74 research outputs found

    Thermodynamic Properties of Propanol and Butanol as Oxygenate Additives to Biofuels

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    Alternative and renewable energy technologies are being sought throughout the world to reduce pollutant emissions and increase the efficiency of energy use. Oxygenate second-generation biofuels fuels lead to a reduction in pollutant emissions and their thermodynamic and transport properties allow that the facilities for transport, storage and distribution of fuels could be used without modification. Higher alcohols, like propanol and butanol, enhance the octane number, boosting the anti-knock effect in gasoline. Then the compression ratio of the engines can be increased without risk of knocking, leading to higher delivery of power. From the combustion point of view, the production of carbon monoxide and volatile hydrocarbons from the combustion of alcohols is less than the one of gasoline. This chapter covers mixtures of butanol and propanol with hydrocarbons. The properties reviewed are excess volume or density (VE), vapour-liquid equilibrium (VLE), and heat capacity (Cp)

    High pressure and high temperature volumetric properties of (2-propanol + di-isopropyl ether) system

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    New experimental density data are reported for binary mixtures of 2-propanol + di-isopropyl ether over the composition range (6 compositions; 0.15 ≀ 2-propanol mole fraction x ≀ 0.85), between 293.15 and 393.28 K, and for 23 pressures from 0.1 MPa up to 140 MPa. Measurements were performed by means of an Anton Paar vibrating tube densitometer, calibrated with an uncertainty of 7 × 10−4 g cm−3. A Tait like equation was used to fit the experimental density data, with low standard deviations. Excess volumes have been calculated from the experimental data and fitted by the Redlich–Kister equation. Moreover, the isothermal compressibility and the isobaric thermal expansivity have been derived from the Tait-like equation.Ministerio de Ciencia e InnovaciĂłn, Spain, Project ENE2009-14644-C02-0

    In vitro neurotoxicity of particles from diesel and biodiesel fueled engines following direct and simulated inhalation exposure

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    Combustion-derived particulate matter (PM) is a major source of air pollution. Efforts to reduce diesel engine emission include the application of biodiesel. However, while urban PM exposure has been linked to adverse brain effects, little is known about the direct effects of PM from regular fossil diesel (PMDEP) and biodiesel (PMBIO) on neuronal function. Furthermore, it is unknown to what extent the PM-induced effects in the lung (e.g., inflammation) affect the brain. This in vitro study investigates direct and indirect toxicity of PMDEP and PMBIO on the lung and brain and compared it with effects of clean carbon particles (CP). PM were generated using a common rail diesel engine. CP was sampled from a spark generator. First, effects of 48 h exposure to PM and CP (1.2–3.9 ”g/cm2) were assessed in an in vitro lung model (air–liquid interface co-culture of Calu-3 and THP1 cells) by measuring cell viability, cytotoxicity, barrier function, inflammation, and oxidative and cell stress. None of the exposures caused clear adverse effects and only minor changes in gene expression were observed. Next, the basal medium was collected for subsequent simulated inhalation exposure of rat primary cortical cells. Neuronal activity, recorded using microelectrode arrays (MEA), was increased after acute (0.5 h) simulated inhalation exposure. In contrast, direct exposure to PMDEP and PMBIO (1–100 ”g/mL; 1.2–119 ”g/cm2) reduced neuronal activity after 24 h with lowest observed effect levels of respectively 10 ”g/mL and 30 ”g/mL, indicating higher neurotoxic potency of PMDEP, whereas neuronal activity remained unaffected following CP exposure. These findings indicate that combustion-derived PM potently inhibit neuronal function following direct exposure, while the lung serves as a protective barrier. Furthermore, PMDEP exhibit a higher direct neurotoxic potency than PMBIO, and the data suggest that the neurotoxic effects is caused by adsorbed chemicals rather than the pure carbon core

    A robust binary supramolecular organic framework (SOF) with high CO2 adsorption and selectivity

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    A robust binary hydrogen-bonded supramolecular organic framework (SOF-7) has been synthesized by solvothermal reaction of 1,4-bis-(4-(3,5-dicyano-2,6 dipyridyl)dihydropyridyl)benzene (1) and 5,5’-bis-(azanediyl)-oxalyl-diisophthalic acid (2). Single crystal X-ray diffraction analysis shows that SOF-7 comprises 2 and 1,4-bis-(4-(3,5-dicyano-2,6-dipyridyl)pyridyl)benzene (3), the latter formed in situ from the oxidative dehydrogenation of 1. SOF-7 shows a three-dimensional four-fold interpenetrat-ed structure with complementary O−H···N hydrogen bonds to form channels that are decorated with cyano- and amide-groups. SOF-7 exhibits excellent thermal stability and sol-vent and moisture durability, as well as permanent porosity. The activated desolvated material SOF-7a shows high CO2 sorption capacity and selectivity compared with other po-rous organic materials assembled solely through hydrogen bonding

    Tunable Porous Organic Crystals: Structural Scope and Adsorption Properties of Nanoporous Steroidal Ureas

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    Previous work has shown that certain steroidal bis-(N-phenyl)ureas, derived from cholic acid, form crystals in the P61 space group with unusually wide unidimensional pores. A key feature of the nanoporous steroidal urea (NPSU) structure is that groups at either end of the steroid are directed into the channels and may in principle be altered without disturbing the crystal packing. Herein we report an expanded study of this system, which increases the structural variety of NPSUs and also examines their inclusion properties. Nineteen new NPSU crystal structures are described, to add to the six which were previously reported. The materials show wide variations in channel size, shape, and chemical nature. Minimum pore diameters vary from ∌0 up to 13.1 Å, while some of the interior surfaces are markedly corrugated. Several variants possess functional groups positioned in the channels with potential to interact with guest molecules. Inclusion studies were performed using a relatively accessible tris-(N-phenyl)urea. Solvent removal was possible without crystal degradation, and gas adsorption could be demonstrated. Organic molecules ranging from simple aromatics (e.g., aniline and chlorobenzene) to the much larger squalene (Mw = 411) could be adsorbed from the liquid state, while several dyes were taken up from solutions in ether. Some dyes gave dichroic complexes, implying alignment of the chromophores in the NPSU channels. Notably, these complexes were formed by direct adsorption rather than cocrystallization, emphasizing the unusually robust nature of these organic molecular hosts

    Chain-Walking Polymerization of α-Olefins by α-Diimine Ni(II) Complexes: Effect of Reducing the Steric Hindrance of Ortho- and Para-Aryl Substituents on the Catalytic Behavior, Monomer Enchainment, and Polymer Properties

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    With Brookhart type α-diimine Ni(II) based catalysts, it is highly challenging to tune polymers branching level and branch-type distribution, which in turn strongly affects thermal and mechanical properties, through the aryl ortho-positions modification, while maintaining high turnover frequencies (TOFs). Herein, we are interested in performing a systematic investigation on the polymerization of 1-octene, 1-decene, and 1-octadecene catalyzed by a series of α-diimine nickel(II) complexes with methyl ligand backbone and different substituents in aryl positions (Ni1-Ni6). In addition to bulky isopropyl and tert-butyl substituents described in the original Brookhart's work, complexes with different aryl ortho- and para-substituted α-diimine ligands, including the less sterically demanding methyl and ethyl substituents, are investigated. The 13C NMR spectra of the polymers have been assigned in detail, and some unique features have been identified and related to the chain-walking coordination/insertion mechanism. Changes in the ligand structure and monomer size have important effects on the numerous combinations of insertion and chain-walking paths from which different branches are installed. We have also carried out a comprehensive investigation of the mechanical behavior of the polymers by means of uniaxial stretching until failure, step-cycle, and creep tensile tests. Overall, the resulting polymers exhibited a broad spectrum of tensile properties, depending on their microstructure and crystallinity which in turn are strongly affected by monomer length and type of α-diimine ligand. 1-Octene and 1-decene polymers behave as elastomers with excellent mechanical properties, i.e., high elongation at break (up to 2000%) and good strain recovery, while 1-octadecene polymers behave as plastomers

    Thermophysical Study on the Mixing Properties of Mixtures Comprising 2-(2-Methoxyethoxy)ethanol, Butan-1-ol, Butan-2-ol, and Propan-1-ol

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    Excess enthalpy (HE), dynamic and kinematic viscosities (η, υ), density (ρ), and refractive index (nD) of mixtures comprising 2-(2-methoxyethoxy)ethanol, butan-1-ol, butan-2-ol, and propan-1-ol are presented at p = 0.1 MPa and at T = 298.15 and 313.15 K. Deviations in refractive index (ΔnD) is generated from experimental data of refractive index. Experimental data of ρ for all binary mixtures are predicted using the PC-SAFT (Perturbed Chain-Statistical Associating Fluid) EoS. Furthermore, HE and ΔnD are adjusted using the Redlich–Kister equation. However, the correlation of measured data of HE is performed by using the UNIQUAC and NRTL models
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