Mother of all folding: cold isolated linear alkanes C(n)H(2n+2) prefer an extended all-trans conformation before cohesive forces between the chain ends induce a folded hairpin structure for longer chains. It is shown by Raman spectroscopy at 100-150 K that the folded structure becomes more stable beyond n(C) = 17 or 18 carbon atoms. High-level quantum-chemical calculations yield n(C) = 17 ± 1 a...

The diffusion of longer n-alkanes (n-C8-n-C16) in silicalite was studied using molecular dynamics (MD) simulations at a temperature range of 300-400 K, with loadings appropriate for direct comparison with previously carried out quasielastic neutron scattering (QENS) studies. The calculated diffusion coefficients were in close agreement with experimental values, significantly closer than those c...

Polycyclic aromatic hydrocarbons (PAHs) and n-alkanes are important specific organic constituents in fine particulate matter (PM2.5). Seventy-five PM2.5 samples were collected Spring Changzhou, to investigate the concentrations sources of (C9–C40) PAHs. The average total PAHs (∑PAHs) (∑n-alkanes) 4.37 ± 4.95 ng/m3 252.37 184.02 ng/m3, ranging from 0.43 22.22 57.37 972.17 respectively. ∑n-alkane...

The aim of this study was to determine the presence and nature of organic micropollutants in river overbank and floodplain sediments from the border between Croatia and Bosnia and Herzegovina following the catastrophic 2014 flood. The study involved ten sediment samples from the Sava and Bosna river floodplain. The volatile aromatic compounds, i.e. benzene, toluene, ethylbenzene, and xylene (BT...

Phase separation in mixtures of polymers and alkanes is investigated with the aid of a recently developed lattice model, based on the Born-Green-Yvon (BGY) integral equation approach to fluids. The system-dependent parameters of the BGY lattice model for binary mixtures are deduced from those of its pure components, which in turn are determined from a comparison with experimental data. The lowe...

Coverage-dependent desorption-kinetics parameters are obtained from high-quality temperature-programmed desorption data for seven small n-alkane molecules on MgO(100). The molecules, CNH2N+2 (N=1-4,6,8,10), were each studied for a set of 29 initial coverages at a heating ramp rate of 0.6 K/s as well as at a set of nine ramp rates in the range of 0.3-10.0 K/s. The inversion analysis method with ...

Microorganisms can degrade saturated hydrocarbons (alkanes) not only under oxic but also under anoxic conditions. Three denitrifying isolates (strains HxN1, OcN1, HdN1) able to grow under anoxic conditions by coupling alkane oxidation to CO(2) with NO(3) (-) reduction to N(2) were compared with respect to their alkane metabolism. Strains HxN1 and OcN1, which are both Betaproteobacteria, utilize...

Biomarkers in Late Pleistocene sediments collected from the Integrated Ocean Drilling Program (IODP)-Arctic Coring Expedition (ACEX) Hole M0004C (central Arctic Ocean) were investigated. The major biomarkers are long chain n-alkanes, n-fatty acids and n-alkan1-ols, indicating fresh organic matter (OM) derived predominantly from higher plants. The dominance of terrestrial biomarkers is attribute...

the dried aerial parts of scutellaria lateriflora l. (family labiatae), have been used for many years as a domestic remedy for epilepsy, hysteria, and nervous tension states. although several phytochemical investigations have been made regarding the constituents present in this species (i. e. flavonoids, iridoids), none has been recorded concerning the cuticular wax. using thin-layer chromatogr...

background petroleum hydrocarbons are mix compounds and divided into four groups: saturates, aromatics, resins and asphalten. among various phases of crude-oil, the alkanes with medium length chain are favorable substrates that rapidly degraded, although short-chain alkanes are very toxic and long-chain alkanes have low solubility in water that reduce its bioavailability and make resistant to b...