Pentane Solubles Research Articles

A Lipophilic, Fluorine‐Free, Thermostable, Inexpensive, S4‐Symmetric, Highly Soluble, Weakly Coordinating, Protolabile Aluminate

AbstractThis communication presents the facile and cost‐effective synthesis as well as properties of salts of a lipophilic aluminate anion. Its unprecedented solubility in pentane makes possible tetrabutylammonium salt extraction with pentane. Nevertheless, its symmetry leads to high melting points of its thermostable salts. Several single crystals for X‐ray diffraction studies have been obtained. The anion is devoid ofhalogens, but is stable against sterically demanding electrophiles such as the trityl cation. However, it is unstable in protic media and hydrolyzes in the presence of water within days.

Liquefaction of Harbul (Silopi SE Anatolia, Turkey) Asphaltite by Flash Pyrolysis

Asphaltite, being petroleum originated solid fossil fuel, can be converted into a variety of secondary products such as light hydrocarbon gases, liquid product and high quality fuel char by means of pyrolysis. Liquefaction of Harbul (Silopi, Turkey) asphaltite,-0.60+0.25 mm particle size, and using flash pyrolysis was performed in a fixed bed reactor with a heating rate 40°C min−1 at a temperature ranging from 400 to 800°C under nitrogen atmosphere. The effect of temperature on conversion and liquid yield was examined. The flash pyrolysis temperature resulted in a large increase in the oil yield, tar, gases, large increase in the yield of hydrocarbon gases occurred as a result of temperature at 550°C which was attributed to an increase thermal cracking of pyrolysis vapours. The yield of asphaltite liquid at the condition of 550°C reached a maximum 19.66 wt %. The asphaltenes of the pyrolytic oils were precipitated by addition of n-pentane. Pentane solubles were fractioned by column chromatography into aliphatic, aromatic and polar fractions using n-hexane, toluene and methanol, respectively. The composition of these fractions from silica gel column chromatography of oil obtained by nitrogen pyrolysis was characterized by FTIR.

Effect of n-Pentane and n-Heptane Insolubles on the Pyrolysis of Vacuum Residue

Tests have been performed using a vacuum residue from the Middle East and its subfractions, pentane solubles (C5S), pentane insoluble−hepane solubles (C5IC7S), and heptane insolubles (C7I), as feedstock in different solvents, to evaluate their ability upon coke formation. The feedstock including those three subfractions produced a negligible amount of coke (1−1.2 wt %) and 14.7−16.7 wt % asphaltene; the latter was formed more in the feedstock (9.4 wt %), at 420 °C. There was no significant effect on coke and asphaltene formations in the products depending upon the solvent used in the tests. Heptane-soluble subfraction (C7S) formed 9.2−13.6 wt % asphaltenes but no coke at 420 °C using 1-methylnaphthalene and decahydronaphthalene, while the asphaltene contents were only 2.4−6.0 wt % in the case of C5S. The properties and average molecular structural parameters indicated that C5S included only 5.1 aromatic rings per average fused ring system, while C5IC7S and C7I contained 8.3 and 10.1 aromatic rings, respec...

Comparative analysis of pyrolysis oils and its subfractions under different atmospheric conditions

In this paper comparative analysis of bio-oils and their subfraction from static, sweeping gas and steam pyrolysis of apricot pulp, a food industry waste, was investigated. Experimental studies were conducted in a well-swept fixed-bed reactor with a heating rate of 5 °C min− 1, to a final pyrolysis temperature of 550 °C. The oil yield which was 22.4% at the static atmosphere reached to the value of 23.2% in the sweeping gas atmosphere by using 100 cm3 min− 1 N2 flow rate. The yield of liquid product in steam pyrolysis was higher (27.2%) than the static and inert gas atmosphere.The elemental analyses of the pyrolysis oils were determined, and the chemical compositions of the oils were investigated using chromatographic and spectroscopic techniques. The liquid products were fractionated into pentane solubles and insolubles (asphaltenes). Pentane solubles were then solvent fractionated into pentane, toluene, and methanol subfractions by fractionated column chromatograpy. The aliphatic subfractions of the oils were then analysed by capillary column gas–liquid chromatography and GC/MS. For further structural analysis, the pyrolysis oils' aliphatic, aromatic and polar subfractions were conducted using FTIR and 1H NMR spectra.

Structural Analysis of Pyrolysis Products From Pyrolysis of Hazelnut (Corylus Avellana L.) Bagasse

Fixed-bed pyrolysis biooils of hazelnut (Corylus Avellana L.) bagasse have been identified for their structures. The condensed biooils were analyzed for their properties as fuels and compared with petroleum-derived products. The biooil was analyzed by Fourier Transform infrared spectroscopy (FTIR) and 1H-NMR spectra. The biooils were fractionated into pentane solubles and insolubles. Pentane solubles were then solvent fractionated into pentane, toluene and methanol subfractions by fractionated column chromatograpy. The aliphatic subfractions of the biooils were then analyzed by capillary column gas-liquid chromatography (GC). In addition, the physical properties, higher heating value and elemental analysis of the biooil were determined. The empirical formula of biooil that has a heating value of 34.57 MJ/kg was established as CH1.45O0.33N0.127. Chromatographic and spectroscopic studies on the biooil showed that the oil obtained from hazelnut bagasse could be used as a renewable fuel and chemical feedstock.

Titanium and zirconium complexes that contain a tridentate bis(phenolato) ligand of the [OOO]-type

The oxygen-linked bis(phenol) 2-oxapropanediyl-1,3-bis(2- tert-butyl-4-methylphenol), [OOO]H 2, was prepared in good yield by the condensation of 2- tert-butyl-6-hydroxymethyl-4-methylphenol at 155 °C. This bis(phenol) reacted cleanly with titanium tetrachloride to give the orange titanium dichloro complex [OOO]TiCl 2 in virtually quantitative yield. The solubility in pentane indicates a monomeric structure for [OOO]TiCl 2 in solution. The reaction of titanium tetra(isopropoxide) gave the di(isopropoxy) complex [OOO]Ti(O iPr) 2 which also adopts a monomeric structure of C 2 v -symmetry in solution. The reaction of the dichloro complex [OOO]TiCl 2 with benzyl Grignard reagent in diethyl ether gave the highly light- and air-sensitive, orange dibenzyl complex [OOO]Ti(CH 2Ph) 2 in good yield. Single crystal X-ray crystallography revealed a penta-coordinate titanium center coordinated to two monohapto benzyl ligands and the tridentate [OOO] ligand in a meridional fashion. The reaction of zirconium tetrabenzyl with [OOO]H 2 gave the bis(ligand) complex [OOO] 2Zr, regardless of the stoichiometry employed. Crystallographic analysis shows an octahedral coordination geometry with cis-configuration of the two ligands. The compound can be transformed into the dichloro complex [OOO]ZrCl 2 by disproportionation with zirconium tetrachloride. Polymerization tests using [OOO]TiCl 2 under methylaluminoxane activation revealed moderate polymerization activity towards ethylene and styrene.

Structural analysis of bio-oils from pyrolysis and steam pyrolysis of cottonseed cake

Structural analysis and the effect of the water vapour on the structure of the products obtained by low temperature thermal destruction of biomass at atmospheric pressure has been investigated. The liquid products were fractionated into pentane solubles and insolubles (Asphaltenes). Pentane solubles were then solvent fractionated into pentane, toluene, ether and methanol subfractions by fractionated column chromatograpy. The aliphatic subfractions of the oils were then analysed by capillary column gas-liquid chromatography and GC/MS. For further structural analysis, the pyrolysis oils and aromatic and polar subfractions were conducted using FTIR and 1H-NMR spectra.

Effect of Catalytic Hydropretreatment of Petroleum Vacuum Resid on Coprocessing with Coal

The coprocessing of coal with petroleum vacuum resids can be used to produce distillable oils. Improved coprocessing performance by using hydrotreated resids as host oils in coprocessing with coal was studied. Four host oils were prepared from petroleum vacuum resids (538 °C+/1000 °F+) by catalytic hydrogenation and hydrocracking. The untreated and pretreated resids were then thermally coprocessed with an Illinois No. 6 and with a Wyodak coal. Using solubility in tetrahydrofuran (THF) and pentane, products were separated into asphaltenes, pentane-soluble oils (PSO), coke, and gas. Phenolic compounds, derived mainly from coal, were present in the PSO products and their concentration, measured by IR spectroscopy, was used to estimate the fraction of coal liquids in the PSO products. The yield of PSO was strongly affected by the concentration of coal in the feed; depending on the pretreatment used, the yields of PSO from a 33% coal/resid mixture varied from 48 to 78 wt %. The yield of PSO from Illinois No. 6 coal and untreated resid, as well as resids hydrogenated at temperatures where cracking was low, was greater than that predicted from runs made when the resids and coal were processed separately for coal-feed concentrations up to about 33 wt %. Coal conversion during thermal coprocessing with petroleum vacuum resid can be significantly increased if the resid is first hydrogenated at conditions where cracking is suppressed. However, pretreatment of the resids, by methods used in this study, resulted in only minor improvements in PSO yields.

Catalyst performance in resid containing recycle solvents

A number of problems were encountered in evaluating catalyst performance in full-range liquefaction recycle solvents containing sizable amounts of resid, unconverted coal and ash. In a liquefaction plant in which only distillate products are produced, resid is recycled to extinction. In such a configuration the feed to the plant will contain a distillate to coal ratio of less than one with the remaining portion of the solvent made up of residual material having reduced donor capacity. In recycle solvents obtained from the Wilsonville pilot plant, which were produced when running in the distillate-only mode, the presence of an insoluble fraction that was easily converted into THF insoluble material was found in the residual fraction of all the Wilsonville recycle solvents that have been tested in our laboratory. When using these recycle solvents for evaluating catalysts, conversion of this residual fraction leads to abnormally high coal conversions even under the mildest of conditions. The presence of catalysts that have accumulated in all of the recycle solvents masks the effect of added fresh catalysts on both dissolution of the coal and 565°C+ resid conversion. Results from this study have shown that catalyst testing in these solvents requires careful control of the components in the residual fraction. Results from liquefaction of Wyodak coal in recycle solvents containing up to 1060 mg freshly added Mo per kg maf coal indicates that coal conversion, pentane solubles and 565°C− distillate yields increase as Mo concentration increases. The activity of recycled Mo is much greater than freshly added Mo. Exceptional activity with nanometer-size iron oxide in the absence of any Mo was also observed.

Stability of liquids derived from reaction of coal and lignin

Addition of lignin to coal is synergetic in that it significantly improves the quality and yield of the liquid products produced from coal under relatively mild condition of pressure and temperature. This paper describes the stability of coal- and coal-lignin-derived liquid, because the usefulness of coal-derived liquids is dependent to a certain extent on their stability during storage. The stability of liquid products was characterized by determining their solubility in pentane and benzene, and by analyzing the change of boiling point and molecular weight distributions with aging condition. Percent of conversion, and individual atomic mass balances on various experiments conducted with coal, lignin and coal-lignin mixtures are also reported.

ANALYSES OF FUEL OIL SEDIMENTS DERIVED FROM ARAB LIGHT, MINAS, OR SHENGLI VACUUM RESIDS

ABSTRACT Fuel oil sediments from visbreaking Arab Light, Minas or Shengli vacuum resids have been compared. These sediment samples were separated into pentane solubles and pentane insolubles. Arab Light and Shengli resids are aromatic in nature and show similar trends in sediment formation and composition. For these results, small amounts of pentane insoluble sediments (<1 wt%) tend to be metal oxides, sulfides, precoke and coke, while larger amounts of pentane insoluble sediments are thermally cracked, lower H-content, polar asphaltic type materials. Waxy Minas resid, on the other hand, produces sediment that is composed of asphaltenes and waxes. Prevention of fuel oil sediment will be discussed.

Separation schemes for coal tar analysis — a comparison of methods

A standard tar fractionation scheme used to separate coal-derived materials at CRE involves a solvent separation based on solubility in pentane and benzene. This method is operator-dependant. The solvent fractionation has been followed by open-column liquid chromatography on silica/alumina to generate saturate, aromatic and polar fractions. Our published work has shown that the aromatic fraction contains both saturate and polar material. Alternative methods have been investigated using three tars to compare performance. An initial separation into pentane solubles, asphaltenes and pre-asphaltenes by sequential elution of tar coated on beads, appears to be reproducible and not subject to operator variations. The subsequent fractionation of pentane soluble material into chemical class fractions has been investigated by three methods. They are open column chromatography on alumina, open column chromatography on OPN Porasil-C and HPLC on a semi-preparative PAC10 column. The alumina and OPN Porasil methods are more satisfactory than the silica column method, giving heterocyclic fractions which contained very little aromatic material. OPN Porasil-C is the more expensive packing, but it can be reused. The HPLC method is best for isolation of PAH ring size fractions free from polar compounds. A solvent gradient can be used to elute polar material free from the aromatics but large volumes of relatively expensive solvents are needed. It is cheaper to back-flush the column after elution of the aromatics and collect the polars with no separation. Mass spectrometry has been used to evaluate the various class fractions.

Characterization of pentane-solubles from low rank coal extract

The structural characterization by FT-i.r. and 1H n.m.r. spectroscopy of the pentane-soluble fraction of a toluene extract from a Spanish low rank coal has been performed. The pentane-solubles have been fractionated on deactivated SiO 2 by sequential elution with hexane, benzene and tetrahydrofuran. The structural parameters calculated for these fractions indicate branched and cyclic alkanes on the aromatic units, and the number of aromatic rings and rings containing ring-joining methylene and heteroatoms appears to be between 1 and 5. Benzene and THF eluates showed the presence of hydroxyl and carbonyl groups. A comparison with the pentane-solubles from BF 3-phenol depolymerized lignite was made to evaluate the influence of this process on the nature of the soluble products. The pentane solubles of lignite extract have a more aliphatic and less polar character than the same fraction of chemically depolymerized lignite, which contains a maximum of four aliphatic carbon atoms in the average molecule of its benzene and tetrahydrofuran eluates.

Formation of the Carbonaceous Mesophase from a Petroleum-Derived Paving Asphalt

Abstract Preliminary studies on the formation of the carbonaceous mesophase from a petroleum-derived asphalt by Conoco was carried out through solvent fractionation. The pentane solubles fraction produced a mesophase with a texture of medium-grained mosaics, while the asphaltene fraction yielded fine-grained mosaic structures, but gave a much higher carbonization yield. Further separation of the pentane solubles was achieved through elution with the following solvents of increasing polarity: (1) hexane, (2) toluene, (3) toluene/ methanol (4:1), (4) toluenelmethanol (2:1) (5) methanol. It was found that the toluene fraction gave the best mesophase with a coarser grained mosaic texture than even that of the pentane solubles fraction from which it was derived. The results were explained in terms of the plasticity of the system, which differed depending on the nature of the precursor molecules present in the various fractions.

Kinetics of short contact time coal liquefaction. Part I: Effect of operating variables

AbstractThe liquefaction kinetics of Powhatan No.5 mine coal (Pittsburgh Seam) in the presence of SRC‐II recycle solvent at short contact times (&lt;10 min) and temperature and pressure ranges of 573–723 K and 10.3–13.8 MPa is examined in a well‐mixed reactor. In the initial stages of liquefaction, while overall coal conversion (tetrahydrofuran solubles) increases with temperature, oil (pentane solubles) is lost with an increase in temperature. An increase in solvent‐to‐coal ratio results in an increase of conversion. The initial coal particle size distribution, total pressure, and nature of gas phase (nitrogen or hydrogen) have no significant effect on the production of any of the product of liquefaction for contact times up to 10 min. A lumped kinetic model is presented to describe the product distribution.

Hydrocracking of Athabasca asphaltene over ZnCl 2-KCl-NaCl melts with or without an additive of some transition metal chlorides

Hydrocracking of Athabasca asphaltene over molten salts has been studied at 400 °C for 1 h at an initial hydrogen pressure of 9.8 M Pa. The hydrocracking over ZnCl 2-KCl-NaCl produced 57.0 wt% of pentanesolubles (PS), 4.7 wt% of benzene-solubles (BS) and 22.7 wt% of gases together with 15.6 wt% of coke. These melts containing NiCl 2 and CuCl, respectively, were examined, the former exerting a little better influence on reducing the coke yield. A small amount of coke (3.7%) and a higher conversion attained with ZnCl 2-KCl-NaCl-MoCl 5 suggested excellent properties of MoCl 5 for the hydrocracking of asphaltene. The sulphur contents of the PS and BS were lowest with melt catalysts containing MoCl 5. A compound-type separation of each pentane-soluble showed that in the presence of melt catalyst, monoaromatic and diaromatic contents increased greatly at the expense of polyaromatics and polar materials. The trend of catalytic activity of each melt for hydrocracking of asphaltene was found to be quite different from that for the decomposition reaction of tetrahydrothiophene in a continuous flow system.