Straight-chain Saturated Hydrocarbons Research Articles

Identification of hydrocarbons from Abies pindrow leaves

The genus Abies family Pinaceae consists of 51 species ranged mainly in temperate and boreal regions of the northern hemisphere, chiefly in mountainous regions [1]. The literature data on phytochemical and biological investigations of the genus of Abies revealed that up to now, 277 compounds were isolated from 19 plants of Abies species. The chemical constituents are mostly terpenoids, flavonoids, and lignans, together with minor constituents of phenols, steroids, and others. The crude extracts and metabolites have been found to possess various bioactivities, including insect juvenile hormone, antitumor, antimicrobial, antiulcerogenic, antiinflammatory, antihypertensive, antitussive, and CNS (central nervous system) activities [2]. Abies pindrow Royle, commonly known as west Himalayan fir, is a large evergreen tree growing up to 40–60 m tall with a trunk diameter of up to 2–2.5 m. It has a conical crown with level branches. In Pakistan, Abies pindrow Royle, known as partal or palundar, is widely distributed at elevations between 2000 and 3000 m throughout the western Himalayas from Afghanistan to Nepal [3]. Pindrow species of Abies is regarded as carminative, stomachic, astringent, expectorant, tonic, antispasmodic, and antiperiodic [4]. Phytochemical studies of the species resulted in the isolation of glucopyranoside, hydroxyflavanone, chalcone glycoside, bioflavonoids, flavonoids and pindrolactone [5], and pentacyclic triterpenoids [6]. Different extracts from the leaves of Abies pindrow Royle exhibited anti-inflammatory, analgesic, and hypnotic activities in rats, attenuated swim stress in mice, and produced hypotension in dogs. Abies pindrow Royle leaves also have an antiulcerogenic effect on the cold-restrained gastric ulcer model in rats [5]. A review of the literature revealed that no hydrocarbons have yet been reported from Abies pindrow Royle. We have previously reported the fatty acid composition of the ethanol extract of the leaves of Abies pindrow Royle. A total of 11 fatty acids, including eight saturated and three unsaturated, was characterized [4]. The present investigation of aerial part (leaves) of Abies pindrow Royle describes the occurrence of long chain hydrocarbons. The presence of these hydrocarbons is detected by GC-MS and supported by FTIR. A careful look at the fragmentation pattern in the mass spectral data reveals the presence of saturated and unsaturated hydrocarbons. These hydrocarbons have been reported for the first time from Abies pindrow Royle. The GC-MS of the hexane fraction revealed the presence of tricosane, eicosane, heneicosane, docosane, tetracosane, nonadecane, octadecane, 1-docosene, 1-octadecene, heptadecane, and 2,6,10,14-tetramethylhexadecane. The identity of these common hydrocarbons was made by comparison of these peaks with the standards by gas chromatography and confirmed by comparison of the fragmentation pattern with those of standard mass spectrum. FTIR analysis supported the structures of these hydrocarbons. The FTIR spectrum exhibits the diagnostic peaks relating to C-H stretching at 2956 cm–1, 2923 cm–1, and 2852 cm–1, C-H bending (scissoring) at 1465 cm–1, C-H methyl rocking at 1378 cm–1, and long-chain methyl rocking at 722.9 cm–1. These peaks verify the required data regarding the hydrocarbons. The GC-MS study of major peaks revealed the presence of straight-chain saturated hydrocarbons. It showed the presence of 11 compounds. The GC-MS pattern showed 11 major peaks along with small peaks. All major peaks were detected as hydrocarbons by GC-MS at different retention times.

Gas chromatographic investigation of rose concrete, absolute and solid residue

The chemical composition and physical properties of the rose absolute produced from rose concretes and the extract, supplied by three different companies, were determined by GC and GC–MS. It was found that rose absolute consists mainly of β-phenylethyl alcohol, citronellol, geraniol, nerol, eugenol, methyl eugenol, geranyl acetate, benzyl alcohol, nonadecane, nonadecene and farnesol. The solid residue, which is the by-product of absolute production, was further divided on a silica gel column into three fractions by solvents having different polarities (n-hexane, 5% diethyl ether in n-hexane, and diethyl ether alone). A fraction eluated with n-hexane was analysed directly by GC and GC–MS. Two other fractions, after saponification, were converted to their methyl ester derivatives and then analysed by GC and GC–MS. It was observed that the solid residue contains mainly straight-chain saturated hydrocarbons with high molecular weight (C15–C31) and the esters of carboxylic acids and a homologous series between them exists. It was also concluded that the extract obtained by solvent extraction from the residue of rose flower (Rosa damascena Mill.) which was subjected to steam distillation is also a valuable raw material. Copyright © 2005 John Wiley & Sons, Ltd.

Identification and Quantitation of the Rice Aroma Compound, 2-Acetyl-1-pyrroline, in Bread Flowers (Vallaris glabra Ktze)

The aroma impact compound, 2-acetyl-1-pyrroline (2AP), has been identified for the first time in headspace of fresh bread flowers (Vallaris glabra Ktze) in which volatile components were extracted by solid-phase microextraction (SPME) at room temperature prior to analysis by gas chromatography-mass spectrometry. A total of 50 volatiles were detected. Among these, 23 volatiles were identified, predominantly in a group of terpenes. More volatiles were found in the extract of fresh bread flowers obtained by continuous steam distillation and solvent extraction (SDS). Of the 40 volatiles identified, the additional components were mainly straight-chain saturated hydrocarbons. 2AP was found in the extracts obtained by both SPME (0.37%) and SDS (2.71% relative proportion). Quantitative analyses of 2AP in bread flowers and other plant materials were performed by solvent extraction employing acidic solutions and capillary GC with flame ionization detection. The highest concentration of 2AP was found in dried flowers of V. glabra at 26.1 mg/kg. By comparison with other plant sources, fresh leaves of Pandanus amaryllifolius Roxb contain 2AP at 10.3 mg/kg and Thai fragrant rice, Khao Dawk Mali 105, at 3.0 mg/kg.

Gas sampling analysis of combustion processes in a homogeneous charge compression ignition engine

In-cylinder gas sampling experiments were conducted to clarify the chemical reaction processes of homogeneous charge compression ignition (HCCI) combustion. To study the differences in ignition processes by the ignitability of fuels, three kinds of straight-chain saturated hydrocarbons, such as n-pentane, n-hexane and n-heptane, were used as the fuels. Also, to study specific differences in the ignition processes between a single-component fuel and a dual-component fuel, n-pentane was used as the single-component fuel and n-hexane and ethylene, with compositions adjusted in order to have the same ignitability as n-pentane, were used as the dual-component fuel. The results show that the chemical processes in the low-temperature oxidation range, from 700 to 900 K, need to be controlled for the ignition timing control of HCCI combustion. Controlling ignition timing by dual fuel means controlling the oxidation starting time by the ignitability of a high cetane number fuel and controlling the low-temperature oxidation rate by varying the composition of the high and low cetane number fuels.

Gas-Phase Coordination of Mg+, (c-C5H5)Mg+, and (c-C5H5)2Mg+ with Saturated Hydrocarbons

The coordination of the electronic ground states of Mg+, (c-C5H5)Mg+, and (c-C5H5)2Mg+ with the straight-chain saturated hydrocarbons methane, ethane, n-propane, n-butane, n-pentane, n-hexane, and n-heptane has been investigated in the gas phase in helium at room temperature and moderate pressures. Reaction rate coefficients and product distributions were measured with the selected-ion flow tube (SIFT) technique operating at 294 ± 3 K and a helium buffer-gas pressure of 0.35 ± 0.01 Torr. Rate coefficients were measured for all observed ligation steps (or upper limits in the case of nonreactions), and bond connectivities in the coordinated ions were probed with multicollision-induced dissociation. Only single ligation was observed. The rate of ligation was found to depend on the size of the saturated hydrocarbon, increasing with increasing size until the collision rate is reached, and on the degree of ligation with c-C5H5. Mg+ was found to be unreactive with methane and ethane, k < 10-13 cm3 molecule-1 s-1, but ligation was observed with the other hydrocarbons, k ≥ 7 × 10-12 cm3 molecule-1 s-1. Single ligation of Mg+ with c-C5H5 substantially enhances the efficiency of subsequent ligation: the ligation is rapid, k ≥ 1.4 × 10-10 cm3 molecule-1 s-1, with all the saturated hydrocarbons investigated. Double ligation with c-C5H5 completely shuts down the efficiency of ligation: no reaction was observed between the saturated hydrocarbons and the full-sandwich magnesocene cation, k < 10-13 cm3 molecule-1 s-1. A linear correlation is reported between the measured thresholds for multicollision-induced dissociation and the polarizability of the hydrocarbon ligand. With a view to published calculations by Bauschlicher et al. for Mg+−CH4 and Mg+−C2H4, this correlation is consistent with end-on structures for the Mg+−L and (c-C5H5)Mg+−L species observed in this study. A detailed study using density functional theory for the interaction of Mg+ with three rotamers of n-pentane indicates that interconversion of different isomers of Mg+−n-C5H12 should be easy, even at room temperature and that the ligated species Mg+−n-C5H12 is “dynamic” rather than “static”. Stronger bonding (by a factor of about two) is indicated for (c-C5H5)Mg+−L by the multicollision CID experiments, and this is consistent with a formal description of (c-C5H5)Mg+ as (c-C5H5)-Mg2+.

Possible anti-tumour-promoting activity of components in Japanese soybean fermented food, Natto: effect on gap junctional intercellular communication.

In order to detect any protective agent against tumor formation, we examined the anti-tumor-promoting effect of a Japanese traditional soybean fermented food, Natto. Dye transfer was employed as an assay method. When fluorescent dye was microinjected into cultured BALB/3T3 cells, the dye was transformed into the neighboring cells through the gap junction. This dye transfer was blocked by the treatment with the tumor promoters 12-O-tetra-decanoylphorbol-13-acetate (TPA), a high concentration of NaCl and lithocholic acid (LCA). This reduction of the dye transfer by TPA treatment was not observed when the cells were pretreated with retinoic acid, an anti-tumor promoter. Thus, the recovery of the dye transfer in TPA-treated BALB/3T3 cells was proven to ge a good indicator for detecting some possible anti-tumor promoters. After extraction and fractionation of Natto, we obtained an active fraction (H1) which showed recovery of the dye transfer in TPA-treated cells. The fraction contained straight-chain saturated hydrocarbons. A comparison of the fraction and the authentic samples by GC analysis suggests that the H1 fraction contained straight-chain saturated hydrocarbons from around C30 to C32. Among these hydrocarbons, hentriacontane (C31) was found at the highest concentrations, and was shown to have the highest activity. Hentriacontane at a very low concentration of 0.65 ng/ml was shown to recover the dye transfer inhibited by the treatment with TPA as well as with NaCl and LCA.

Growth of aerobic bacteria on alkali- solubilized lignite

Coal contains a complex mixture of organic compounds, the variety of which depends on the particular type of coal. There is a general agreement that coal is composed of a macromolecular fraction and a lower-mol-wt fraction that are noncovalently associated with each other. Huttinger and Michenfelder have proposed a structural unit for the macromolecular portion of a lignite coal that comprises 2 and 3-ring fused aromatics, paraffin, terpene, cycloaliphatics, hydrocarbon bridges, several carboxyl moieties, straight-chain saturated hydrocarbons, branched-chain hydrocarbons, sulfur heterocyclics, ether linkages, alcohol groups, nitrogen heterocyclics, and chelated metals. Low-mol-wt compounds found in coal can be separated from macromolecules by extraction with organic solvents, such as tetrahydrofuran. Low-mol-wt organic compounds that have been revealed by such extractions include straight-chain (C{sub 13}-C{sub 33}), branched, and cyclic alkanes; aryl and aryl alkyl compounds with 1-6 rings; and phenolic compounds. In low-ranked coals, branched alkanes predominate over straight chain. This report describes the enrichment for, and isolation of, microorganisms that are capable of modifying lignite.

Digestibilité des hydrocarbures saturés chez la truite

The digestibility of alkanes has been investigated in rainbow trout Salmo gairdneri R. using an indicator method, based on the utilisation of chromic oxide as a marker. Fish were fed experimental diets containing 1% of pristane, or dodecylcyclohexane, or a mixture of n-paraffins (from C 14 plus C 24). Faeces were collected automatically during 7 days. The absorption of n-alkanes in trout was found to follow a parabolic relationship with carbon chain length of these compounds. The maximum digestibility was observed for pentadecane. Moreover, for the same total carbon number, straight-chain saturated hydrocarbons were preferentially retained over cycloalkanes but less absorbed than branched-paraffins.

Le grégarisme chez Blaberus craniifer: Isolement et identification de la phéromone

In the gregarious cockroach, Blaberus craniifer, an aggregation pheromone is produced by all individuals (larvae and adults) except at ecdysis. The pheromone, secreted by the mandibular glands, was analysed by thin-layer and gas chromatography and by mass spectrometry. The mandibular glands secrete three major volatile products: undecane, tetradecane, and ethyl-caproate. The last component is of unknown significance, but a mixture of undecane and tetradecane ( 1 1 ) reproduces all the effects of the natural pheromone. The distance of perception is short: 40 cm for the adults and old larvae and 10 cm for the first instar larvae. The threshold is about 0·2 ng for the adults and 0·4 ng for the first instar larvae. The mixture undecane and tetradecane is specific: it is not attractive for other gregarious cockroaches (many of which are devoid of mandibular glands), and other straight-chain saturated hydrocarbons are not attractive for B. craniifer.

Mammalian Metabolism of Straight-chain Saturated Hydrocarbons

Abstract The metabolism of straight-chain saturated hydrocarbons has been demonstrated in the goat, rat and chicken. Studies with [1-14C]octadecane and [1-14C]hexadecane shwoed that the hydrocarbons were converted directly to fatty acids of the same chain length. Since both the initial substrates were symmetrical molecules with a methyl group on either end, the reaction must be omega oxidation. The studies have suggested a widespread occurrence of the oxidation in various tissues, and among widely divergent animal types. Although, only tracer quantities of hydrocarbons were administered, many intriguing questions for further study have been indicated.

Etude chimio-taxonomique du genre Hypericum—V. : Identification de quelques constituants non volatils d' Hypericum perforatum L

Straight-chain saturated hydrocarbons (C 28 and C 30), alcohols (C 24, C 26 and C 28) and β-sitosterol have been isolated from the aerial parts of Hypericum perforatum L.

Mammalian metabolism of straight-chain saturated hydrocarbons

The metabolism of straight-chain saturated hydrocarbons has been demonstrated in the goat, rat and chicken. Studies with [1- 14C]octadecane and [1- 14C]hexadecane shwoed that the hydrocarbons were converted directly to fatty acids of the same chain length. Since both the initial substrates were symmetrical molecules with a methyl group on either end, the reaction must be omega oxidation. The studies have suggested a widespread occurrence of the oxidation in various tissues, and among widely divergent animal types. Although, only tracer quantities of hydrocarbons were administered, many intriguing questions for further study have been indicated.

Atomic Beam Resonance Experiments with Stored Beams

The atomic-beam separated, oscillatory-field resonance technique has been used to study the hyperfine frequency of cesium which is perturbed by collisions with storage box walls. With a wall coating of long straight-chain saturated hydrocarbons, resonances are observed after as many as 200 wall collisions. A theory of the effect of wall collisions on the hyperfine frequency which is in qualitative agreement with experimental results is described. The shape of the resonance curve is analyzed by a detailed consideration of the statistical nature of the wall collision.