Oil Chain Length Research Articles

Molecular Dynamics and Chain Length of Edible Oil Using Low-Field Nuclear Magnetic Resonance

Nuclear magnetic resonance (NMR) techniques are widely used to identify pure substances and probe protein dynamics. Edible oil is a complex mixture composed of hydrocarbons, which have a wide range of molecular size distribution. In this research, low-field NMR (LF-NMR) relaxation characteristic data from various sample oils were analyzed. We also suggest a new method for predicting the size of edible oil molecules using LF-NMR relaxation time. According to the relative molecular mass, the carbon chain length and the transverse relaxation time of different sample oils, combined with oil viscosity and other factors, the relationship between carbon chain length and transverse relaxation time rate was analyzed. Various oils and fats in the mixed fluid were displayed, reflecting the composition information of different oils. We further studied the correlation between the rotation correlation time and the molecular information of oil molecules. The molecular composition of the resulting fluid determines its properties, such as viscosity and phase behavior. The results show that low-field NMR can obtain information on the composition, macromolecular aggregation and molecular dynamics of complex fluids. The measurements of grease in the free-fluid state show that the relaxation time can reflect the intrinsic properties of the fluid. It is shown that the composition characteristics and states of complex fluids can be measured using low-field nuclear magnetic resonance.

Effect of Vinyl-Terminated Silicone Oil Chain Length and Reinforcing Agent on the Properties of Silicone Rubber

To solve the problems of low strength and high viscosity of room temperature vulcanized liquid silicone rubber, a series of terminated vinyl silicone oil were designed and synthesized, and low viscosity and high strength silicone rubber were prepared by the mechanical reinforcing agent. the results show that the molecular structure of the vinyl-terminated silicone oil has a significant effect on the mechanical properties and viscosity of the silicone rubber, and the best performance is found when the content of vinyl-terminated silicone oil is 0.16%. The low viscosity and high strength silicone rubber prepared from it was reinforced by vinyl MQ resin and fumed silica, which had a significant effect on improving the performance. Its tensile strength increased to 5.03 MPa, elongation at break to 338.90%, and tear strength to 7.15 kN/m compared to conventional silicone rubber, while the hardness increased to 43°. The viscosity is 34.9 Pa•s. The compression modulus is 7.48 MPa.

Effect of Polymeric Additives on Ignition, Combustion and Flame Characteristics and Soot Deposits of Crude Oil Droplets

ABSTRACT Many oil fires have resulted from the crude oil train derailments in recent years. Given the importance of crude oil shipping by rail to the energy security of the US, it is important to consider various methods that will decrease the likelihood of crude oil catching fire in case of a crude oil derailment. Present study examines the effect of polybutadiene polymer on the combustion properties and soot deposits of Bakken crude. Treating crude oil as multicomponent liquid fuels and polybutadiene as an additive, droplet combustion experiments were conducted with sub-millimeter sized spherical droplets suspended on very fine support fibers. Polybutadiene polymer additive of two different chain lengths has been investigated. Results show that both polymer chain length and origin of crude oil have a significant effect on various combustion properties like combustion rate, ignition delay, and total combustion time. Polymeric additives also change the soot deposit structure and particle size compared to the base fuel. Present research is envisioned to aid in understanding combustion behavior of crude oil as isolated droplets, as well as to generate interest in investigating more polymeric additives for liquid fuels.

The miscible behaviors and mechanism of CO2/CH4/C3H8/N2 and crude oil in nanoslits: A molecular dynamics simulation study

Using molecular dynamics simulations, we have investigated the miscible behaviors of different gas (CO2, N2, CH4, C3H8) and different crude oils in nanoslits at 413 K and 60 MPa. In this study, the effect of gas type, the polarity and the chain length of crude oil on the miscible process of gas and crude oil is explored. The simulation results show that CO2, CH4, C3H8 and N2 are more miscible with apolar crude oil than polar crude oil due to the stronger interaction between polar crude oil and silica surface. It is worth noting that the solubility of polar crude oil in CO2 phase is higher than that in hydrocarbon gas phase and N2 phase. In addition, it is found that the chain length of crude oil could affect the dissolution of crude oil in hydrocarbon gas and N2. In contrast, it has a negligible effect on the miscibility of crude oil and CO2. The simulation results could provide valuable guidance for enhancing oil recovery in the development of deep and ultra-deep reservoirs.

Optimized formulation of thermoresponsive nanoemulsion-based gel for enhanced oil recovery (EOR) application

A thermoresponsive system of a nanoemulsion-based gel with favorable characteristics to enhanced oil recovery (EOR) application is presented. A full factorial design study with different formulations of thermosensitive nanoemulsion-based gels was performed to assess the influence of the oil chain length, concentration of polyethylene glycol (PEG 400) and concentration of oil on the rheological behavior of the system. A formulation with low viscosity at room temperature and high viscosity at the temperature of the oil extraction well was presented. Hexane (6-carbon chain), capric acid (10-carbon chain) and isopropyl myristate (17-carbon chain) were used in concentrations of 5%, 10%, 15% and 20% wt%, also varying the concentration of PEG 400 in 0%, 3%, 6% and 9% wt%. The thermosensitive polymer used was a mixture of Pluronic® F-127 and Pluronic® F-68 6:1 wt% at 4.7% concentration. The surfactants used were Tween 80 and Span 80 (HLB = 13) at 20%. The formulation containing 20% isopropyl myristate (IPM) without the addition of PEG 400 showed a better response, with an increase in viscosity of more than 38 times in relation to its viscosity at 25 °C, and the maximum viscosity was reached at 53 °C. This is a promising formulation for EOR technology.

Natural oils as coupling agents in recycled polypropylene wood flour composites: Mechanical, thermal and morphological properties

Recycled polypropylene was reinforced with treated and non-treated wood flour with different natural oils. Four natural oils were used as coupling agents, namely hexanoic (C6), octanoic (C8), decanoic (C10) and dodecanoic (C12) acids. The mechanical, thermal and morphological properties of the resulting composites were evaluated. The usage of natural oils as coupling agents clearly improved the interfacial adhesion between wood flour and the polypropylene matrix while enhancing the mechanical and thermal properties. Better results were obtained when C8 was used. The improvement in the mechanical and thermal properties of the composites imparted by C8 is similar to that promoted by maleic anhydride-grafted polypropylene. The mechanical and thermal properties of the composites were affected by the boiling temperature and chain length of the natural oil used.

Kerosene-Like Fuel Production from Coconut Oil and Cashew-Nut Oil - Effects of Fatty Acid Degree of Saturation and Chain Length

This research tested the hypothesis of whether fatty acid saturation and chain length of feedstock oil has any effect on the physico-chemical properties of synthesized kerosene-like fuel. Biodiesel was obtained from the feedstocks via transesterification and were subjected to distillation under vacuum between 50 to 100 o C to obtain kerosene-like fuel as the final product. The heat value, flash points, kinematic viscosity and specific gravity values were obtained and found to be within the stipulated range of fossil kerosene. The products were analysed using infrared spectrometer to confirm the presence of the functional groups in the kerosene-like fuel produced. Furthermore, Analysis by the elemental analyser showed that the kerosene-like fuel obtained from coconut oil has a significantly higher heat content value (9211.9 Kcal.Kg -1 ) than that from cashew-nut oil (5699.4 Kcal.Kg -1 ). This distinction in heat value can be ascribed to the nature of fatty acid in the oils as coconut oil is significantly more saturated and has shorter fatty acid hydrocarbon chain length than cashew-nut oil.

Effect of chain length of oil on location of dye within AOT nanometer-sized droplet microemulsions at constant water content

In this work, effect of chain length of oil from C-10 (n-decane) to C-5(n-pentane) as continuous phase of AOT microemulsion on the droplet size and location of hydrophilic dye of Rhodamine B (RhB) in the water/AOT/oil microemulsions was studied at the water-to-AOT molar ratio of 40 by means of dynamic light scattering (DLS) and fluorescence spectroscopy. The results of dynamical study of AOT micelles by using DLS technique showed that by increasing the chain length of oil in the AOT microemulsion, the droplet size increased and the interactions between nano-droplets were more attractive as a function of the mass fraction of nano-droplets (MFD). It was also observed that hydrophilic dye of Rhodamine B can be located in the continuous phase of microemulsion because of the surfactant-dye electrostatic interactions and the number of formed AOT-RhB ion pair complex in the continuous phase of AOT microemulsion increased as the chain length of oil decreased.

Effects of water content and oil on physicochemical and microenvironmental properties of mixed surfactant microemulsions

In this report, phase behavior, conductivity, viscosity, dynamic light scattering, fluorescence lifetime, steady state fluorescence anisotropy and Fourier transform infrared spectroscopy (FTIR) techniques were employed for understanding of the physicochemical properties and microenvironment of water-in-oil microemulsion comprising equimolar (1:1) cetyltrimethylammonium bromide (C16TAB) and polyoxyethylene (20) cetyl ether (C16E20)/1-butanol/heptane or decane, with varying water content (ω) at 303K. Both conductivity and viscosity of these systems were increased with increase in ω in both oils. Droplet size was also increased with increase in ω and corroborated well with the conductance and viscosity measurements, and depends on oil chain length. The physicochemical changes in the microenvironment with increase in ω were presented by measuring the changes in decay time using a fluoroprobe (7-hydroxycoumarin). The effect of hydration on the microstructure of these systems was studied by polarized fluorescence measurements. FTIR measurements reveal three states of water molecules, viz. trapped, bound and bulk water, in water pool of these systems. Further, the interfacial composition and free energy of transfer of 1-butanol from oil to the interface were evaluated by the dilution method. Changes in interfacial composition as a function of ω corroborate well with FTIR results indicating bound and bulk water.

Glycerin Revalorization Using Anaerobic Digestion of Organic Waste

A novel process for the revalorization of glycerine from biodiesel production is proposed. Glycerol is converted to short chain oils by reaction with volatile fatty acids. The volatile fatty acids can be obtained from anaerobic digestion of organic waste streams. It is shown that there is a minimum viscosity according to the oil chain length. Therefore the obtained short chain oils present viscosity values that make them useful as biodiesel additives increasing its lubricant properties. Listing some experimental results from literature, the process requirements are determined providing a maximum reaction rate to the desired volatile fatty acids, i.e. high substrate content and low acid content. A novel process satisfying these requirements with a low energy demand is provided. A frying potatoes factory is used as illustrative example.

Water solubilization capacity, interfacial compositions and thermodynamic parameters of anionic and cationic microemulsions

The water solubilization capacity of a particular microemulsion depends upon the partitioning of cosurfactants among water, oil and interfaces, chain length and nature of oil and cosurfactant, and their interaction with surfactant. Maximal water solubilization of microemulsion systems has been investigated by titration method. The interfacial compositions and associated thermodynamic parameters of the formation of microemulsion droplets have been studied by dilution method. The Bansal, Shah, O’Connell (BSO) equation has been verified by determination of solubilization capacity of microemulsion. Among the alkanes (C6–C18) employed in this work, maximal water solubilization for sodium dodecyl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB) microemulsion systems with cosurfactant (pentan-1-ol, and 3-methyl-1-butanol) have been found in case of heptane and undecane respectively. A correlation between the change in free energy of cosurfactant transfer at the interface and the alkane carbon number was examined. With increase in oil chain length, the negative value of the change in Gibbs free energy of cosurfactant transfer decreases.

Comparison of the effects of the lubricant-molecule chain length and the viscosity on the friction and wear of diamond-like-carbon coatings and steel

For steel contacts it is usual for the longer molecular chain lengths of saturated linear hydrocarbons and their acids and alcohols to reduce the coefficient of friction in the boundary-lubrication regime. However, the effect of these lubricant properties on DLC contacts is still unknown. Since the boundary-lubrication mechanisms between DLC coatings and conventional additives do not appear to be as effective as with metals, other potential mechanisms, even though based on weaker interactions or the oil's physical and rheological properties, may thus be very relevant. In this study we focus on the influence of the base oil's chain length and viscosity on the friction and wear in DLC/DLC contacts, and we compare this behaviour with conventional steel/steel contacts, using several simple linear hydrocarbons, i.e., alkanes, and complex branched hydrocarbons, i.e., polyalphaolefins. The results show that in both the steel/steel and DLC/DLC contacts the wear decreases with a longer molecular chain length and a higher viscosity of the oil. However, in DLC/DLC contacts the coefficient of friction increases when oil with a longer molecular chain length or a higher viscosity is used, and decreases with the lower oil viscosity and shorter chain lengths, which is just the opposite to conventional steel/steel behaviour. These results are analysed and discussed in view of lubricant cohesive energy, surface tension, shear strength, viscosity and chain length.

Growth Control of Nonionic Reverse Micelles by Surfactant and Solvent Molecular Architecture and Water Addition

This paper describes a facile route to the shape, size, and structure control of reversed micelles by surfactant and solvent molecular architecture and water addition. Nonionic reverse micellar size is found to increase with increase in hydrophilic headgroup size of surfactant, whose scheme is understood in terms of decrease in the critical packing parameter (cpp). On the other hand, an opposite trend is observed with increase in lipophilicity of the surfactant. This is caused by the repulsive excluded volume interactions, which increases with the volume of lipophilic moiety of surfactant; as a result, the micelle interface tends to become more curved and micelles shrink. Solvent molecular structure has played a crucial role; increasing hydrocarbon chain length of alkanes favored one dimensional micellar growth. We note that long chain oil has a poor penetration tendency to lipophilic tail of surfactant and decreases the cpp. Solvent polarity is also crucial; globular micelles are formed in short chain oil cyclohexane. We note that decreasing chain length of oil mimic the decrease in the headgroup size of surfactant; rod-to-sphere type transition in the micellar structure. Addition of trace water favors micellar growth; maximum dimension and micellar cross section increases with increase in water concentration. The sizes of the water incorporated reverse micelles (or w/o microemulsion) are much bigger than the empty micelles. Micellar structure was confirmed by small angle X-ray scattering (SAXS) and supported by rheology.

Reverse micelle microstructural transformations induced by oil and water

Effects of alkyl chain length of oil and water on the shape, size, and internal structure of glycerol monooleate (GMO) reverse micelle have been investigated using small-angle X-ray scattering (SAXS) and rheometry techniques. The generalized indirect Fourier transformation (GIFT) method has been employed to analyze the SAXS data, also supported by the direct modeling. It has been found that under ambient conditions the GMO spontaneously self-structure into an ellipsoidal prolate type micelle with a maximum size of ca. 5.7 nm in n-hexane and the size increases in parallel to the chain length of oil reaching a size of ca. 10.7 nm in n-hexadecane. However, the micellar core radius remains essentially the same, i.e., the growth is one dimensional. The increasing tendency of zero-shear viscosity, η0, with the chain length of oil further confirmed the micellar growth. The relative viscosity, ηr, of the reverse micelles was higher and exhibited a steeper solvent (chain length) dependence behavior than those predicted for a dispersion of spherical particles based on the Krieger–Dougherty relation sustaining the SAXS results. The micelles swell with water causing a significant micellar growth; the maximum size and core radius of 0.3% water incorporated reverse micelles were found to be respectively 53%, and 28% larger than the empty micelles.

Partition coefficients of nonionic surfactants in water/ n-alkane systems

In water/oil systems, surfactants partition between the water phase and the oil phase according to their solubility in both phases. The ratio between the concentration of the surfactant in the oil phase and in the water phase at equilibrium is known as the partition or distribution coefficient ( K p). The partition coefficient ( K p) is an important fundamental parameter essential to understanding and controlling phenomena in water–oil-surfactant systems under both equilibrium and non-equilibrium conditions. In the present work we report on the partitioning of three different classes of nonionic surfactants in the pre-cmc regime, namely polyoxyethylene alkyl ethers (C i E j ), alkyl dimethyl phosphine oxides (C n DMPO) and alkyl glycosides (β-C n G m ) between water and different n-alkanes. We focus on the influence of the surfactant’s molecular structure (alkyl chain length, head group size and type), and oil chain length on K p to derive systematic structure–property relationships. Moreover, we discuss the influence of the surfactant purity on partition coefficients of technical grade alkyl glycosides and polyoxyethylene alkyl ethers, respectively.

α-Chymotrypsin catalyzed hydrolysis of p-nitrophenyl acetate in cationic microemulsions

The catalytic activity of α-chymotrypsin (α-CT) for the hydrolysis of p-nitrophenyl acetate has been studied in oil-in-water microemulsions formed by cetyltrimethylammonium bromide, n-butanol and alkanes (organic solvents). The specificity of α-chymotrypsin regarding the chain length of the organic solvent ( n-hexane, n-heptane and isooctane) in CTAB/ n-butanol microemulsions was tested in hydrolytic reactions of PNPA. The stability and activity of α-CT depend upon organic solvents. Under all the conditions employed, the reaction follows a Michaelis–Menten mechanism. The second order rate constant, k 2 was determined for α-CT catalyzed hydrolysis of p-nitrophenyl acetate at 27 °C. The chain length of oil influences the k cat and K M. The CTAB/ n-butanol/isooctane ( z = 1.07) system of o/w microemulsion shows the higher activity and stability of α-CT.

Solubilization, microstructure, and thermodynamics of fully dilutable U-type Brij microemulsion

A U-type microemulsion of Brij 96 has been characterized with respect to the change in cosurfactant, oil chain length on dilution, water solubility, and water solubilization capacity. The phase behavior of the systems has been mapped with different oils. Several techniques, viz., conductivity, optical microscopy, dilution method, absorption, and FT-IR spectroscopy, have been used for microemulsion analysis. The equilibrium within the microemulsion droplets and liquid crystals has been visualized using optical microscopy. The microemulsions have evidenced volume-induced conductance percolation in all the cosurfactants ( n 2– n 6 alcohols). The energetics of transfer of alcohol from the bulk oil to the interface has been determined through dilution method. To gain insight into the microenvironment of microemulsion, two optical probes, hydrophilic (Methyl orange) and hydrophobic (Nile red), have been utilized in absorption spectroscopy. Lastly, FT-IR has been explored to observe the state and dissolution behavior of water with increasing weight fraction.

On the Possible Role of Surface Elasticity in Emulsion Stability

We have measured the short-time and long-time elastic responses to compression of various types of surfactant layers adsorbed at oil-water interfaces. We prepared reasonably monodisperse oil-in-water emulsions with the same surfactants and monitored the time evolution of the emulsion droplets' diameter. We used a broad variety of surfactants (cationic, nonionic, and small polymers) and alkanes with different chain lengths. The emulsion drop size evolution is first controlled by Ostwald ripening and later on by drop coalescence, the later step being quite short. The overall emulsion lifetime is therefore dominated by ripening and for a given oil appears well correlated with the low-frequency surface elasticity as expected (and not with the high-frequency one, which is expected to control coalescence). When the oil chain length is changed, the stability is related more to the oil solubility in water, which also controls ripening. The overall results demonstrate the great importance of surface elasticity in emulsion stability.

Tunable Parameters for the Structural Control of Reverse Micelles in Glycerol Monoisostearate/Oil Systems: A SAXS Study

Formation of reverse micelles in surfactant/oil binary systems without water addition and the tunable parameters for the structure control of such micelles are presented. The small-angle X-ray scattering (SAXS) technique has been used for the structural characterization of micelles. It has been found that the nonionic surfactant glycerol monoisostearate (abbreviated as iso-C18G1) forms reverse micelles in different organic solvents such as cyclohexane, n-decane, and n-hexadecane without the addition of water. The structure (shape and size) of the reverse micelles has been found to depend on the solvent nature (alkyl chain length of oil), composition, temperature, and added water. Phase behavior study has shown that iso-C18G1 forms isotropic single-phase solutions in the aforementioned oils at 25 degrees C. At lower temperatures (<20 degrees C) II phases (dispersion of solid or liquid crystal phase) has been observed. SAXS data were evaluated by the generalized indirect Fourier transformation (GIFT) method, which has drawn a clear picture on the structural variations of the reverse micellar aggregates. Small globular types of micelles are found in the iso-C18G1/cyclohexane system. On the other hand, elongated ellipsoidal prolatelike or rodlike micelles are found in iso-C18G1/decane or iso-C18G1/hexadecane systems. The underlying mechanism of this structural evolution may be explained in terms of the transfer free energy of hydrophilic glycerol moiety from hydrophilic to hydrophobic environment of oils with different chain lengths. Besides, the penetration of oils to the lipophilic chain of the surfactant in reverse micellar systems differs depending on the chain length of oils. Lowering temperature and increasing surfactant concentration similarly lead to micellar growth while the cross-section structure remains essentially unchanged. Addition of trace water induced micellar growth, which is accompanied by the rapid swelling of the micellar core. The results obtained by this study demonstrate that the solvent nature, temperature, composition, and water addition can be the tunable parameters for the size, shape, and internal structure control of the iso-C18G1-based reverse micelles.

Study of Winsor I to Winsor II Transitions in a Lattice Model

Experiments show that with increasing temperature, microemulsion systems undergo Winsor transitions. The transitions occur from Winsor I (oil droplets in water media) to Winsor II (water droplets in oil media) via Winsor III (bicontinuous phase) with an increase in the temperature. In this paper, it has been shown, for the first time, how one can study the qualitative effects of temperature, head, tail, and oil chain lengths, on these transitions. Simple cubic lattice with excluded volume and periodic boundary conditions is used to mimic the box of the simulation as a bulk of solution. The simulations have been done using the standard traditional Metropolis algorithm in the canonical ensemble (N, V, T). Configurational bias Monte Carlo and reptation moves are used with an equal probability to relax the systems. A very simple interaction model, i.e., the repulsions of water (or heads of surfactants) with oil (or tails of surfactants), is used due to the main characteristic of oil-water mixtures or amphiphilic molecule that is the hydrophobicity. The interfacial tension between oil and water (gammaow) is related to the averaged total energy of the lattice. The model shows that the Winsor III has a minimum interfacial tension (gammaow) similar to experimental results. Changing the phase structure from Winsor III to Winsor I (or Winsor II), increases the interfacial tension which is in agreement with experiments. To relate interfacial tension with the interaction parameter, the simple theory of Bragg-Williams has been used. All of the results such as the effects of oil chain length, head and tail beads number are all similar to the experimental results. Using the Davies method for calculating hydrophilic-lypophilic Balance (HLB), similar to the experimental results, Winsor III phase is formed at HLB value nearly to 10.