2-ethylhexyl Esters Research Articles

Evaluation of Spirulina spp. Crude Extract Revealed Antimicrobial, Antioxidant and UV Photoprotective Properties

The antimicrobial, UV photoprotective and antioxidant capabilities of Spirulina spp. methanolic extracts were determined using Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS). Notable compounds were reported to be 5 fatty acid methyl esters, 4- methoxyallocinnamic acid, 2-ethylhexyl esters and bumetrizole. Moreover, these metabolites contained functionalities including hydroxyl, alkyl and carbonyl, as supported by the FTIR result. After 24 h, there was no zone of inhibition in the antibacterial activity as measured by the agar well diffusion method at doses of 30, 50 and 70 g/mL. The ABTS radical scavenging assay revealed that the methanolic Spirulina spp. exhibited an inhibitory concentration of 1,047.91 g/mL for antioxidant activity and SPF values of 0.40, 0.23 and 0.93 were calculated using Mansur’s equation for concentrations of 30, 50 and 70 g/mL, respectively. The results of the study showed the potential of cyanobacterial extracts as a bioactive ingredient in cosmetic product development. HIGHLIGHTS Methanolic extraction of Spirulina spp. comprises 5 fatty acid methyl esters, 4-ethoxyallocinnamic acid 2-ethylhexyl esters and bumetrizole characterized by GC-MS. Constituents of the extract contain functional groups including –OH, –C–H and C=O. The extracts were classified as weak radical stabilizers, confirmed by ABTS assay and possessed UV photoprotective capacity confirmed by the in vitro SPF assay. GRAPHICAL ABSTRACT

Cytotoxicity Activity, Metabolite Profiling, and Isolation Compound from Crude Hexane Extract of Cleome rutidospermae.

This study isolated the chemical compounds and evaluated the cytotoxic activity of the crude hexane extract of Cleome rutidospermae herb (CRH). The isolate was purified using silica gel, column chromatography, and preparative thin layer chromatography (PTLC). Furthermore, the structure of the compounds was identified by spectroscopic methods using 1D, 2D NMR, and mass spectrometry. The cytotoxic activity of CRH at a concentration of 20 ug/mL was also tested against MCF-7, A549, KB, KB-VIN, and MDA-MB-231 cancer cells using the sulforhodamine B (SRB) method. The CRH contained compounds of unsaturated fatty acid, saturated fatty acid, lipid, glycerol, ω-3 fatty acid, and cholesterol. Two compounds were obtained from the plant, and their structures were identified as (1) Stigmasta-5,22-dien-3-ol (STML) and (2) 1,2-Benzene dicarboxylic acid, 1,2-bis (2-Ethylhexyl) esters (DEHP). These compounds were reported in this plant for the first time. In comparison, CRH had % growth inhibition in the proliferation of MCF-7 cells up to 28.1%, with cancer cells A549, KB, KB-VIN, and MDA-MB-231 by >50% Compared to the negative DMSO of 0.20%, while the positive control could inhibit the growth of all cancer cells (100%). Our findings suggested that crude herb from the plant CRH was the potential for breast cancer treatment.

Characterization of swelling behavior and elastomer properties of acrylate polymers containing 2-ethylhexyl and isobornyl esters

Characterization of swelling behavior and elastomer properties of acrylate polymers containing 2-ethylhexyl and isobornyl esters

Iso-oleic estolide products with superior cold flow properties

One of the drawbacks of using vegetable oils directly as a lubricant is poor low temperature performance, mainly pour and cloud points. Oleic estolides were developed to improve these properties as well as increase the oxidative stability of the oil. However, additional low temperature properties are desirable to increase the field of use of these materials. A new series of iso-oleic estolide free acids and 2-ethylhexyl (2-EH) esters capped with various fatty acids had superior physical properties and cold flow properties, compared to traditional oleic based estolides. The average pour point of the iso-oleic estolide 2-EH esters was − 41°C, compared to − 23°C of iso-oleic estolide free acids. The iso-oleic-octanoic and iso-oleic-decanoic estolide 2-EH esters had excellent pour points of − 60°C. The cold flow properties of iso-oleic estolides decrease with increasing the carbon number of the saturated capping fatty acid, while the viscosity index and oxidation stability were only slightly improved. Therefore, saturated mid-chain fatty acids are more suitable as the capping fatty acid for iso-oleic acid based estolides. Iso-oleic-coconut estolide 2-EH esters exhibited good physical properties, with pour points as low as − 45°C. The iso-oleic estolide free acids and 2-EH esters are a new kind of low-cost materials for bio-lubricants with excellent cold flow properties.

Correlating viscosity of 2-ethylhexyl oleic estolide esters to their molecular weight

Estolides are a relatively new class of biobased materials, and their properties are not thoroughly investigated. Since they have been recently commercialized as lubricants, a deeper investigation of their viscosity was warranted. Five 3-parameter viscosity models with theoretical derivations were found in the literature. Additionally, several empirical 2- and 3-parameter models, including one empirical 4-parameter model, used to describe the viscosity of lipids, were selected for investigation. These models were used to fit the experimental viscosity of 13 oleic estolide ester samples. The viscosity was measured at six temperatures between 20 and 100 °C. The jackknife procedure was used to estimate the uncertainty of the fitted parameters. For the theory-based models, correlations were derived between the fitted coefficients and the molecular weight of the sample. The results allowed for simple prediction of the viscosity of estolide esters as a function of the temperature, based only on number-average molecular weight (or on the estolide number). The best model required additional knowledge of the weight-average molecular weight.

Enzymatic production of isopropyl and 2-ethylhexyl esters using γ-linolenic acid rich fungal oil produced from spent sulphite liquor

The enzymatic production of isopropyl and 2-ethylhexyl esters was investigated using fungal oil produced via fermentation of nanofiltrated spent sulphite liquor (SSL). Screening of five oleaginous fungi showed that Cunninghmamella echinulata could accumulate lipids with 12 % (w/w) γ-linolenic acid content in shake flask cultures. Ester formation by the commercial lipase Novozym 435 was favored when transesterifications of fungal oil with isopropyl and 2-ethylhexyl alcohols were performed at 60 °C, 1:3 microbial oil to alcohol molar ratio and 10 % biocatalyst concentration. Transesterifications of individual neutral lipids (NL), glycolipids and sphingolipids (GL + SL) and phospholipids (PL), with isopropanol and 2-ethyl-hexanol showed that the presence of GL + SL and PL in fungal oil hindered ester production. Transesterification of the NL fraction alone with isopropanol and 2-ethylhexanol led to the highest conversion yield of 80.2 % and 73.8 %, respectively. Conversion yields to isopropyl and 2-ethylhexyl esters reached up to 90 % and 80 % (w/w), respectively, when hydrolyzed fungal oil was used. The biocatalyst showed good stability in 5 repeated enzymatic reactions. The physicochemical properties and the ICP-MS analysis of esters demonstrated their potential utilization in cosmetic formulations. This study showed a perspective of valorizing SSL towards the production of value-added fatty acid esters for chemical, cosmetic and pharmaceutical applications.

Tribological Properties of 10-Undecenoic Acid-Derived Schiff Base Lubricant Additives

Four 10-undecenoic acid-based Schiff bases were synthesized by condensation of methyl 11-(2-aminoethylthio) undecanoate with various aromatic aldehydes. Synthesized compounds were characterized by spectral techniques and evaluated for their tribological and antioxidant performances in biolubricant base oil, namely epoxy 2-ethyl hexyl esters of karanja fatty acids. The tribological test results indicate that all the synthesized thioethers containing Schiff bases act as good antiwear and extreme pressure additives. A significant reduction in wear scar diameter was observed at a very low concentration (0.6 wt%), whereas, at 1 wt% concentration, weld point enhancement observed from 160 to 230 kg. Quantum chemical calculations based on density functional theory for the interactions of Schiff bases with surfaces correlated with experimental wear data. Overall, the dimethoxy-substituted phenyl ring containing Schiff base was more effective in enhancing the antiwear and extreme pressure performance of base oil, whereas dihydroxy-substituted phenyl ring containing Schiff base exhibited good antioxidant property.

Synthesis and evaluation of stearic acid based heterocyclic Schiff bases as biolubricant additives in epoxy karanja fatty acid 2-ethyl hexyl esters base oil

Four novel stearic acid derived Schiff bases containing heterocyclic aromatic groups (furan, thiophene, pyrrole and pyridine) were synthesized in a three step reaction procedure. All the products were characterized by FT-IR, NMR and ESI-MS. The lubricity and antioxidant properties of synthesized Schiff bases were evaluated with 4-ball machine and differential scanning calorimeter. The morphologies and composition of elements on the worn surfaces were studied by using scanning electron microscope and energy-dispersive X-ray spectroscopy. Results show that these stearic acid based derivatives possess good tribological properties and antioxidant performance. The difference in the additive performance of the derivatives is closely related to the difference in their molecular structure. Pyridine containing Schiff base was more effective as both antiwear and extreme pressure additive while thiophene derivative exhibited higher efficacy as antioxidant.

Measurement and correlation of the density, viscosity and vapor pressure of fatty acid 2-ethyhexyl esters

Fatty acid 2-ethylhexyl esters are used for the eco-friendly production of biolubricant. There are several reports on their synthesis, but thermodynamics and transport data of these compounds are lacking. Herein, density and viscosity of palmitic acid 2-ethylhexyl ester, stearic acid 2-ethylhexyl ester and soya oil 2-ethylhexyl esters in the temperature range of T = (298.18–368.15) K at atmospheric pressure were measured and the vapor pressure in the temperature range of T = (476.95–500.85, 477.05–498.05, 477.75–500.05) K was determined. The obtained experimental data were correlated using temperature-dependence correlation equations, and the correlation coefficients of all the equations were over 0.999. In order to examine the reliability of the data, the GCVOL group method was used to evaluate densities for these fatty acid 2-ethylhexyl esters with the maximum relative deviation of −1.34%. The experimental viscosity data of synthesized 2-ethylhexyl esters were compared with those of lauric acid 2-ethylhexyl ester, palmitic acid n-octyl ester and oleic acid 2-ethylhexyl ester from previous studies. In addition, the molar enthalpy of vaporization at the mean temperature of the experimental range was calculated for the first time using the Clausius-Clapeyron equation.

Structural modification of waste cooking oil methyl esters as cleaner plasticizer to substitute toxic dioctyl phthalate

Abstract Most of the plasticizers used during poly (vinyl chloride) processing are typically toxic petroleum-based phthalates. Furthermore, large amount of edible oils become waste all over the world, fortunately, waste cooking oils have the potential to be an economic alternative for synthesizing different biomaterials. This study aimed to synthesis an improved properties and cost competitiveness cleaner bio-plasticizer using waste cooking oil methyl esters as staring raw materials. In this paper, waste cooking oil methyl esters were structurally modified i.e., transesterification and epoxidation reaction, to prepare epoxide waste cooking oil 2-ethylhexyl esters. The in-situ epoxidation was mainly studied by response surface methodology, with optimum conditions: reaction time was 7 h, molar ratio of C C bonds/FA/H2O2 was 1.00/0.35/2.41, and reaction temperature was 65.84 °C with a maximum relative percentage conversion to oxirane of 92%. Also, the plasticizing effectiveness of epoxide waste cooking oil 2-ethylhexyl esters to substitute toxic plasticizer dioctyl phthalate were studied. Results showed that the mechanical and thermal performance of PVC samples was significantly improved with partial substitutions, while the migration resistance was slightly decreased. Comparison with conventional epoxy compound highlighted that epoxide waste cooking oil 2-ethylhexyl esters had superior low temperature property, oxidation stability, and remarkably reduced the glass transition temperature of PVC. In conclusion, the prepared epoxide via structural modification from waste cooking oil methyl esters proved to be an effective alternative to dioctyl phthalate, replacing about 40% of the total plasticizer. This may lead to the eco-development of waste cooking oil materials, and makes the plasticizing process more environmentally friendly.

A renewable lipid source for biolubricant feedstock oil from housefly (Musca domestica) larva

Biolubricants are gaining increased attention because of their low toxicity, high biodegradability, and miscibility with additives. These features render them ideal for lubrication, especially in total-loss processes. In this study, housefly (Musca domestica) larvae were used as low-cost, non-food biolubricant feedstock. A larval lipid with high acid value (AV) of 63 mg KOH/g was used as feedstock for esterification to produce 2-ethylhexyl fatty acid esters (2-EH esters). We developed a method of producing high-purity 2-EH esters in which housefly larva free fatty acids (HLFFAs) were derived from larvae fed with kitchen waste. HLFFAs were esterified with 2-ethyl-1-hexanol (2-EHOH) catalysed with benzenesulfonic acid (BSA). The optimum esterification conditions were as follows: catalyst loading, 0.5 wt%; 2-EHOH-to-HLFFAs molar ratio, 3:1; temperature, 130 °C; and reaction time, 2 h. These conditions yielded 98.6% esterification rate. Excess 2-EHOH was removed by molecular distillation at 80 Pa and 110 °C. Residual fatty acids were neutralised by alkali refining. The chemical and physical properties, including the tribological properties, of the produced high-purity 2-EH esters (>99.7%) were also tested.

VOCs monitoring of new materials for ceramic tiles decoration: GC–MS analysis of emissions from common vehicles and inkjet inks during firing in laboratory

The decoration of ceramic tiles “ink-jet revolution” has brought significant advantages to tiles manufacturing, but the explosive diffusion, until 4–5 years ago, of this technique has not been accomplished by an adequate scientific research. Among all the features that have to be studied yet, one of the most important is the influence of the new generation inks on the total emission at ceramic chimneys. In this paper, we present a first characterization of emissions from a set of commercial inks and vehicles: they were collected by propter firing of samples in an electric kiln and analyzed by GC–MS. This study is part of a larger research project, which includes the chemical characterization and the evaluation of thermal behavior of inks and vehicles by TG-DTA and other techniques. The obtained results permit to divide common vehicles into 3 classes, depending on their thermal behavior and emissions pattern. Inks, most of which present an ester based formulation, sometimes mixed with glycols or paraffins, follow the behavior of their single components. The most common formulation leads to the presence in the emission pattern of evaporation products (2-ethylhexyl esters of lauric, myristic, decanoic and octanoic acids) and decomposition products (mainly aldehydes and 2-ethyl-1-hexanol).

Synthesis, Characterization, and Evaluation of Castor Oil-Based Acylated Derivatives as Potential Lubricant Base Stocks

Synthesis, characterization, and evaluation of a series of novel acylated derivatives of castor oil as biolubricant base stocks are described. The acylated derivatives of castor oil, castor oil fatty acid methyl and 2-ethylhexyl esters were synthesized using different anhydrides (C1–C6) in about 90–95% yield. All the products were structurally characterized using NMR and IR spectral data. The acylated products were evaluated for their physicochemical and lubricant properties. Although these products belong to group V, based on viscosity index (130–156), acylated derivatives of castor fatty acid alkyl esters belong to group III, the category of base fluids as per API classification. The acylated products exhibited excellent pour point (−21 to −39 °C) and flash point (174–280 °C). The hexanoylated and butanoylated esters of castor oil exhibited excellent flash points of 280 and 272 °C, respectively. The air release value was found to be excellent in the range of 0.38–0.99 min, and NOACK volatilities in the range of 3.25–3.92%. The other lubrication properties such as load carrying capacity, and emulsion stability were found to be good. Therefore, these derivatives will have utility in hydraulic and metal working fluids and other industrial fluids with their wide range of properties.

Synthesis and physical properties of pennycress estolides and esters

A new series of pennycress (Thlaspi arvense L.) based free-acid estolides was synthesized by an acid-catalyzed condensation reaction, followed by an esterification reaction to produce the 2-ethylhexyl (2-EH) esters of the initial estolides. The physical properties of the estolides are highly affected by the length and unsaturation level of the capping fatty acid, the base fatty acid unit, and estolide linkage position. Both the free-acid estolides and the estolide 2-EH esters produced proved to have marked viscosity increases over previously synthesized estolides. Kinematic viscosities of the free-acid estolides were higher than the corresponding estolide 2-EH esters, ranging from 494.4cSt to 870.5cSt at 40°C and 53.6 to 75.3cSt at 100°C with viscosity indices (VI) from 134 to 163. Viscosities of the estolide esters ranged from 116.3 to 245.75cSt at 40°C and 18.2 to 33.6cSt at 100°C with viscosity indices (VI) from 169 to 183. The highest viscosity values belonged to the pennycress estolides made with pennycress fatty acids in the reaction acting as the base material, as well as the capping material. The oleic capped pennycress estolide 2-EH esters had the best low-temperature properties with a pour point (PP) of −33°C and cloud point (CP) of −31°C. With the exception of palmitic acid, there was very little variation in the low-temperature properties of the remaining saturate capped estolide 2-EH esters, PP ranging from −18 to −21°C. Pennycress is currently being developed for green diesel applications; the development of other industrial applications is a necessity for the success of an alternative crop. The combination of high viscosity and modest cold temperature properties of these pennycress estolides could fill a specialty niche as a high viscosity industrial lubricant.

Novel acyloxy derivatives of branched mono- and polyol esters of sal fat: multiviscosity grade lubricant base stocks.

Sal fat, a nontraditional seed oil, was chemically modified to obtain base stocks with a wide range of specifications that can replace mineral oil base stocks. Sal fatty acids were enriched to 72.6% unsaturation using urea adduct method and reacted with branched mono alcohol, 2-ethylhexanol (2-EtH), and polyols namely neopentyl glycol (NPG) and trimethylolpropane (TMP) to obtain corresponding esters. The esters were hydroxylated and then acylated using propionic, butyric, and hexanoic anhydrides to obtain corresponding acylated derivatives. The acylated TMP esters exhibited very high viscosities (427.35-471.93 cSt at 40 °C) similar to those of BS 150 mineral oil base stock range, ISO VG 460, while the acylated NPG esters (268.81-318.84 cSt at 40 °C) and 2-EtH esters viscosities (20.94-24.44 cSt at 40 °C) exhibited viscosities in the range of ISO VG 320 and 22 respectively with good viscosity indices. Acylated NPG esters were found suitable for high temperature and acylated 2-ethylhexyl esters for low viscosity grade industrial applications. It was observed that the thermo-oxidative stabilities of all acylated products were found better compared to other vegetable oil based base stocks. Overall, all the sal fat based lubricant base stocks are promising candidates with a wide range of properties, which can replace most of the mineral oil base stocks with appropriate formulations.

Preparation and Properties of Lubricant Base Stocks from Epoxidized Karanja Oil and Its Alkyl Esters

Lubricant base stocks of epoxidized oil and its alkyl esters namely epoxidized karanja fatty acid methyl, butyl, 2-methyl-1-propyl, and 2-ethylhexyl esters were synthesized from renewable nonedible...

N-Octyl esters of long-chain fatty acids are not anthropogenic pollution markers

n-Octyl esters of higher fatty acids have been reported as markers of urban wastewater in sediments, polychaeta, fish, crabs and oysters (Chaler et al. in J Chromatogr A 1046:203–210, 2004)). However, up to date, there were no subsequent studies to confirm this claim. Likewise, Chaler and co-workers did not consider that the mentioned compounds might occur naturally in the environment. Here we found seven n-octyl straight-chain alkanoates, from C-20 to C-26, in the wild-growing plant Heracleum sphondylium L., Apiaceae, from 14 locations. Those plant metabolites were unambiguously identified by gas chromatographic co-injection of the synthesized esters with the inflorescence washings. All identified octyl esters represent new natural compounds, except for octyl docosanoate. Since we have demonstrated that n-octyl esters occur naturally, and in abundance, they cannot be recognized any longer as wastewater markers. Additionally, here we provide evidences that the compounds identified by Chaler et al. (2004) are in fact 2-ethylhexyl esters, mistakenly identified as n-octyl esters.

Enzymatic synthesis of rapeseed oil-based lubricants

The application of enzyme preparations, such as immobilized lipases from Candida Antarctica, Pseudomonas cepacia and Rhizomucor miehei, in the synthesis of rapeseed oil fatty acid esters with selected alcohols has been tested. The synthesis was based on transesterification reactions of rapeseed oil fatty acid methyl ester with 2-ethylhexanol, neopentyl glycol and trimethylolpropane, using immobilized lipases as catalysts in a solvent free medium. Using C. Antarctica lipase, above 98% conversion degree of substrates was achieved after 50, 150 and 200h for 2-ethylhexyl esters, neopentyl glycol esters and esters of trimethylolpropane, respectively. The synthesized esters are characterized by better viscosity properties, lower pour point and higher thermo-oxidative stability as compared with native rapeseed oil.

Synthesis and physical properties of petroselinic based estolide esters

A new series of petroselinic (Coriandrum sativum L.) based estolide 2-ethylhexyl (2-EH) esters were synthesized, as the capping material varied in length and in degrees of unsaturation, in a perchloric acid catalyzed one-pot process with the esterification process incorporated into an in situ second step to provide the coriander estolide 2-EH ester. The kinematic viscosities ranged from 53 to 75 cSt at 40°C and 9.1 to 14.6 cSt at 100°C with a viscosity index (VI) ranging from 151 to 165. The caprylic (C8) capped coriander estolide 2-EH ester had the lowest low-temperature properties (pour point=−33°C and cloud point=−33°C), while the coco-coriander estolide 2-EH ester produced an estolide with modest low-temperature properties (pour point=−24°C and cloud point=−25°C). The coco-coriander estolide 2-EH ester was explored for the ability to resist oxidative degradation with the use of an biodegradable additive package added in 1.5%, 3.5%, or 7.0% units based on weight. The oxidative stability increased as the amount of stability package increased (rotating pressurized vessel oxidation test (RPVOT) times 65–273min). Along with expected good biodegradability, these coriander estolide 2-EH esters had acceptable properties that should provide a specialty niche in the U.S. as a biobased lubricant.

Transparent poly(bisphenol A carbonate)-based nanocomposites with high refractive index nanoparticles

Transparent organic–inorganic nanocomposites were successfully synthesized from sulfonic acid-modified poly(bisphenol A carbonate) (SPC) and TiO 2 or ZrO 2 nanoparticles. The dispersibility of nanoparticles was significantly improved by both the surface treatment of nanoparticles with phosphoric acid 2-ethylhexyl esters (PAEH) and the introduction of a sulfonic acid moiety into the PC chain. It was found that in some cases, crystallization of the matrix caused a reduction in transparency. Efficient dispersion of nanoparticles and the absence of crystallization resulted in highly transparent nanocomposites with up to 42 wt% TiO 2 and 50 wt% ZrO 2 nanoparticles. The refractive indices of the nanocomposites based on SPC increased with the increasing amount of nanoparticles. Theoretical equation based on Maxwell–Garnett effective medium theory provided reasonably close estimation of the refractive indices to the experimentally observed values. The prepared nanocomposites had lower thermal stability than the host matrix polymers.