Solubility In Pyridine Research Articles

Synthesis of novel heat-resistant and soluble poly(aryl ether sulfone ketone)s containing ether-type bisphthalazinone moiety

A series of poly(bisphthalazinone ether sulfone ketone)s with pendant phenyl groups (POPESKs) were synthesized via aromatic nucleophilic substitution polycondensation. The thermal degradation mechanism of POPESKs was determined investigated by TG-FTIR. The Tgs of POPESKs range from 296 to 326 °C and the storage modulus retention is up to 46.1 % at 290 °C. POPESKs have good solubility in dichloroethane, chloroform, tetrachloroethane, N-methyl-2-pyrrolidone and pyridine, and exhibit good film-forming property. The tensile strength, tensile modulus, and tensile elongation of POPESK films are 85–96 MPa, 1.34–1.86 GPa, and 8.9–11.6 %, respectively. Meanwhile, the polymer films exhibit the high light transmittance of up to 83 % at 800 nm and its water contact angle are in the range of 82.3–94.3°. Its superior overall performance shows great potential in aerospace, petrochemical and energy applications.

Insight into pore structures evolution and applications in lithium-sulfur battery of pitch fractions-based activated carbons

Difference in composition of pitch determines the porosity of pitch-based activated carbons on a large scale. Toluene-soluble (TS), toluene-insoluble and pyridine-soluble (PS), pyridine insoluble (PI) fractions were separated by extracting pitch with different solvents followed by the activation using alkali KOH to obtain porous carbons which were used as sulfur host materials. It is found that different fractions possess different reactivity which mainly relies on the molecular weight and structures. The light component TS, equipped with more active sites, tends to be activated to porous carbon with well-developed pores and it promotes the optimal distribution of sulfur compared to heavy fractions PS and PI. When used as sulfur host, TS-based carbon displays better electrochemical performance compared to PS/PI-based carbon. The relationship between the structure and electrochemical performance of fraction-based porous carbon has been established. The findings provide a method for judging and regulating the structure and electrochemical performance of porous carbons derived from pitch-based precursors.

Insight into the oxidative reactivity of pitch fractions for predicting and optimizing the oxidation stabilization of pitch

Oxidative stability is of particular importance to maintain the morphology and adjust physicochemical properties of pitch-based carbon products. Due to the complex composition of pitch, the oxidative reactivity of the pitch components has rarely been reported to date, so that the oxidative stabilization conditions of pitch have been mainly selected from experience. In the study, a coal tar pitch was fractionated into toluene-soluble (TS), toluene-insoluble and pyridine-soluble (PS), pyridine-insoluble and quinoline-soluble (QS), and quinoline-insoluble (QI) fractions. The molecular structural features of each fraction and their reactivity with oxygen at varying oxidation temperature were characterized and evaluated. The results reveal that light fractions (TS and PS) with more alkyl side chains exhibit a higher reactivity at the low oxidation temperature range from 200 to 250 °C, leading to the formation of more cross-linked structures. Meanwhile heavy fractions (QS and QI), with relatively rich isolated aromatic hydrogen, seem to be remarkable in O2 uptake and the formation of C–O structures until the oxidation temperature rises above 250 °C. Insight into group composition of the pitch allows predicting its oxidative stability characteristics and further allowing it to quickly fine-tune operational conditions for time-effective and energy-saving stabilization.

Insight into controllability and predictability of pore structures in pitch-based activated carbons

Tailoring porosity of pitch-based activated carbons (PACs) on a large scale is of high importance and usually achieved by introducing additives or templates and adjusting activation conditions. Since pitch is a kind of extraordinarily complex mixtures, it is highly necessary to investigate the effect of pitch composition on pore structure of PACs. Herein, a coal-tar pitch was subdivided by solvent fractionation into toluene-soluble (TS), pyridine-soluble (PS), quinoline-soluble (QS), and quinoline-insoluble (QI) fractions followed by activation using KOH or steam, respectively, to obtain PACs. It is found that the formation of pores in PACs is significantly dependent on pitch composition and activation methods. The light fractions (TS and PS) are more favorable for pore development in the KOH-activated carbons, whereas pores in the H2O-activated carbons are easily achieved by using the heavy fractions (QS and QI). The possible pore-formation mechanisms were also proposed, which indicates that the big differences intrinsically originate from the chemical properties (such as molecular size, structures, reactivity with activation agents and rheological behaviors of the molecular aggregations) of pitch compositions. When commercial pitches are employed for the precursors, a synergistic effect on pore development occurs both in KOH- and H2O-activated PACs seriously depending on their mass percentages of light or heavy fractions. It suggests that the mass percentage can be an index to foresee the porous properties of PACs. These findings open up a significantly important and more practical approach applicable to tailor the pores in PACs on an industrial scale just through adjusting pitch compositions.

Obtaining needle coke from coal liquefaction residue

Chromatography/mass spectrometry (GS/MS) was used to study toluene-soluble (TS) and pyridine-soluble (PS) fractions obtained from coal liquefaction residue by solvent extraction. It was found that the toluene-soluble fraction, containing mainly polycyclic aromatic hydrocarbons with 2-4 rings, is a good feedstock for making needle coke. The pyridine-soluble fraction cannot be used for these purposes because it contains more aromatic hydrocarbons with 5 or more rings. The composition of the studied samples determines their different behavior in carbonization (coking).

Low-Temperature Treatment of Illinois No. 6 Coal in Ionic Liquids

Certain ionic liquids can fragment coals to a remarkable degree at temperatures below 100 °C. Here, it is shown that when Illinois No. 6 coal is mixed with the ionic liquid 1-butyl-3-methylimidazolium tetrafluoromethanesulfonate and tetralin and held at temperatures of 300 °C or less under hydrogen, a dramatic increase in pyridine solubility is obtained. The highest yield of soluble material was in excess of 90% [dry and ash-free (daf) basis], but the results were very variable, partly as a result of the small sample sizes used.

Synthesis, Thermal Behavior, and Antimicrobial Activity of Polyether Based on 4,7-dichloro 6-nitroquinazoline

The polyethers based on 4,7-dichloro 6-nitroquinazoline were synthesized and characterized by FT-IR and 1H-NMR. The thermal properties and solubility were also performed with TGA, DSC, and viscometer. The molecular weight and degree of polymerization were determined with GPC. The method gave polyethers with inherent viscosities, good thermal stability, and solubility in solvent-like pyridine and DMF and also inhibited the growth of the microorganisms to a considerable extent.

Addition Effects of Coal Extract Fractions on Coke Strength

Coal extract fractions were blended with coals, and their effects on coke strength were evaluated. Since the pyridine-soluble (PS) fraction of coal has a high thermoplasticity, its addition to a slightly-caking Kouryusho (KRS) coal greatly increased the strength of cokes. While, by the addition of the pyridine-insoluble (PI) fraction, the strength of cokes was decreased. The reason for decrease may be decline of thermoplasticity due to the PI addition, since its thermoplasticity is significantly low.

Synthesis and properties of the copolymers based on aniline and 2-aminobenzyl alcohol

A kind of novel conducting copolymer with different compositions based on aniline and 2-aminobenzyl alcohol was prepared by chemical oxidative polymerization method. The copolymers were characterized by the methods of FT-IR, UV–Vis, XRD and DSC. It indicated that 2-aminobenzyl alcohol could copolymerize with aniline by this method. In addition, the solubility and conductivity of the copolymers were also studied in detail. The results showed that the copolymers had better solubility in pyridine than pure HCl doped polyaniline and the conductivities were decreased with the increase of the molar ratio of 2-aminobenzyl alcohol in copolymer.

Molecular Dynamics Simulation of Polyamidoamine Dendrimer-Fullerene Conjugates:Generations Zero Through Four

Previously the synthesis of the polyamidoamine (PAMAM) (G4)-C60 conjugate with a molar ratio of 1 : 30 was reported. Because PAMAM G4 has sixty-four primary amine groups, it was hypothesized that approximately two surface amine groups react with each fullerene molecule to form the conjugates. A computational energy minimization study of various G4 PAMAM-fullerene conjugates containing 1 dendrimer but different amounts of fullerenes shows excellent stability for the 1 : 30 dendrimer to fullerene product. Attempts to prepare other PAMAM dendrimer-fullerene (C60) conjugates, using generations G0-G3 of PAMAM and C60 via the same procedure in pyridine were not successful, possibly due to solubility differences. The same computational techniques used to study the G4 conjugates were then used to determine (1) the stability of the G0-G3 conjugates (with a 2 : 1 primary amine to fullerene ratio), and (2) their solubility in pyridine compared to the (G4)-C60 conjugate. The findings allow for a better understanding of structure-property relationships of these nano-hybrid materials, through investigation of the molecular shape and radius of gyration. The findings reported herein may lead to improved syntheses of fullerene-dendrimer conjugates of various sizes and a better understanding of their nanoscopic structures and topographical influences.

Molecular simulation of relaxation behaviors of coal-aggregated structures

Upper Freeport coal (Argonne Premium Coal Sample, APCS 1) was extracted and fractionated with a carbon disulfide/ N-methyl-2-pyrrolidinone mixed solvent, acetone and pyridine at room temperature, and three extract fractions were obtained: acetone-soluble (AS), acetone-insoluble–pyridine-soluble (PS) and pyridine-insoluble (PI) fractions. A molecular dynamics (MD) computer simulation method was used to study the structural relaxation behaviors of the fractions during heating. The calculation was carried out at 373–773 K in order to see changes in various properties by heat. For the PS and PI fractions, the temperature at which the average volume of unit cell discontinuously changed was observed. The DSC thermograms of PS and PI showed a reversible endothermic peak at 610–710 and 650–710 K, respectively, corresponding to the temperature ranges in which the structural relaxation was estimated by the simulation. The simulation suggests that the endothermic peak is the result of physical relaxation of the aggregated structures through dissociation of nonbonded interactions.

Polycondensation of Terephthalic Acid and 3,3′-Dimethyl Bisphenol A with TsCl/DMF/Py in the Presence of Salts

When activated with TsCl/dimethylformamide/pyridine in the presence of lithium, ammonium, or phosphonium salts, activated terephthalic acid of difficult solubility in pyridine became soluble. Depending on the kind and amount of the salt, terephthalic acid reacted smoothly with 3,3′-dimethyl bisphenol A to yield the corresponding polymer having high molecular weight. However, this reaction could not be successfully applied to the preparation of polyesters from other dicarboxylic acids of difficult solubility.

Evaluation of the Thermoplasticity of Upper Freeport Coal and Its Extracts Using Dynamic Viscoelasticity

The viscoelastic properties of Upper Freeport coal and extracts, including carbon disulfide/N-methyl-2-pyrrolidinone mixed solvent (1:1 by volume) solubles and pyridine solubles, were characterized by controlled strain oscillatory rheometry to evaluate the thermally induced relaxation of coal molecules. The dynamic viscoelastic modulus of the pelletized sample was measured at temperatures where the samples plasticize, while the frequency was increased from 0.05 to 5 Hz, to yield a data set suitable for analysis by time-temperature superposition. Although the applicability of the time-temperature superposition principle to the coal samples may be doubtful, it allows the empirical construction of master curves at reduced temperatures, yielding data for the frequency dependencies of the modulus over a wide range, i.e., 10 -3 -10 3 Hz. However, the temperature dependencies of the shift factor are not explainable by means of the assumptions that underlie the William-Landall-Ferry equation. Arrhenius-type plots of the shift factors show that the apparent activation energy (ΔH a ) is temperature dependent. The approximate distribution ranges of ΔH a are from 50 to 230 kJ/mol for pyridine solubles, and 50 to 370 kJ/mol for raw coal. The multiexponential behaviors of the shift factors suggest that the thermorheological characteristics of coal molecules in the plastic phase are not simple, but involve multiple viscoelastic mechanisms with different temperature dependencies.

Effect of lighter constituents on the solubility of heavy constituents of coals

Zao Zhuang, Shin-Yubari and Upper Freeport bituminous coals were extracted with a carbon disulfide/ N-methyl-2-pyrrolidinone (CS 2/NMP) mixed solvent at room temperature. Extracts were further fractionated with acetone to give acetone-soluble (AS) and acetone-insoluble (AI) fractions; the AI fraction was further extracted with pyridine to give pyridine-soluble (PS) and pyridine insoluble (PI) fractions. Despite the fact that they were part of the whole solute in the original extract, the PI fractions from all coals were only partially soluble in the mixed solvent. Combination of the AS and PS, which are lighter fractions than the PI, from the parent coal with the respective PI fraction greatly enhanced the solubility of PI in the mixed solvent. In addition, the solubility in mixed solvent of the PI fraction from Zao Zhuang coal was increased by addition of AS and PS fractions from Miike, Shin-Yubari, and Illinois No. 6 coals; the amount of enhanced solubility in comparison with the solubility of PI alone depended on the coal fraction used, i.e. AS and PS. In general, the enhancement caused by PS fractions was greater than that by AS fractions. The mechanism of solubility enhancement of the heavy constituent (PI fraction) by the addition of lighter constituents (AS and/or PS) is discussed, from the viewpoint of differences in the chemical structures of the constituents, i.e. AS, PS and PI fractions.

99/01003 Transformation of carbon black sludge to stable combustible emulsion : Coroiu, C. et al. Rom. RO 106,577 (Cl. C10L1/32), 31 May 1993, Appl. 144,455, 15 Mar 1990, 4 pp. (In Romanian)

A series of semi-cokes, containing from virtually 0 to 100% mesophase, were produced from the THF-soluble fraction of a soft coal tar pitch. The mesophase contents were estimated by high temperature in situ 1H NMR and optical microscopy with extremely close agreement being obtained between the two techniques. Quantitative solid state 13C NMR measurements using the single pulse excitation technique indicated that the extent of anisotropy in the pitch is a function of the condensation of the aromatic structure, where isotropic pitches contain 5–6 rings on average, assuming pericondensation, which increases to 9–10 rings for the fully converted mesophase pitches. Characterisation of the pyridine-solubles (PS) and insolubles (PI) from the pitches confirmed that development of mesophase in the coal tar pitch is limited by the loss of low molecular mass compounds, in that the PS contain 5–6 rings throughout the series while the PI, even in largely the initial isotropic state, are as condensed as in the anisotropic pitches.

99/00997 Studies on preparation of hot-formed coke by lean coal : Cao, Q. et al. Meitan Zhuanhua, 1997, 20, (4), 86–89. (In Chinese)

A series of semi-cokes, containing from virtually 0 to 100% mesophase, were produced from the THF-soluble fraction of a soft coal tar pitch. The mesophase contents were estimated by high temperature in situ 1H NMR and optical microscopy with extremely close agreement being obtained between the two techniques. Quantitative solid state 13C NMR measurements using the single pulse excitation technique indicated that the extent of anisotropy in the pitch is a function of the condensation of the aromatic structure, where isotropic pitches contain 5–6 rings on average, assuming pericondensation, which increases to 9–10 rings for the fully converted mesophase pitches. Characterisation of the pyridine-solubles (PS) and insolubles (PI) from the pitches confirmed that development of mesophase in the coal tar pitch is limited by the loss of low molecular mass compounds, in that the PS contain 5–6 rings throughout the series while the PI, even in largely the initial isotropic state, are as condensed as in the anisotropic pitches.

Simulation of Interaction of Coal Associates with Solvents Using the Molecular Dynamics Calculation

The extract obtained from a carbon disulfide−N-methyl-2-pyrrolidinone mixed-solvent extraction at room temperature for Upper Freeport coal (APCS1) was fractionated with acetone and pyridine into three fractions, i.e., acetone-soluble (AS), acetone-insoluble−pyridine-soluble (PS), and pyridine-insoluble (PI) fractions. For the three extract fractions, the model structures based on the structural parameters were constructed, and the energy-minimum conformation was calculated by the molecular mechanics and molecular dynamics methods. As the fractions got heavier, more stable associates formed among the model structures by several cooperative interactions through aromatic−aromatic interactions, hydrogen bonds, and electrostatic interactions. Furthermore, the molecular dynamics calculation in the presence of pyridine showed that a part of the coal associates was broken by their interactions with pyridine molecules. When benzene or methanol was used as the solvent, the breaking of coal associates did not take p...

Effect of Precipitating Some of the More Intractable Material from a Hydrogen-Donor Solvent Coal Extract Solution on Its Hydroprocessing Behavior

In view of the fact that the Ni/Mo γ-alumina catalysts currently used deactivate rapidly during coal liquids hydroprocessing, the feasibility of removing the more intractable material from a typical coal extract solution prepared with hydrogenated anthracene oil (HAO) was examined by precipitation with toluene both prior to and after filtration. The reductions in total conversion to pyridine solubles of only 3-4% achieved were accompanied by a decline of nearly 50% in the THF-insoluble concentrations for the modified extract solutions. As the amount of toluene added to approximately 1 kg of the coal/HAO digest was reduced below 300 cm 3 , the ash contents of the resultant filtered extract solutions increased toward the normal concentration of ca. 0.03% obtained without precipitation. Batchwise and continuous hydroprocessing tests conducted on the normal and modified coal extract solutions with a commercial Ni/Mo γ-alumina-supported catalyst demonstrated that the lower concentrations of THF insolubles gave rise to significant improvements in conversion for the n-hexane, toluene, and THF insolubles in the feeds. In accord with their higher surface areas and lower carbon contents, the HDS activities of catalyst samples recovered from a continuous run with feed modified by toluene addition were considerably higher than those for the corresponding samples for the normal feed.

Solid state 13C NMR and high temperature 1H NMR determination of bulk structural properties for mesophase-containing semi-cokes prepared from coal tar pitch

A series of semi-cokes, containing from virtually 0 to 100% mesophase, were produced from the THF-soluble fraction of a soft coal tar pitch. The mesophase contents were estimated by high temperature in situ 1H NMR and optical microscopy with extremely close agreement being obtained between the two techniques. Quantitative solid state 13C NMR measurements using the single pulse excitation technique indicated that the extent of anisotropy in the pitch is a function of the condensation of the aromatic structure, where isotropic pitches contain 5–6 rings on average, assuming pericondensation, which increases to 9–10 rings for the fully converted mesophase pitches. Characterisation of the pyridine-solubles (PS) and insolubles (PI) from the pitches confirmed that development of mesophase in the coal tar pitch is limited by the loss of low molecular mass compounds, in that the PS contain 5–6 rings throughout the series while the PI, even in largely the initial isotropic state, are as condensed as in the anisotropic pitches.

Characterization of the Soluble and Insoluble Fractions of Upper Freeport Coal in NMP/CS2 and Pyridine Using Small Angle Neutron Scattering

Small angle neutron scattering (SANS) was used to characterize the solution structure of coal extract/solvent systems as well as swelling-induced structural changes in the nonextractable residues derived from the Upper Freeport (UF), medium-volatile bituminous, coal. Studies were performed on the pyridine soluble (PyS) fraction dispersed in perdeuterated pyridine (dPy); the PyS fraction dispersed in the mixed solvent [dm, perdeuterated N-methylpyrrolidinone (NMP) and carbon disulfide, CS2], and the mixed solvent soluble fraction (MS) in dM. No coherent scattering was observed for the UF-MS/dM sample in the accessible Q range, indicating that the solution contains no large particles or aggregates. Strong coherent scattering was observed for the UF-PyS/dPy and UF-PyS/dM solutions, indicating the presence of large particles, presumably molecular aggregates. Comparison of the SANS behavior of the three samples suggests that there exist molecular components intrinsic to the pyridine insoluble NMP/CS 2 soluble fraction that may play a significant role in the enhanced solvation of the mixed soluble fraction of the Upper Freeport coal in NMP/CS 2 solvent. SANS analysis of the dry and pyridine (d5)-swollen UF-PyI and UF-MI residues revealed significant structure evident by power-law scattering behavior in the low Q region of both sets of samples. In the case of the UF-MI samples, significant scattering intensity was also observed in the intermediate Q region. Significant structural changes were observed in the UF-MI fractions upon swelling in pyridine, whereas minimal structural changes were observed in the case of UF-PyI sample during solvent swelling. These results reveal that the physical consequences of mixed solvent extraction are significantly different from those due to pyridine extraction.