Methyl Octadecanoate Research Articles

Contribution of Malang quartzite-based silica in K2O/zeolite Y catalyst for methyl ester synthesis of off grade crude palm oil

Malang quartzite contains a highly silica content. The silica changes the structural composition of Zeolite Y. Currently, a heterogeneous catalyst is developed to optimize transesterification of Off Grade CPO (Crude Palm Oil). The aims of this study are: (1) synthesize K2O/Zeolite Y using silica from Malang quartzite, (2) synthesize methyl esters from Off Grade CPO using K2O/Zeolite Y catalyst, and (3) to evaluate quartzite based-silica contribution in Zeolite Y for the reaction activity via GC-MS analysis. The experimental stages were: the oil preparation, esterification of the prepared oil, preparation of K2O/zeolite Y catalyst, and the transesterification. This study applied variations of [KOH] in Zeolite Y (10, 20, and 30 % w/w) and the concentration of the transesterification catalyst (2, 3, and 4 % w/w). The K2O/Zeolite Y catalyst was successfully synthesized by impregnation method. Methyl esters of Off Grade CPO resulted the highest yield of 95.05 % with 4 wt% of 30-K2O/Zeolite Y (30 % KOH impregnation). The synthesized methyl esters have a density of 0.877 g/mL, a viscosity of 4.6 cSt, a refractive index of 1.445 and an acid number of 0.384 mg/g according to the standard (SNI 7182:2015). The main components of the methyl ester based on GC-MS results were methyl octanoate, methyl decanoate, methyl dodecanoate, methyl 9-octadecanoate, methyl octadecanoate and methyl tetracosanoate. Using quartzite-based silica, a co-activity of the reaction has occurred.

Identification of Pharmaceutically Important Constituents of Quinoa Root

The present investigation was carried out to explore the bioactive compounds from the n-hexane fraction of methanolic extract of quinoa (Chenopodium quinoa Willd.) roots. For this purpose, C. quinoa roots were collected, shade dried, and crushed into a fine powder. The powdered material was extracted in methanol, filtered, and the filtrate was partitioned with n-hexane, followed by GC-MS analysis of the n-hexane fraction. The quantitative determination of this fraction revealed the presence of 15 phytochemical constituents of diverse nature. Among these, octadec-9-enoic acid (44.18%); n-hexadecanoic acid (18.87%); methyl (Z)-octadec-9-enoate (12.87%); methyl hexadecanoate (4.30%); 2,3-dihydroxypropyl elaidate (3.63%); phthalic acid (3.08%); methyl octadecanoate (2.27%) and 1,12-tridecadiene (2.00%) were prevailing as the most abundant to moderately occurring compounds. A thorough literature survey was carried out to collect information regarding the pharmaceutical properties of the identified compounds. It showed some of the identified compounds namely dodecanoic acid; tetradecanoic acid; 2-benzoyl-d-galactosan; n-hexadecanoic acid; methyl octadecanoate; octadec-9-enoic acid; and 2,3-dihydroxypropyl elaidate possess antifungal, antibacterial, antioxidant, antiviral, anti-inflammatory, and/or anti-cancer properties.

Production and physicochemical properties of safflower seed oil extracted using different methods and its conversion to biodiesel

The production and physicochemical characterization of high quality biodiesel from the from safflower seed oil extracted by different extraction methods was studied. The oil extraction efficiencies of various extraction methods were compared. The hydraulic press, continuous pressing (expeller) and soxhlet extraction methods were used to extract oil from safflower seeds. The soxhlet extraction method was found to have the highest oil extraction efficiency up to 32.49%. The majority of fatty acid compositions of the safflower seed oil obtained were oleic acid (C18:1) and linoleic acid (C18:2) with 30.9% and 56.4%, respectively. In other words, it has been determined that the unsaturated fatty acids of safflower seeds oil constitutes more than 89% of total fatty acids. The synthesis of safflower seeds oil into a high quality biodiesel product was carried out by a one-step transesterification process catalyzed by an alcohol/oil molar ratio of 4.799/1 and KOH catalyst. The synthesis of biodiesel by transesterification process was confirmed by FT-IR, 1H NMR, 13C NMR spectroscopy and GC-FID chromatograms. Fatty acid methyl esters (FAME) in safflower seeds oil biodiesel were identified by GC-FID analysis. Majority of FAMEs were methyl hexadecanoate (C16:0), methyl octadecanoate (C18:0), methyl 9 octadecanoate (C18:1), methyl octadec-9-enoate (C18:1), methyl 9,12-octadecadienoate (C18:2) and methyl octadecatrienoate (C18:3). The percentage conversion of safflower seed triglycerides to the corresponding methyl esters determined by 1H NMR was calculated as 94.12%. In addition, various fuel properties of the synthesized biodiesel were determined using ASTM and EN standards and compared with relevant studies. The biodiesel product synthesized from safflower seed oil meets both ASTM-D6751 and EN-14214 standards. In conclusion, safflower seed oil is promising in terms of high productivity, quality and potential in the production of biodiesel products that can be used as a substitute for fossil-based diesel fuel.

The Antimicrobial Activity and Characterization of Bioactive Compounds in Peganum harmala L. Based on HPLC and HS-SPME-GC-MS.

Peganum harmala L. is a perennial herb of the Tribulus family and its aerial parts and seeds can be used as medicine in the traditional medicine of China. However, the differences in chemical components and antibacterial activity between different parts have not been reported. In this study, the chemical composition of the different parts of P. harmala was characterized by high-performance liquid chromatography (HPLC) and headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The antimicrobial activities of the different parts and some isolated components were also carried out on 12 bacterial strains and phytopathogenic fungi. The HPLC results revealed that the contents of harmine and harmaline in the seeds were higher than that in the aerial parts. A total of 94 volatile organic compounds (VOCs) were tentatively identified by HS-SPME-GC-MS for the first time. The major components were methyl hexadecanoate, p-xylene, octane, (Z)-9-octadecanoate, ethylbenzene, methyl octadecanoate, ethyl hexadecanoate, and methyl tetradecanoate. At the concentration of 800 μg·mL−1, the methanol extracts of seeds showed stronger antimicrobial activities with a wide antimicrobial spectrum, inhibiting Escherichia coli (ATCC 24433), Xanthomonas oryzae (ACCC 11602), and Xanthomonas axonopodis with inhibitory rates of more than 90%. Furthermore, harmine and harmaline showed better antibacterial activities against all the bacteria. These findings indicated that alkaloids from P. harmala could account for antimicrobial activity, which could be used as lead molecules in the development of new antimicrobial drugs.

Characterization of novel euryhaline microalgal cultures from Punjab, India for bioactive compounds.

Microalgae have gained recognition due to the occurrence of nutraceuticals which are sustainable reservoir to substitute the organic chemical-based health supplements. The biomass of microalgae incorporates various functional biomolecules like chlorophyll, carotenoids and phenols that exhibit therapeutic properties and act as nutraceuticals. In spite of the higher production of the microalgal biomass, difference in their biochemical composition, and lack of characterization for nutraceutical properties are the prime hindrance in upscaling these bio-factories. Two euryhaline microalgal strains viz. BGLR8 and BGLR16, isolated from water-logged areas of Punjab, India were screened for biomass production and characterized for the nutraceutical properties using biochemical estimations. Results of the study indicated that BGLR8 retained maximum amount of lipids (86mg/g), total chlorophyll (29.42mg/g), carotenoids (28.82mg/g), phenols (4.46mg/g), phycocyanin (52mg/g), astaxanthin (19.27mg/g) and β-carotene (5.6mg/g) and anti-oxidant activity (31.73%) as compared to BGLR 16. The results of gas chromatography-mass spectrometry (GC-MS) study revealed the presence of 8 therapeutic compounds like Dimethyl (E)-but-2-enedioate, Hexasilacyclododecane, Heptasilacyclotetradecane, Methyl (Z)-pentadec-8-enoate, Methyl octadec-13-enoate, Methyl hexadecanoate, Methyl octadecanoate, Methyl-octadeca-9,12-dienoate in BGLR8. Molecular identification through 18S rRNA gene sequencing confirmed BGLR8 to be a member of genus Coelastrella. (GenBank accession no. MW443083.1). Microalgae can be used as an alternate and feasible source of PUFAs; however, only a few species are employed for PUFA synthesis, necessitating additional in-depth research and the isolation of novel strains.

Nitrogen Deprivation in Fremyella diplosiphon Augments Lipid Production without Affecting Growth

Metabolic products such as lipids and proteins produced in cyanobacteria represent an excellent source of biomass and do not compete with agricultural land use unlike soybean and corn. Given their potential use as novel materials for biodiesel production, we aimed to explore the effect of cultivation period and nitrogen concentration on the growth rate and lipid content of Fremyella diplosiphon, a model cyanobacterium. In this study, F. diplosiphon grown in BG11/HEPES medium supplemented with 1.5 g L−1 sodium nitrate (NaNO3) for 7, 10, 15, and 20 days were compared to the untreated control in media amended with 0.25, 0.5, and 1.0 g L−1 NaNO3. Cultures were inoculated in liquid media and grown under continuous fluorescent light in an orbital incubator shaker, and extracted lipids subjected to gravimetric analysis and gas chromatography-mass spectroscopy to determine the best culture conditions for lipid production. Our results demonstrated that a reduction in nitrogen concentration had no significant effect on the growth rate across all cultivation periods; however, the accumulation of total lipid content was significantly influenced by nitrogen concentration. A maximum lipid production (40%) with no reduction in growth was observed in 10-day old cultures in a BG11/HEPES medium supplemented with 1.0 g L−1 NaNO3. Fatty acid methyl ester composition of transesterified lipids demonstrated high amounts of methyl palmitate (50–70%) followed by methyl octadecenoate (17–30%) in the accumulated lipids at all treatments. Trace quantities of methyl dodecanoate, methyl hexadecanoate, methyl octadecanoate, and methyl octadecadienoate (1–8%) were also observed in all tested samples, indicating that nitrogen deprivation in culture media increases lipid production without affecting growth.

Effects of drying techniques on chemical composition and volatile constituents of bee pollen

Bee pollen is used as a food supplement by humans as it is rich in carbohydrates, proteins, lipids, vitamins, minerals and trace elements. Bee pollen has many biological activities such as antibacterial, antifungal, antitumor and antioxidant. Fresh bee pollen is not suitable for long-term storage because of its moisture content. In order to protect the nutrient content and freshness, the bee pollen can be dried by using different drying techniques. In this study, the biochemical characterization of the bee pollen samples dried by different techniques and drying effects on the biochemical properties of bee pollen were determined. Moisture, total lipid and protein, pH and total phenolic content of pollen samples were determined. The results ranged 6.23–20.62%, 4.98–5.57%, 16.812–1.477%, 4.08–4.33 and 15.2–22.73 mg GAE g<sup>–1</sup>, respectively. All samples are rich in squalene and methyl octadecanoate. It is clear that bee pollen bioactive components will be less damaged by using drying methods performed under more moderate conditions like lyophilization than when the traditional method is used.

Influence of Some Factors on the Progress of a New Reaction in the Chemistry of Organoaluminum Compounds

We earlier discovered a new reaction in the chemistry of organoaluminum compounds (OACs), specifically, the formation of O-isobutyl acetals on low-temperature (–70°C) treatment of seven-membered lactones with a double (or more) molar amount of diisobutylaluminum hydride (DIBAH) in methylene chloride. To assess the boundaries for the formation of isobutyl acetals depending on the ring size, we involved in the low-temperature hydride reduction six-, eight-, and thirteen-membered lactones. To determine how the scope of the new reaction depends on the nature of the organoaluminum reagent, we tested triisobutylaluminum (TIBA). To determine how the formation of isobutyl acetals on low-temperature (–70°C) reduction with excess DIBAH in CH2Cl2 depends on whether the starting ester is cyclic or acyclic and, if the former is the case, on the ring size in the ester, we used the acyclic methyl octadecanoate as the starting compound. It was found that the new reaction in the chemistry of AOC with DIBAH as the reducer is characteristic only of seven-membered lactones and atypical of acyclic methyl octadecanoate and ricinoleate (i.e. acids with the carbon chain length more than 6).

CHEMICAL ANALYSIS OF THE SEED OIL OF CANAVALIA ENSIFORMIS LINN. FOR NUTRITIONAL AND INDUSTRIAL QUALITIES

The extensive demand for oils by man for consumption and industrial applications has led to an increasing search for oils from non-conventional sources to augment the available ones. Thus, the seed oil of Canavalia ensiformis Linn., a leguminous plant abundantly found in South-western Nigeria was extracted and analysed for its nutritional and industrial applications. Phytochemical screening and proximate analysis of the seeds along with physicochemical parameters of the oil using standard procedures were done. Different weights of the powdered seeds were extracted using a soxh let extractor with four solvents- n-hexane, chloroform, petroleum ether and ethanol. The fatty acid composition of the oil was characterized by Gas chromatography-Mass spectrometry (GC-MS). Canavalia ensiformis seed contained saponins, anthracene derivatives, phenols, tannins, sapogenin and reducing sugar. The proximate analysis gave 1.50±0.84, 25.51±0.21, 2.10±0.23, 3.05±0.92, 56.94±1.96, 10.90±1.11 for moisture content, protein, ash content, crude fibre, carbohydrate, and oil extracts respectively. The physicochemical parameters of the oil were: pH-4.69, specific gravity0.89±0.01, acid value-6.2, saponification value-203.3 mg KOH/g, free fatty acid-3.1, peroxide value18.50 and iodine value-61.0 g of I/100 g oil, while the oil is miscible with petroleum ether. The fatty 2 acid compositions were 11-octadecenoic acid (43.86%) 9-octadecenoic acid (27.49%), hexadecanoic acid (17.07%), cis-11-eicosenoic acid (4.32%), ethyl cis-9-octadecenoate (3.80%) and methyl octadecanoate (3.46%). The presence of 75.67% monoenoic acids in its composition, high saponification value, good foaming and emulsion properties makes the oil useful as an emollient, excipient in pharmaceuticals and solubilizing agents in aerosol products and also of great importance in soap and cosmetics industries.

Synthesis of Methyl Ester from Rice Bran Oil through the Esterification Reaction

Vegetable oil is one of rice bran components. As triglycerides, vegetable oil can be converted to fatty acid and alkyl esters for further treatments. Synthesis of alkyl ester oil can be carried out by esterification or transesterification reaction, depending on the quality of the oil and the catalyst. The purposes of this study are 1) Rice bran oil isolation, 2) Oil esterification 3) Characterization and identification of the methyl ester that compose rice bran oil. The stages in this research are 1) Extraction of rice bran oil, 2) Synthesis of methyl ester from rice bran through esterification reaction, 3) Methyl ester characterization of rice bran oil and its potential test as biodiesel included determination of density, viscosity, refractive index, and acid number test, 4) The identification of synthesized methyl esters composition using GC-MS. The results showed that rice bran oil has a yield of 18.09%. Synthesis of methyl esters from rice bran oil through the esterification reaction with a catalyst acid yields 72.37%. The characters of the synthesized methyl ester are on the range of biodiesel quality standards, namely, the density is 0.850 g/mL, viscosity is 4.73 cSt, a refractive index is 1.45871, and an acid number is 0.76 g KOH/g methyl ester, therefore it is claimed that the synthesized methyl esters have the potential as biodiesel. The GC-MS result showed the presence of compounds methyl tetradecanoate (0.38%), methyl hexadecanoate (40.67%), methyl 9-octadecenoate (53.68%), methyl octadecanoate (5.02%), and methyl eicosanoate (0.14%).

Metabolites identification of oil palm roots infected with Ganoderma boninense using GC–MS-based metabolomics

An approach to metabolomics profiling of non-infected and Ganoderma boninense (G. boninsense) infected oil palm roots crude extracts that utilize gas chromatography-mass spectrometry (GC–MS) and multivariate statistics of principal component analysis (PCA) have been tested. This combination has provided a rapid approach in investigating the changes in the metabolite variations of non-infected and infected oil palm roots at 14 and 30 days post-infection. The extracts were prepared by using 80% (v/v) of methanol. In identifying the metabolites responsible for each differentiation, PCA model was generated in loading bi-plot. Dimethyl benzene-1,4-dicarboxylate, methyl 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate, ergost-5-en-3-ol, (3β), stigmast-5-en-3-ol, (3β), stigmasterol, methyl hexadecanoate, methyl (9Z,12Z)-octadeca-9,12-dienoate, methyl octadecanoate, 2-(hydroxymethyl)-2-nitropropane-1,3-diol, methyl (Z)-octadec-6-enoate and (E)-icos-5-ene were found more abundant in G. boninense infected roots than in non-infected roots. Steroidal compounds and fatty acid derivatives which has been determined in the non-infected and G. boninense infected roots regulate a variety of responses to the G. boninense. The abundant of these metabolites in G. boninense infected roots are due to the crucial roles in pathogen defence.

GC-MS analysis of the methanolic extracts of Smilax china and Salix alba and their antioxidant activity.

Smilax china L. (family Smilacaceae) and Salix alba L. (family Salicaceae) are plants that have been traditionally used to treat various ailments in Indian and Chinese medicine. A quantitative estimation of the methanolic extracts of these plants was performed by GC-MS analysis to obtain insight into its phytoconstituents responsible for therapeutic action. The antioxidant potential of the methanol extracts of Smilax china (MESC) and Salix alba (MESA) were assessed with DPPH by using a UV spectrophotometer at a wavelength of 517 nm. The prevailing compounds found in MESC were lactam sugars including 2,5-dimethyl-2,4-dihydroxy-3(2H)-furanon (1.40%), 1,5-anhydro-6-deoxyhexo-2,3-diulose (4.33%), and alpha-methyl-1-sorboside (1.80%); the two alkaloids found were 1,4-methane-4,4a,5,6,7,8,9,9a-octahydro-10,10-dimethyl cyclohepta[d] pyridazine (0.87%) and 1,3,7-trimethyl-2,6-dioxopurine(0.54%); terpenes included deltacadinene (0.39%), terpineol, (+)-cedrol (22.13%), 3-thujanol (0.77%), and 9,10-dehydro-cycloisolongifolene (0.34%); fatty acids included cis-vaccenic acid (4.98%) and telfairic acid (1.10%); esters included 1,2,3-propanetriol diacetate (7.56%), 7-hexadecenoic acid, methyl ester (1.77%), eicosanoic acid, and methyl ester (0.95%); and glycerol included 1,2,3-propanetriol (28.75%). The interesting compounds found in MESA were reducing sugars like D-allose (4.40%) and pyrogallol (10.48%), alkaloids like caffeine (63.49%), and esters like methyl octadecanoate (0.53%). Both fractions revealed considerable antioxidant activity. The reported existing phenolic compounds and terpenes are responsible for the antioxidant activity of the plant extracts.

Pengaruh Pemberian Variasi pH Terhadap Produksi Trigliserida Total dan Komposisi Asam Lemak dari Chlorella Vulgaris Air Tawar

Chlorella vulgaris is a microalgae that has high lipid content and potential as raw material for biofuel production. This study aims are to determine the effect of pH on growth, lipid production and fatty acid composition of C. vulgaris by using Growmore 32-10-10 fertilizer as a culture medium. Microalgae were cultured in medium Growmore 32-10-10 for 10 days. Afterward, pH of medium was varied into pH 5, 7, 8.2 and 9 and continued cultivate for 3 days. C. vulgaris cultured at pH 8.2 which is a control pH reached optimum growths. The GC-MS analysis for lipid productivity of C. vulgaris was 0.5020 g/L/day and 0.2902 g/L/day for microalgae grew at pH 8.2 and 9, respectively. Cultures at pH 8.2 and 9 produce methyl hexadecanoate, methyl 9-octadecanoate, methyl octadecanoate, methyl 9,12-octadecadienoate, methyl 9,11-octadecadienoate. Additional fatty acid methyl nonadecanoate was also found in C. vulgaris grew at pH 9. The low and high pH stress of C. vulgaris culture medium did not affect culture growth but altered lipid production and fatty acid composition.

Pengaruh Pemberian Variasi pH terhadap Produksi Trigliserida Total dan Komposisi Asam Lemak dari Chlorella Vulgaris Air Tawar

Chlorella vulgaris is a microalgae that has high lipid content and potential as raw material for biofuel production. This study aims are to determine the effect of pH on growth, lipid production and fatty acid composition of C. vulgaris by using Growmore 32-10-10 fertilizer as a culture medium. Microalgae were cultured in medium Growmore 32-10-10 for 10 days. Afterward, pH of medium was varied into pH 5, 7, 8.2 and 9 and continued cultivate for 3 days. C. vulgaris cultured at pH 8.2 which is a control pH reached optimum growths. The GC-MS analysis for lipid productivity of C. vulgaris was 0.5020 g/L/day and 0.2902 g/L/day for microalgae grew at pH 8.2 and 9, respectively. Cultures at pH 8.2 and 9 produce methyl hexadecanoate, methyl 9-octadecanoate, methyl octadecanoate, methyl 9,12-octadecadienoate, methyl 9,11-octadecadienoate. Additional fatty acid methyl nonadecanoate was also found in C. vulgaris grew at pH 9. The low and high pH stress of C. vulgaris culture medium did not affect culture growth but altered lipid production and fatty acid composition.

Phytochemical and pharmacological profile with biogenetic correlation of bioactive phytoconstituents from the stems of Cordia sinensis Lam

Present investigation reports first phytochemical profile of Cordia sinensis Lam. stems utilising GC-FID and GC-MS analyses. Moreover, antibacterial, antifungal, phytotoxic and insecticidal potential of stems was also evaluated. Altogether 33 (∼69%) compounds were identified. n-Hexadecanoic acid (15.62–35.55%), methyl hexadecanoate (11.22–29.49%), methyl octadecanoate (4.10–8.66%) and n-octadecanoic acid (4.24–6.64%), present in all the fractions were the major components identified. Overall 4 hydrocarbons, 7 fatty acids, 12 fatty acid esters, 3 phytosterols, 2 terpenes, a terpenoid and 4 aromatics were identified. It is important to note that methanolic mother extract showed moderate phytotoxic activity at higher dose only. However, GC-MS identifications revealed the presence of several phytoconstituents with reported bioactive potential. Moreover, biogenetic correlation of identified phytoconstituents with other parts of plant confirms their natural existence. Newly identified secondary metabolites of C. sinensis stems may also serve as the chemotaxonomic markers and can be correlated with the genus Cordia and Boraginaceae.

Volatile Constituents of the Leaf Essential Oil of Crinum asiaticum and their Antimicrobial and Cytotoxic Activities

Crinum asiaticum, locally known as “bunga tembaga suasa” in Malaysia has been used since ancient ages in folk medicine. The present study was aimed to examine the volatile constituents of the leaf essential oil of C. asiaticum and their antimicrobial and cytotoxic activities. The chemical constituents obtained by hydrodistillation were analyzed using GC and GC/MS. Seventeen constituents were identified in the leaf essential oil, representing 93.14 % of the sample. The major constituents found in the leaf essential oil were 1-hexadecanol (27.69 %), oleic acid (23.32 %) and methyl octadecanoate (12.45 %). In the in vitro MTT assay, the leaf essential oil induced cytotoxic effects of 20-25 % towards MCF-7 cells within 24-72 h of incubation period at 20-70 mg/ml. Moreover, the leaf essential oil also showed antimicrobial activity against Shigella boydii, Candida albicans and Rhizopus sp. with MIC values of 1.25, 0.078 and 0.078 mg/ml, respectively.

Hydrodeoxygenation–Alkylation Pathway for the Synthesis of a Sustainable Lubricant Improver from Plant Oils and Lignin-Derived Phenols

Fatty acid methyl esters (FAMEs) derived from plant oils are excellent lubricant improvers, but they do not have desirable oxidative stability and cold-flow properties. This study investigated phenol hydrodeoxygenation in hexadecane and aromatic alkylation of FAMEs over a K30 montmorillonite catalyst to give phenyl-branched FAME (PBFAME) as a potential lubricant improver. The high selectivity to aromatic hydrocarbons during hydrodeoxygenation over Pd/C was likely due to the slow hydrogenation rate of phenols in hexadecane, absence of hydrogen bonding in nonpolar solvents allowing hydroxyl groups to participate in dehydration reactions, and limited diffusion of hydrogen from bulk solution to Pd sites. Isomers of methyl (methylphenyl)octadecanoate (n-MMPO) were produced during toluene alkylation of methyl oleate. The presence of both Brønsted and Lewis acid sites in K30 facilitated selective synthesis of n-MMPOs. The oxidative stability and cold-flow properties of n-MMPO were better than those of canola biodiesel.

Fatty acids methyl esters: Complementary measurements and comprehensive analysis of vaporization thermodynamics

Vapour pressures of methyl decanoate, methyl undecanoate, methyl tetradecanoate, methyl hexadecanoate and methyl octadecanoate were measured by using the static technique. Vapour pressures of methyl dodecanoate, methyl tridecanoate, methyl tetradecanoate, methyl heptadecanoate, and methyl octadecanoate were measured by using the transpiration method. In the present work, vapour pressures of methyl esters of the saturated fatty acids from methyl propanoate to methyl eicosanoate were collected from the literature. These data together with own complementary results were used for validation of methods for assessment of the difference ΔlgCp,mo required for the correct adjustment of vaporization enthalpies to the reference temperature 298.15 K. The evaluated vaporization enthalpies for esters from methyl propanoate to methyl eicosanoate demonstrate impeccable linear chain-length dependence. The CH2 group contributions for different homologous series were derived and compared. Quantitative analysis of dispersion interactions in the long-chained esters have been performed.

Comparative analyses of biodiesel produced from jatropha and neem seed oil using a gas chromatography–mass spectroscopy technique

Biodiesel from jatropha, neem and cottonseed were produced and their compositions were analyzed using gas chromatography–mass spectroscopy. The results revealed that the jatropha, neem and cottonseed oils are reliable sources of biodiesel and are renewable, and hence have a potential to partially meet energy demands in an eco-friendly manner. The biodiesels produced from jatropha contained 91.97% methyl ester, and that produced from neem contained 70.2% methyl ester, whereas that produced from cotton contained 89.75% methyl ester.The greater proportion of prolific ester in the jatropha biodiesel is mono-saturated methyl octa-decanoate which contributes 53.44% by volume. This ester has the tendency of assigning stability to biodiesel. For neem-based biodiesel, the profile evaluation revealed that octadecanoic acid methyl ester is the dominant compound in the mixture with 54.69% by volume. For cotton, the profile revealed that the methyl octadecenoate (C19H36O2) is the predominant compound in the mixture, having the highest percentage of 17.72%. The physico-chemical analyses of the three biodiesels has indicated that the three conform with the American Society for Testing and Materials (ASTM) standards for specific gravity, viscosity, acid value, cold flow properties and sulfur content, and hence are suitable for use in compression ignition engines. Statistical analyses confirmed that there was no significant difference between the experimental values of all the physico-chemical properties investigated; therefore, the experimental data is validated.

IN SILICO ANALYSIS OF XANTHINE OXIDASE INHIBITOR OF ETHYL ACETATE FRACTION OF ETHANOLIC EXTRACT OF STELECHOCARPUS BURAHOL (BL.) HOOK F. AND TH. LEAVES

Objective: The research was conducted by in silico analysis of xanthine oxidase inhibitors of volatile compounds from ethyl acetate fraction of ethanolic extract of Stelechocarpus burahol (Bl.) Hook f. and Th. leaves. The objective of the research was to determine the active compounds as a potential inhibitor of xanthine oxidase by using in silico screening method.Methods: The research was conducted using volatile compounds that were obtained by using gas chromatography of ethyl acetate fraction of ethanolic extract of S. burahol leaves and models of xanthine oxidase inhibitor downloaded via Protein Data Bank (PDB) with code 3BDJ, then performed docking process using the PyRx program, and then evaluated of the free energy (ΔG) as docking process results.Results: Volatile compounds in the ethyl acetate fraction of ethanolic extract were 3 heptene, 2,2,4,6,6-pentamethyl (2.15%), methyl hexadecanoate (4.16%), ethyl tridecanoate (34.63%), methyl octadecanoate (7.26%), ethyl hexadecanoate (51.8%). The result showed that three of the chemical compounds have the lower free energy value as xanthine oxidase inhibitors than oxypurinol.Conclusion: They were ethyl tridecanoate, methyl octadecanoate, ethyl hexadecanoate with free energy (ΔG) -10.7, -7.6, -7.1 kcal / mol.Keywords: Stelechocarpus burahol (Bl.) Hook f. and Th., xanthine oxsidase, in silico analysis.