBSF), the chloroform soluble fraction from EAF (ECSF), the chloroform soluble fraction from MF (MCSF), and the ethyl acetate soluble fraction from MF (MESF), these fractions showed no effect on H2O2-induced lipid peroxidation and pBR322 DNA damage. High-performance liquid chromatography (HPLC) and TLC-Iatroscan analysis revealed that the greater efficacy of EBIF, ECIF, MCIF, and MEIF may be due to the presence of more polar compounds such as nimbolide and quercetin. Our studies suggest that the antioxidant and protective effects of active neem leaf fractions against H2O2-induced lipid peroxidation and pBR322 DNA damage can be attributed to their ability to inhibit various free radicals.

Myricetin-3',4',7-trimethyl ether from the leaves of Premna tomentosa

Chemical investigation of the leaves of Premna tomentosa afforded myricetin-3',4',7-trimethyl ether from the benzene insoluble fraction of the methanol extract.

99/01073 Coliquefaction of coal and waste plastics under milder hydrogen pressures : Yamaguchi, H. et al. Koatsuryoku no Kagaku to Gijutsu, 1998 7, (Proceedings of International Conference — AIRAPT-16 and HPCJ-38 — on High Pressure Science and Technology, 1997), 1233–1235

This chapter discusses the synergistic effects of coprocessing originated from interactions between coal and heavy oil. In a study described in the chapter, mixtures of Japanese Taiheiyo coal and Athabasca oil sand bitumen (AOB) with different coal concentrations were used as feeds. The results of the coprocessing reactions of mixtures with different coal concentration are shown. Although the original AOB contained no benzene insoluble fraction (BI), BI was produced with 5 wt% yield after the reaction of pure AOB. A mixture containing 2 wt% coals produced larger amount of HS and smaller amount of BI than the reaction of pure AOB. The addition of a small amount of Taiheiyo coal to AOB resulted in synergistic oil production by suppressing retrogressive reactions, similarly to a mixture of Forestburg Subbituminous C coal and Cold lake vacuum bottoms. With an increase in the coal concentration, the hexane soluble yield decreased, accompanied by an increase in the BI yield. Degree of hydrogen consumption for mixtures containing less than 25 wt% coal was relatively small while a serious increase was observed for mixtures containing more than 30 wt% coal.

Transesterification reaction of polyarylate and copolyester (PETG) blends

AbstractTransesterification reactions between polyarylate (PAr) and a copolyester (PETG) have been investigated by proton nuclear magnetic resonance (NMR), Fourier‐transform infrared spectroscopy (FTIR), and differential scanning calorimetry. Blends of PAr and PETG were prepared by melt mixing and solution‐casting with weight fractions of PAr in the blends varying from 0.90 to 0.10. The PETG is a copolyester containing ethylene‐1,4‐cyclohexylene dimethylene terephthalate. From the thermal analysis of the PAr/PETG melt blends, a single glass transition temperature is observed, which indicates a miscibility between the PAr and PETG. The benzene insoluble fraction of the PAr/PETG (50/50) melt blends and solution‐cast blends were characterized using NMR and FTIR. The results of NMR and FTIR support the conclusion that transesterification reactions between the PAr and PETG occurred under the melt blending conditions applied.

Application of liquid crystal theory to the estimation of mesophase pitch phase-transition behavior

The molecular field treatment developed for analysis of phase equilibria of meson-nonmesogen liquid crystal mixtures was applied to a quantitative description of the phase transition behavior of mesophase pitches, which were prepared by mixing a benzene-soluble fraction with a benzene-insoluble fraction of coal-tar pitch. The result showed that such a simplified theoretical treatment can be used to describe a phase diagram for a mesophase pitch.

96/00245 Texaco gasification process and its application in China

This chapter discusses the synergistic effects of coprocessing originated from interactions between coal and heavy oil. In a study described in the chapter, mixtures of Japanese Taiheiyo coal and Athabasca oil sand bitumen (AOB) with different coal concentrations were used as feeds. The results of the coprocessing reactions of mixtures with different coal concentration are shown. Although the original AOB contained no benzene insoluble fraction (BI), BI was produced with 5 wt% yield after the reaction of pure AOB. A mixture containing 2 wt% coals produced larger amount of HS and smaller amount of BI than the reaction of pure AOB. The addition of a small amount of Taiheiyo coal to AOB resulted in synergistic oil production by suppressing retrogressive reactions, similarly to a mixture of Forestburg Subbituminous C coal and Cold lake vacuum bottoms. With an increase in the coal concentration, the hexane soluble yield decreased, accompanied by an increase in the BI yield. Degree of hydrogen consumption for mixtures containing less than 25 wt% coal was relatively small while a serious increase was observed for mixtures containing more than 30 wt% coal.

96/00256 Characterization of ash and char formations in advanced high temperature particulate filtration systems

This chapter discusses the synergistic effects of coprocessing originated from interactions between coal and heavy oil. In a study described in the chapter, mixtures of Japanese Taiheiyo coal and Athabasca oil sand bitumen (AOB) with different coal concentrations were used as feeds. The results of the coprocessing reactions of mixtures with different coal concentration are shown. Although the original AOB contained no benzene insoluble fraction (BI), BI was produced with 5 wt% yield after the reaction of pure AOB. A mixture containing 2 wt% coals produced larger amount of HS and smaller amount of BI than the reaction of pure AOB. The addition of a small amount of Taiheiyo coal to AOB resulted in synergistic oil production by suppressing retrogressive reactions, similarly to a mixture of Forestburg Subbituminous C coal and Cold lake vacuum bottoms. With an increase in the coal concentration, the hexane soluble yield decreased, accompanied by an increase in the BI yield. Degree of hydrogen consumption for mixtures containing less than 25 wt% coal was relatively small while a serious increase was observed for mixtures containing more than 30 wt% coal.

96/00250 The anode: Its position in carbon history

This chapter discusses the synergistic effects of coprocessing originated from interactions between coal and heavy oil. In a study described in the chapter, mixtures of Japanese Taiheiyo coal and Athabasca oil sand bitumen (AOB) with different coal concentrations were used as feeds. The results of the coprocessing reactions of mixtures with different coal concentration are shown. Although the original AOB contained no benzene insoluble fraction (BI), BI was produced with 5 wt% yield after the reaction of pure AOB. A mixture containing 2 wt% coals produced larger amount of HS and smaller amount of BI than the reaction of pure AOB. The addition of a small amount of Taiheiyo coal to AOB resulted in synergistic oil production by suppressing retrogressive reactions, similarly to a mixture of Forestburg Subbituminous C coal and Cold lake vacuum bottoms. With an increase in the coal concentration, the hexane soluble yield decreased, accompanied by an increase in the BI yield. Degree of hydrogen consumption for mixtures containing less than 25 wt% coal was relatively small while a serious increase was observed for mixtures containing more than 30 wt% coal.

Structural analysis of mesophase pitch with high-resolution, high-temperature 13C-NMR

The structural parameters of mesophase pitch with optical anisotropy have been successfully obtained by using high-temperature 13C-NMR spectroscopy. Well-resolved spectra were obtained from the mesophase pitch with the addition of pyrene, which played the role of solvent for a quinoline-insoluble rich mesophase pitch during NMR measurement at 573 K. The resolution of NMR spectra was improved due to the decline in viscosity, without any influence on the chemical shift for aliphatic carbons. Hydrogen distribution has been converted from the intensities of aliphatic carbon obtained by a high-temperature 13C-NMR spectrum. Average structural parameters of whole mesophase pitch were calculated with the distribution of hydrogen by using Brown-Ladner equations. Structural characteristics of the benzene-insoluble fraction in two kinds of mesophase pitch have been discussed as well as that of the benzene-soluble fraction and whole pitch.

Liquefaction of newsprint and cellulose in tetralin under moderate reaction conditions

Liquefaction of newsprint and cellulose in tetralin at 350°C and pressure of 1.07–2.51 MPa for 1 h resulted in their 37% and 40% by weight conversion to organic liquids, respectively. A significant amount of water was also formed. The gases produced consisted of mainly CH 4 and CO. The total amount of gases produced was about 3–5% of the original amount of solid charged to the reactor. A first order kinetic model was proposed for the conversion of newsprint and cellulose. Rate constants and Arrhenius parameters were also calculated. Material balance for the process showed a good correlation between the carbon and oxygen contents of the reactant solid and products. Data indicate that most of the hydrogen supplied to the products is supplied by the solvent (tetralin). Fractionation of liquid products show that a major portion can be classified as pentane-soluble and asphaltenes with negligible benzene-insoluble fraction. The molecular weight distribution of the three fractions for the liquids obtained from newsprint and cellulose liquefaction was determined by size exclusion chromatography.

Electrolytic pretreatment of coal for enhanced liquefaction

Mild oxidation of coal can result in enhanced coal liquefaction yields, presumably due to the formation and decomposition of carbonyl or hyperoxide groups from the benzylic groups of alkyl bridges in the coal structure. Due to the ability to closely control the oxidizing or reducing conditions at the electrode, electrochemical routes for coal pretreatment have attracted considerable interest. Electrolysis of an Illinois coal in NaOH and H 2SO 4 electrolytes at potentials of between 1.0 and 1.3 V vs. saturated calomel electrode (SCE) resulted in hydrogen production at current efficiencies of about 100% while a significant amount of sulfur was removed from the coal. Liquefaction of the coal was carried out in tetralin at 375°C with an initial hydrogen pressure of 140 psig (10.5 bar). The data obtained clearly indicate that electrochemical oxidation of coal slurries results in significant enhancement (up to 27%) in coal liquefication yields. The products (liquid) obtained from the liquefication of the electrolyzed coal contained substantially larger amounts of the more desirable pentane soluble fraction, while the undesirable benzene insoluble fraction content diminished. The data also show that the molecular weight of the liquid products obtained from pre-electrolyzed coal samples is very much lower than the corresponding molecular weight of the liquid products obtained from an untreated coal under the same liquefaction conditions.

An important factor affecting synergism on coprocessing of Taiheiyo coal with Athabasca oil sand bitumen

A series of mixtures of Japanese subbituminous Taiheiyo coal and Athabasca oil sand bitumen (AOB) with various coal concentrations (0–100 wt%) was coprocessed in a 70 ml autoclave at 420°C for 1 h in the presence of H 2 (50 kg/cm 2 at room temperature) and sulfided Ni Mo/Al 2O 2 catalyst. The mixture containing 2 wt% coal produced the largest amount of hexane soluble fraction (HS) and the smallest amount of benzene insoluble fraction (BI). Thus, a synergistic liquid production occurred for this mixture with 2 wt% coal by suppressing the retrogressive reactions which proceeded for pure AOB. The HS obtained from mixtures with 2–30 wt% showed higher H/C ratios and lower heteroatom contents than those obtained from pure AOB and the mixtures with more than 30 wt% coal. The amounts of transferable hydrogen contained in the mixtures were estimated using anthracene as a hydrogen acceptor. The mixtures with 2–10 wt% coal contained higher amounts of donor hydrogen than pure AOB. The HS yield from the various mixtures was correlated with the amount of donor hydrogens contained in the mixtures, except for the mixture with 10 wt% coal. Thus, the important factor which results in synergism is suggested to be the amount of donor hydrogens contained in the feed mixtures.

Coal fly ash induces hepatic and pulmonary cytochrome P-450 and sigma-aminolevulinic acid synthetase in rats.

The effect of intratracheal administration of coal fly ash, its benzene-soluble and benzene-insoluble fractions has been studied on the levels of hepatic and pulmonary cytochrome P-450, cytochrome b5, and the activities of sigma-aminolevulinic acid synthetase and heme oxygenase. Fly ash and both its fractions significantly increased the levels of hepatic and pulmonary cytochrome P-450. Benzene-soluble and benzene-insoluble fractions of coal fly ash significantly increased the levels of cytochrome b5 also in both lung and liver. Fly ash and both its fractions increased the activity of sigma-aminolevulinic acid synthetase and reduced the activity of heme oxygenase in lung and liver. Glass bead particles of similar size did not show any effect on hepatic and pulmonary cytochrome P-450 and cytochrome b5.

Inhibition of coal fly ash polycyclic aromatic hydrocarbons and metals induced mixed-function oxidase activity in rat lung and liver by vitamin A and citrate.

Administration of benzene-soluble fraction (FAE) and benzene-insoluble fraction (FAR) of fly ash for 3 consecutive days to rats significantly raised cytochrome P-450 levels, aryl hydrocarbon hydroxylase (AHH) activity, and glutathione S-transferase activity in liver. This treatment also significantly increased pulmonary AHH and glutathione S-transferase activity. Intratracheal administration of FAR (5 mg/100 g body weight) alone for 6 consecutive days also significantly increased hepatic cytochrome P-450 levels and the activity of glutathione S-transferase. Intragastric administration of retinyl palmitate (5000 IU/100 g body weight), along with intratracheal FAE and FAR administration, significantly reduced P-450 levels, activity of glutathione S-transferase in liver, and activity of AHH and glutathione S-transferase in lung of rats. Intraperitoneal administration of citrate (40 mg/100 g body weight) along with FAR significantly reduced FAR-induced increase in hepatic cytochrome P-450 levels and glutathione S-transferase activity. The activity of AHH was not affected by these treatments.

Kinetic analysis of autocatalytic action in the hydrogenating depolymerization of benzene-insoluble fractions of coal extract

This paper analyses, from the standpoint of kinetics, the possibility of autocatalytic effects of the asphaltene formed during the hydrogenating depolymerization of benzene-insoluble fractions. The autocatalytic and linear models were tested against experimental data and it was concluded that the asphaltenes had no autocatalytic function.

Mathematical analysis of the kinetics of hydrogenating depolymerization of benzene-insoluble coal extract fraction in the absence of catalyst

The paper analyses some kinetic models for the process of hydrogenating depolymerization of benzene-insoluble fractions of coal in the absence of a catalyst. Considerations as to the direction of decomposition of benzene-insoluble fractions to oils are presented.

Role of catalyst in hydrocracking of heavy oil

The relative contributions of the catalytic reaction and thermal cracking in the hydrocracking of heavy oil were evaluated in detail. It is concluded that light oil fractions are formed mainly by thermal cracking and the main role of the catalyst is to supply hydrogen to the heavy oil fraction and prevent its carbonization. The behavior of sulfur and nitrogen in hydrocracking without a catalyst was clarified. Sulfur transfers to both light and heavy fractions, but nitrogen transfers to asphaltene and the benzene-insoluble fraction and practically no nitrogen transfers to the light oil fraction.