Saturated N-alkanes Research Articles

Photosensitized biohybrid for terminal oxygenation of n-alkane to α, ω-dicarboxylic acids

To date, oxyfunctionalization of saturated hydrocarbons in a selective fashion is a prime challenge in industry. Currently, Inorganic-biohybrid catalysts have shown tremendous potential for sustainable conversion of fine chemicals by integrating light harvesting potential of inorganic materials with metabolic activity of microbes. Herein, we have developed a biohybrid system combining a highly efficient light-harvesting inorganic material MoS2-CNT-Eosin-Y and yeast Candida tropicalis (C.tropicalis) for efficient preparation of α, ω- dicarboxylic acid (α, ω-DCA) using saturated n-alkanes. The yeast C.tropicalis harvests photo generated electrons from the illuminated MoS2-CNT-Eosin-Y and uses them for the activation of the P450 catalytic cycle. This process enables the efficient regeneration of nicotinamide cofactors (NADH/NAD+) facilitating production of α, ω-DCA. Under irradiation condition the biohybrid catalyst shows 4.01 times higher dodecanedioic acid production compared to that of native yeast strain. Analysis of NADH/NAD+ ratio and alcohol dehydrogenases (ADH) activity clearly indicates that light illumination on MoS2-CNT-Eosin-Y/C.tropicalis promotes regeneration of cofactor during cellular metabolism of C. tropicalis thereby improving the activity of ADH enzyme resulting higher production of α, ω-DCA. The present work opens up a new avenue for the sustainable synthesis of fine chemicals through tailoring of complex biohybrid pathways.

Corresponding state principle based correlation for the thermal conductivity of saturated refrigerants liquids from Ttr to 0.90Tc

We here report that the corresponding state principle well stands for the temperature dependent thermal conductivity of the saturated refrigerants liquids by using the reduced quantities proposed here. A corresponding state principle based correlation is proposed and proven to be accurate in the temperature range from the triple point temperature to 0.90 times the critical temperature. Additionally, this correlation also stands for the saturated n-alkanes liquids. For the 23 refrigerants and 11 n-alkanes considered here, the proposed correlation can reproduce the REFPROP data with AAD<2% for 21 liquids, and AAD<5% for all the liquids considered.

Regioselective C–H hydroxylation of n-alkanes using Shilov-type Pt catalysis in perfluorinated micro-emulsions

In this work, the potential of combining Shilov-type PtII and micellar catalysis to realize the challenging terminal C–H hydroxylation of saturated n-alkanes using water as the reaction medium is demonstrated.

Fungal proliferation and hydrocarbon removal during biostimulation of oily sludge with high total petroleum hydrocarbon.

A laboratory-scale study was conducted to investigate the effect of bioaugmentation (BA) and biostimulation (BS) on the remediation of oily sludge with high total petroleum hydrocarbon (TPH) content (269,000mg/kg d.w. sludge). TPH concentration significantly decreased by 30.4% (P < 0.05) in the BS treatment after 13-week incubation, and 17.0 and 9.1% of TPH was removed in the BA and control treatments (amended with sterile water only), respectively. Aliphatic and other fractions (i.e., saturated n-alkanes and cyclic saturated alkanes) were reduced in the BS treatment, whereas no decrease in aromatic hydrocarbons occurred in any treatment. Gas chromatography-mass spectrometry analysis of aliphatic fractions showed that low-chain-length alkanes (C8-C20) were the most biodegradable fractions. The BS treatment supported fungal proliferation, with Sordariomycetes and Eurotiomycetes as the dominant classes. BS increased fungal diversity and decreased fungal abundance, and changed bacterial community structure. The findings show the potential of using BS to treat oily sludge with high TPH content. Graphical abstract.

Equation for compressibility factor and density of saturated n-alkanes (C1–C10) vapor, parahydrogen, and water at the boiling line

An equation is obtained for calculating the compressibility factor and saturated vapor density of n-alkanes (C1–C10), parahydrogen, and water at temperatures of the triple point up to critical point. The calculation error is close to that for experimental data.

The morphology of integrated self-assembled monolayers and their impact on devices – A computational and experimental approach

We report on a combined experimental and computational study on self-assembled monolayers (SAMs). The dielectric properties of SAMs based on n-alkyl phosphonic acids in large area thin film devices (organic field-effect transistors with good hole mobilities up to 0.3 cm 2 V −1 s −1 at −1 V and capacitors) depend on their chain length, but not consistently to theoretical pictures of tunneling through saturated n-alkanes. An unexpected saturation of current density with increasing chain length was obtained in devices, what impact on the leakage current in transistors and current density in capacitors. This is attributed to different self-assembled monolayer morphology ranging from an amorphous state for short alkyl chains to a quasi-crystalline state for longer alkyl chains. Molecular dynamics (MD) simulations provide a deeper insight into the nature of the three-dimensional intermolecular interactions and support the proposed SAM morphology. The change in morphology leads to a reduced effective SAM thickness in devices, which could be described by a Simmons approach quantitatively. The morphological aspect of self-assembled molecules is of enormous importance beyond the applications of SAMs in low-voltage, high mobility organic transistors because of it’s relevance for the hole field of molecular scale electronics. It demonstrates that even small changes in the molecular design can change the molecular interactions and monolayer assembly.

Desiccation intolerance of the red palm weevil, Rhynchophorus ferrugineus (oliv) adults in relation to their cuticular hydrocarbons

The desiccation tolerance of red palm weevil (RPW), Rhynchophorus ferrugineus was investigated in the laboratory. Adults exposed to 35 or 75% relative humidity showed high rate of water loss. Water loss rate averaged 2.32 ± 0.35 and 6.71 ± 0.73 mg /g fresh body weight/hr at 35 or 75% RH, respectively, and cumulative loss increased with time. Adults exposed to 35% RH died within a maximum of 4 days. Cuticular hydrocarbons (CHCs) were isolated and identified from adults to elucidate the physiological basis of their intolerance to desiccation. They were dominated by saturated n-alkanes (75%), while the ester compound 1-henicosyl formate, the fatty alcohol 3-(E) eicosanol and the alkene tricosene represented 25% of total surface CHCs. The desecration intolerance of weevils was attributed to the presence of relatively high proportion of 1-henicosyl formate (17.5%) which could form large pores within the waxy waterproofed CHCs layer of weevils.

The role of alkenes produced during hydrous pyrolysis of a shale

Hydrous pyrolysis experiments conducted on Messel shale with D2O demonstrated that a large amount of deuterium becomes incorporated into the hydrocarbons generated from the shale kerogen. In order to understand the pathway of deuterium (and protium) exchange and the role of water during hydrous pyrolysis, we conducted a series of experiments using aliphatic compounds (1,13-tetradecadiene, 1-hexadecene, eicosane and dotriacontane) as probe molecules. These compounds were pyrolyzed in D2O, shale/D2O, and shale/H2O and the products analyzed by GC–MS. In the absence of powdered shale, the incorporation of deuterium from D2O occurred only in olefinic compounds via double bond isomerization. The presence of shale accelerated deuterium incorporation into the olefins and resulted in a minor amount of deuterium incorporation in the saturated n-alkanes. The pattern of deuterium substitution of the diene closely matched the deuterium distribution observed in the n-alkanes generated from the shale kerogen in the D2O/ shale pyrolyses. The presence of the shale also resulted in reduction (hydrogenation) of olefins to saturated n-alkanes with concomitant oxidation of olefins to ketones. These results show that under hydrous pyrolysis conditions, kerogen breakdown generates n-alkanes and terminal n-alkenes by free radical hydrocarbon cracking of the aliphatic kerogen structure. The terminal n-alkenes rapidly isomerize to internal alkenes via acid-catalyzed isomerization under hydrothermal conditions, a significant pathway of deuterium (and protium) exchange between water and the hydrocarbons. These n-alkenes simultaneously undergo reduction to n-alkanes (major) or oxidation to ketones (minor) via alcohols formed by the hydration of the alkenes.

Cuticular lipids of adults and nymphal exuviae of the desert cicada, Diceroprocta apache (homoptera, Cicadidae)

1. 1. Hydrocarbons were the most abundant lipid constituent in the cuticles of nymph (exuviae) and adult desert cicadas, Diceroprocta apache. 2. 2. In both developmental stages, this fraction was comprised of saturated n-alkanes (43%) and branched alkanes (57%) ranging in size from 16 to over 43 carbon atoms. 3. 3. Hydrocarbon quantity per adult was approx five times higher than per nymphal exuvium. 4. 4. This difference is correlated with the increased transpiration potential experienced by the adult.

The surface lipids of hydnocarpus wightiana leaves

The surface lipids of Hydnocarpus wightiana leaves were analysed by thin-layer chromatography and gas chromatography in conjunction with mass spectrometry. The hydrocarbon fraction contained saturated n-alkanes, n-C 35, with n-hentriacontane as the major component. Analyses of the prim-alcohols revealed the presence of saturated n-, iso- and anteiso-compounds with n-C 32 as the major component. The sec-alcohols consisted mainly of the saturated n-C 29 and n-C 31 compounds, whereas the ketones consisted chiefly of the saturated n-C 30 compound. The aldehyde fraction contained saturated n-alkanals, n-C 23 to n-C 32, with n-octacosanal as the major component. A number of saturated and unsaturated fatty acids were also identified in the lipids on the surface of H. wightiana leaves, the major components being palmitic, behemic, lignoceric and cerotic acids which together constituted more than 60% of the total fatty acids present. In contrast to the seed lipids, the surface lipids of H. wightiana leaves do not contain compounds having a terminal cyclopentene ring.

The effect of extraneous hydrocarbons on the yield of steroidal sapogenin from the tuber tissue of Dioscorea deltoidea

The addition of hydrocarbons to incubating tuber tissue of Dioscorea deltoidea increases the sapogenin yield. The effect is relatively non structure specific; squalane, saturated n-alkanes and mono- and di-unsaturated n-alkenes are effective although some long chain ( C 28) n-alkanes reduce the yield. The added hydrocarbon disappears rapidly and 0·054% incorporation of label from 1- 14C-octadecane into diosgenin was obtained.