Hexadecanoic Acid Ethyl Ester Research Articles

A Method of Central Composite Design (CCD) For Optimization of Biodiesel Production from Chlorella vulgaris

The direct transesterification of the oleaginous biomass using chloroform resulted in a high biodiesel yield and FAME content than the chloroform-based extraction transesterification method and the yield was almost 100%. Hexane (89%) and petroleum ether (80%) also produced biodiesel but the yield was low when compared with chloroform. Our study showed that the biodiesel yield and FAME content of the wet biomass in the direct transesterification was significantly lower than those obtained from freeze-dried biomass suggesting that drying the algae was necessary for direct transesterification. The optimization procedures were carried out with algae: ethanol ratio, catalyst amount, reaction temperature and reaction time. The central composite design (CCD) was used to optimize the various processes. The analysis of variance (ANOVA) was also carried out and the results were found to be significant. The ρ value less than 0.0001 indicated that the model was statistically significant. The optimization procedures revealed that a yield of 95% was obtained. The 3D plot was done by keeping two components constant and other two components variable. In GC-MS, the results showed that the main components found were tetradecanoic acid ethyl ester (C14:0) 2-5%, Hexadecanoic acid ethyl ester (C16:0) 26-45%, Hexadecanoic acid ethyl ester (C16:1) 25-38%, octadecanoic acid ethyl ester (C18:0) 1-2%, oleic acid ethyl ester (C18:1) 9-13%, Eicosapentaenoic acid ethyl ester (C20:5) 1.2-5.1%. As the temperature was increased the percentage of C20:5 were decreased to 1.2% which was a good indication for fuel properties.

PENCAIRAN TONGKOL JAGUNG SECARA TERMOKIMIA DALAM ETANOL SUPERKRITIK

<p>Abstract: The use of corn cobs as the biomass feedstock offers promising possibilities for<br />renewable energy production. Corn cobs can be converted into oil by thermochemical<br />liquefaction in the supercritical ethanol. The aims of this research were to find the optimal<br />temperature which produce the maximum yield of oil and the contained substances in the oil. In<br />this research, 5 gram dry corn cob powder was put into 81 ml autoclave in addition of 0.25 gr<br />sodium carbonate and 75 ml ethanol as solvent. After nitrogen was blown into autoclave, it was<br />heated in the tube furnace until it reaches 75 minutes and maintained with the various<br />temperature.The liquid product was distilled to separate oil and volatile matter, meanwhile the<br />solid product was dried for 24 hours. The solid product was extracted with n-hexane to remove<br />glucose. The composititions of oil was analyzed by using GC-MS. The experimental result<br />showed that the maximum yield was 47.10 % when heating time 75 minute. The oil mostly<br />contained esters from C-20 to lower. The main compound was hexadecanoic acid ethyl ester by<br />37.10 % weight and other consist of alkyl esters, phenols, alkanes, etc.<br />Keywords: biomass, corn cobs, thermochemical liquefaction</p>

Fatty acids and their esters from Cicuta virosa L.

n-Hexane and chloroform fractions of aerial parts and roots of Cicuta virosa L. were investigated by GC-MS. As a result of the study 25 fatty acids and their esters have been identified. Two unsaturated esters such as linoleic acid ethyl ester (IX, 16.66%), and n- hexadecanoic acid ethyl ester (VII, 10.12%), the fatty acid n-hexadecanioc acid (VI, 8.10%) made up the bulk of the aerial parts. Four unsaturated esters such as linoleic acid ethyl ester (IX, 10.15%), dibutylphthalate (XII, 9.55%), n-hexadecanoic acid ethyl ester (VII, 8.19%) and 9, 12, 15 - octadecatrienoic acid ethyl ester (X, 5.9%), two fatty acids as n-hexadecanoic acid (VI, 8,15%) and 9,12-octadecadienoic acid (VIII, 4,5%) predominated in the roots of Cicuta virosa L. These known fatty acids and their esters were found for the first time in this plant species. DOI: http://dx.doi.org/10.5564/mjc.v14i0.203 Mongolian Journal of Chemistry 14 (40), 2013, p71-74

Optimization of Ethanol Supercritical Fluid Extraction of Medicinal Compounds from St. John's Wort by Central Composite Design

Extraction of medicinal compounds from St John's Wort was performed using supercritical ethanol. The supercritical fluid extraction parameters were optimized via response surface methodology which included a central composite design. The independent variables were extraction temperature (ranging from 300°C to 340°C), extraction times (ranging from 60 to 120 min), and plant concentration (ranging from 8% to 12%). The response was the St John's Wort extract yield. The extraction temperature was the most significant factor which affects St John's Wort yields according to statistical results. The coefficient of determination was estimated to be 0.98 which indicates the effectiveness of the model and its adaptability to the experimental data. The extract of St John's Wort was comprised of a wide array of compounds including phenols, acids, acid esters, and alkanes. The most prominent components of the extract of St. John's Wort in terms of their relative concentrations were linoleic acid ethyl ester, oleic acid ethyl ester, hexadecanoic acid ethyl ester, and nonacosane.

Inhibitory effect of Tridax procumbens against human skin pathogens

Tridax procumbens is a common herb with significant medicinal properties traditionally used in the treatment of many skin diseases. The methanol extract of T. procumbens exhibited high antifungal activity against clinically important human skin pathogens such as Microsporum fulvum, Microsporum gypseum, Trichophyton mentagrophytes, Trichophyton rubrum, Trichosporon beigelii and Candida albicans with low MIC values. The fractionation of a methanol extract with dichloromethane yielded an oily viscous fluid with antifungal activity which was separated and characterized. The GC–MS analysis revealed the presence of 26 compounds. The major constituents were characterized as 9,12-octadecadienoic acid ethyl ester (18.04%), 5α-cholestane (12.42%), hexadecanoic acid ethyl ester (4.86%) and 9-octadecenoic acid ethyl ester (4.72%). This study demonstrated the efficacy of this herb against clinically important dermatophytes and also justified its traditional use.

Triterpene Esters and Biological Activities from Edible Fruits ofManilkara subsericea(Mart.) Dubard, Sapotaceae

Manilkara subsericea (Mart.) Dubard (Sapotaceae) is popularly known in Brazil as “guracica.” Studies with Manilkara spp indicated the presence of triterpenes, saponins, and flavonoids. Several activities have been attributed to Manilkara spp such as antimicrobial, antiparasitic and antitumoral, which indicates the great biological potential of this genus. In all, 87.19% of the hexanic extract from fruits relative composition were evaluated, in which 72.81% were beta- and alpha-amyrin esters, suggesting that they may be chemical markers for M. subsericea. Hexadecanoic acid, hexadecanoic acid ethyl ester, (E)-9-octadecenoic acid ethyl ester, and octadecanoic acid ethyl ester were also identified. Ethanolic crude extracts from leaves, stems, and hexanic extract from fruits exhibited antimicrobial activity against Staphylococcus aureus ATCC25923. These extracts had high IC50 values against Vero cells, demonstrating weak cytotoxicity. This is the first time, to our knowledge, that beta- and alpha-amyrin caproates and caprylates are described for Manilkara subsericea.

Composition of the essential oil and petroleum ether extract of Lycium chinense Miller fruits and antioxidant activity of its several extracts

The essential oil and petroleum ether extract from the fruits of Lycium chinense Mill. (Solanaceae), were analyzed by gas chromatography-mass spectrometry (GC-MS). Out of 42 peaks, 40 components, which constituted 99.81%, were identified in the oil. The oil was dominated by acid and esters which accounted for 66.61 and 8.43%, respectively. The major constituents were hexadecanoic acid methyl ester (4.92%), hexadecanoic acid ethyl ester (9.92 %), ethyl linoleate (3.45%), tetradecanoic acid (3.72%) and hexadecanoic acid (62.89%). Forty components, which constitute 99.50 %, were identified in the petroleum ether extract. The major components of petroleum ether extract were hexadecanoic acid (17.43%), hexadecanoic acid ethyl ester (9.51%), hexadecanoic acid methyl ester (3.72 %), ethyl linoleate (10.26%), and phytol (3.58%). The petroleum ether extract components were identified for the first time. The identity of constituents of essential oil and petroleum ether extract was confirmed on the basis of retention time and mass and supplemented library.Extracts of different polarity from fruits of L. chinense were investigated for their antioxidant activity. Two different bioassays were used, namely scavenging of the diphenylpicrylhydrazyl (DPPH) radical method and the other reducing power of Fe3+ method. The total phenolic content was quantified of each extract as well. Butanol, ethyl acetate and methanolic extracts contributed to the strongest antioxidant activity. The fruit extracts of medicinal plant (L. chinense) has potential as a natural antioxidant and thus inhibit unwanted oxidation process. Key words: Lycium chinense, Solanaceae, fruits, essential oil, petroleum ether extract, gas chromatography-mass spectrometry (GC-MS), antioxidant activity.

Comparative studies of thermochemical liquefaction characteristics of microalgae using different organic solvents

The effect of different organic solvents, such as methanol, ethanol and 1,4-dioxane, on thermochemical liquefaction characteristics of Spirulina (a kind of high-protein microalgae) was systematically studied. The liquefaction experiments were conducted in a 1000 mL autoclave at different temperatures from 573 to 653 K with a fixed solid/liquid ratio. Liquefaction of Spirulina processed in methanol and ethanol favored the conversion rate and bio-oil yield compared with that in 1,4-dioxane solvent. The bio-oil generated in methanol contained higher C and H concentrations but a lower O content, resulting in a higher caloric value (39.83 MJ/kg). The results of FT-IR (Fourier Transform Infrared Spectroscopy) and GC–MS (Gas Chromatography–Mass Spectroscopy) analyses indicated that the compositions of bio-oil products were greatly affected by the type of solvent used for the liquefaction process. The major component of bio-oil produced with methanol was hexadecanoic acid methyl ester (C 17H 34O 2, 35.53%). However, ethanol favored the formation of hexadecanoic acid ethyl ester (C 18H 36O 2, 26.27%). When Spirulina were operated with 1,4-dioxane, the bio-oil was dominated by hexadecanenitrile (C 16H 31N, 22.7%). The presence of methanol and ethanol might promote the formation of esters. Low-boiling-points compounds with phenol ring structure or heterocyclics can be generated when 1,4-dioxane was employed as solvent.

Rapid and efficient gas chromatographic method for measuring the kinetics of lipase-catalyzed transesterification of phosphatidylcholine

Both n-3 polyunsaturated fatty acids (n-3 PUFA) and phospholipids have a lot of special functions on human body. n-3 PUFA includes α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Among them, ALA is the precursor of EPA and DHA. The synthesis of ALA-containing phospholipids can solve the problems of low content of EPA and DHA in phospholipids and show an increased double effect on human body. At a water activity of 0.33, a rapid and efficient method was used for kinetics of the transesterification of phosphatidylcholine (PC) with α-linolenic acid ethyl ester (ALAEE). The rate equation was obtained using palmitic acid ethyl ester (PAEE) as index for reaction rate and the reaction proved to proceed via a Ping-Pong mechanism without inhibition by both the substrates.

Effects of Ethanol and Its Metabolites on Human Pancreatic Stellate Cells

Pancreatic stellate cells (PSCs) play a pivotal role in pancreatic inflammation and fibrosis. In the pancreas, in addition to oxidative metabolism, ethanol can be metabolized by esterification with fatty acids to form fatty acid ethyl esters such as palmitic acid ethyl ester (PAEE). We here examined the effects of ethanol (at 20 or 50 mM), acetaldehyde (at 200 microM), or PAEE (at 100 microM), on PSCs functions. PSCs did not express mRNAs for pancreatic triglyceride lipase and carboxyl ester lipase. Ethanol and acetaldehyde, but not PAEE, induced production of procollagen type I C-peptide. Ethanol, but not acetaldehyde or PAEE, induced interleukin-8 production. PAEE activated activator protein-1, but not nuclear factor kappaB. In addition, PAEE activated extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase. Specific activation of signal transduction pathways and cell functions by ethanol and its metabolites may play a role in alcohol-induced pancreatic injury.

Comparison of volatile components of Marchantia convoluta obtained by supercritical carbon dioxide extraction and petrol ether extraction

The volatile components of Marchantia convoluta were obtained by petrol ether extraction and supercritical (carbon dioxide) extraction methods. These oils were analysed by capillary gas chromatography with mass spectrometric detector (GC-MS). The compounds were identified according to their retention indices and mass spectra (EI, 70 eV). The effects of different parameters, such as pressure, temperature, modifier volume and extraction time, on the supercritical fluid extraction (SFE) of M. convoluta oil were investigated. A total of 11 compounds accounting for 73.62% of SFE extracts were identified. 22, 23-dihydro-stigmasterol (31.26%), n-hexadecanoic acid (20.35%), stigmasterol (4.55%) and octadecanoic acid (5.75%) were the major compounds identified in M. convoluta SFE extracts. The SFE method has been compared with petrol ether extraction method. SFE products were found to be markedly different from the corresponding petrol ether extract. A total of 10 compounds accounting for 74.04% of petrol ether extraction (PEE) extract were identified. Hexadecanoic acid ethyl ester (36.97%), ethyloleate (10.47%), E-11-hexadecenoic acid ethyl ester (9.77%) and linoleic acid ethyl ester (4.63%) were the major compounds identified.

Volatiles from Ficus hispida and their attractiveness to fig wasps.

Volatile compositions of receptive (ready to be pollinated), postpollinated, and postparasitized figs. and leaves of Ficus hispida were analyzed. Differences among them were examined, and the specificity of fig wasp attractiveness was investigated. Linalool was the major constituent of steam-distilled oil of either male or female receptive figs, while dibutyl phthalate was the major compound of the oils of postparasitized and postpollinated figs. In petroleum ether extracts, palmitic oil, and 9,12-octadecadienoic acid were the main constituents of male and female receptive figs, while hexadecanoic acid ethyl ester was the major compound of postparasitized and postpollinated figs. In dichloromethane extracts, linalool was the major constituent of male and female receptive figs, 1-hydroxylinalool was the major component of male postparasitized figs, and 1-hydroxylinalool and benzyl alcohol were the major constituents of female postpollinated figs. Bioassays with sticky traps showed that Ceratosolen solmsimarchal was attracted to dichloromethane extracts of male and female receptive figs and to petroleum ether extracts of female receptive figs, but was not attracted to dichloromethane and petroleum ether extracts of male postparasitized and female postpollinated figs. Figs were attractive to pollinating wasps only at the receptive stage. The volatile constituents of receptive figs were different from those of postpollinated or postparasitized figs. From a receptive to a postpollinated state, figs changed in their volatile composition. Some compounds disappeared or decreased in amount. These include linalool, linalool oxide, alpha-terpeneol, and 2,6-dimethyl-1,7-octadiene-3,6-diol, which may act as the attractants of the wasps. Others increased in amount, or several additional chemicals appeared. These include dibutyl phthalate, 1-hydroxylinalool, and benzyl alcohol, which may be repellents of the wasps. That dichloromethane extracts of male and female receptive figs showed similar activities in attracting fig wasps indicates that receptive figs of both sexes are similarly attractive to fig wasps, which is further supported by their similar volatile composition. Leaf extract was not attractive to the wasps.

ACUTE TEMPORAL DISTRIBUTION OF FATTY ACID ETHYL ESTERS IN PREGNANT LONG-EVANS RATS

Fetal alcohol syndrome is a term used to describe the birth defects associated with maternal ethanol use during pregnancy. Ethanol, a rapidly biotransformed compound, is currently the only biochemical marker used to detect maternal ethanol use during pregnancy. A minor pathway of ethanol biotransformation is the nonoxidative enzymatic reaction which leads to esterification of free fatty acids with the ethyl group of ethanol. This research explored the formation of two fatty acid ethyl esters (FAEEs), palmitic acid ethyl ester (PAEE) and stearic acid ethyl ester (SAEE), in the pregnant rat and its offspring. In this acute study, pregnant (gestational day 9) Long-Evans rats were dosed 5 g/kg with ethanol (25%) p.o., and animals were sacrificed at 15, 30, 60, 120, 240, 480, and 720 min postdose. Tissues removed for PAEE and SAEE analysis included maternal blood, liver, brain, and fetal/ placental tissue. Analysis for the FAEEs was accomplished using a one-step liquid-liquid extraction. The extracts were then...

Distribution of Fatty Acid Ethyl Esters in Long Evans Rats Following Acute Ethanol Ingestion

Summary: Fatty acid ethyl esters (FAEEs) are members of a class of nonoxidative metabolites of ethanol. These lipophilic moieties have been detected in various animal and human tissues in vivo and in vitro. A one-step liquid-liquid extraction method with subsequent analysis by GC/MS is described for the identification and quantitation of palmitic acid ethyl ester and stearic acid ethyl ester in blood, liver, and brain from Long Evans rats administered ethanol by feeding needle. Animals received one of four doses of ethanol (1, 2, 4, and 5 g/kg) as a 25% w/v gavage solution. Control animals received tap water. One hour after gavage, a blood specimen (3-5 mL) was collected by cardiac puncture and the animals were euthanized in accordance with guidelines promulagated by the Institutional Animal Care and Utilization committee. Necropsies included the complete resection of liver and removal of whole brain. Blood ethanol concentrations (BECs) were determined by GC headspace with n-propanol as internal standard. Heptadecanoic acid ethyl ester was added as internal standard to 1.0 mL aliquots of blood or 2 g liver or whole brain homogenates and extracted in toluene-hexane (1:1) at pH 5. Extraction mixtures were throroughly mixed and centrifuged. Solvent layers were removed and evaporated to dryness under nitrogen. Reconstituted residues were injected into a GC/MS equipped with an HP INNOWax GC column. Selected ions in the SIM mode included 88, 101, and 157. BEC data and FAEE concentrations for blood, liver, and brain are reported. These results suggest that a one-step extraction method coupled with GC/MS analysis could be used in identifying and quantitating nonoxidative fatty acid ethyl ester metabolites of ethanol in vivo.