Commercial Oleic Acid Research Articles

Antimicrobial activities of microbial essential fatty acid against foodborne pathogenic bacteria.

Background and Objectives:Human health and development have been related to dietary intake of essential fatty acids (omega 3, 6 and 9) and important for brain development, immune system function, and blood pressure regulation. Microbial essential oils are more natural and safer alternatives to synthetic preservatives. These oils have been demonstrated to have antibacterial activity within food systems and may be ideal additives to food formulations. Zygomycete fungi are well-known as good candidate for production of essential oils.Materials and Methods:Essential oils of fungi Mucor rouxii, Mucor circinelloides and Cuninghamella echinulata were extracted and fatty acids were analyzed by GC, for the first, antimicrobial activity of the fungi essential oils against foodborne pathogenic bacteria E. coli, S. aureus, B. cereus, B. subtilis, and S. enterica was examined by disc diffusion and well diffusion methods and the minimal inhibitory concentrations (MIC) of oils were determined by microtiter plate.Results:The fungi oils were exhibited the stron g antibacterial effect against Gram-positive bacteria, B. cereus, S. aureus and B. subtilis higher than Gram-negative and commercial oleic acid and linoleic acid. The MIC of the fungi oil extracts was 0.25 mg/ml for B. cereus and B. subtilis and 0.5 mg/ml about S. aureus. This research demonstrated microbial essential oils may be suitable for their antimicrobial properties in food.Conclusion:Microbial essential oil with good antibacterial activity could also be used in selected cases like foodborne disease.

Study of enzymatic production of biodiesel using vegetable oils and commercial ethanol

Biodiesel is a combination of alkyl fatty acid esters generated by a catalyst and supported by acid, basic, or enzymatic processes from vegetable oils to short-chain alcohols such as methanol or ethanol. However, the high costs for raw materials utilising vegetable oil of food grade have made it commercially impracticable to produce this biofuel. Research has therefore expanded with residual oil indicating that biomass from household and industrial waste has been technically feasible. The outcome of this investigation coincides with the enzyme production study of biodiesel utilising residual oil and ethanol, according to this principle. In esterification of commercial oleic acid, the behaviour of commercial immobilised lipase from CAL-B was examined and the variables affecting the process were investigated. Based on the results presented and discussed in this paper, the use of immobilized Candida antarctica lipase type B (CAL-B) for biodiesel production is more viable when using acidic substrates, since the best results were achieved with such raw materials and with a reaction rate comparable to esterification with an acid catalyst. The results of this work showed that the enzymatic esterification of commercial oleic acid with ethanol provided a conversion of 87.3% within 60 minutes of reaction, at a temperature of 30 °C, in a stoichiometric proportion and without adsorption of water. Both biocatalysts showed good stability, which produced over 80% conversion and 60 minutes of reaction and could be repeated without substantial loss of activity for at least 10 consecutive occasions

Synthesis and kinetics study of trimethylolpropane fatty acid triester from oleic acid methyl ester as potential biolubricant

The use of trimethylolpropane triesters as biodegradable lubricant base oil substitute mineral oils could significantly reduce the environmental pollution. In the present work, a commercial oleic acid (72% C18) was utilized as a precursor for the manufacture of trimethylolpropane triesters (TMPTE) through a two-step transesterification process. Oleic acid methyl ester (OME) produced from the first step was subsequently interacted with trimethylolpropane (TMP) using sodium methylate to produce TMPTE. The effect of the operating parameters, temperatures (90 °C, 100 °C, 110 °C, 120 °C, and 130 °C), molar ratio of OME to TMP (3:1, 4:1, 5:1, and 7:1), vacuum pressure (20, 50, 100, and 200 mbar), and catalyst amount (0.5, 0.7, 0.9, and 1.1(w/w)) was investigated. Under the selected reaction conditions (temperature 120 °C, oleic acid methyl ester to trimethylolpropane molar ratio 4:1, catalyst amount 0.9%w/w, vacuum pressure 20 mbar and reaction time 2 h), the final product composition was approximately 85.47% TMPTE, 10.80% TMPDE, 1.40%TMP ME, and 2.33% OME. The kinetics/mathematical model explains the chemical kinetics of transesterification of oleic acid methyl esters (OME) with trimethylolpropane (TMP) to produce biolubricant which has been investigated at temperature 120 °C. To support forward reaction, the excess amount of OME was increased by 10:1 (OME/TMP). The kinetic model suggested for the transesterification process of OME with TMP in this work based on three reversible series-parallel reaction mechanisms. The kinetics equations were solved using LINGO PROGRAM. A harmony between the experimental data and theoretically estimated values was achieved.

High strength and ductility of graphene-like carbon nanosheet/copper composites fabricated directly from commercial oleic acid coated copper powders.

Recently, copper matrix composites reinforced with graphene or graphene-like carbon nanosheets (GNS) have attracted great attention due to their excellent properties. However, the fabrication technologies of the composites are generally complex and expensive; it is necessary to develop facile and cheap synthesis methods for industrial applications of the composites with high performance. Here, we present a very simple method to fabricate GNS reinforced copper composites: commercial Cu powders with oleic acid coating are directly fabricated into GNS/Cu composites by spark plasma sintering. This work provides a facile method with low cost and high efficiency for the preparation of GNS reinforced metal matrix composites with high performance, which opens a new window for the large-scale production of graphene based composites.

Flotation separation of diaspore from aluminosilicates using commercial oleic acids of different iodine values

A systematic study of diasporic bauxite flotation using commercial oleic acids with different iodine values as collector was conducted in this paper. Bench scale flotation tests for diasporic bauxite ore and micro-flotation tests for relevant pure minerals (including diaspore, pyrophyllite and kaolinite) were carried out at different conditions using commercial oleic acids with iodine values of 65, 121 and 131. The results suggest that an increase in the iodine value of oleic acid would lead to improved flotation separation of diaspore from aluminosilicates. Use of the commercial oleic acid with iodine value of 131 in closed-circuit flotation tests allowed us to obtain a concentrate with alumina-to-silica (A/S) ratio of 5.33 and alumina recovery of 85.56% from the feed ore (A/S ratio=3.39). Chemical analyses of these commercial oleic acids found that an increase in the iodine value was associated with increased proportion of linoleic acid in the commercial oleic acids. To fundamentally understand the correlation between the iodine value of commercial oleic acids and the efficiency of flotation separation of diaspore from aluminosilicates, the computational studies of frontier molecular orbital energy of oleic and linoleic acid were done, and the results suggest that linoleic acid has higher chemical activity than oleic acid and its chemical adsorption on diaspore is more stable than that of oleic acid.

Synthesis of Fully Biobased Polyesters from Plant Oil

Self-metathesis of fatty acid methyl esters (FAMEs) from natural oils and commercial oleic acid was carried out using a microwave reactor in solvent-free conditions. Self-metathesis products were further identified and quantified by gas chromatography–mass spectroscopy (GC–MS) and gas chromatography–flame ionization detector (GC–FID). Conversion of ∼50% was achieved within a short span (∼2 min) in the presence of 0.05 mol % Hoveyda–Grubbs second generation catalyst (HG2) giving an equilibrium mixture of alkenes, α,ω-diester, and FAMEs. Highly pure dimethyl-9-octadecene-1,18-dioate (diester) was separated, and the desired quantity of it was reduced to 9-octadecene-1,18-diol (diol). Condensation polymerization of diester and diol as monomers was performed using conventional heating, microwave irradiation, and microwaves coupled with conventional heating. Characterization and analysis of synthesized biopolyesters were carried out using different techniques including nuclear magnetic resonance (NMR), Fourier ...

Aspergillus oryzae Lipase‐Catalyzed Synthesis of Dioleoyl; Palmitoyl‐Rich Triacylglycerols in Two Reactors

AbstractDioleoyl; palmitoyl‐rich triacylglycerols (OPO‐rich TAG) were synthesized through Aspergillus oryzae lipase (AOL)‐catalyzed acidolysis of palm stearin with commercial oleic acid by a one‐step process in a stirred tank reactor and continuous packed bed reactor to evaluate the feasibility of using immobilized AOL. AOL was found to be valuable for the synthesis of OPO‐rich TAG when compared with commercial lipase from Thermomyces lanuginose (Lipozyme® TL IM; Novozymes A/S, Bagsvaerd, Denmark). The C52 (triglycerides with a carbon number of 52, stands for OPO, OPL, LPL and their isomers) content of AOL was higher (45.65 %), and the intensity of treatment (IOT: lipase amount × reaction time/TAG amount) of AOL was just 6.25 % of that of Lipozyme® TL IM under similar reaction conditions in the stirred tank reactor. Response surface methodology were used to optimize the reaction conditions of the AOL‐catalyzed acidolysis is reaction in the packed bed reactor. The optimal point for the set of experimental conditions generated were as follows: residence time 3.0 h; temperature 62.09 °C; substrate molar ratio 7.13 mol/mol. The highest C52 content obtained was 48.60 ± 2.36 %, with 57.46 ± 1.72 % total palmitic acid at the sn‐2 position and 74.21 ± 2.45 % oleic acid at the sn‐1,3 positions. The half‐life of AOL was 24 h in the stirred tank reactor and 140 h in the packed bed reactor. The immobilized AOL achieved similar conversion and selectivity to commercial lipases for the catalyzed synthesis of OPO‐rich TAG and may offer a cheaper alternative.

Safety and efficacy of polyoxyethylene (20) sorbitan monooleate as a feed additive for all animal species

The additive is a mixture of the partial esters of sorbitol and its mono- and dianhydrides with edible commercial oleic acid and condensed with approximately 20 moles of ethylene oxide per mole of sorbitol and its anhydrides. It contains a minimum of 65% of oxyethylene groups, equivalent to not less than 96.5% of polyoxyethylene (20) sorbitan monooleate on the anhydrous basis and less than 3% water. The following concentrations of polyoxyethylene (20) sorbitan monooleate per kg complete feedingstuffs are considered safe: 1,260 mg for salmonids, 1,100 mg for cattle for fattening, 830 mg for pigs for fattening and sows, 750 mg for turkeys for fattening, 720 mg for dairy cows, 500 mg for piglets, 420 mg for chickens for fattening and laying hens, 1,320 mg for dogs and 1,100 mg for cats; and 5,000 mg/kg milk replacer are considered safe for calves. The use of polyoxyethylene (20) sorbitan monooleate as feed additive for all animal species at the maximum concentration proposed of 5,000 mg/kg complete feedingstuffs would not raise concerns for the consumer. Polyoxyethylene (20) sorbitan monooleate is non-irritant to skin and eyes, and is not a skin sensitiser. There is evidence that dermal or oral exposure to the additive can exacerbate the symptoms in individuals who are already sensitised. Users are unlikely to be exposed to the additive by inhalation. The lack of data and the inherent uncertainties do not allow concluding on the safety for the environment. Polyoxyethylene (20) sorbitan monooleate is a recognised emulsifier used in food and it is expected to have the same effect when applied to feed. From the practical examples provided, polyoxyethylene (20) sorbitan monooleate appears to be effective in aiding and maintaining the homogeneous distribution of feed materials and/or additives in feedingstuffs.

The Use of Acid-Activated Montmorillonite as a Solid Catalyst for the Production of Fatty Acid Methyl Esters

The esterification of lauric and stearic acids, tall oil fatty acid, and a commercial oleic acid with methanol was investigated using an acid-activated standard montmorillonite (AASM) as a catalyst. Reaction variables such as the methanol:fatty acid molar ratio, catalyst content, and temperature were evaluated. Comparative reactions were performed with K10 catalyst, and similar or even better results were obtained with AASM, indicating that this could be employed as a suitable Lewis/Brönsted esterification catalyst. The experimental results obtained for the esterification of lauric acid with methanol were compared to a thermodynamic model. For this purpose, the UNIFAC model was used for the activity coefficient calculation for components in the nonideal mixture. This model has shown that the catalytic system was able to drive the reaction to equilibrium within 2 h, and this was confirmed by comparing the experimental results with thermodynamic predictions.

An improved method for the synthesis of 1-monoolein

Monoacylglycerols (MAGs) are precursors for the synthesis of many active lipids and an important amphiphilic emulsifiers which are widely used in food, pharmaceutical, and cosmetic industries. In this study, we reported an improved method for the synthesis of 1-monoolein using 1,2-acetonide glycerol as starting reactant. Firstly, commercial oleic acid was purified using our previous method and then 1,2-acetonide-3-oleoylglycerol was synthesized by the esterification of 1,2-acetonide glycerol with purified oleic acid using Novozym 435 lipase as catalyst. Finally, the cleavage of unpurified 1,2-acetonide-3-oleoylglycerol in methanol was conducted to obtain 1-monoolein. The effects of reaction system, addition amount of solvent, lipase load, reaction temperature and time on 1,2-acetonide-3-oleoylglycerol content in the crude reaction mixture were investigated. Under the optimal conditions, 94.6% 1,2-acetonide-3-oleoylglycerol in crude reaction mixture was obtained. 1-Monoolein was synthesized further by cleaving unpurified 1,2-acetonide-3-oleoylglycerol in methanol at room temperature with Amberlyst-15 resin as catalyst. The cleavage reaction resulted in the formation of 76.5% 1-monoolein and 96.2% 1-monoolein was obtained at 72.8% yield after repeated recrystallization in hexane to remove nonpolar impurities and water washing to remove glycerol. The main novelties for the synthesis of 1-monoolein are the use of Novozym 435 lipase instead of chemical catalysts used in previous studies to catalyze the esterification of 1,2-acetnode glycerol with free fatty acids and scalable crystallization method used instead of column chromatography to purify 1-monoolein.

Oleic Acid and Diketopiperazines Produced by Marine Bacteria Reduce the Load of the Pathogen Vibrio parahaemolyticus in Argopecten purpuratus

The aquaculture industry must often deal in its cultures with bacterial contamination by Vibrio parahaemolyticus, which causes gastroenteritis in humans when they eat contaminated organisms. Until recently these pathogens were treated with antibiotics which are now forbidden because of their negative effects on humans and on the ecosystem. In the last few years there have been attempts to solve this problem by searching for active metabolites from antagonist bacteria. The objetive of this work was to evaluate the decrease of the load of the pathogen V. parahaemolyticus in Argopecten purpuratus scallops by the addition of oleic acid and diketopiperazines isolated from marine bacteria known for having an antibacterial effect against the pathogen, and with commercially available products similar to the molecular structures isolated from the bacteria. The decrease of the pathogen load was determined by the most probable number method from the absence in the samples of the gene tdh that codes for thermostable direct hemolysin (TDH), the main virulence factor in this species. The A. purpuratus bivalves treated with the oleic acid and diketopiperazines isolated from the bacteria showed preliminarily that they cause a reduction of the bacterial load of the V. parahaemolyticus pathogen. The same trend was seen when the scallops were treated with commercial oleic acid and diketopiperazines. Based on the inhibiting activity seen with the commercial products we suggest the possibility of experimenting with these products against V. parahaemolyticus or other pathogens in different commercially important organisms, mainly in depuration systems that require a short time (12 to 24 hours) to reduce the concentration of human pathogens like V. parahaemolyticus.

Experimental data for liquid–liquid equilibrium of fatty systems with emphasis on the distribution of tocopherols and tocotrienols

The present paper reports liquid–liquid equilibrium data for systems composed of degummed soybean oil+commercial linoleic acid+anhydrous ethanol, degummed soybean oil+commercial linoleic acid+ethanol+water, refined rice bran oil+commercial oleic acid+anhydrous ethanol and refined rice bran oil+commercial oleic acid+ethanol+water at 298.15K, 313.15K and 323.15K. α, β, γ and δ tocopherol and tocotrienol contents in both phases were analyzed. The parameters of the NRTL model were adjusted to the experimental data. For higher temperatures and the free fatty acid contents, higher are distribution coefficients of tocopherols and tocotrienols, due to the increase in solubility among the systems components. In contrast, the distribution coefficients of tocopherols and tocotrienols decrease when water is added to ethanol, which represents the increase in retention of tocopherols and tocotrienols in the oil phase. The NRTL model represented well the experimental data, and the global deviations between calculated and experimental data were 1.02% and 0.95% for systems composed of degummed soybean oil and refined rice bran oil, respectively.

Liquid–Liquid Equilibrium Data for the System Lard + Oleic Acid + Ethanol + Water at 318.2 K: Cholesterol Distribution Coefficients

This research reports liquid–liquid equilibrium data for the system lard (swine fat), cis-9-octadecenoic acid (oleic acid), ethanol, and water at 318.2 K, as well as their correlation with the nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) thermodynamic equations, which have provided global deviations of 0.41 % and 0.53 %, respectively. Additional equilibrium experiments were also performed to obtain cholesterol partition (or distribution) coefficients to verify the availability of the use of ethanol plus water to reduce the cholesterol content in lard. The partition experiments were performed with concentrations of free fatty acids (commercial oleic acid) that varied from (0 to 20) mass % and of water in the solvent that varied from (0 to 18) mass %. The percentage of free fatty acids initially present in lard had a slight effect on the distribution of cholesterol between the phases. Furthermore, the distribution coefficients decreased by adding water in the ethano...

Synthesis of Oleoylethanolamide Using Lipase

An effective process for the enzymatic synthesis of oleoylethanolamide is described in this study. The process included purification of a commercial oleic acid product and then optimization of the reaction between the purified oleic acid and ethanolamine in the presence of hexane and a lipase. Under the optimal amidation reaction conditions identified, oleoylethanolamide was obtained with 96.6% purity. The synthesis was also conducted on a large scale (50 mmol of each of the reactants), and oleoylethanolamide purity and yield after crystallization purification were 96.1 and 73.5%, respectively. Compared to the previous studies, the current method of preparing high-purity oleoylethanolamide is more effective and economically feasible. The scalability and ease for such synthesis make it possible to study the biological and nutritional functions of the cannabinoid-like oleoylethanolamide in animal or human subjects.

Solid–Liquid Equilibrium of Binary Mixtures Containing Fatty Acids and Triacylglycerols

Solid–liquid phase diagrams of the following systems were measured using differential scanning calorimetry (DSC): tristearin (2,3-di(octadecanoyloxy)propyl octadecanoate) + tripalmitin (2,3-di(hexadecanoyloxy)propyl hexadecanoate), tristearin (2,3-di(octadecanoyloxy)propyl octadecanoate) + palmitic acid (n-hexadecanoic acid), tristearin (2,3-di(octadecanoyloxy)propyl octadecanoate) + linoleic acid (cis-9,cis-12-octadecadienoic acid), tripalmitin (2,3-di(hexadecanoyloxy)propyl hexadecanoate) + triolein (2,3-bis[[(Z)-octadec-9-enoyl]oxy]propyl (Z)-octadec-9-enoate), and tripalmitin (2,3-di(hexadecanoyloxy)propyl hexadecanoate) + commercial oleic acid (commercial (Z)-octadec-9-enoic acid). The eutectic point was observed for two systems, tristearin with tripalmitin or with palmitic acid. Polarized optical microscopy was employed to investigate the solid phase of the systems and confirmed the occurrence of a solid solution at the extreme of the phase diagram rich in the component with a higher melting temperature. Margules-2-suffix, Margules-3-suffix, nonrandom two-liquid (NRTL), and universal quasichemical functional group activity coefficient (UNIFAC) models were employed to describe the liquidus line of the studied systems, except for the system formed by tripalmitin (2,3-di(hexadecanoyloxy)propyl hexadecanoate) + commercial oleic acid (commercial (Z)-octadec-9-enoic acid) which is a pseudobinary system that was well-described by the UNIFAC model. The best results for the other systems were obtained when employing the Margules-3-suffix and NRTL models.

Vegetable Oils Deacidification by Solvent Extraction: Liquid−Liquid Equilibrium Data for Systems Containing Sunflower Seed Oil at 298.2 K

Liquid−liquid equilibrium experimental data for refined sunflower seed oil, artificially acidified with commercial oleic acid or commercial linoleic acid and a solvent (ethanol + water), were determined at 298.2 K. This set of experimental data and the experimental data from Cuevas et al.,(1) which were obtained from (283.2 to 333.2) K, for degummed sunflower seed oil-containing systems were correlated using NRTL and UNIQUAC models with temperature-dependent binary parameters. The deviation between experimental and calculated compositions presented average values of (1.13 and 1.41) % for NRTL and UNIQUAC equations, respectively, indicating that the models were able to correctly describe the behavior of compounds under different temperature and solvent hydration.

Liquid−Liquid Equilibrium Data for Fatty Systems Containing Refined Rice Bran Oil, Oleic Acid, Anhydrous Ethanol, and Hexane

The objective of this work was to determine liquid−liquid equilibrium data for fatty systems of interest in the extraction/refining process of vegetable oils and in the biodiesel production. The following systems were investigated: refined rice bran oil + anhydrous ethanol + hexane at (298.15 ± 0.2) K and (313.15 ± 0.2) K and refined rice bran oil + commercial oleic acid + anhydrous ethanol + hexane at (298.15 ± 0.2) K with mass fractions of (5.08, 7.98, 10.65, and 15.09) % of fatty acid in oil. The instrumental technique of near-infrared spectroscopy allied to multivariate calibration (in this work, termed “NIR method”) was used for quantification of the phase compositions. For the pseudoternary system, the relative deviations for global mass balance were (0.10 and 0.11) % for the temperature of (298.15 and 313.15) K, respectively. For the pseudoquaternary systems, the relative deviations for global mass balance varied in the range from (0.15 to 0.31) %. The experimental data were correlated using the NRTL model with overall deviations lower than 1.15 %. We can conclude that the NIR method is highly accurate, and the low deviations obtained indicate the good quality of the equilibrium data.

Studies of anionic reagents for phosphate beneficiation

A multiyear, comprehensive study of flotation reagents used in phosphate beneficiation was conducted. The study involved the evaluation of pure fatty acid compounds, comparison of various anionic collectors and testing of iso-acids. Various C12 to C22 fatty acids were tested as Florida phosphate collectors. The saturated fatty acids were found to be very poor collectors when using the standard conditioning procedure, whereas the unsaturated C16 to C22 fatty acids showed fair to good phosphate collecting ability. The C18 fatty acids oleic, impure oleic and linoleic and the C20 eicosenoic acid were shown to be the best phosphate collectors. The best flotation results were obtained using Liqro GA tall oil and oleic acid. Four isostearic/iso-oleic acid type fatty acid collectors were compared with a commercial grade oleic acid and with Liqro GA tall oil as phosphate collectors using standard laboratory conditioning and flotation procedures. The most selective collector evaluated was Century 1108, a high isostearic acid-type reagent. However, it was concluded that this excellent-performing reagent was too expensive for commercial use. Overall, the most promising reagent was probably Century MO-5. This collector is essentially an iso-oleic acid/stearic acid mixture (not isostearic acid), and it costs much less. This program laid a sound foundation for developing single collector, all anionic flotation processes.

Extraction of Free Fatty Acids from Peanut Oil and Avocado Seed Oil: Liquid−Liquid Equilibrium Data at 298.2 K

The present paper reports phase equilibrium experimental data for two systems composed by peanut oil or avocado seed oil + commercial oleic acid + ethanol + water at 298.2 K and different water contents in the solvent. The addition of water to the solvent reduces the loss of neutral oil in the alcoholic phase and improves the solvent selectivity. The experimental data were correlated by the NRTL and UNIQUAC models. The global deviations between calculated and experimental values were 0.63 % and 1.08 %, respectively, for the systems containing avocado seed oil. In the case of systems containing peanut oil those deviations were 0.65 % and 0.98 %, respectively. Such results indicate that both models were able to reproduce correctly the experimental data, although the NRTL model presented a better performance.

Tribological Behavior of Phosphor Bronze against SAE52100 Steel under Different Lubricants

The friction and wear properties of phosphor bronze discs sliding against SAE52100 steel balls were evaluated using an Optimol SRV reciprocating friction and wear tester under the lubrication of pure poly-alpha-olefin (PAO) and PAO containing commercial phosphite ester, zinc dialkyldithiophosphate (ZDTP) and oleic acid additives. The morphologies of the worn surfaces of the phosphor bronze discs were observed using a scanning electron microscope (SEM). In addition, the elemental compositions and chemical states of several typical elements on the worn surfaces of the phosphor bronze discs were examined by means of X-ray photoelectron spectroscopy (XPS). The findings indicated that the phosphor bronze discs exhibited higher wear resistance under the lubrication of PAO containing phosphite ester than pure PAO, PAO containing ZDTP, and PAO containing oleic acid. Also, the phosphor bronze discs exhibited stable friction coefficients as low as 0.09-0.11 when lubricated with PAO containing phosphite ester. According to the XPS analyses, it was considered that the formation of CuO and phosphate led to lower friction coefficient and high wear resistance of phosphor bronze specimens lubricated with PAO containing phosphite ester. In the case of the phosphor bronze specimens lubricated with PAO containing ZDTP and oleic acid, the formation of organic compounds seemed to lead to lower friction coefficient, but did not seem to affect the wear resistance.