Naphthalene Type Research Articles

FORMATION OF RESIDUAL STRENGTH OF STRUCTURAL FIBER IN CONDITIONS AFTER FIRE

The article presents the results of dynamic mechanical tests of fiberglass specimens under the conditions of the effects of intense heating on them, which corresponded to the development of a slowly developing fire. It is established that with intensive heating at the initial stage of fire, the considered type of fiberglass loses its initial strength, but then, upon cooling, acquires increased rigidity, while maintaining sufficient integrity and relative structural functionality. In our view, this increase is due to the significant increase in the carbon fraction in the polymer binder with the formation of a more densely packed structure due to the formation of sites with associated aromatic fragments. At the same time, the drop in strength occurs due to the formation of a sufficient number of voids (pores and cracks), the occurrence of which is characteristic of materials of organic nature (plastics based on synthetic polymers) in the process of thermal oxidation destruction under intense heating. It is established that the degree of conservation of the load-bearing strength of the fiberglass can be arranged in the following order: bending> stretching> compression. This behavior of the material indicates the use of additional structural measures when using it as the supporting elements of construction and technological structures. The determining factor in the observed modification of the composite is the extent of the passage of the pyrolytic transformations of the polymer bond, which can indirectly be characterized by a change in the dynamic mechanical properties of the material under intense heating. The main role is played by the binder component - the epoxidized naphthalene type oligomer, whose function is reduced to the ability to play a role in the volume of the polymer matrix of coke formation germs. The above composition of components and the method of its production allows to develop polymeric composite materials without the use of additional components - flame retardants (retardants), which complicate the technology of obtaining the composite and in some cases reduce its initial physical and mechanical properties. Keywords: fiberglass, residual strength, fire aftereffect, dynamic mechanical tests, epoxidised dinaftol

Effect of resin chemical structure on the dispersibility of hexagonal boron nitride

ABSTRACT The dispersibility of hexagonal boron nitride (hBN) particles in epoxy resin with different chemical structures, such as bisphenol and naphthalene, was investigated. The viscosities of hBN slurries changed considerably depending on the diol compound chemical structures. Sedimentation testing of the hBN slurries revealed that the hBN particles in slurries containing naphthalene structures were densely packed due to improved dispersibility of hBN, while the hBN particles in slurries containing bisphenol structures were aggregated. These results suggested that the π–π interaction was more dominant in the dispersion of hBN particles than the hydrophobic interaction. Furthermore, the naphthalene type epoxy resin was more effective in improving the dispersibility of hBN as compared to bisphenol A type epoxy resin. The interaction between the basal plane of hBN particles and the chemical structure in the matrix is very important for hBN dispersibility improvement.

Accumulation of Polycyclic Aromatic Hydrocarbons in Sealed Soils and Their Environmental Hazard for Eastern Moscow

The contents of 11 PAHs in asphalt concrete of road pavements and in sealed soils of Eastern Moscow have been determined and compared with those in the unsealed urban soils and in background natural soils. Sealed soils and asphalt concrete have the naphthalene type of pollution, whereas phenanthrene predominates in the background soddy-podzolic soils (Retisols). The prevalence of low-molecular-weight PAHs in sealed soils indicates the pronounced effect of emissions from diesel-powered vehicles and from asphalt bitumen, in which the total PAHs content varies from 14.8 to 128.1 μg g−1. The total PAHs content in the soils sealed with road pavements averages 14.5 μg g−1, which is 4.5 times higher than in the unsealed urban soils and 142 times higher than in the background soils. The enhanced accumulation of PAHs in the sealed soils is explained by the conservation of PAHs by the soil organic matter under the anaerobic conditions. Mapping the sum of PAHs and benzo[a]pyrene in the upper part of the profiles of sealed soils showed the formation of several contrasting human-induced anomalies of polyarenes that are mainly confined to highways. Their environmental hazard was assessed via carcinogenic potential of PAHs, which exceeds MPC for benzo[a]pyrene by 10–13 times.

Oxidation of Orange G by persulfate activated by Fe(II), Fe(III) and zero valent iron (ZVI)

Persulfate (PS) was employed in the oxidation of Orange G (OG), an azo dye commonly found in textile wastewaters. Activation of PS was conducted with iron to generate sulfate free radicals (SO4-) with high redox potential capable to oxidize most of the organics in water. Identification of oxidation intermediates was carried out by analyzing at different times organic by-products generated from treatment of a concentrate dye solution (11.6mM) with 153mM of PS and 20mM of Fe(II) at 20°C. Intermediate reaction products (mainly phenol (PH) and benzoquinone (BQ), and in less extent aniline, phenolic compounds and naphthalene type compounds with quinone groups) were identified by GC/MS and HPLC, and an oxidation pathway was proposed for the oxidation of OG with iron activated PS. The effect of iron valence (0, II and III) in the oxidation of an aqueous solution of OG (containing 0.1mM) was studied in a 0.5L batch reactor at 20°C. Initial activator and PS concentrations employed were both 1mM. Complete pollutant removal was achieved within the first 30min when iron II or III were employed as activators. Quinone intermediates generated during pollutant oxidation may act as electron shuttles, allowing the reduction of Fe(III) into Fe(II) in the redox cycling of iron. Therefore, activation of PS by Fe(III) allowed complete OG removal. When zero valent iron (ZVI) was employed (particle diameter size 0.74mm) the limiting step in SO4- generation was the surface reaction between ZVI and the oxidant yielding a lower oxidation rate of the dye. An increase in the oxidant dosage (0.2mM OG, 2mM Fe(III) and 6mM PS) allowed complete pollutant and ecotoxicity removal, as well as mineralization close to 75%.

The Flowability and Adsorption of Low Sulfate Cement with Superplasticizers

The compatibility of low sulfate cement with naphthalene (NS) and polycarboxylate (PCE) type superplasticizers was discussed. The flowability of slurry and the adsorption of superplasticizers (SP) were investigated by mini slump test and TOC. The results show that severe compatibility degeneration is caused by low sulfate content in cement slurry. The water demand of slurry, the standard dosage and adsorbed amount of SPs were dramatically raised. In the cement slurry with low sulfate content, polycarboxylate type superplasticizers presents better performance than naphthalene type. The PCE with lower charge density presents better robustness. It is recommended in the preparation of concrete to avoid the incompatibility problems caused by lack of sulfate in cement paste.

Synthesis and biological evaluation of novel (−)-cercosporamide derivatives as potent selective PPARγ modulators

Selective peroxisome proliferator-activated receptor gamma (PPARγ) modulators are expected to be a novel class of drugs improving plasma glucose levels without PPARγ-related adverse effects. As a continuation of our studies for (−)-Cercosporamide derivatives as selective PPARγ modulators, we synthesized substituted naphthalene type compounds and identified the most potent compound 15 (EC50 = 0.94 nM, Emax = 38%). Compound 15 selectively activated PPARγ transcription and did not activate PPARα and PPARδ. The potassium salt of compound 15 showed a high solubility and a good oral bioavailability (58%). Oral administration of the potassium salt remarkably improved the plasma glucose levels of female Zucker diabetic fatty rats at 1 mg/kg. Moreover, it did not cause a plasma volume increase or a cardiac enlargement in Wistar–Imamichi rats, even at 100 mg/kg.

고성능 감수제 종류에 따른 실리카흄이 혼입된 시멘트 수화 특성

In this study, the effect of superplasticizers on the dispersibility and hydration properties of cement with silica fume were investigated. Superplasticizers are used Naphthalene type, Ligno-sulfate type and polycarboxylate type. Compared with plastic viscosity of cement paste without superplasticizers(Plain), plastic viscosity of cement paste with superplasticizers are reduced and yield stress of cement pastes with each superplasticizer is increased rather than Plain. And then, plastic viscosity of cement paste with Naphthalene type superplasticizer was the least of all types. Compared with other two types, setting and hydration of cement paste with Polycarboxylate type(PC) superplasticizer is very fast. At compressive strength after 3-day, PC is higher than other two types, But, compressive strength of after 7-day and 28-day, PC is smaller than other two types.

Structural characterization of the kerogen from Youssoufia phosphate formation using mild potassium permanganate oxidation

A 10 step alkaline KMnO 4 degradation of a Type II kerogen from Moroccan Youssoufia phosphate rock was carried out under mild conditions to give a 61 wt% yield of oxidation products. These consisted mainly of diethyl ether-insoluble, high molecular weight (HMW) acids and diethyl ether-soluble acids. Detailed gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS) analysis of the soluble acids and products of further controlled KMnO 4 degradation of the HMW acids allowed quantitative estimation of the contribution (based on gravimetry and chromatographic area) of the various types of products. The acid oxidation products are dominantly aromatic (63.5 wt% of oxidation products) and aliphatic acids (36.2 wt%). The products suggest a prevalently aromatic nature for the complex matrix of Youssoufia kerogen, with a significant contribution of aliphatic structures. Detailed analysis of the acids indicates that the network is formed by aromatic structures, mainly of naphthalene type, with aliphatic cross linked chains. The basic network is substantially substituted by aromatic moieties and alkyl chains acting as monosubstituents (giving monocarboxylic acids on oxidation). However, the matrix contains a high amount of tightly trapped hydrocarbons which can be released when it is partly or completely destroyed. If these hydrocarbons are included in the total balance of oxidation products, the proportion of aromatic structures in the Youssoufia kerogen is 32%. This value is consistent with the aromaticity factor ( f a = 0.29) determined using cross polarization-magic angle spinning 13C nuclear magnetic resonance spectroscopy (CP-MAS 13C NMR).

Influence of superplasticizers on the hydration of cement and the pore structure of hardened cement

This paper describes the influence of various types of superplasticizers such as naphthalene type (β-NS), refined lignin sulfonate type (LS) and polycarboxylate types (P34, S34) on the hydration of cement and the pore structure of hardened cement. Other superplasticizers except β-NS delayed the initial hydration of cement. In any case, it hardly influences the hydration reaction at late stage of cement. The retardation by the addition of superplasticizers is not observed after 28 days of curing. Large pores of 0.1 μm or more for hardened cement with LS or β-NS are larger than those of hardened samples with P34 or S34 cured for 28, 56 and 91 days. This is related to the coagulated structures of fresh cement pastes with various types of superplasticizers. It was presumed that the size of the cluster of aggregated particles became small when S34 or P34 that has a high dispersing ability was added compared to LS or β-NS that has a lower dispersing ability.

Transient absorption spectra of bifunctional probes of a chromophore-sterically hindered amine type in solution; study of the triplet route to deactivation

Laser flash photolysis was used to study formation and decay of triplet states of bifunctional probes of type chromophore (naphthalene, 1,8-naphthaleneimide, pyrene)-sterically hindered amine (HAS). For all types of probes, the formation of the triplet state with absorption in the range 400–500 nm occurred after 266 nm excitation. The same triplet was formed at 355 nm excitation for probes extending absorption to this region. Triplet states of all probes were quenched by oxygen with rate constant 1–5×10 9 dm 3 mol −1 cm −1. Intermolecular quenching of triplet states of the parent probes by N-oxyl (1-oxo-2,2,6,6-tetramethyl-4-hydroxypiperidine) was effective for naphthalene type probes and practically no effective for pyrene ones. The efficiency of intramolecular quenching in oxidised probes was determined by type of chromophore. The most effective intramolecular quenching was observed for N-(1-oxo-2,2,6,6-tetramethyl-4-piperidinyl)-1,8-naphthaleneimide in methanol.

Detailed characterisation of heavy alkylated benzene fluids by multipulse one- and two-dimensional NMR spectroscopy

In this paper, the results of a characterisation of heavy alkylated benzenes (HAB) using multipulse NMR spectroscopy are presented. Four commercial samples of heavy alkylated benzene have been characterised in detail in terms of various structural parameters, such as percentage aromatic carbon (Ca), degree of aromatic substitution, average alkyl chain length, type of alkyl chain and their proportions. Three of the HAB samples were very similar in structure, whereas, in the fourth, the structures present were entirely different. The latter had an abundance of 2-phenyl alkane-type structures, and did not contain methyl substituted tetralin or naphthalene type molecules. The influence of the structures on lubricating oil properties, including viscosity index, pour point, and viscosity, as well as FreonTM floc point, are also discussed.

Catalytic hydrogenation of recycle solvent in a 150t/d pilot plant of the NEDOL coal liquefaction process

Effect of reaction temperature on hydrotreatment of a recycle solvent in the NEDOL coal liquefaction process was studied from the data obtained by the operation of a 150t/d pilot plant. Hydrotreatment of the recycle solvent was carried out under a hydrogen pressure of 100kg/cm2G over Ni–Mo/Al2O3 catalyst in a fixed bed reactor. As the reaction temperature increased from 290 to 330°C, the hydrogen gas consumption increased from 0.4 to 1.0wt%. About 50% of consumed hydrogen was utilized for the hydrogenation of aromatic rings in the recycle solvent, and the rest for the removal of nitrogen and oxygen from the recycle solvent, and for cracking of the recycle solvent. Among aromatic compounds contained in the recycle solvent, two-ring aromatics and hydroaromatics and their derivatives (aromatics of naphthalene type) shared the largest fraction. The aromatics of the naphthalene type underwent hydrogenation faster than those of the phenanthrene type, the anthracene type, and the pyrene type. Under the reaction conditions examined, excess hydrogenation of the aromatics of the naphthalene type to form perhydrogenated compounds (naphthenes) did not take place so extensively; i.e. tetrahydronaphthalenes formed much more than decahydronaphthalenes.

Lignans from the liverworts Lepidozia incurvata, Chiloscyphus polyanthos and Jungermannia exsertifolia ssp. cordifolia

Three foliose liverworts from the order Jungermanniales were examined for the presence of lignans. They all contained the typical liverwort lignans, i.e. cyclolignans of the dihydronaphthalene and naphthalene type and conjugated with α- l-rhamnose, malic acid and shikimic acid, respectively. The new lignans were 3-carboxy-6-methoxy-1-(3′,4′-dihydroxyphenyl)-naphthalene-7- O-α- l-rhamnopyranoside, 3-carboxy-6,7-dihydroxy-1-(3′,4′-dihydroxyphenyl)-naphthalene-9,2″- O-malic acid ester and 3-carboxy-6,7-dihydroxy-1-(3′,4′-dihydroxyphenyl)-naphthalene-9,5″- O-shikimic acid ester.

Characterization of Hydrogenation of Aromatics in Coal-derived Middle Distillate and 1-Methylnaphthalene.

Effects of reaction temperature and partial pressure of hydrogen on the hydrogenation of a coal-derived middle distillate were examined over Ni-Mo/alumina catalyst. As the aromatics of naphthalene type were major components of the coal-derived middle distillate, hydrogenation of 1-methylnaphthalene was also examined to quantify the conversion rate of the hydrogenation of aromatics. The hydrogenation proceeded via first-order reaction, with respect to both the content of 1-methylnaphthalene and the partial pressure of hydrogen. In conditions of temperature above 350°C and the hydrogen pressure around 4 MPa, not only rate of hydrogenation, but also thermodynamic limitation controlled the hydrogenation conversion of aromatics. At partial pressure of hydrogen around 12 MPa, the thermodynamic limitation of the hydrogenation of aromatics was effectively released up to the temperature of 400°C.

Nucleophilic addition reactions of [(polyarene)Mn(CO) 3] + complexes containing naphthalene type ligands

[(η 6-Polyarene)Mn(CO) 3] + complexes containing naphthalene type ligands undergo regioselective nucleophilic addition reactions with H- and C-donors to give moderate to good yields of η 5-cyclohexadienyl complexes. Products derived from hydride addition to naphthalene, phenanthrene and acenaphthene complexes have been characterized by X-ray diffraction.

Hydrolysis of schiff bases 2: Intramolecular catalysis of an ortho‐hydroxy group in nonionic surfactant systems

AbstractThe rates of hydrolysis of N‐(2&4‐hydroxybenzylidene)‐2‐aminobenzothiazoles has been studied in the pH range 4–13 in a 10% dioxane‐water system and in various nonionic surfactant systems. The reaction is found to be due to water mediated intramolecular general base catalysis within the pH range 4.0 to 12.0 and due to nucleophilic catalysis beyond pH 12.0. A ten membered intermediate facilitating transannular attack of a water molecule on the methine carbon forming a naphthalene type transition state has been proposed. The reactivity difference in water and nonionic surfactants has been explained by a suitable entrapment model.

The determination of241Pu by liquid scintillation spectrometry using the Packard 2250CA

The results of this study indicate that in terms of efficiency, the Packard 2250Ca liquid scintillation spectrometer is sensitive to the scintillation cocktail employed for241Pu analysis, particularly when the burst counting circuit is enabled. Cocktails exhibiting low t-SIE values should be avoided since quenching has a critical influence on such a low energy β− emitter. This effect would be independent of burst circuitry use. Cocktails which include naphthalene type derivatives such as the alkylnaphthalene solvent employed in Optiphase HiSafe 3 and Ultima Gold should be avoided since the broad pulse shapes produced are incompatible with the burst counting circuit which distinguishes background events from true β− events by means of pulse shape/duration analysis. Efficiency is also sensitive to the concentration of bis-MSB employed in conjunction with the primary fluor. Enhancements in efficiency are observed with appropriate concentrations. These results are in line with previous work with14C and are postulated as being a consequence of sharpening prompt pulse widths or suppression of afterpulsing. It is recommended that Instafluor should be used to maximize response, or a cocktail such as butyl-PBD/bis-MSB in pseudocumene at rates of 6 and 1.5 mg ml−1, respectively, where a lower vapor pressure solvent is particularly required.

Thermodynamics of surfactant-dye complex formation in aqueous solutions II. Sodium dodecyl sulfate and some azo oil dye systems

Spectrophotometric and thermodynamic investigations are reported of the interactions between anionic surfactant (sodium dodecyl sulfate) and six azo oil dyes (benzene azo naphthalene type) which have an amino group at 4-position of naphthalene. A pronounced spectral change in the dye solution occurs on addition of surfactant. For increasingly surfactant concentrations (below the CMC), the interaction between dye and surfactant is so sharp that the systems may be said to exhibit an isosbestic point; then a new absorption band appears at longer wavelengths. The spectral data can be quantitatively interpreted in terms of a complex formation. The equilibrium coefficients of the complex formation are determined at different temperatures. The thermodynamic parameters of the complex formations (the free energy change (ΔG), enthalpy change (ΔH) and change in entropy (ΔS) are also calculated. The reaction of complex formation is exothermic (ΔH negative).ΔG is dependent on the hydrophobic nature andpKa of the dye. These complexes will form due to hydrophilic-hydrophilic interaction and will become more stable due to hydrophobic-hydrophobic interaction.

Chemical Structure of Coal-derived Liquids

Akabira coal-derived neutral oil, free of the acidic and the basic portions, was separated according to boiling range into 25 fractions with 4°C-25°C interval using spinning band distillation. These fractions were separated into 6 compound classes, which were Fr-P (paraffin), Fr-M (monoaromatic), Fr-D1 (naphthalene type diaromatic), Fr-D2 (biphenyl type diaromatic), Fr-T (tri and/or tetraaromatic) and Fr-PP (polar and/or polyaromatic), using HPLC equipped with Zorbax BP-NH2 column.Using simulated distillation gas chromatographic technique (SD-GC), the boiling point of each distillation-HPLC fraction was determined. The result showed that the apparent boiling point estimated by SD-GC for each compound class having the same distillation fraction had the highest value for paraffin series and decreased gradually with increase in aromatic ring number from Fr-M to Fr-T, although the difference in the boiling point between SD-GC method and the fractional distillation method was not so large (less than nr) for each fraction.The distribution of each compound class by boiling point was determined by SD-GC of all the neutral oil-HPLC fractions. Fr-P was widely distributed in each boiling range from 183°C to 423°C, and the boiling ranges of the aromatic fractions (Fr-M, Fr-D1, Fr-D2 and Fr-T) were shifted to higher boiling point with increasing aromatic ring number in this order.

Toxic effects of naphthalene and methylnaphthalenes on marine plankton organisms

Sea urchin eggs, fish eggs, and adult copepods showed different sensitivity towards aromatic hydrocarbons of the naphthalene type. Methylated naphthalenes were, however, more toxic than naphthalene. The toxicity was apparently not dependent on the number of methyl groups, but rather on their position on the naphthalene molecule. Ultrastructural studies of exposed sea urchin embryos did not reveal specific effects at the cellular level.