Toluene Oil Research Articles

A comparison study on adsorption and interaction behaviors of diluted bitumen and conventional crude oil on model mineral surface

The increasing volume of petroleum products being transported from the Canadian oil sands raises concerns of potential impacts of accidental oil discharges in-land. Understanding the adsorption behavior of petroleum on mineral surfaces is important for oil spill modeling and response. In this work, a comparison study is conducted to probe the interaction behaviors of two distinct petroleum products, diluted bitumen (DB) and conventional crude oil (CCO), with molecularly smooth mica surfaces (as a model mineral) in toluene solutions using a surface forces apparatus (SFA) and an atomic force microscope (AFM). It is observed that DB exhibits adsorption behavior distinct from that of CCO at the tested concentrations. At low concentrations of oil in toluene (e.g., 0.1 v/v%), the adsorbed DB film on mica is twice as thick as the CCO film on mica. Weak adhesion (<1 mN/m) is measured when separating two oil-adsorbed mica surfaces in toluene. Alternatively, when the concentration of oil is increased to 10 v/v%, the initial oil-film thickness is doubled for the two oils tested. Adhesion (∼10 mN/m) with long stretching or bridging (>70 nm) is observed in DB-toluene but not in CCO-toluene. The distinct adsorption behavior of DB is demonstrated to be mainly due to the high concentration of surface-active components, such as asphaltenes. The AFM imaging and Fourier-transform infrared spectroscopy results further support the SFA results. Our study provides fundamental insights into the adsorption and interaction behaviors of DB and CCO on mineral surfaces, with implications for predicting oil spill behavior and improving spill response measures.

Porous polymer oil sorbents based on PET fibers with crosslinked copolymer coatings

Oil sorbents—namely materials that can be used to extract oil after a spill—were fabricated from non-woven polyethylene terephthalate (NWPET) fibers modified by the adherence of crosslinked polymer coatings to the fiber surface. The NWPET fibers, which serve as a structural support for the applied functional coatings, were produced from recycled PET (polyethylene terephthalate) bottles. The oil absorbing coatings were comprised of crosslinked homopolymers and copolymers based on octadecyl acrylate (ODA), maleic anhydride (MA), and related esters of MA. The crosslinked polymer networks were synthesized by both suspension and bulk polymerization techniques using divinylbenzene (DVB) as the crosslinking agent. Efficacy of the coated NWPET fibers as oil sorbers was determined by oil absorption tests in toluene and in 10% crude oil in toluene. Rigidity, porosity and swelling of the crosslinked polymers were evaluated and correlated to the chemical structures, composition, and reaction media. Suspension polymerization yielded the desired morphology and function, providing higher porosity and in consequence a high absorption capacity.

Features of analysis of associative hydrocarbon media. Applicability of refractometric methods

The refractive index and optical absorption of solutions of crude oil in toluene were investigated. It was found that the optical properties of systems with an extremely low content of macromolecular substances deviate significantly from Bouguer-Lambert-Beer and other laws. The sensitivity of the refractive index to association of the macromolecular components of hydrocarbon systems was revealed. To increase the accuracy of the analysis, the necessity of a detailed study of the optical properties of associative hydrocarbon systems before plotting calibration curves was demonstrated.

Predicting sizes of toluene-diluted heavy oil emulsions in turbulent flow. Part 1—Application of two adsorption kinetic models for [formula omitted] in two size predictive models

Predicting oil-in-water emulsion droplet size and stability in turbulent flow is useful for choosing separation processes in heavy oil extraction. In order to study the process, averaged droplet sizes for toluene, n-heptane and mineral oil were measured during stepped-down turbulent mixing. Droplet sizes were measured for five concentrations of heavy oil in toluene at oil fraction 0.05 in model process water as a function of time during turbulent mixing. Mixing was conducted with a Rushton turbine in a cylindrical tank. Size distributions were measured with the Mastersizer 2000 laser diffraction instrument. Dynamic interfacial tensions σ dyn (by drop volume technique, DVT) and static interfacial tensions σ (by du Nouy ring) as a function of time were measured. Data were fitted with two adsorption kinetic models (diffusion limited Dl, and Langmuir based Lb) to find “equilibrium” interfacial tensions σ E needed to predict Sauter mean diameter d 32 in Hinze–Kolmogorov (H–K) and Wang–Calabrese (W–C) models. Data were also analyzed by using a classical breakage–coalescence kinetic model. Results showed that by using σ dyn with W–C model the predicted d 32 changed proportionately with σ dyn . For any σ E the d 32 predicted using the W–C model was closer to the experimental d 32 than the d 32 predicted by the H–K model. The σ E 's obtained by the Dl and Lb models were similar when fitted to DVT data giving identical W–C predicted d 32 . However, only the Dl model fitted the σ -time data obtained by the du Nouy ring technique and the σ E in W–C model gave d 32 closest to experimental d 32 for droplets of 1–10 wt% heavy oil in toluene. The predicted d 32 of droplets for the 25-wt% heavy oil was larger than the experimental d 32 . This difference was attributed to interfacial film thickness and decreased elasticity discussed in an earlier publication.

Circular dichroism of crude oil and its derivatives. Role of permolecular structures

Petrols with different octane numbers, diesel fuel and solutions of crude oil in toluene have been studied by the methods of absorption spectroscopy, circular dichroism spectroscopy and correlation spectroscopy of scattered light. Circular dichroism signal was registered for crude oil solutions in the spectral ranges corresponding to the measured earlier resonance absorption of asphaltene solutions in toluene. We show that the optical activity of crude oil solutions is due to the aggregation of asphaltene molecules in one spectral range and is intensified with the aggregation of asphaltene molecules in another spectral range. Petrols have no optical activity. The optical activity registered for diesel fuel is possibly due to the aggregation of asphaltene molecules.

Size distributions and stability of toluene diluted heavy oil emulsions

AbstractThe sizes and stability of oil droplets created from various concentrations of heavy oil‐in‐toluene at a fixed oil:water ratio were investigated during turbulent flow in model process water. The Reynolds number (Re) ranged from 17,000 to 34,500 and was obtained by stirred tank mixing with a Rushton turbine. The droplet sizes were monitored using laser light scattering. Results showed that at high Re and low oil concentrations (that is, low drop‐surface coverage), breakage of the droplets was the dominant process, but as Re was reduced, coalescence was dominant. Droplets were less prone to breakage as the oil concentrations in toluene increased, and droplet sizes approached a steady state quickly during mixing. Their size distributions broadened and stability increased as heavy oil in toluene increased. Stability was attributed to a surface coverage by asphaltenes and the consequent interfacial elasticity that provided resilience to breakage. Equilibrium interfacial tension σE was determined by fitting a diffusion‐limited kinetic mathematical model to the data. The Gibbs adsorption model gave a monolayer surface coverage of 3 nm2/mol asphaltenes, consistent with other published results. High zeta potential of the droplets also hindered coalescence. © 2005 American Institute of Chemical Engineers AIChE J, 2006

05/02444 Economic and policy implications of public support for ethanol production in california's San Joaquin Valley

During petroleum refining, a large number of products are generated which have varying chemical and physical properties. These are known in the industry as petroleum streams. In order to characterize their carcinogenic activity, a number of these commercially produced streams were administered to C3H/HeJ mice in chronic dermal bioassays. The bioassays were conducted using one of two study designs: the first set of test materials was applied for a lifetime and the second set for 24 months. In the lifetime study, the last mice in the test groups survived for periods of 31 to 32 months. Middle distillates, boiling in the range 115–390°C, were found to decrease the lifespan of exposed mice compared to controls or streams of higher and lower boiling ranges. These middle distillate streams included straight run kerosine, hydrodesulfurized middle distillate, straight run middle distillate, light catalytic cracked distillate, and 90/10% and 70/30% mixtures of the last two. The middle distillate streams also proved to be active as carcinogens, with tumor incidence ranging from 16 to 67%. Light alkylate naphtha, heavy catalytic reformed naphtha, vacuum residuum, and unleaded gasoline did not demonstrate significant carcinogenic potency. Heavy thermal cracked naphtha, heavy catalytic cracked naphtha, and hydrotreated light naphthenic distillate were dermal carcinogens of low potency in this study. Administration of light catalytic cracked naphtha led to a low incidence of very late developing tumors with a mean latency of 118 weeks. Application of the 0.1% solution of catalytic cracked clarified oil in toluene did not result in a significant incidence of tumors, but the 10% solution caused almost 100% mortality and 100% tumor incidence in 12 months. There was no correlation between carcinogenic potency and the indices of irritation, alopecia, erythema, and scabbing. Only two of the streams tested, hydrotreated light naphthenic distillate and 10% catalytic cracked clarified oil, contain polynuclear aromatic hydrocarbons (PNAs) and may be presumed to be complete carcinogens. The middle distillates and heavy naphthas are nonmutagenic and essentially free of PNAs. Their activity may result from promotion of already-initiated skin sites. Where comparisons could be made, reducing the exposure period from a lifetime (29–32 months) to 24 months did not change the evaluations of stream carcinogenicity except in the case of light catalytic cracked naphtha where six of the seven mice that developed tumors did so after 24 months.

Precipitation of asphaltenes from solvent-diluted heavy oil and thermodynamic properties of solvent-diluted heavy oil solutions

Ratios of n-heptane (hep) to toluene (tol) affect the solubility of the asphaltenes in heavy oil extraction processes. Consequently phase changes and time after mixing n-heptane and heavy oil in toluene are important for understanding produced emulsions. The kinetics of phase change when n-heptane is added to toluene-diluted heavy oils, and the thermodynamic properties of partially deasphalted heavy oils were studied. The methods used were monitoring precipitation in time using light microscopy, quantitative asphaltenes analysis by near infrared spectroscopy, refractive index and densities measurements, and calculated solubility parameters of mixtures. At critical mass ratios of hep/tol from 1.37 to 2.0 in diluted heavy oil the precipitated asphaltene particles were observed under the microscope after lag times from 2 h to instantly. Lag times were longer at low initial oil concentration. The floc growth time decreased as heavy oil concentration in toluene increased. The growth patterns in time appeared as dots to beads (strings) to clusters (fractal-like flocs). Final wt% precipitated asphaltenes vs. mass fraction (hep+tol)/heavy oil followed sigmoidal relationships. Curves showing wt% soluble asphaltenes vs. mass fraction hep/tol after 24 h initially followed the same shape as time zero curves and diverged at the onset ratios of hep/tol. Slope for precipitated asphaltenes vs. solubility parameters curve showed a break at 16.4 MPa 1/2. Linear correlations were established for concentrations of soluble asphaltenes in residual oils and density, for refractive index and density and for refractive index and solubility parameter. The latter correlation was in accordance with Lorenz–Lorentz theory. These equations provided a means by which oil density, refractive index and solubility parameter can be predicted when these measurements are difficult to measure practically.

Epoxidation of soybean oil in toluene with peroxoacetic and peroxoformic acids— kinetics and side reactions

The kinetics of the epoxidation of soybean oil and the extent of side reactions were studied at 40, 60, and 80 °C. Epoxidation was carried out in toluene with “in situ” formed peroxoacetic and peroxoformic acid and in the presence of an ion exchange resin as the catalyst. The reaction was found to be first-order with respect to the double bond concentration. At higher temperatures and at higher conversions a deviation from the first-order kinetics was observed. The rate constants for the epoxidation with peroxoacetic acid were 0.118 (h−1) at 40 °C, 0.451 (h−1) at 60 °C and 1.278 (h−1) at 80 °C, while those for peroxoformic acid were 0.264, 0.734, and 1.250 (h−1). The activation energy was found to be 54.7 kJ/mol for the epoxidation with peroxoacetic acid and 35.9 kJ/mol for that with peroxoformic acid. Three factors indicated that side reactions did not occur on a large scale: The absence of an OH band in the IR spectra, the formation of less than 2% of higher molecular weight products from gel permeation chromatography and the selectivity values between 0.9 and 1.

Some Features of the Supramolecular Structures in Petroleum Media

The structure of the disperse phase of crude oils and liquid petroleum products is determined by the characteristics of formation of molecular aggregates of asphaltenes. The characteristics of these processes in dilute solutions of crude oil in toluene were investigated by measuring the proton spin‐spin relaxation time as a function of the concentration of asphaltenes. These measurements allowed explaining the conditions of formation of dimers and more complex aggregates of asphaltene molecules. The data obtained by the NMR‐relaxation method are confirmed by the results of measurements of the viscosity and optical absorption of the petroleum solutions investigated.

Changes in Asphaltene Stability during Hydrotreating

The conversion of asphaltenes in heavy oil hydroprocessing is important as the asphaltenic fraction often contains the most refractive components. In residual oil feeds, the content of asphaltenic sulfur amounts to less than 20% of the total sulfur content; in hydrotreated oil products, however, more than 60% of the sulfur content may be asphaltenic. When hydrotreating heavy oils, both the non-asphaltenic phase and the asphaltenes undergo a chemical conversion, which may lead to unstable products as well as to increased coke lay-down on the catalyst. To be able to explain the behavior of different catalysts, the asphaltene conversion and particularly the stability of asphaltenes in hydrotreated heavy oil products were investigated. The stability of the asphaltenes was characterized by a flocculation onset titration procedure. With this method, several different concentrations of oil in toluene were titrated with heptane, and the stability parameters were derived. This study shows how the product stability is affected by changes in reaction temperature. The critical solubility parameter for the solubility of asphaltenes follows the assumed chemistry of the hydrotreating processes in question. At low severity hydroprocessing, the stability of the product increases, but when the severity is increased, the asphaltene stability is reduced.

The effect of dissolved transition metal complexes on the rate of yellowing of linseed oil

AbstractA number of metal complexes were examined as potential antiyellowing additives for linseed oil‐based coatings. Yellowing was measured as the rate of increase of the absorbance at 400 nm of solutions of 20% linseed oil in toluene. Most metal complexes increased the yellowing rate, but 1,1‐bis(diphenylphosphino)ferrocene retarded the rate by 50% over a wide concentration range, and some complexes caused nonlinear changes that might make them useful as additives.

Chronic Dermal Studies of Petroleum Streams in Mice

During petroleum refining, a large number of products are generated which have varying chemical and physical properties. These are known in the industry as petroleum streams. In order to characterize their carcinogenic activity, a number of these commercially produced streams were administered to C3H/HeJ mice in chronic dermal bioassays. The bioassays were conducted using one of two study designs: the first set of test materials was applied for a lifetime and the second set for 24 months. In the lifetime study, the last mice in the test groups survived for periods of 31 to 32 months. Middle distillates, boiling in the range 115–390°C, were found to decrease the lifespan of exposed mice compared to controls or streams of higher and lower boiling ranges. These middle distillate streams included straight run kerosine, hydrodesulfurized middle distillate, straight run middle distillate, light catalytic cracked distillate, and 90/10% and 70/30% mixtures of the last two. The middle distillate streams also proved to be active as carcinogens, with tumor incidence ranging from 16 to 67%. Light alkylate naphtha, heavy catalytic reformed naphtha, vacuum residuum, and unleaded gasoline did not demonstrate significant carcinogenic potency. Heavy thermal cracked naphtha, heavy catalytic cracked naphtha, and hydrotreated light naphthenic distillate were dermal carcinogens of low potency in this study. Administration of light catalytic cracked naphtha led to a low incidence of very late developing tumors with a mean latency of 118 weeks. Application of the 0.1% solution of catalytic cracked clarified oil in toluene did not result in a significant incidence of tumors, but the 10% solution caused almost 100% mortality and 100% tumor incidence in 12 months. There was no correlation between carcinogenic potency and the indices of irritation, alopecia, erythema, and scabbing. Only two of the streams tested, hydrotreated light naphthenic distillate and 10% catalytic cracked clarified oil, contain polynuclear aromatic hydrocarbons (PNAs) and may be presumed to be complete carcinogens. The middle distillates and heavy naphthas are nonmutagenic and essentially free of PNAs. Their activity may result from promotion of already-initiated skin sites. Where comparisons could be made, reducing the exposure period from a lifetime (29–32 months) to 24 months did not change the evaluations of stream carcinogenicity except in the case of light catalytic cracked naphtha where six of the seven mice that developed tumors did so after 24 months.

Chronic Dermal Studies of Petroleum Streams in Mice

During petroleum refining, a large number of products are generated which have varying chemical and physical properties. These are known in the industry as petroleum streams. In order to char acterize their carcinogenic activity, a number of these commer cially produced streams were administered to C3H/HeJ mice in chronic dermal bioassays. The bioassays were conducted using one of two study designs: the first set of test materials was applied for a lifetime and the second set for 24 months. In the lifetime study, the last mice in the test groups survived for periods of 31 to 32 months. Middle distillates, boiling in the range 115–390°C, were found to decrease the lifespan of exposed mice compared to controls or streams of higher and lower boiling ranges. These middle distillate streams included straight run kerosine, hydrodesulfurized middle distillate, straight run middle distillate, light catalytic cracked distillate, and 90/10% and 70/30% mixtures of the last two. The middle distillate streams also proved to be active as carcinogens, with tumor incidence ranging from 16 to 67%. Light alkylate naphtha, heavy catalytic reformed naphtha, vacuum residuum, and unleaded gasoline did not demonstrate significant carcinogenic potency. Heavy thermal cracked naphtha, heavy catalytic cracked naphtha, and hydrotreated light naphthenic distillate were dermal carcinogens of low potency in this study. Administration of light catalytic cracked naphtha led to a low incidence of very late developing tumors with a mean latency of 118 weeks. Application of the 0.1% solution of catalytic cracked clarified oil in toluene did not result in a significant incidence of tumors, but the 10% solution caused almost 100% mortality and 100% tumor incidence in 12 months. There was no correlation between carcinogenic potency and the indices of irritation, alopecia, erythema, and scabbing. Only two of the streams tested, hydrotreated light naphthenic distillate and 10% catalytic cracked clarified oil, contain polynuclear aromatic hydrocarbons (PNAs) and may be presumed to be complete carcinogens. The middle distillates and heavy naphthas are nomnutagenic and essentially free of PNAs. Their activity may result from promotion of already-initiated skin sites. Where comparisons could be made, reducing the exposure period from a lifetime (29–32 months) to 24 months did not change the evaluations of stream carcinogenicity except in the case of light catalytic cracked naphtha where six of the seven mice that developed tumors did so after 24 months.

Some Factors Affecting the Coating of Open Tubular Columns for Gas Chromatography

Coating of chemically modified glass open tubular columns with SF-96 silicone oil in toluene by the dynamic plug method yields a stationary phase layer whose thickness depends directly on the column radius and on the square root of the coating velocity. The dependence of efficiency and other column characteristics on coating velocity was also investigated with special reference to the behavior of the film of phase. The static coating method apparently offers few advantages over the plug procedure.