Showing papers on "Aromatic hydrocarbon published in 1995"

Studies on the Catalytic Conversion of Canola Oil to Hydrocarbons: Influence of Hybrid Catalysts and Steam

Abstract: The conversion of canola oil (used as a representative feed material for waste oils and fats) was studied in the presence and absence of steam using silica-alumina, HZSM-5, and 4 Hybrid catalysts. The hybrid catalysts were prepared by adding H-Y to silica-alumina in the weight ratios 1:3 and 3:1 and HZSM-5 to silica-alumina in the weight ratios 1:3 and 3:1. The conversions were performed at atmospheric pressure, a temperature range of 400-550 °C, and weight hourly space velocities of 1.8 and 3.6 h -1 (WHSV) in a fixed bed reactor. The objective was to investigate the production of both liquid and gaseous hydrocarbon products from the catalytic conversion of canola oil. In addition, it was intended to study the effect of steam on the product selectivities. The conversions were high on all the catalysts and ranged between 81 and 100%. Conversion to an organic liquid product (OLP) varied significantly with temperature and space velocity. The yields were between 22-53 wt % with silica-alumina and between 23 and 63 wt % with HZSM-5 catalyst. In most cases, hydrocarbons formed the major components in the OLP. HZSM-5 provided a high selectivity for aromatic hydrocarbons than silica-alumina catalyst, while the selectivity for aliphatic hydrocarbons was higher with silica-alumina than HZSM-5 catalyst in the OLP products. The olefin/paraffin ratio in the gas products was low but it increased tremendously in the presence of steam, indicating that dehydrogenation reactions were predominant in the presence of steam. The gas yield increased with temperature and decreased with increase in WHSV. Ethylene, propylene, isobutylene, propane, and n-butane were some of the major components of the gas products. Prolonged catalyst life (decrease in coke formation) and enhanced olefin formation were the main advantages of cofeeding steam during conversion. When zeolite catalysts were added to silica-alumina catalyst, the coke formation and OLP yields decreased whereas the gas yields increased. With silica-alumina-H-Y hybrid catalysts, the aromatic content of OLP increased, resulting in an overall increase in the hydrocarbon content of the OLP. On the other hand, the aromatic hydrocarbon content increased at the expense of aliphatic hydrocarbons. With silica-alumina-HZSM-5 hybrid catalysts, the hydrocarbon content of the OLP was similar to those obtained with pure HZSM-5 catalyst; i.e., they were composed mostly of aromatic hydrocarbons and only small fractions of aliphatic hydrocarbons. In general, cracking and aromatization reactions increased significantly with addition of H-Y or HZSM-5 to silica-alumina.

Alkylation of Benzene or Toluene with MeOH or C2H4 over ZSM-5 or .beta. Zeolite: Effect of the Zeolite Pore Openings and of the Hydrocarbons Involved on the Mechanism of Alkylation

Abstract: A comparative study of the alkylation of benzene or toluene with MeOH or C{sub 2}H{sub 4} over a medium (ZSM-5) and a large pore ({beta}) zeolite of comparable acidities was carried out. It was observed that the reaction temperature in combination with the structure of the zeolite plays an important role in the reactions that take place. The maximum yield of either the primary or secondary alkylation products may occur at an intermediate temperature, which is lower over {beta} zeolite. Due to its pore structure, {beta} zeolite favors secondary alkylation reactions and also disproportionation reactions of the generated alkylaromatics to a higher extent than ZSM-5 does. MeOH generates both primary and secondary alkylation products, while C{sub 2}H{sub 4} favors oligomerization reactions, primary alkylation reactions, and particularly, disproportionation reactions. Toluene is more reactive than benzene. The aromatic/alkylating agent molar ratio plays an important role in the relative importance of the reactions that take place. The size of the pores of the zeolite in combination with the sizes of the aromatic hydrocarbons and the alkylating agents employed determines whether the alkylation occurs via a Langmuir-Henshelwood (LH) or Rideal-Eley (RE) mechanism. When a LH mechanism occurs, the alkylation rate passes through a maximummore » with respect to the concentration of the aromatic hydrocarbon employed; no such maximum occurs for the RE mechanism.« less

Aliphatic and aromatic hydrocarbons in particulate fallout of alexandria, egypt: sources and implications.

Abstract: Particulate fallout samples (PFS) were collected in Alexandria, and their aliphatic and aromatic hydrocarbon compositions were determined both quantitatively and qualitatively to characterize the homologous and biomarker compounds in terms of their original sources. The results show that all samples contain aliphatic hydrocarbons, including n-alkanes, UCM, isoprenoids, tri- and tetracyclic terpanes, hopanes, and steranes/diasteranes. The main source of these compounds is from petrochemical contamination with trace input of terrestrial higher plant wax. In addition, polycyclic aromatic hydrocarbons, which are considered to be combustion products from fossil fuels such as petroleum, are also widely distributed in all samples. Multivariate statistical analysis, including extended Q-mode factor analysis and linear programming technique, was performed in order to reduce the hydrocarbon data set into a meaningful number of end members (sources). This analysis indicates that there are two significant end members explaining 90% of the total variation among the samples and confirming petrochemical (79.6%), and thermogenic/pyrolytic (10.4%) sources in the PFS model. 65 refs., 7 figs., 4 tabs.

Process for the preparation of isobutylene polymer

Abstract: An isobutylene is polymerized in the presence of an aromatic initiator and a catalyst under the conditions that either a chlorinated hydrocarbon or an aromatic hydrocarbon is used singly or in admixture with an aliphatic hydrocarbon so that the reaction solution has a dielectric constant of 1 to 5 and a solubility parameter of 7.5 to 9.0.

Transformation of chrysene and other polycyclic aromatic hydrocarbon mixtures by the fungus Cunninghamella elegans

Abstract: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous and persistent environmental pollutants; some are mutagenic, toxic, and carcinogenic and remain a public health concern. We investigated the metabolism of mixtures of PAHs and a tetracyclic aromatic hydrocarbon, chrysene, by the filamentous fungus, Cunninghamella elegans ATCC 36112. Cunninghamella elegans metabolized a mixture of PAHs including the carcinogen benzo[a]pyrene, phenanthrene, fluoranthene, pyrene, and acenaphthene completely to hydroxylated intermediates within 24 h. The metabolites from the PAH mixtures were similar to those formed in earlier studies of individual PAH compounds. In separate experiments with chrysene, C. elegans metabolized about 45% of the [5,6,11,12-14C]chrysene added to cultures during 144 h incubation. The two major metabolites of chrysene were separated by reverse-phase high performance liquid chromatography and identified by ultraviolet–visible, mass spectral, and 1H-nuclear magnetic resonance techniques as sulfate ...

Dual bed xylene isomerization

Abstract: A mixture of aromatic hydrocarbons, comprising ethylbenzene and at least one xylene, is isomerized using a two component catalyst system to convert the ethylbenzene to compounds that may be removed from the aromatic hydrocarbon stream and to produce a product stream wherein the para-xylene concentration is approximately equal to the equilibrium ratio of the para-isomer. The first catalyst comprises an intermediate pore size zeolite that is effective for ethylbenzene conversion. The first catalyst is preferably silica-bound. The second catalyst comprises an intermediate pore size zeolite, which further has a small crystal size and which is effective to catalyze xylene isomerization. Each of the catalysts of this invention may contain one or more hydrogenation/dehydrogenation component.

Selective ethylbenzene conversion

Abstract: A mixture of aromatic hydrocarbons, comprising ethylbenzene and at least one xylene, is treated to convert the ethylbenzene to compounds that may be removed from the aromatic hydrocarbon stream and to isomerize any xylenes present. The ethylbenzene conversion catalyst is one that is effective for ethylbenzene conversion with minimal xylene loss, e.g., a silica bound intermediate pore size zeolite that has been selectivated. The xylene isomerization catalyst is one which is effective to catalyze xylene isomerization. Each of the catalysts of this invention may contain one or more hydrogenation or dehydrogenation components.

Process for the formation of hydrocarbyl bis(hydrocarbyl phosphate)

Abstract: A process for the synthesis of a hydrocarbyl bis(dihydrocarbyl phosphate), such as a hydrocarbyl bis(diaryl phosphate), comprises the reaction of an unstable hydrocarbyl-containing diol, such as an aromatic group-containing diol, with a dihydrocarbyl halophosphate, such as diphenyl chlorophosphate, in the presence of a Lewis acid catalyst, such as magnesium dichloride, in the additional presence of an effective amount (e.g., up to about 100 % by weight of diol and halophosphate) of a liquid hydrocarbon, such as an aliphatic hydrocarbon, like heptane, or an aromatic hydrocarbon, such as toluene, to enhance the removal of hydrogen halide by-product and thereby increase the yield of hydrocarbyl bis(dihydrocarbyl phosphate).

Low viscosity adhesive compositions containing asymmetric radial polymers

Abstract: A low viscosity adhesive composition which comprises: (a) an asymmetric radial block copolymer of a vinyl aromatic hydrocarbon and at least one conjugated diene having from 3 to 6 polymer arms, which: (i) contains from 33 to 85% by weight of polyvinyl aromatic hydrocarbon block/polydiene block copolymer arms and the balance polydiene homopolymer arms, (ii) has vinyl aromatic hydrocarbon blocks with block molecular weights of from 8000 to 30,000, (iii) has conjugated diene blocks in the copolymer arms with a molecular weight of at least 6000, and (iv) has a polyvinyl aromatic hydrocarbon content of from 10 to 40% by weight; and (b) from 20 to 400 parts per hundred parts of polymer of a tackifying resin. The invention also encompasses the polymers used in the adhesive.

Process for the removal of nitrogen compounds from an aromatic hydrocarbon stream

Abstract: This invention relates to a process for the removal of nitrogen compounds from an aromatic hydrocarbon stream comprising the nitrogen compounds by contacting the hydrocarbon stream with a selective adsorbent having an average pore size less than. about 5.5 Angstroms. The selective adsorbent is a molecular sieve selected from the group consisting of pore closed zeolite 4A, zeolite 4A, zeolite 5A, silicalite, F-silicalite, ZSM-5 and mixtures thereof. In one embodiment, the present invention comprises a combination of a fractionation zone and an adsorption zone wherein the feedstream is passed to the fractionation zone to provide a dry bottoms product stream essentially free of the nitrogen compounds and an overhead stream. The overhead stream is condensed to provide an aqueous stream and a hydrocarbon stream. The hydrocarbon stream is passed to an adsorption zone and a treated effluent recovered therefrom is returned to the fractionation zone. The invention provides significant cost advantages when the feedstream is subject to slugs or surges in levels of nitrogen compounds which can be detrimental to downstream catalyst as found in aromatic conversion reactions.

Mechanism of Aromatic Hydrocarbon Formation in FCC Naphtha

Abstract: A microactivity test study of the FCC naphtha composition at increasing conversions was carried out. At low conversions (ca. 10--20%), the naphtha is rich in olefinic and aromatic hydrocarbons. As the conversion increases, the composition changes dramatically. The olefins initially increase and then decrease sharply. The paraffins increase continually, and the aromatics initially decrease and then increase slightly. The naphthenics remain constant in the conversion range studied. These results indicate that, at low conversions, the aromatics in the gasoline are mainly formed by dealkylation of heavy aromatic molecules present in the feed. At higher conversions, however, the aromatics in the naphtha are mainly formed by cyclization followed by hydrogen transfer of the olefins formed during cracking. This reaction also increases the relative concentration of paraffinic hydrocarbons. The distribution of C9 aromatics showed that, as the conversion increases, there occurs an isomerization of the alkyl chain, to increase the branching of the ring.

Coupling transport and biodegradation of VOCs in surface and subsurface soils.

Abstract: Volatile organic chemicals present at Superfund sites preferentially partition into the soil gas and may be available for microbial degradation. A simple mass transfer model for biodegradation for volatile substrates has been developed for the aerobic decomposition of aromatic and aliphatic hydrocarbons. The mass transfer analysis calculates diffusive fluxes from soil gas through water and membrane films and into the cell. This model predicts an extreme sensitivity of potential biodegradation rates to the air-water partition coefficients of the compounds. Aromatic hydrocarbons are removed rapidly while the aliphatic hydrocarbons are much slower by orders of magnitude. Furthermore, oxygen transfer is likely to limit aromatic hydrocarbon degradation rates. The model presents results that cast doubt on the practicality of using methane or propane for the co-metabolic destruction of trichloroethylene in a gas phase bioreactor. Toluene as a primary substrate has better mass transfer characteristics to achieve more efficient trichloroethylene degradation. Hence, in sites where these contaminants coexist, bioremediation could be improved.

Anaerobic biodegradation of unsaturated, saturated, aromatic and halogenated hydrocarbons

Abstract: An apparatus and method for anaerobic biodegradation, bioremediation or bioprocessing of hydrocarbons dissolved in an aqueous matrix, such as wastewater, groundwater, or slurry. Dissolved alkanes (saturated hydrocarbons), alkenes (unsaturated hydrocarbons), aromatic hydrocarbons and/or halogenated hydrocarbons are metabolized or cometabolized. In one form, the invention involves introducing an aqueous stream comprising at least one dissolved aromatic hydrocarbon (such as benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene, phenol, o-cresol, m-cresol, or p-cresol) and a dissolved oxide of nitrogen such as nitrate (NO 3 - ), nitrite (NO 2 - ), nitric oxide (NO) and nitrous oxide (N 2 O)!to a reactor, and operating said reactor under conditions that support denitrification of the aromatic hydrocarbon. Alternatively, the aqueous stream may comprise at least one alkane (such as ethane) and/or at least one alkene (such as ethene or ethylene) and biodegradation of these compounds is accomplished. In a preferred form, the aqueous stream also comprises at least one dissolved halogenated hydrocarbon (such as tetrachloroethylene, trichloroethylene, or 1,1,1-trichloroethane) and dehalogenation of the halogenated hydrocarbon is accomplished. The reactor may be a continuous stirred tank reactor, a batch (or sequencing batch) reactor, a plug-flow reactor, a fixed-film reactor, or a pore space in an underground aquifer in situ. The reactor is operated in such a way that molecular oxygen is excluded from the space or zone in which the biodegradation is occurring and the other requirements of denitrifying bacteria are met. In some implementations, kinetic control (control of mean cell residence time) is used to enrich a denitrifying culture in the reactor.

Aromatic polycarbonate resin and its production

Abstract: PURPOSE: To obtain an aromatic polycarbonate resin having triarylamine structures on side chains, having an excellent electric charge transfer ability and an excellent mechanical strength, and useful as a photosensitizer for electrophotography and as an electric charge transfer polymeric material for electroluminescence. CONSTITUTION: This resin comprises repeating units of formula I {R 1 -R 3 are a halogen, a (substituted) alkyl; R 4 is H, a (substituted) alkyl; Ar 1 , Ar 2 are a (substituted) aromatic hydrocarbon group; X is a divalent (cyclic) aliphatic group, a group of formula II [R 5 , R 6 are R 1 , an aromatic hydrocarbon group; Y is a 1-12C (branched) alkylene, a 3-12C cyclic alkylene,-O-,-S-,-SO-,-SO 2 -,-CO-; O, P are 0-4]; l, m, n are 0-4; k is 5-5000}. The resin is obtained by reacting a compound of formula III with a compound of formula: ClCO-O-X-O-COCl. COPYRIGHT: (C)1996,JPO

Process for recovering pure benzene and pure toluene from aromatic hydrocarbon products

Abstract: The production of high purity benzene and high purity toluene is obtained by utilizing the initial gas separating column for the treatment of the aromatic containing starting material as a separating column for separating a benzene rich from a toluene rich component. The benzene rich component is subject directly to distillation while the toluene is subject to predistillation to separate high boiling components and only then to extractive distillation is distilled to separate the high purity benzene from the high purity toluene.

Method of catalytic hydrocarbon conversion with a silver zeolite catalyst

Abstract: The present invention provides a catalyst to produce a monocyclic aromatic hydrocarbon from hydrocarbons, which comprises a zeolite containing substantially no proton and having an intermediate pore diameter, a molar ratio of SiO 2 to Al 2 O 3 of at least 20 and silver, and which further comprises at least one metal belonging to Group IIb, IIIb and Group VIII of the Periodic Table. Further, the present invention provides a method to catalytically convert hydrocarbons by using the above catalyst. By means of the present invention, there can be provided a stable catalyst for conversion of hydrocarbons, which is capable of obtaining monocyclic aromatic hydrocarbons with good balance and a high yield, and which is hardly deteriorated by steam having a high temperature.

METHOD OF LIQUID-PHASE ALKYLATION OF AROMATIC HYDROCARBON BY USING beta-ZEOLITE

Abstract: A method of liquid-phase alkylation of aromatic hydrocarbon by conducting a liquid-phase reaction of an aromatic hydrocarbon with a C2-C4 olefin in a fixed-bed reactor packed with a β-zeolite catalyst at a temperature of 100-300 °C in a vapor-liquid descending parallel-flow system in the following trickle-bed zone: ςl.ul.{(σwater/σ)(ςwater/ςl)?2}1/3(kgm-2s-1?) < 20 and ςg.ug.{ςair.ςwater/(ςg.ςl)}?1/2(kgm-2s-1?) < 5 wherein ςl, ςg, ςair, and ςwater (kgm-3) represent respectively the liquid density of aromatic hydrocarbon, the gas density of olefin, the gas density of air, and the liquid density of water; σ and σwater (Nm-1) represent respectively the surface tension of aromatic hydrocarbon and that of water; and ul and ug (ms-1) represent respectively the superficial velocity of aromatic hydrocarbon and that of olefin.

Flame-retardant aromatic polycarbonate resin composition and molded article

Abstract: A flame-retardant aromatic polycarbonate resin composition has excellent flame retardancy and high transparency without impairing excellent properties inherent to an aromatic polycarbonate resin, and is free from corroding a molding machine or a processing machine, the flame-retardant resin composition comprising 100 parts by weight of an aromatic polycarbonate resin, 0.01 to 1 part by weight of (a) a perfluoroalkane-sulfonic acid alkali salt and 0.02 to 2 parts by weight of (b) a halogenated triaryl phosphate of the formula [1], ##STR1## wherein each of Ar 1 , Ar 2 and Ar 3 is independently an aromatic hydrocarbon, and at least one halogen atom is substituted on ring-forming carbon of each aromatic hydrocarbon group.

Production of cycloolefin

Abstract: PURPOSE: To stably produce cycloolefins in high selectivity and yield by partially reducing a monocyclic aromatic hydrocarbon using a ruthenium supported catalyst having a specific value or above of a metal dispersion degree. CONSTITUTION: A catalyst supported on a carrier and prepared by supporting ruthenium on the carrier in a state so as to provide the chemical adsorptivity for hydrogen of at least (0.6/1) expressed in terms of the ratio (H/Ru) of the number of the adsorbed hydrogen atoms to the total number of metallic ruthenium atoms in the catalyst is used as a hydrogenation catalyst to carry out partial hydrogenating reaction in partially reducing a monocyclic aromatic hydrocarbon with hydrogen in the coexistence of the hydrogenating catalyst consisting essentially of the ruthenium and water. The hydrogenating catalyst is prepared by using a ruthenium complex compound comprising a reactive ligand selected from carbonyl and an olefin as a precursor of the ruthenium. COPYRIGHT: (C)1996,JPO

Hydrogenated diblock copolymers for adhesives and sealants with improved resistance to degradation

Abstract: Adhesive and sealant compositions having improved resistance to a degradation which comprises: (a) a hydrogenated triblock, multiblock, radial, or star block copolymer of a vinyl aromatic hydrocarbon and a conjugated diene, (b) from 3 to 50 percent by weight of the total composition of a hydrogenated diblock copolymer of a vinyl aromatic hydrocarbon and a conjugated diene wherein the overall molecular weight of the diblock ranges from 8000 to 100,000, the molecular weight of the poly vinyl aromatic hydrocarbon block ranges from 4000 to 32,000, the molecular weight of the poly conjugated diene block ranges from 3000 to 90,000, and the vinyl aromatic hydrocarbon content ranges from 30 to 70 percent by weight of the diblock copolymer, and (c) 20 to 400 parts by weight per 100 parts by weight of total block copolymers of a tackifying resin.

ALIPHATIC C-H BOND RESPONSES IN THE 900-700 cm−1 REGION OF THE FTIR SPECTRA OF COAL TARS

Abstract: Four bituminous coals were comprehensively separated by column chromatography into a number of fractions. Four aromatic hydrocarbon fractions of each tar were analyzed by FTIR spectroscopy, and the 900-700 cm−1 spectral region was evaluated. This spectral region was found to be composed of at least 14 separate bands, which were resolved by using self-deconvolution and curve-fitting procedures. The bands near 821 cm−1, 791 cm−1, and 784 cm−1 were proposed to originate from rocking vibrations of aliphatic C-H bonds. For the tar samples with a proton aromaticity between 0.21 and 0.37, these bands account for on average 12% of the total integral intensity of the 900-700 cm−1 region. This percentage cannot likely be neglected in a correct quantitative evaluation of the region and calculation of the aromatic hydrogen concentration. However, a correct resolution of the bands can be very difficult in the FTIR spectra of a complex material, such as coal.

Water-resistant grease composition

Abstract: PROBLEM TO BE SOLVED: To obtain a water resistant lubricating grease excellent in adhesive properties, sealing properties in a circumstance where much water exists and capable of retaining excellent lubrication for a long time. SOLUTION: This grease comprises a diurea compound, as a thickening agent, expressed by the following general formula and 0.1-10wt.% of a surface active agent having HLB of 3-14. In the formula R1 -NHCONH-R2 -NHCONH-R3 , R2 is a 6-15C aromatic hydrocarbon, R1 and R3 are each a 6-12C aromatic hydrocarbon or a 8-20C alkyl and the ratio of aromatic hydrocarbon group in R1 and R3 is 40-100mol%.

Polymer solid electrolyte lithium secondary battery

Abstract: PROBLEM TO BE SOLVED: To make it easy for a negative electrode material to store lithium ion by using a polymer solid electrolyte having an aromatic hydrocarbon group, and provide a lithium secondary battery with high capacity and long charge and discharge cycle life. SOLUTION: In a polymer solid electrolytic lithium secondary battery using a carbon material as negative electrode material, a polymer solid electrolyte consisting of a polymer compound having at least one of aromatic hydrocarbon group and complex aromatic hydrocarbon group is used. When a one having aromatic hydrocarbon group in the side chain is used as the polymer compound, electrode reaction is smoothly advanced to improve the battery characteristic. When a one in which methyl group in the side chain of methoxyoligoethyleneoxy polyphosphazene is substituted by aromatic hydrocarbon group, for example, a polymer compound represented by the formula, is used as the polymer compound, the battery characteristic is significantly improved because of the high conductivity of the polyphosphazene in the main chain. This polymer solid electrolyte is high in close adhesion to the carbon material of the negative electrode.