Showing papers on "Hydrocarbon published in 1998"

Infrared Spectral Interpretation: A Systematic Approach

Abstract: THE BASICS OF INFRARED INTERPRETATION Advantages and Disadvantages of Infrared Spectroscopy The Properties of Light What Are Infrared Spectra Used For? How Molecules Absorb Infrared Radiation The Origins of Peak Positions, Peak Intensities, and Peak Widths Dealing with Mixtures Performing Identities Infrared Spectral Interpretation: A Systematic 10-Step Approach HYDROCARBONS Straight Chain Alkanes Estimating Hydrocarbon Chain Length Branched Alkanes Alkenes Distinguishing cis and transisomers Alkynes Aromatic Hydrocarbons Distinguishing Mono and Di- Substituted Benzene Rings FUNCTIONAL GROUPS CONTAINING THE C-O BOND Alcohols and Phenols The Affects of Hydrogen Bonding Distinguishing Primary, Secondary, and Tertiary Alcohols Ethers Distinguishing Saturated and Aromatic Ethers Methyl Groups Attached to an Oxygen THE CARBONYL GROUP Ketones Aldehydes Carboxylic Acids and Derivatives Carboxylic Acids Carboxylates (soaps) Acid Anhydrides Esters Distinguishing Saturated and Aromatic Esters Organic Carbonates ORGANIC NITROGEN COMPOUNDS Amides Distinguishing Primary, Secondary, and Tertiary Amides Proteins Imides Amines Distinguishing Primary, Secondary, and Tertiary Amines Nitriles The Nitro Group ORGANIC COMPOUNDS CONTAINING SULFUR, SILICON, AND HALOGENS Organic Sulfur Compounds Thiols Sufloxides, Sulfates, etc. Organic Silicon Compounds Silicones (Siloxanes) Halogenated Organics C-X Stretches INORGANIC COMPOUNDS The Impact of Water on Inorganic Spectra Sulfates Silica and Silicates Carbonates Nitrates Phosphates INFRARED SPECTRA OF POLYMERS Polyethylenes Polypropylene Polystyrene Polyesters Acrylates Isocyanates and Polyurethanes Polycarbonates Polyimides Polytetrafluoroethylene SPECTRAL INTERPRETATION AIDS Atlases Spectral Subtraction Library Searching "Expert" Software Programs The Internet

Production of synthetic crude oil from heavy hydrocarbons recovered by in situ hydrovisbreaking

Abstract: An integrated process is disclosed for treating, at the surface, production fluids recovered from the application of in situ hydrovisbreaking to heavy crude oils and natural bitumens deposited in subsurface formations. The production fluids include virgin heavy hydrocarbons, heavy hydrocarbons converted via the hydrovisbreaking process to lighter liquid hydrocarbons, residual reducing gases, hydrocarbon gases, and other components. In the process of this invention, the hydrocarbons in the production fluids are separated into a synthetic-crude-oil product (a nominal butane to 975° F. fraction with reduced sulfur, nitrogen, metals, and carbon residue) and a residuum stream (a nominal 975° F.+ fraction). Partial oxidation of the residuum is carried out to produce clean reducing gas and fuel gas for steam generation, with the reducing gas and steam used in the in situ hydrovisbreaking process.

Catalytic combustion of C3 hydrocarbons and oxygenates over Mn3O4

Abstract: The catalytic oxidation of the C3 organic compounds: propane, propene, 1-propanol, 2-propanol, prop-2-en-1-ol (allyl alcohol), propanal, propanone (acetone) and propenal (acrolein) has been investigated over Mn3O4 in the presence of excess oxygen. Total combustion to CO2 occurs at temperatures >623 K (673 K for propane). However, the production of pollutant products (such as propene from propane, CO from propene, acetaldehyde from propanols, propanal and propanone, carboxylic acids) persists even at very high volatile organic compounds (VOC) conversions. On the basis of the reaction products, a tentative reaction pathway for propane and propene combustion is proposed.

Isoparaffinic lube basestock compositions

Abstract: A liquid hydrocarbon composition, containing paraffinic hydrocarbon components in which the extent of branching, as measured by the percentage of methyl hydrogens (BI), and the proximity of branching, as measured by the percentage of recurring methylene carbons which are four or more carbons removed from an end group or branch (CH2⊃4), are such that: (a) BI - 0.5(CH2⊃4)⊃15; and (b) BI + 0.85(CH2⊃4)∫45 as measured over said liquid hydrocarbon composition as a whole.

Photooxidation of crude oils

Abstract: Photooxidation is a potentially significant process in the degradation of crude oil spilled at sea. Moreover, a fundamental understanding of the effect of photochemical degradation on crude oil is a prerequisite for providing an accurate description of the recent history and potential fate of oil spilled in a marine environment. In this report we examine the effect of ultraviolet illumination on crude oil using a variety of techniques including gas chromatography/mass spectroscopy and X-ray absorption spectroscopy. The saturated compounds are resistant, but the aromatic compounds are particularly sensitive to photooxidation. Greater size and increasing alkyl substitution increase the sensitivity of aromatic compounds to photochemical oxidation. The photooxidized products appear in the resin and polar fractions as determined by thin-layer chroma tography. Thus, the effect of photooxidation is distinctly different from that of biodegradation, where larger and more substituted compounds are more resistant to...

Identification of Products Containing −COOH, −OH, and −C=O in Atmospheric Oxidation of Hydrocarbons

Abstract: Atmospheric oxidation of hydrocarbons by hydroxyl radicals and ozone leads to products containing −COOH, −OH, and −C=O functional groups. The high polarity of such compounds precludes direct GC−MS analysis. In addition, many such compounds often exist in a single sample at trace levels. An analytical method has been developed to identify compounds containing one or more functional groups of carbonyl, carboxy, and hydroxy in atmospheric samples. In the method, −C=O groups are derivatized using O-(2,3,4,5,6-pentafluorobenzyl) hydroxy amine (PFBHA), and −COOH and −OH groups are derivatized using a silylation reagent N,O-bis(trimethylsilyl)-trifluoroacetamide (BSTFA). The derivatives are easily resolved by a GC column. The chemical ionization mass spectra of these derivatives exhibit several pseudomolecular ions, allowing unambiguous determination of molecular weights. Functional group identification is accomplished by monitoring the ions in the electron ionization mass spectra that are characteristic of each functional group derivative: m/z 181 for carbonyl and m/z 73 and 75 for carboxyl and hydroxy groups. The method is used to identify products in laboratory studies of ozone oxidation of α-pinene and Δ^3-carene. Among products from ozone oxidation of α-pinene, we have detected pinonaldehyde, norpinonaldehyde, pinonic acid, norpinonic acid, C_(10) hydroxy dicarbonyls, pinic acid, 2,2-dimethyl-3-(formylmethyl)-cyclobutane-formic acid, and a product that has a molecular weight of 156 and contains a CO and a COOH/OH group. The latter two products have not been reported previously. Δ^3-Carene is structurally analogous to α-pinene in that both have an internal unsaturated bond where ozone oxidation takes place. We have also identified the corresponding analogous products, of which all but caronaldehyde are reported for the first time.

Effect of operating conditions and membrane quality on the separation performance of composite silicalite-1 membranes

Abstract: The separation capacity of silicalite-1 membranes for various hydrocarbon mixtures is determined as a function of membrane quality, operating conditions, and orientation of the composite membrane with respect to the feed side. The quality of the membranes is judged on the basis of the n-butane/i-butane permselectivity. Membranes with a different n-butane/i-butane permselectivity showed an identical separation capacity for ethane/methane mixtures, but the quality difference was affecting separation of hydrogen from the butane isomers. The selectivity of the membrane is significantly affected by the operating conditions, such as mixture composition, temperature, and absolute pressure. These effects are shown for ethane/methane, propene/ethene, and n-butane/i-butane mixtures. The selectivity for ethane in ethane/methane mixtures, found when the zeolite layer is facing the feed side, is completely lost when the orientation of the composite membrane is reversed, due to concentration polarization. Depending on the membrane orientation, the major resistance of the composite is in the support layer or in the zeolite layer.

Aromatization of methane in the absence of oxygen over Mo-based catalysts supported on different types of zeolites

Abstract: The catalytic performance of Mo-based catalysts supported on various zeolites has been studied for methane aromatization in the absence of oxygen in a fixed-bed continuous-flow quartz reactor, and their catalytic properties are correlated with features of zeolite structure. It was found that H-type silica–alumina zeolites, such as ZSM-5, ZSM-8, ZSM-11 and β possessing two-dimensional structure and pore diameter equaling the dynamic diameter of a benzene molecule (about 6 A) simultaneously, are fine supports for methane activation and aromatization catalysts. Among them, MoO3/H-ZSM-11 has the best activity and stability; for instance, a methane conversion of 8.0% and selectivity higher than 90% was obtained at 973 K. The catalytic performance of MoO3/H-ZSM-8 is somewhat lower than that of MoO3/H-ZSM-5, while activity of MoO3/H-β is lower than that of MoO3/H-ZSM-8. Catalysts supported on H-MCM-41 and H-SAPO-34 exhibit low activity for methane aromatization and those supported on H-MOR, H-X and H-Y give only a little amount of ethylene. Over MoO3/H-SAPO-5 and MoO3/H-SAPO-11 no hydrocarbons were detected.

Carbon deposition and hydrocarbon formation on group viii metal catalysts

Abstract: Carbon formed from CO in CO2 at around 500 °C deposited as nanotubes and encapsulating carbons on a supported Ni catalyst without H2 or as filaments if H2 was present. A thermodynamic model explains how hydrogen in low concentrations controls filament morphology and why equilibrium is shifted from that for graphite during carbon deposition. Carbon deposition reaction rates at low carbon activity in the absence of hydrogen are reported. A new concept of the rate limiting step for metal-catalyzed carbon formation is proposed, where conditions inside the bulk metal are at least as important as the surface chemistry. A mechanism with an unusual type of active site can qualitatively explain carbon formation rates through a broad range of reaction conditions. When hydrogen is present, a series of hydrocarbons are believed to form, as in fuel synthesis (Fischer−Tropsch) chemistry. Surface vinyl species that have been recently shown to be intermediates in Fischer−Tropsch chemistry also may polymerize to form grap...

Recycling of carbon dioxide into methyl alcohol and related oxygenates or hydrocarbons

Abstract: A regenerative electrochemical cell system (10) based on a fuel cell (12) to oxidize methyl alcohol or other oxygenated hydrocarbons coupled with a regenerative cell (14) to reduce carbon dioxide to form oxygenated hydrocarbons is disclosed. Methods to reversibly interconvert oxygenated hydrocarbons and carbon dioxide, to recycle carbon dioxide produced as a by-product of industrial processes, and to store and release chemical and electrical energy are also disclosed. The carbon dioxide and water produced in the fuel cell may be supplied (16) to the regenerative cell, while the oxygenated hydrocarbon and oxygen produced in the regenerative cell may be supplied (18) to the fuel cell.

Catalytic Conversion of Used Oil to Hydrocarbon Fuels in a Fractionating Pyrolysis Reactor

Abstract: Pyrolysis of used sunflower oil was carried out in the presence of different amounts of HZSM-5 at 400 and 420 °C in a reactor equipped with a fractionating packed column, the length of which was varied. The products consisted of gaseous and liquid hydrocarbons, acids, CO, CO2, water, and coke. The compositions of the gaseous and liquid products were studied by gas chromatography. The product yields and compositions were affected by catalyst content, temperature, and column length. Nearly complete conversion (96.6%) of the used oil and the maximum liquid hydrocarbon yield (33%) were obtained at the highest temperature (420 °C), highest catalyst content (20%), and the lowest column length (180 mm) employed. The aromatic hydrocarbon contents of the liquid hydrocarbon products, which consisted of hydrocarbons of gasoline range, were in general lower than those obtained using fixed bed reactors but increased parallel to the increase in catalyst content. Additional thermal reactions taking place in this type of...

Fenton Reagent Advanced Oxidation of Polynuclear Aromatic Hydrocarbons in Water

Abstract: Aqueous oxidation of three polynuclear aromatic hydrocarbons, fluorene, phenanthrene and acenaphthene with the combination of hydrogen peroxide and ferrous ion, Fenton reagent, has been studied The effect of variables such as concentration of both reactants, pH and presence of bicarbonate ion and humic substances has been investigated Products resulting from oxidation have also been identified From experimental results and kinetic data determined the process is confirmed as an advanced oxidation involving the generation of hydroxyl radicals Oxidation rates are even higher than those from other advanced oxidation systems involving ozone, UV radiation and hydrogen peroxide Reactivity is in the following decreasing order: Phenanthrene > Fluorene > Acenaphthene

Effect of dimethyl ether, NOx, and ethane on CH4 oxidation: High pressure, intermediate-temperature experiments and modeling

Abstract: The effects of small amounts of dimethyl ether (DME), NO, and NO2 on the autoignition and oxidation chemistry of methane, with an without small amounts of ethane present, were experimentally studied in a flow reactor at pressures and temperatures similar to those found in spark- and compression-ignition engines (under autoignition conditions). The reactions were studied at pressures from 10 to 18 atm, temperatures from 800 to 1060 K, and equivalence ratios from 0.5 to 2.0. It is found that 1% DME addition is as effective in stimulating the autoignition and oxidative behavior of methane as 3% C2H6 addition, and that NOx at even ppm levels is more effective than hydrocarbon additives. For the same reaction time and temperatures below 1200 K, addition of small amounts of NOx lowered the temperature at which reaction becomes significant by more than 200 K. Chemical kinetic mechanisms in the literature for the interactions of methane, ethane, and NOx do not predict the reported observations well. The most significant rate-controlling reactions for CH4 autoignition is found to be CH3+HO2=CH3O+OH. Good agreement, with and without NOx perturbations can be obtained by modifying the rate constants of three reactions (CH3+HO2=CH3O+OH; CH3+HO2=CH4+O2: CH2O+HO2=HCO+H2O2) and by adding the reaction CH3+NO2=CH3O+NO to the GRI-Mech v2.11 mechanism. These modifications do not significantly affect predictions for shock tube, flame, and other results used in developing GRI-Mech v2.11. Results strongly suggest that exhaust gas residuals and/or exhaust gas recirculation can have as profound an effect as natural gas contaminants on the apparent octane and cetane behavior.

Method of producing hydrogen from heavy crude oil using solvent deasphalting and partial oxidation methods

Abstract: Heavy crude oil is recovered and processed at a refinery through (a) a distillation zone(s), (b) a solvent deasphalting unit (c ) a high pressure air partial oxidation gasifier to produce a CO-rich gas mixture including hydrogen, (d) a shift reactor and (e) a purification step to produce 99.9% pure hydrogen. The hydrogen is used to treat a deasphalted oil fraction and distillate hydrocarbon fractions obtained from the crude oil. The process is considered integrated in the sense that the purified hydrogen recovered from the heavy crude oil is used to treat hydrocarbons recovered from the same crude oil.

Polymeric Anionic Surfactant for Electrokinetic Chromatography: Separation of 16 Priority Polycyclic Aromatic Hydrocarbon Pollutants

Abstract: Electrokinetic chromatography (EKC) with poly(sodium undecylenic sulfate) (poly-SUS) is utilized to separate environmental pollutants such as 2-6-ring polycyclic aromatic hydrocarbons (PAHs). Parameters such as pH, concentration of polymeric surfactants, and the use of organic modifiers were investigated to follow the retention trends of PAHs. A baseline separation of all 16 PAHs in about 30 min, using 0.50% (w/v) of poly-SUS/12.5 mM sodium phosphate-borate buffer (pH 9.2) with 40% (v/ v) acetonitrile, was possible for the first time in EKC by a single-surfactant system. After the first publication on micellar electrokinetic chromatography (MEKC) more than 10 years ago,1 many researchers have explored various types of monomeric surfactants above their critical micelle concentrations (cmc’s) as pseudostationary phases for the separation of both ionic and nonionic compounds.2-6 Among the pseudostationary phases investigated, sodium dodecyl sulfate (SDS) has been successful in the MEKC separation of many water-soluble solutes.7,8 However, in the case of highly hydrophobic analytes such as polycyclic aromatic hydrocarbons (PAHs), the binding with SDS micelle is often too strong to permit adequate resolution of these compounds.9,10

Conversion of ethane into benzene on Mo2C/ZSM-5 catalyst

Abstract: The reaction of ethane on unsupported and supported molybdenum compounds has been investigated at 773–973 K. ZSM-5 was used as support. Reaction products were analyzed using gas chromatography. Changes in the composition of catalyst samples were followed by X-ray photoelectron spectroscopy. Unsupported MoO3 is partially reduced with ethane above 800 K to give H2O and CO2. The formation of H2, C2H4 and CH4 was also observed. Mo-free ZSM-5 exhibited relatively high activity towards dehydrogenation, hydrogenolysis and aromatization of ethane above 773 K. Deposition of MoO3 on ZSM-5 significantly enhanced the conversion of ethane and also the selectivity of benzene production. Alteration of the catalytic behaviour of MoO3/ZSM-5 in time on-stream at 773–973 K was attributed to the reaction of MoO3, to carbon deposition and to the formation of Mo2C. Unsupported Mo2C catalyzed the dehydrogenation of ethane without producing benzene. In contrast, Mo2C/ZSM-5 was found to be an effective catalyst in the aromatization of ethane. At 973 K the conversion of ethane was ∼67% and the selectivity to benzene formation 31%.

Rapid gel formation in hydrocarbon recovery

Abstract: Method and composition for gel formation in hydrocarbon recovery, in which an organic phosphate ester is gelled by a novel activator composition comprising iron sulfate, dibutylaminoethanol, and a phosphate surfactant.

Perovskite-type oxides – catalysts for the total oxidation of chlorinated hydrocarbons

Abstract: Chloromethane, dichloromethane and 1,2-dichloroethane were completely decomposed in air on perovskite-type catalysts (LaMnO3, LaCoO3, (La0.84,Sr0.16)(Mn0.67,Co0.33)O3) at reaction temperatures above 550°C. Besides the main reaction products (carbon dioxide, water and hydrochloric acid), by-products (higher chlorinated-, C–C coupling- and cracking products) were formed in the low temperature range. Depending on the reaction temperature, residence time and kind of chlorinated hydrocarbon a reversible catalyst deactivation takes place. In the case of LaCoO3 catalysts an irreversible deactivation was observed. X-ray diffraction (XRD) and electron probe microanalysis (EPMA) measurements with the perovskite-type catalysts after interaction of chlorinated hydrocarbons indicate the formation of chlorinated species on the catalyst surface and in the bulk.

An Experimental Design Approach for the Determination of Polycyclic Aromatic Hydrocarbons from Highly Contaminated Soil Using Accelerated Solvent Extraction

Abstract: An experimental design approach, based on central composite design, has been used to investigate the dependence of accelerated solvent extraction operating variables (pressure, temperature, extraction time) on the recovery of 16 polycyclic aromatic hydrocarbons (PAHs) from native, contaminated soil. At the 95% confidence interval, no significance in terms of the three operating parameters was found when considering the total PAH recovery. However, when individual PAHs were considered, some compounds were found to be dependent on operating variables. The most significant operating variable was extraction temperature. Low extraction temperature (40 °C) was found to be significant for naphthalene, chrysene, and benzo[b]fluoranthene. Using constant operating conditions (100 °C, 14 MPa and an extraction time of 5 min plus 5 min equilibriation time), the influence of extraction solvent was evaluated. No dependence on recovery was found when polar organic solvents, i.e., a dipole moment of >1.89, were used.