Synthetic Base Oils Research Articles

Effect of ionic liquid on dispersion stability and antiwear behavior of CuO nanoparticles added to polyalphaolefin base oil

The experimental study assessed the impact of choline chloride cation-based ionic liquid (IL), on the dispersion stability and wear characteristics of copper (II) oxide (CuO) nanoparticles (NPs) in synthetic base oil (PAO 10). CuO NPs, averaging 50 nm in size, underwent surface modification using varying concentrations of the IL (0.25%, 0.5%, 0.75%, and 1% by weight). The formulations were subjected to sliding wear tests to evaluate their wear behavior. Analysis of the worn surfaces utilized scanning electron microscopy, energy-dispersive x-ray spectroscopy, and atomic force microscopy. The results indicated that the combination of 0.75% IL and 1% CuO NPs provided optimal dispersion and exhibited effective surface mending, enhancing wear protection by 21.1% than that of PAO 10. The formulation containing 1% IL and 1% CuO NPs demonstrated the highest load carrying capacity among all tested compositions. In terms of wear behavior, the nanolubricant formulations with 0.75% and 1% IL outperformed the lubricant formulation containing 1 wt% of the commercial antiwear additive Zinc dialkyldithiophosphates (ZDDP).

Supported Ni-W Bimetallic Catalysts for Hydrogenation of Poly-Alpha-Olefins Synthetic Base Oil

Supported Ni-W Bimetallic Catalysts for Hydrogenation of Poly-Alpha-Olefins Synthetic Base Oil

Tribological behavior of DLC film models in base oils: Analysis of influence of sp3/sp2 ratio and hydrogen content

DLC coatings have been proven in formulated oils used in the automotive industry. The development of electric cars and its consequences on the future of the internal combustion engine makes it increasingly necessary that these coatings take their place in other applications where lubrication is generally of lower quality such as for example strips cold rolling where DLC shows significant potential both for production and finishing cold rolling. As a result, the interest of the behavior of these coatings in base oils takes on a new dimension. In this study, we explore the influence of the composition and the sp3/sp2 ratio on tribological behavior of DLC coatings in mineral and synthetic base oils. Hydrogenated DLC films deposited by conventional PECVD with various levels of hydrogen measured by Elastic Recoil Detection Analysis (ERDA) and non-hydrogenated DLC films deposited by PLD in the nanosecond mode (ns-PLD) and by cathodic arc evaporation, thus allowing to have different sp3/sp2 ratios confirmed by Multiwavelength Raman spectrometry, are tested and compared. The tests are performed on a ball-on-flat device with coated balls to better evaluate wear level. The behavior of highly hydrogenated DLC is of particular interest; with a very high level of durability in both base oils and friction level which comparatively varies between low and very low depending on the base oil.

Synthesis and biodegradation testing of some synthetic oils based on ester

Synthetic ester oils are widely used in many applications due to their ideal cleaning properties, lubricating performance and assured polarity. The majority of esters oils are more biodegradable. than any other base stock. For instance, oil soluble polyalkyleneglycols (PAGs) or polyalphaolephins (PAOs), are only biodegradable in the lower viscosity grades. The goal of this study is to create some synthetic base oils by two major protocols; the first is esterifying valeric acid with various glycols (ethylene glycol, propylene glycol, butylene glycol and poly (ethylene glycol 400). The second involves esterification of propanoic acid, heptanoic acid, or octanoic acid with ethylene glycol. The reaction yield varies between 85 and 94%. The chemical composition of the prepared esters was examined using various spectroscopic methods (Fourier-transform infrared (FT-IR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The thermal properties investigation by thermo gravimetric analysis (TGA) showed pronounced thermal stability of the prepared esters. The biodegradability was verified versus two bacterial isolates (B1, B2). The results showed that percentage of degradation of the lube oil was in the range of 34% to 84% after 3 days of incubation. Moreover, the rheological study revealed that the prepared esters exhibited Newtonian rheological behaviours. Viscosity examination displayed that the esters based on ethylene glycol, such as (A), had the highest VI: 179 values when compared to those based on higher glycols. Viscosity and viscosity index results showed slight increase as the number of carbon atoms in the acid chain increases. At last, most of the synthesized esters possessed pour points ≤ − 32 °C: ≤ − 40 except in case of using higher acids like heptanoic acid and octanoic acid in preparation the pour point increases to − 9 °C and − 15 °C.

The influence of various grease compositions and silver nanoparticle additives on electrically induced rolling-element bearing damage

Leakage currents accelerate surface degradation of metal contacts via small scale arcing across lubricating films, but recent observations suggest that metallic nanoparticle additives in lubricants may be useful to improve contact performance. These findings prompted a study that examined electrically induced surface pitting of steel contacts in the presence of several lubricating greases including some containing nanometer-sized colloidal silver (Ag) particles. Reciprocating rolling sphere-on-disk experiments were conducted under electro-tribological loads employing polyurea greases derived from mineral and synthetic base oils with and without additives. Friction forces and electrical resistance were monitored continuously during the tests; surface changes were characterized by means of optical spectroscopy, stylus profilometry, and scanning electron microscopy (SEM) including compositional analysis using energy dispersive spectroscopy (EDS). The observations demonstrate that surface pitting induced by arcing occurs mainly at the points were the rolling motion changes direction and that eroded metal is deposited along the wear grove. Micron-sized pits are formed which contain carbon and oxygen indicating that arcing causes decomposition of the hydrocarbon lubricants. Numerous findings indicate a significant inhibition of pitting is induced by the Ag nanoparticles; some greases containing other additives exhibit a similar, although less pronounced, effect.

Техніко-економічні передумови доцільності створення в Україні виробництва синтетичного моторного палива

The article formulates the main scenarios for organizing the supply of motor fuel to Ukraine. It is shown that a significant reduction in imports of motor fuel in the post-war period is possible only through the restoration and development of oil production and refining with the simultaneous search for options for organizing the production of synthetic motor fuel from non-oil raw materials. The article compares the technical characteristics of a full-cycle oil refinery and a plant producing synthetic motor fuels from coal. It is shown that in the USA and Western Europe, the depth of oil refining is 90-95 %. In Ukraine, these figures were much lower - only 72.1 %. In addition, the European Union's environmental standards governing the content of harmful substances in exhaust gases from cars and specialized machinery are becoming stricter, which should stimulate the development of oil refining and transport engineering technologies. When synthetic motor fuels are produced, the degree of carbon conversion of the original fossil coal into the target light products is 56.0 %, which is objectively less than the depth of oil refining. Under such conditions, the main advantages of obtaining synthetic motor fuels from coal compared to oil refining for the conditions of our country are: reduction of import dependence of the country's economy; sulphur content in the products obtained meets the requirements of modern European standards; the depth of processing of synthetic products reaches 90 % and more with the use of relatively simple equipment; favorable technological properties of synthetic oil determine its price on the world market by about 30 % higher than the best light oil ‘brent’; the obtaining of a by-products of increased demand (light hydrocarbons, thermal and electrical energy); the possibility of obtaining synthetic base oils. Keywords: fossil coal, motor fuel, synthetic fuel, oil refining, refining depth, Nelson index. Corresponding author: I.V. Shulga, e-mail: ko@ukhin.org.ua

Controlled Radical Polymerization of Lauryl Methacrylate in the Synthetic Polyalphaolefin Base Oil

Controlled Radical Polymerization of Lauryl Methacrylate in the Synthetic Polyalphaolefin Base Oil

Synthesis and characterization of polyvalent high-performance synthetic base oil for drilling operations in recalcitrant and unconventional oil and gas reservoirs

Synthetic ester fluid is one of the most widely recommended drilling fluids for unconventional and recalcitrant reservoirs owing to its numerous technical advantages, high sustainability, non-toxic and inherently biodegradable. However, there are serious concerns about its thermal and hydrolytic stability at high temperatures and pressures (HTHP) as well as its viscosity and flow characteristics in low temperature climates such as deep-water wells. Hence, its inability to maintain stable borehole and flat rheology characteristics may invariably threaten its application under these aforementioned scenarios.In this study, a high-performance ternary mixture of synthetic ethyl esters of plants oil (SEEP mixture) fluid was synthesized by a non-catalyzed supercritical ethanol transesterification process using coconut, castor seed and linseed oil as starting materials. The nature, chemistry and fluid particle interactions of the individual components that make up the synthetic ester fluid were critically studied. The process equipment consists of a continuous flow reactor equipped with a PID controlled furnace as heat source to the reactor and a high- pressure transducer. The conversion efficiency was monitored by an Agilent 5500a FTIR machine with attenuated total reflectance (ATR) system while a GC-EIMSD system was used for fatty acid ester compositional analysis. The oil was extracted by a Soxhlet apparatus mechanism. The extracted Plant oil and the synthetic esters were characterized under standard recommended laboratory procedures by API, ASTM and the European Union (EN) standard protocols. Also, fluid's toxicity and biodegradability tests were conducted according to OECD recommended practices. The results were compared with existing synthetic hydrocarbon fluids (SHFs) for HTHP and deep-water wells.The conversion efficiency of the non-catalyzed transesterification process was 96.50%. The amount of oil yield from the plant oil after Soxhlet extraction is commendable. Hence, synthetic ester fluid raw materials are readily available in large quantities and in a sustainable manner. The GC-MS analysis shows that the coconut oil contains 92% saturated fatty acid. Whereas, the castor seed oil contains 98.31% unsaturated fatty acid with 89.75% of mono-unsaturated ricin-oleic acid (D-12-hydroxyoctadec-cis-9-enoic acid). The linseed oil has high content of linolenic acid with 89.60% unsaturated fatty acid. The designed fluid has excellent lubricity characteristics, extremely low cloud and pour point temperatures, higher oxidative stability, low peroxide value, lower copper strip corrosion value and lower kinematic viscosity and density variations with temperatures which signals flat rheology when used to form a synthetic based mud. Also, its flash point and auto-ignition temperatures are high and thus forestall possible fire hazard in high temperature zones. Finally, the fluid is non-toxic and inherently biodegradable.

The Effect of an Electric Field on the Sliding Friction of the Silicone Rubber against Selected Metals in Motor Base Oils

The effects of applying external electric fields on the coefficient of friction of a selected elastomer during mechanical interaction with steel and copper surface oil (counter samples) immersed in a pin-on-disc setup were studied and investigated. The synthetic base oils used were PAG 68 and PAO 6. The elastomer selected for the study is commonly used in the manufacture of rotary lip seals. During the investigations, the viscosity of the oils tested was also experimentally determined in the temperature range of between 286 K and 393 K. It was found that the external electric field had a significant effect on the friction coefficient, depending on the type of base oil, the angular velocity of the load force, and the counterpart. It was observed that for both oils tested, the coefficient of friction values decreased by about 30% when an external DC electric field was applied. In addition, a simple numerical model of the friction interface was proposed and studied. The experimental results were complemented by molecular simulations to determine the interaction between the lubricant molecule and the metal surface. Furthermore, molecular models of the metal surface and lubricant molecules were simulated using ReaxFF and COMPASS force fields to determine adsorption energies.

Synthesis and characterization of synthetic lubricants based on dibasic acid

AbstractSynthetic esters have long been used in a variety of applications due to their excellent thermal stability, excellent cleanliness, natural lubricity, and polarity. In the present work, we aimed to prepare some synthetic base oils through preparation of different dibasic esters by esterification of dicarboxylic acids (adipic acid and azelaic acid) with different linear alcohols (hexanol, octanol, and decanol) and branched alcohol (2‐ethyl hexanol) at 120°C. The reaction yield ranges between 85% and 94%. Fourier‐transform infrared spectroscopy (FT‐IR) and proton nuclear magnetic resonance (1H‐NMR) spectroscopy were used to analyze the structures of the produced compounds. Using thermo gravimetric analysis (TGA), the heat stability of the produced esters was determined, and it was found that the prepared esters have high thermal stability. The degradation of the prepared esters takes place in the range between 300 and 600°C. The rheological behaviour of prepared esters shows Newtonian behaviours, which means that Newtonian fluids obey viscosity Newton's law. The viscosity is independent of the shear rate. The results showed that the lubricity properties, based on their pour point, flash point, and oxidation stability of the esters, were significantly affected by the linear and branched alcohols used. There is a slight increase in kinematic viscosity and viscosity index values with decreasing the internal chain length of the dibasic acid. The esters which were based on adipic acid such as C1 exhibited maximum values of VI: 187 compared to those which were based on azelaic acid such as F1 with VI: 182. Viscosity and viscosity index increases with increasing the number of carbon atoms of the used mono‐ol alcohols. Using branched alcohols gave almost the same viscosity results compared to using linear alcohol with the same number of carbons. Almost all prepared esters give pour point results ≤ −30°C.

High-Pressure Thermophysical Properties of Eight Paraffinic, Naphthenic, Polyalphaolefin and Ester Base Oils

In this work, the thermophysical properties of four mineral (paraffinic and naphthenic) and four synthetic (polyalphaolefin and ester) base oils are measured. Knowledge of these properties is of vital importance for the correct and optimal formulation and design of lubricants, and for the development of equations of state and transport models that adequately represent their properties. Density, isothermal compressibility, thermal expansion coefficient, dynamic viscosity, pressure–viscosity coefficient, and contact angle were determined. To carry out this work, a pρT apparatus, a rotational viscometer, a falling body viscometer, and a contact angle analyzer were used. Highest densities were found for the polyalphaolefin and ester synthetic oils, increasing around 5% from 0.1 to 100 MPa for all the base oils. The density of the synthetic oils is less dependent on temperature changes. For the expansivity and compressibility of all the base oils, decreases with pressure of up to 35% and 45% were observed. From the contact angle measurements, it was observed that base oils with a higher viscosity grade have a worse wetting. The greatest effect of pressure on the dynamic viscosity was obtained for the naphthenic mineral oil and the lowest effect for the polyalphaolefin oil. Paraffinic and naphthenic oils present the highest universal pressure–viscosity coefficients.

Impact of Fatty Triamine on Friction Reduction Performance of MoDTC Lubrication Additive

The impact of a fatty triamine (Triameen YT) additive was investigated on the friction performance and stability of molybdenum dithiocarbamate (MoDTC) in the formulations containing polyalphaolefin synthetic base oil (PAO) and zinc dialkyldithiophosphate (ZDDP). Triamine has no significant effect when mixed with MoDTC and ZDDP, but it improves the performance of MoDTC alone. However, in the MoDTC—Triamine—PAO solutions, a chemical reaction easily occurred and a reddish precipitate was formed upon storage. According to IR, XPS, TEM, and XAS characterizations, this precipitate is poorly crystalline layered alkylammonium oxothiomolybdate. Formation of the precipitate impaired the tribological performance by decreasing the number of active species delivered at the sliding contact interface. However, low friction coefficients were recovered by redispersion of the precipitate in PAO.

Characterization of Mineral and Synthetic Base Oils by Gas Chromatography–Mass Spectrometry and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Base oil is a main component of engine oil that enables smooth operation of an internal combustion engine. There are two types of base oils, such as mineral oil and synthetic oil. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography-mass spectrometry (GC-MS) were used to characterize the base oils. One difficulty in analyzing base oils using MS is that the ionization of alkanes can be problematic due to low ionization efficiencies and the predominance of fragmentation. Despite these limitations, the combination of GC-MS and FT-ICR MS data can provide qualitative insights into the composition differences for these various sample types. The distinctive total ion chromatogram obtained by GC-MS of the different base oils allowed the classification of mineral oil from synthetic oil. The additional structural characteristics of paraffinic compounds were also inferred by GC-MS. FT-ICR MS coupled to two different ionization methods, atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI), was tested for the analysis of base oils. It was determined that APPI was suitable for the analysis of aliphatic hydrocarbon compounds, where APPI minimizes the decomposition of hydrocarbon compounds compared to atmospheric pressure chemical ionization. Using APPI FT-ICR MS, the components of the oils were characterized, including not only paraffinic compounds but also cyclic compounds. In addition, the alpha olefin monomer of the synthetic oil was determined, and the homogeneity of the branched compound of the synthetic base oil was confirmed using GC-MS and FT-ICR MS results.

Growth and morphology of thermally assisted sinterable zirconia nanoparticle tribofilm

Tribofilm formation mechanisms of a novel zirconia (ZrO2) nanoparticle antiwear additive were investigated. Spherical ZrO2 nanoparticles 5 nm in diameter with organic capping ligands were dispersed in a polyalphaolefin (PAO) synthetic base oil and tested between AISI 52100 steel counterfaces in a ball-on-disk tribometer under boundary lubrication contact conditions. Film formation was studied as a function of temperature, using PAO blends to maintain constant viscosity across the different temperatures. A temperature dependence was found, with higher temperatures assisting initial tribofilm growth and maintaining the steady-state tribofilm thickness. Findings are consistent with previous reports indicating the primary mechanism of tribofilm growth for zirconium oxide is nanoparticle capture at the sliding interface followed by particle accumulation and sintering.

A new experimental methodology to assess gear scuffing initiation

ABSTRACT This paper investigates the strong coupling between friction power losses and film thickness that prevent from clearly identifying the mechanism of scuffing through classical test procedures. As the film thickness appears of great influence on the phenomena, a new test method is presented, allowing scuffing initiation study with the film thickness as a key parameter. This new test method allows film thickness variation with minimal friction losses and bulk temperature variations. This procedure has been developed with nitrided steels and a synthetic base oil on a twin disks test rig. Even though asperity contact is considered necessary in literature for scuffing, the test result shows that it can be reached in full film lubrication, potentially through the collapse of the oil film. Different test methods allowing triggering scuffing through different parameters are identified, which shows that a variety of parameters is able to influence scuffing.

Boehmite nanoparticles for potential enhancement of tribological performance of lubricants

A set of nanolubricants was prepared by varying concentrations of Boehmite nanoparticles (0.25,0.5,0.75,1 wt%) in synthetic base oil (PAO-6) with a fixed concentration of dispersant (PIBSA). This is the first study exploring Boehmite mineral for its antiwear and extreme pressure performance. Nanolubricants showed excellent colloidal stability for over 30 days without any sedimentation and improved viscosity index by 4.35% at 1 wt% concentration. Four ball tribometer was used for exploring the tribological performance of Boehmite nanolubricants. A significant 24% wear reduction over base oil was observed for optimum NPs concentration of 0.5 wt% beyond that performance deteriorated. On the other hand, increased NPs concentration enhanced load-bearing capacity for EP test and the highest enhancement of 40% was observed for 0.75 and 1 wt% concentrations. Based on surface characterization techniques, we confirm dehydration of Boehmite NPs into Aluminium oxide (Al2O3) under tribostress. We further confirm regenerative, sacrificial protective tribofilm composed of tribosintered Al2O3 along with oxide film on the rubbing surfaces.

Frictional Properties of Element- and Compound-Doped Diamond-Like Carbon Films under Boundary Lubrication with Synthetic Base Oil

The frictional properties of diamond-like carbon (DLC) films under boundary lubrication with a synthetic base oil were investigated. The specimens tested were a-C:H, Cr-a-C:H, Ti-a-C:H, W-a-C:H, WC-a-C:H, Mo-a-C:H, MoS2-a-C:H, and Sn-a-C:H films. The tribological properties of DLC/steel contacts were evaluated using a reciprocating-type cylinder-on-disk tribotester. The DLC films exhibited different frictional properties depending on the type of doping elements and compounds used. Notably, the Sn-a-C film gave the lowest friction. The friction tests and static contact angle analyses revealed that the average friction coefficient decreased with a decrease in the static contact angle of the worn DLC film surface, demonstrating that the DLC films with relatively high surface wettabilities exhibited relatively low friction properties. Therefore, surface wettability plays an important role in determining the frictional properties of DLC films under boundary lubrication with synthetic base oil..

Synthesis of T-Type low-viscosity hydrocarbon bio-lubricant from fatty acid methyl esters and coconut oil

Biomass-derived long-chain alkanes with highly symmetrical branches, which show comparable properties to traditional petrochemical-based poly-α-olefin (PAO), have great potential economic value for industrial application. In this work, we developed a new strategy to prepare T-type low-viscosity bio-lubricant base oil using inexpensive lipid-derived fatty acid methyl esters (FAMEs) as raw materials with a total carbon yield of around 67.3%. The fatty acid methyl ester compounds (R1-COOCH3) were converted to fatty alcohols using methanol as the solvent and hydrogen donor over the Cu/SiO2 catalyst. Subsequently, fatty alcohol was further brominated to the Bromo-Grignard reagents (R1-CH2-MgBr). In the next step, a T-type synthetic bio-lubricant base oil (R1-C(R2)-R1) was formed by the hydrodeoxygenation of symmetrical tertiary alcohol precursors over Pd/C, where symmetrical tertiary alcohol precursors were obtained via the nucleophilic addition of Bromo-Grignard reagents with fatty acid methyl ester (R2-COOCH3). The specific properties of the branched representative bio-lubricant C32 (12'10'10') are comparable to those of the commercial lubricant PAO 3.6. This strategy offered a new promising route for synthesizing high-quality bio-lubricant base oil.

Three-way compatibility study among Nanoparticles, Ionic Liquid, and Dispersant for potential in lubricant formulation

Lubricants are indispensable for human civilization and may consist of over half a dozen of performance additives. The overall performances of lubricants depend on the compatibility among these additives. This study explores the interesting three-way interaction among phosphonium phosphate ionic liquid, oxide nanoparticles (ZnO), and a commercial dispersant PIBSA in synthetic base oil under boundary lubrication. Generally, to enhance the colloidal stability of various non-soluble additives dispersants are used in lubricant formulation. We observed no precipitation or cloudy phase while mixing dispersant PIBSA with any of the additives, inferring no chemical reaction between these additives. Contrary to an earlier study the dispersant PIBSA was able to coexist with aprotic ILs and did not hamper the synergistic interaction between ionic liquid and nanoparticles which showed 50% wear reduction. Surface characterization techniques confirm regenerative sacrificial protective film formation on the rubbing surfaces composed of tribosintered nanoparticles and phosphate compounds (due to disintegration and chemical reaction of IL). This study gives a fundamental understanding of the interaction among ionic liquid, nanoparticles, and dispersants which may help formulate future lubricants.

Development of a combustion reaction model for lubricant synthetic base oil by experimental and numerical methods

The synthetic base oil (SyBO) is the main component of lubricant oil, determining its basic physical and chemical properties, as well as impacting the pre-ignition, in-cylinder combustion and emission characteristics during the engine applications. Yet the involvement of SyBO in the engine combustion process is rarely investigated, primarily due to the lack of a proper combustion reaction model. The objective of the present study was to develop a fundamentally based combustion reaction model for SyBO, through the joint experimental and theoretical methods. A comprehensive set of experimental techniques was used to characterize the physicochemical properties of SyBO. Results showed that SyBO consisted of 13 large hydrocarbon molecules, ranging from C21 to C54, with mostly linear or lightly branched alkanes. A kinetic modeling approach was developed to systematically construct the reaction model for each component, which were then combined to create the full-component reaction model of SyBO. The accuracy of the thus-developed combustion reaction model was verified by a theoretically calculated ignition delay (ID) data and experimental measurements. The full-component model of SyBO was then reduced by the directed relation graph with error propagation (DRGEP) method to contain 87 species and 647 reactions. To further reduce the size of kinetic model as well as predict the physiochemical properties of SyBO, one surrogate molecule, i-C39H80, through the quantitative structure-property relationship (QSPR) of functional groups in SyBO, as well as one surrogate component, n-C54H110, were proposed. Again, the reaction model for the surrogate molecule was developed, verified, and then reduced to contain 73 species and 530 reactions, which might be applicable to computational fluid dynamics (CFD) simulations for practical engine systems.