Presence Of Decane Research Articles

Separation of Azeotropic Mixtures of Ethyl Acetate + Methylcyclohexane: Vapor–Liquid Equilibrium Measurements

It is a challenge to separate ethyl acetate from methylcyclohexane because of the azeotropic phenomenon. To provide a basis for the design of the separation process, the isobaric vapor–liquid equilibria for an ethyl acetate + methylcyclohexane binary system were measured at 101.3 and 20.0 kPa using a modified Othmer-type still. The results show that ethyl acetate and methylcyclohexane form a miscible azeotropic mixture with minimum boiling temperature (349.99 K at 101.3 kPa), of which the composition varies slightly with decreasing pressure (≤101.3 kPa). It implies that ethyl acetate cannot be separated from methylcyclohexane by pressure-swing distillation. The azeotropy of ethyl acetate and methylcyclohexane disappears in the presence of decane (∼0.5 mole fraction), which means that ethyl acetate can be separated from methylcyclohexane by extractive distillation with decane as an entrainer.

Pseudomonas veronii strain 7–41 degrading medium-chain n-alkanes and polycyclic aromatic hydrocarbons

Pollution of the environment by crude oil and oil products (represented by various types of compounds, mainly aliphatic, mono- and polyaromatic hydrocarbons) poses a global problem. The strain Pseudomonas veronii 7–41 can grow on medium-chain n-alkanes (C8–C12) and polycyclic aromatic hydrocarbons such as naphthalene. We performed a genetic analysis and physiological/biochemical characterization of strain 7–41 cultivated in a mineral medium with decane, naphthalene or a mixture of the hydrocarbons. The genes responsible for the degradation of alkanes and PAHs are on the IncP-7 conjugative plasmid and are organized into the alk and nah operons typical of pseudomonads. A natural plasmid carrying functional operons for the degradation of two different classes of hydrocarbons was first described. In monosubstrate systems, 28.4% and 68.8% of decane and naphthalene, respectively, were biodegraded by the late stationary growth phase. In a bisubstrate system, these parameters were 25.4% and 20.8% by the end of the exponential growth phase. Then the biodegradation stopped, and the bacterial culture started dying due to the accumulation of salicylate (naphthalene-degradation metabolite), which is toxic in high concentrations. The activity of the salicylate oxidation enzymes was below the detection limit. These results indicate that the presence of decane and a high concentration of salicylate lead to impairment of hydrocarbon degradation by the strain.

Non-catalytic gas phase NO oxidation in the presence of decane

Experiments without a catalyst revealed that NO was oxidized in a diesel exhaust gas phase mixture due to the presence of n-C10H22 (decane). This reaction was observed to occur following the low temperature oxidation catalyst test protocol (LTC-D) defined by U.S. DRIVE. The purpose of LTC-D conditions is to simulate an aftertreatment diesel combustion gas mixture in order to test candidate catalyst materials. 100% NO conversion was observed, without a catalyst, after beginning to react at 330 °C accompanied by consumption of decane. After experiments that isolated hydrocarbons, ethylene was also observed to facilitate NO oxidation to a lesser degree (>470 °C). Density functional theory (DFT) calculations were conducted to investigate thermodynamically-possible initiating elementary steps during n-C10H22 consumption and NO oxidation. Two feasible intermediate radicals to oxidize NO to NO2 are ·C10H21O2 and ·HO2.

Oil-water pore occupancy in the Vaca Muerta source-rocks by NMR cryoporometry

Abstract The main motivation of this work is to determine quantitatively the pore occupancy of water and oil in some source rocks. The pore occupancy might be imposed by differences in chemical composition, wettability behavior and sorption of fluids in organic and inorganic porosities and will dramatically affect the hydrocarbons flow through the porous medium. We address this issue using NMR cryoporometry in two phase situations complemented by other NMR measurements. Using oil-wet samples originating from the Vaca Muerta formation, oil saturation as large as 70% were obtained by simply immersing fully water saturated samples into decane. At 100% water saturation, the measured pore size distributions indicate two main peaks around 2 and 80 nm. After immersion into oil, the pores occupied by water in the presence of decane are mostly around 2 nm and less. The pore sizes occupied by decane in the presence of water can then be deduced by subtracting the distributions obtained at 100% water saturation and after spontaneous drainage. Oil is mainly located in pores around 80 nm. These measurements are confirmed by high resolution SEM images showing the presence of porosity in the organic matter (sponge-like structure). Most of the oil can be associated with the porous organic matter network. These observations are complemented by the determination of the porosity below 2 nm and the water connectivity. From D2O diffusion experiments at 100% water saturation, we observed that about 19% of the total porosity is non-exchangeable with D2O. From the measurements of the liquid signal at −29 °C, we observed that on average 58% of the total porosity is located in pores smaller than 2 nm.

Chemical Composition of Three Different Fractions Obtained from the Leaves of Cassia occidentalis

The chemical composition of three different fractions (dichloromethane, methanol, benzene) obtained from the leaves of Cassia occidentalis via column chromatography was studied. The aim of the research is to identify the fraction with the highest composition of insecticidal compounds which may be responsible for the insecticidal activity of the plant. The leaves were dried and milled into fine powder, they were first extracted by maceration in various solvents and thereafter the resulting extracts were purified using column chromatography. Fractions obtained from the columns were analysed using Gas Chromatography-Mass Spectrometry (GCMS). The GC-MS results revealed a total of nineteen compounds, prominent among them were hexadecane (45.10%) and heptadecane 8-methyl (13.61%) in the dichloromethane fraction. In the methanol fraction we had; pentadecanoic acid 14-methyl ester (15.50%) 9-octadecanoic acid (48.76%) and methyl stearate (27.6%). The benzene fraction contained; decane (4.70%); hexadecane (21.60%) and nonadecane (11.65%). The presence of decane, methyl stearate, hexadecane, 9-octadecanoic acic methyl ester, pentadecanoic acid -14 methyl ester, heptadecane 8-methyl and nonadecane in the plant extracts may be responsible for the insecticidal properties of Cassia occidentalis and should be of considerable interest to the development of novel natural insecticdes from this plant. All three fractions contained important insecticidal compounds, thus any of the solvents could be utilised in the formulation of potential biopesticides from C. occidentalis.

Characterization and screening of non-Saccharomyces yeasts used to produce fragrant cider

The objective of this work is to characterize and screen non-Saccharomyces yeast strains for the production of ciders. A total of 199 volatiles were observed in the ciders that were generated from 163 non-Saccharomyces yeasts. Candida zemplinina, Hanseniaspora vineae and Torulaspora delbrueckii were found to produce relatively more volatile compounds than other species. There were 29 volatiles with a relative Odor Activity Value (rOAV) > 1. Based on analysis of aroma content, aroma complexity and aroma impact, 35 samples were further selected for Principal Component Analysis and sensory analysis. The results revealed that two groups of ciders were differentiated by the presence of decanal or β-damascenone, while the remaining samples contained 2-methylbutyl acetate. Additionally, partial least-squares regression showed that tropical fruit, kernel fruit, stone fruit and floral aroma notes had the greatest impact on the overall aroma of these ciders.

Preparation of Dimpled Polystyrene-Silica Colloidal Nanocomposite Particles.

Preparation of polymer-silica colloidal nanocomposite particles with concave shape is challenging and seldom reported. This paper presents a novel and facile method to prepare dimpled polymer-silica nanocomposite particles with a thin silica shell through the judicious combination of alcoholic dispersion polymerization and the decane evaporation method. Submicrometer-sized polystyrene-silica (PS-SiO2) nanocomposite particles were first prepared by dispersion polymerization of styrene in methanol in the presence of a methanolic silica sol, and then dimpled PS-SiO2 particles were prepared by heating the near-spherical PS-SiO2 particles dispersed in methanol/water media in the presence of decane and subsequent cooling. The effects of different heat treatment parameters, such as methanol/water ratio, stirring temperature, and stirring rate on the formation of the nanocomposite particles were investigated. Optimization of the heating conditions allowed ∼100% of dimpled particles to be achieved with one dimple on each particle. Moreover, calcination of the dimpled PS-SiO2 nanocomposite particles led to the formation of hollow dimpled particles with a thin silica shell. This method is expected to enrich the shapes of polymer-silica nanocomposite particles.

Bio-Oil Production from Liquid-Phase Pyrolysis of Giant Leucaena Wood

Bio-oil production from giant leucaena wood was performed by liquid-phase pyrolysis in the presence of decane as the solvent. Three different types of catalyst (ZSM-5, NiMo/Al2O3 and Pt/Al2O3) were evaluated in terms of the bio-oil production yield and quality in an autoclave reactor at a reaction temperature of 350°C and initial hydrogen (H2) pressure of 1 MPa with decane as the solvent. Although the yield was not significantly affected by the catalyst type, CHN analysis revealed that the NiMo/Al2O3 catalysts yielded bio-oil with the lowest oxygen content (10.0 wt. %) in 4.30 wt. % yield so that it was selected as the optimal catalyst. Optimization of the reaction temperature (at 250, 300, 350, and 400°C) and the initial H2 pressure (at 0.5, 1, 2, and 3 MPa) by sequential univariate analysis revealed that the reaction temperature had the greatest influence on the oil yield and oxygen content, reaching a yield of 8.60 wt. % with the lowest oxygen content of 8.50 % at 400°C. Increasing the initial H2 pressure diminished only slightly the oil and char yield and decreased the gas yield.

Antioxidant and Antibacterial Assays onPolygonum minusExtracts: Different Extraction Methods

The effect of solvent type and extraction method was investigated to study the antioxidant and antibacterial activity ofPolygonum minus. Two extraction methods were used: a solvent extraction using Soxhlet apparatus and supercritical fluid extraction (SFE). The antioxidant capacity was evaluated using the ferric reducing/antioxidant power (FRAP) assay and the free radical-scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The highest polyphenol content was obtained from the medium polarity methanol extract of the leaf portion (645.60 ± 166.68 gallic acid equivalents/100 g (GAEs/100 g)). It also showed the highest antioxidant power for FRAP and DPPH radical inhibition and exhibited the largest inhibition zone in antibacterial activity onBacillus subtilis(Gram+),Staphylococcus aureus(Gram+), andEscherichia coli(Gram−). The phase behavior and aldehyde profiles were further investigated using SFE with different cosolvents. The results indicated that a 50% ethanol-water cosolvent yielded the best aldehyde profiles in the presence of decanal, undecanal, and dodecanal.

Effect of kinetic hydrate inhibitor and liquid hydrocarbon on the heterogeneous segregation and deposition of gas hydrate particles

Segregation and deposition of hydrate particles observed in flowloop experiments are required to be investigated more thoroughly to understand the hydrate plugging mechanism in offshore flowlines. We used natural gas as gas phase and selected three different systems as liquid phase, which are pure water only, kinetic hydrate inhibitor added aqueous solution, and water+decane mixture, respectively. Hydrate formation process including onset and growth was studied by measuring the pressure, temperature, and torque changes in high-pressure autoclave. The obtained results suggest that poly-vinyl caprolactam (PVCap) solution shows elongated growth period than pure water until distinct torque change is observed, which also indicates the suppressing effect of PVCap on the growth of hydrate crystals. However, the presence of decane as continuous liquid phase enhances the deposition of hydrate particles on the wall. The torque change with conversion to hydrate used in this study is found to be useful to classify the hydrate formation process into three different regions.

Solubilization of decane into gemini surfactant with a modified Jeffamine backbone: Design of hierarchical porous silica

Herein, we have investigated the solubilization of decane into a novel nonionic gemini surfactant, myristoyl-end capped Jeffamine, synthesized from a polyoxyalkyleneamine (ED900). Starting from this system, porous silica materials have been prepared. Performing the hydrothermal treatment at low temperature, a slight increase of the mesopore diameter is observed in the presence of decane. Increasing the temperature of the hydrothermal treatment, no swelling effect of decane is detected. By contrast, the pore diameter decreases but better mesopore homogeneity and a larger wall thickness are obtained. At high decane concentration the new myristoyl-end capped Jeffamine/decane/water system forms oil-in-water emulsions, which are used as template for the formation of hierarchical porous silica materials.

Imaging of Supported Bilayers Modified by Butanol and Hexanol, and by the Solvent Decane

Ion channels, including voltage-gated channels, are often studied in planar bilayer model membranesthat of necessity incorporate a solvent, typically decane. We are interested in the bilayer mechanics of channel function and have examined the electrophysiology of KvAP channels in bilayers modified by short chain alkanols and by cholesterol (Finol-Urdaneta et al. 2010, Biophysical Journal 98:762). Since both alkanols and cholesterol affect KvAP conductance and kinetics, we need a better understanding of how the mechanical status of these “defined” bilayers is affected by the presence of decane. We prepare supported bilayers of DPPC, DOPC/DPPC 1:1 and DOPC/egg sphingomyelin/cholesterol 2:2:1 (“DEC221”) by vesicle fusion on mica in the presence and absence of decane, and image them with tapping-mode atomic force microscopy (AFM) in aqueous solution. Decane modifies the domain morphology of DEC221 but has minimal effect on DOPC/DPPC or DPPC bilayer patches. Butanol and hexanol in the absence of decane reduce the percent coverage of the liquid-ordered phase in DEC221 and the gel phase in DOPC/DPPC, and induce an interdigitated phase of lower height in DPPC bilayer patches, consistent with literature results for ethanol. Fluorescence assays in vesicles confirm the alkanol-induced increases in fluidity. This work aims to elucidate the interplay between bilayer lipid molecules and solvent molecules in determining the response of planar bilayers to membrane-perturbing additives.

Effect of ozonization on the thermal cracking of black fuel oil in the presence of decane and tetralin

The results of studying the transformations of the components of ozonized and initial black fuel oil (masout) in the decane and tetralin media are presented. The preliminary ozonization leads to an increase in the distillable fraction yield by 22–29% as compared to that for the cracking of the initial masout in the decane medium. It is demonstrated that the product composition is affected by the type of the solvent. For the resins obtained by cracking of ozonized masout, the total average number of cycles in their molecules (3.2) is lower than that for the resins obtained from the initial masout (4.6); in addition, the fraction of saturated cycles in the structural unit of their molecules is also lower, 1.12 versus 2.39. The fraction of relatively volatile n-alkanes, C12–C17, in oils produced by cracking of ozonized masout is higher.

Thermodynamic and kinetic considerations on the morphological stability of “hamburger-like” composite polymer particles prepared by seeded dispersion polymerization

Micrometer-sized, monodisperse, “hamburger-like” polystyrene (PS)/poly(2-ethylhexyl methacrylate)/decane composite particles were obtained by seeded dispersion polymerization of 2-ethylhexyl methacrylate with PS seed particles in the presence of decane. The morphological stability of the hamburger-like particles was investigated based on thermodynamic and kinetic aspects. The hamburger-like morphology was maintained at 60 °C (above glass transition temperature (T g)) for at least 1 week in spite of less thermodynamic stability than hemispherical morphology. T g of the particles gradually increased throughout the polymerization due to monomer consumption. Geometric calculation result indicates that the degree of reduction of the interfacial free energy at the early stage of the morphological development is significantly low. From these results, it is concluded the morphological stability of the hamburger-like particles is considerably high because the development from hamburger-like to hemispherical morphologies is retarded by the gradual increase in viscosity inside the particles and the significantly lower interfacial free energy reduction.

High Resistance of Cu–Ferrierite to Coke Formation During NH3-SCR in the Presence of n-Decane

Selective catalytic reduction of NO x by NH3 over Cu–FER and Cu–ZSM-5 in the presence of n-decane and SO2 was investigated. NO x conversion over Cu–ZSM-5 decreased in the presence of n-decane, owing to inhibition of the active sites by coke formation. In contrast, coke formation was negligible over Cu–FER, which maintained its NO x conversion activity even in the presence of decane. Coke formation was negligible over H–ZSM-5 and H–FER supports, which suggests that Cu species were involved in coke formation. Temperature-programmed reduction by H2 and electron spin resonance spectroscopy indicated that [Cu–O–Cu]2+ was probably the Cu species involved in coke formation over Cu–ZSM-5.

SCR of NO with NH3 over Cu/NaZSM-5 and Cu/HZSM-5 in the presence of decane

Abstract The selective catalytic reduction of NO x with NH 3 in the presence of decane over Cu/ZSM-5 catalysts prepared from H + and Na + ZSM-5 precursors were investigated. Cu/NaZSM-5 catalyst showed significantly higher NO x conversion compared to Cu/HZSM-5. However, the presence of decane decreased the activity of both the catalysts, due to coke formation. Cu/HZSM-5 catalyst showed a larger decline in NO x conversion with time on stream compared to Cu/NaZSM-5. The higher activity of Cu/NaZSM-5 is attributed, to the promoting effect of Na + cations in the formation of active Cu + and nitrite and nitrate intermediates species and retardation of coke formation.

Aerobic biotransformation of decalin (decahydronaphthalene) by Rhodococcus spp.

Mixed bacterial cultures aerobically transformed decalin (decahydronaphthalene) dissolved in an immiscible carrier phase (heptamethylnonane; HMN) in liquid medium. Conversion was enhanced in the presence of decane, a readily degraded n-alkane, and/or HMN. Four Rhodococcus spp. isolates purified from one of the mixed cultures were active against decalin in the presence of n-decane, but their ability to use decalin as a sole carbon source for growth could not be sustained. Isolate Iso 1a oxidized decalin under co-metabolic conditions with decane vapours as the primary carbon source. Mass spectrometry and comparison to authentic standards showed that the oxidized products of decalin biotransformation were 2-decahydronaphthol and 2-decalone. Some evidence of ring-opening was obtained, but the possible ring-opened product was not definitively identified. These results are consistent with co-metabolic oxidation of decalin by enzymes active toward n-alkanes.

Enhancement of decane-SCR-NO x over Ag/alumina by hydrogen. Reaction kinetics and in situ FTIR and UV–vis study

Decane-SCR-NO x , oxidation of NO and decane by molecular oxygen, and these reactions enhanced by hydrogen over Ag/alumina were investigated by monitoring of gaseous product composition, surface intermediates (in situ FTIR), and the state of silver (in situ UV–vis) under realistic reaction conditions in the steady-state and transient modes. It has been shown that oxidation of NO or decane by oxygen is greatly affected by the presence of decane or NO. Monodentate nitrates are formed preferentially and are more reactive compared with the bidentate species. Oxidation of decane mostly yields surface acetates, and the presence of NO x favors the formation of formates (acrylates). The reaction steps most enhanced by the addition of hydrogen to the SCR-NO x reaction are the transformations of the intermediate CN species into NCO and oxidation of the hydrocarbon to formates (acrylates). Although NO–NO 2 oxidation is also enhanced by hydrogen, this effect does not contribute to the increased rate of the SCR-NO x reaction. A small part of very reactive Ag + (estimated to be <5%) is reduced to metallic charged Ag n δ + clusters ( n ⩽ 8 ) during both the decane- and H 2/decane-SCR-NO x reactions. The number of Ag n δ + clusters formed depends mainly on the level of NO conversion to nitrogen, regardless of whether the conversion level is attained by the addition of hydrogen or by an increased concentration of decane or oxygen in the feed. The time-resolved responses of NO x –N 2 conversion and of the number of Ag n δ + clusters to the addition/removal of hydrogen from the reactants indicate that the Ag n δ + clusters are mainly formed because of the reducing effect of adsorbed CH x O-containing reaction intermediates. The active sites are suggested to be single Ag + ions or small Ag 2O species. Hydrogen itself takes part in the SCR-NO x reaction. It is supposed that it dissociates, forms Ag-hydride, and enhances SCR-NO x by initiation radical reactions.

Alkylation of benzene with dodecene. The activity and selectivity of zeolite type catalysts as a function of the porous structure

LAB (Linear Alkyl Benzene) isomers were obtained by the alkylation of benzene with 1-dodecene over FAU, BEA and EMT zeolites in the presence of decane as solvent. The initial activities were compared by fitting the kinetics early data with a pseudo first order law in dodecene. These were in agreement with those determined from the slope of the conversion versus time curve at zero conversion. The activity and stability were discussed in terms of the residual Na + content, Si/Al ratio and porous structure of the catalysts. The selectivity to the most desired 2-phenyl dodecane isomer was found to increase with increased porous constraints. Yields in the preferred isomer over BEA catalysts were very close to those provided by the FAU open structure catalysts in spite of a much lower conversion over BEA catalysts. Deactivation affected not only the alkylation reaction, but the isomerisation of the olefin as well, over BEA catalysts.

Analysis of metabolic pathways by the growth of cells in the presence of organic solvents.

A new approach to the analysis of metabolic pathways involving poorly water-soluble intermediates is proposed. It relies upon the ability of the hydrophobic intermediates formed by a sequence of intracellular reactions to cross the membrane(s) and partition between aqueous and organic phases, when cells are incubated in the presence of a nonpolar and nontoxic organic solvent. As a result of this thermodynamically driven efflux of the formed intermediates from the cell, they accumulate in the organic medium in sufficient quantities for GC-MS analysis and identification. This enables direct determination of the sequence of chemical reactions involved with no requirement for the isolation of each individual metabolite from a cell-free extract. The feasibility of the proposed methodology has been demonstrated by the elucidation of the biosynthesis of (R)-gamma-decalactone from (R)-ricinoleic acid catalyzed by the yeast Sporidiobolus ruinenii grown in the presence of decane. The corresponding 4-hydroxy-acid intermediates, formed in the course of beta-oxidation of (R)-ricinoleic acid, were simultaneously observed in a single experiment on the same chromatogram. Potential applications of this proposed methodology are briefly discussed.