Oils structural studies

A silicone oil being studied for use in artificial limbs has a structure in which each silicon atom in the... 

The phosphino methylene phosphanes so formed occur as yellow oils with little or no tendency towards crystallization. In order to obtain suitable materials for x-ray structure studies, we converted two compounds to convenient derivatives. 

The mobilization of a trapped phase during displacement has been the subject of extensive research (ll>24-26,28-32). These papers all dealt with the concept of viscous forces overcoming capillary trapping forces. Their results can be applied to understand the behavior seen in displacement experiments performed over a range of Ca by several researchers to study residual oil structure and saturation. As Ca increased, the maximum trapped blob size decreased, until eventually singlets were mobile. 

The classical silica gel chromatographic method for determination of percent olefins in shale oils was studied and found wanting, mainly because of cross-contamination from high levels of olefins and heteroatom-containing compounds. This paper describes a new hydroboration/oxidation procedure for olefins, and reports its use in hydrocarbon-type analysis of both whole shale oils and distillate fractions. Percent composition values for three whole oils ranged as follows saturates, 13-26 olefins, 16-20 aromatics, 5-14 polar compounds, 41S2. A discussion of IR analysis for relative amounts of specific olefin types such as terminal, internal trans, and methylene structures is included. 

Low-ionization-potential mass spectral studies provide information on coal-derived liquids, which is useful in following reactions and in elucidating the effect of process variables. Structural studies are helpful in determining procedures for upgrading the liquids. A major limitation of the technique is that it is difficult to apply to the entire heavy-oil... 

Several structural studies have shown that in the oil rich part of the phase diagram, microemulsions consist of a dispersion of mono-disperse water droplets in interaction (7-8). In recent papers (9-10), we have investigated by light scattering the effect of the micellar... 

The chemical structure of the oil phase itself has a pronounced effect on the formation of an interfacial layer. Spinning drop experiments with oil phases of different chemical structure and the same water solubilities illustrated this effect. Comparison of Figures 1 and 3 shows that interfacial layers having significantly different characteristics form between the same 1 1 SLS/CA solution and different oil phases (styrene and EHA, respectively) with approximately the same water solubilities. This may be the result of different types of specific interactions between the various components of the mixed emulsifier system and either one of the two types of oils. NMR studies will be conducted in order to investigate this point. 

R161 J. Zakrzewska, Z. Zujovic and D. Vucelic, Application of NMR Spectroscopy for Structural Studies of Lignins, Humic Materials and Oil Shales , p. Pl/291... 

Below room temperature, the W(100)c(2x2) reconstructed surface is created by lateral movements of the W atoms in first W layer which propagate into at least the second layer of the surface (fig. 3). Alternate atoms move along the (Oil) direction to form zig-zag chains. A LEED structural study (Pendry et al., 1988) determines the amplitude of the lateral movements to be 0.24 0.04 A in the top W layer and 0.028 0.007 A in the second W layer. The top layer relaxes into the surface by -7.0 2.0% of the bulk interlayer spacing, the second layer spacing expands by +1.2 2.0%. These structural parameters are in reasonable agreement with a recent X-Ray diffraction (XRD) determination (Altmann et al., 1988) which finds that the amplitude of the lateral movements is 0.24 0.05 A in the top W layer and 0.10 0.05 A in the second W layer. By XRD, the top layer is found to relax into the surface by -4.0 1.0% of the bulk interlayer spacing. 

Tn studies of copper(I) coordination about 12 years ago (I), Yoke and co-workers observed that the crystalline solids copper(I) chloride and triethylammonium chloride react quickly when brought into contact to produce a light green oil. The oil is quite oxygen sensitive, and it was assumed that the compound triethylammonium dichlorocuprate(I) had been formed which was liquid because of the low lattice energy inherent to the bulky cation. Many previous preparations of polyalkylammonium chlorocuprates (2, 3, 4, 5), however, had yielded only crystalline solids. Consequently, the unusual liquid nature of the system inspired structural studies and the synthesis of comparable compounds. 

Solid-state C NMR techniques provide a powerful means by which to obtain information about the carbon structure of fossil fuel materials. Indeed, CP/MAS measurements have been applied to coals and oil shales almost from their inception around 1976. Solid-state NMR measurements are now made routinely in fossil Riel research, particularly in coal structure studies. For oil shales, solid-state NMR methods are particularly useful because the measurements can be made on raw shale, without the need to remove the mineral matter, which generally accounts for >85 wt% of the rock. However, because of the reduced emphasis in developing oil shale deposits commercially, applications of NMR in oil shale research are now not as common as in the past. Nevertheless, NMR measurements have provided valuable information about various aspects of oil shales. For example, the extent of aromatization of aliphatic carbon moieties during conversion can be obtained by combining solid- and liquid-state NMR measurements with mass balance data. Such information is difficult to obtain by other methods and provides insight into the chemical processes associated with fossil fuel conversion. 

Rojo, J.A., and E.G. Perkins, Cyclic Fatty Acid Monomer Formation in Frying Fats. 1. Determination and Structural Study, J. Am. Oil Chem. Soc. 64 414—421 (1987). 

However, even without structural studies, Friberg et al. [32], Shinoda [33], and others noted that the broad existence range with respect to the water/oil ratio could not be consistent with a micellar-only picture. Also, the rich polymorphism in general in surfactant systems made such a simplified picture unreasonable. It was natural to try to visualize microemulsions as disordered versions of the ordered liquid crystalline phases occurring under similar conditions, and the rods of hexagonal phases, the layered structure of lamellar phases, and the minimal surface structure of bicontinuous cubic phases formed a starting point. We now know that the minimal surfaces of zero or low mean curvature, as introduced in the field by Scriven [34], offer an excellent description of balanced microemulsions, i.e., microemulsions containing similar volumes of oil and water. 

Using various physicochemical techniques such as high resolution NMR, viscosity, and electrical resistivity measurements, Chan and Shah [26] proposed that the middle-phase microemulsion in three-phase systems at or near optimal salinity is a water-external microemulsion of spherical droplets of oil. Extended studies to characterize the middle-phase microemulsions by several techniques including freeze-fracture electron microscopy revealed the structure to be a water-external microemulsion [26]. The droplet size in the middle-phase microemulsion decreases with increasing salinity. A freeze-fracture electron micrograph of a middle-phase microemulsion is shown in Fig. 8. It clearly indicates that the discrete spherical structure of the oil droplets in a continuous aqueous phase is consistent with the mechanism proposed in Fig. 7. This system was extensively studied by Reed and coworkers [20-22]. 

With all these factors in mind, we have attempted to carry out the emulsions aspect of the investigations at the University of Florida Improved Oil Recovery Research Program (4,5). The emulsion systems contain TRS 10-410, isobutanol, sodium chloride, dodecane and water. Extensive physical property data and micro-structural studies of the aqueous surfactant formulations have been already reported by Vijayan et al. (6). Also, the structural aspects of the emulsions containing the same species with aqueous to oil ratio of 1 1 as well as various physical property data as a function of salt concentration have been reported by Vijayan et al. (7). A detailed study of the middle phases formed by the same surfactant formulation with dodecane oil with respect to microstructural changes and microemulsion (swollen micelle) phase inversion has been reported by Ramachandran et al. (8). 

In 1980, Lagarde et al. (08) presented the results of their EXAFS (extended x-ray absorption fine structure) study of NiCl2 solutions. Previous studies, including Raman experiments (03, 04, 012), x-ray diffraction (01, 09, Oil), neutron diffraction (07, 013, 014) and inelastic neutron scattering (02) presented conflicting reports of ion pairing behavior. Lagarde et al. were unable to conclude whether there was complex formation or not. 

Espinat, D. and J.C. Ravey Colloidal Structure of A.sphaltene Solutions and Heavy-Oil Fractions Studied by Small-Angle Neutron and X-Ray Scattering, paper SPE 25187 presented at the 1993 SPE International Symposium on Oilfield Chemistry, New Orleans, March 2-5,1993. 

The glyceride structure of okra seed oil was studied by Crossley and Hilditch (1951). They found close similarities to cottonseed oil. The... 

Structural study of surfactant-based microheterogeneous liquid systems by the example of cetyltrimethylammonium bromide microemulsions under a tame scale alterations in the water-to-oil ratio. The advantages of this approach to study the structure of microcompartmentalized systems with different phase manifestations are shown. The obtained structural information is used to analyze the microenvironment of the reacting species and the kinetic data on the basic hydrolysis of carbon acids esters in the microemulsion reaction medium. Cohen et discussed diffusion NMR in supramolecular and combinatorial chemistry. Pregosin applied H, F, and pulsed field-gradient spin echo (PGSE) diffusion NMR spectroscopy in organometallic and catalytic chemistry. 

Avramiotis, S., Stamatis, H., Kolisis, F.N., Lianos, R, Xenakis, A. 1996. Structural studies of lecithin- and AOT-based water-in-oil microemulsions, in the presence of lipase. Langmuir 12, 6320-6328. 

Mo or W sulEdes which are promoted by Co, Ni supported on alumina or silica-alumina are practically used in large amounts for hydrodesuliiirization of heavy oil. Structure, properties and catalytic function of these catalysts have been studied extensively. These reactions are not simple acid-base reactions. It has been suggested that there are two different active sites on Mo sulfide coordinatively unsaturated Mo (Lewis acid site) and Brensted acid site induced by the interaction of HjS with Mo... 

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