Dioctyl Sebacate Research Articles

Potentially important nighttime heterogeneous chemistry: NO3 with aldehydes and N2O5 with alcohols

We report the first measurements of the reactive uptake of NO(3) with condensed-phase aldehydes. Specifically, we studied NO(3) uptake on solid tridecanal and the uptake on liquid binary mixtures containing tridecanal and saturated organic molecules (diethyl sebacate, dioctyl sebacate, and squalane) which we call matrix molecules. Uptake on the solid was shown to be efficient, where γ = (1.6 ± 0.8) × 10(-2). For liquid binary mixtures the reactivity of aldehyde depended on the matrix molecule. Assuming a bulk reaction, H(matrix)√(D(matrix)k(2°,aldehyde)) varied by a factor of 2.6, and assuming a surface reaction H(matrix)(S)K(matrix)(S)k(2°,aldehyde)(S) varied by a factor of 2.9, where H(matrix)√(D(matrix)k(2°,aldehyde)) and H(matrix)(S)K(matrix)(S)k(2°,aldehyde)(S) are constants extracted from the data using the resistor model. By assuming either a bulk or surface reaction, the atmospheric lifetimes for aldehydes were estimated to range from 1.9-7.5 h. We also carried out detailed studies of N(2)O(5) uptake kinetics on alcohols. We show that uptake coefficients of N(2)O(5) for five different organics at 293 K varied by more than 2 orders of magnitude, ranging from 3 × 10(-4) to 1.8 × 10(-2). We show that the uptake coefficients correlate with √(D(alcohol)(OH concentration)) but more work is needed with other alcohols to completely understand the dependence. Using this kinetic data we show that the atmospheric lifetime of alcohols with respect to N(2)O(5) heterogeneous chemistry can vary from 0.6-130 h, depending on the physical and chemical properties of the organic liquid.

Reactive uptake kinetics of NO3 on multicomponent and multiphase organic mixtures containing unsaturated and saturated organics

We investigated the reactive uptake of NO(3) (an important night-time oxidant in the atmosphere) on binary mixtures containing an unsaturated organic (methyl oleate) and saturated molecules (diethyl sebacate, dioctyl sebacate, and squalane) which we call matrix molecules. These studies were carried out to better understand the reactivity of unsaturated organics in multicomponent and multiphase atmospheric particles. For liquid binary mixtures the reactivity of methyl oleate depended on the matrix molecule. Assuming a bulk reaction, H(matrix)√(D(matrix)k(oleate)) varied by a factor of 2.7, and assuming a surface reaction H(matrix)(S)K(matrix)(S)k(oleate)(S) varied by a factor of 3.6, where H(matrix)√(D(matrix)k(oleate) and H(matrix)(S)K(matrix)(S)k(oleate)(S) are constants extracted from the data using the resistor model. For solid-liquid mixtures, the reactive uptake coefficient depended on exposure time: the uptake decreased by a factor of 10 after exposure to NO(3) for approximately 90 min. By assuming either a bulk or surface reaction, the atmospheric lifetime of methyl oleate in different matrices was estimated for moderately polluted atmospheric conditions. For all liquid mixtures, the lifetime was in the order of a few minutes (with an upper limit of 35 min). These lifetimes can be used as lower limits to the lifetimes in semi-solid mixtures. Our studies emphasize that the lifetime of unsaturated organics (similar to methyl oleate) is likely short if the particle matrix is in a liquid state.

Synergistic and antagonistic effects on oxidation stability of antioxidants in a synthetic ester based oil

Synergistic and antagonistic effects have been observed with the four sulfur-, phosphorus- and heavy metal-free antioxidants, hindered bis-phenol, octylated diphenylamine, octylated phenyl-alpha-naphthylamine and tolutriazole derivative, on the oxidation stability, thermal and physicochemical properties of dioctyl sebacate oil. The oxidation stability was evaluated using a rotary bomb oxidation tester. The results from isothermal and catalytic RBOT oxidation tests suggested that ODPA has an antagonistic effect on the OIT. The combination of HP:OPANA:TZ exhibited the highest and most synergistic antioxidant activity. Furthermore, synergism was observed in terms of both oxidation and thermal stabilities through thermogravimetric analysis (TGA).

Evaluation of thermal denuder and catalytic stripper methods for solid particle measurements

The objective of this study was to compare two methods that are used to separate the solid and volatile components of an aerosol: the thermal denuder (TD) and catalytic stripper (CS). We challenged the TD and CS with atmospheric and laboratory generated aerosols. Laboratory generated particles were composed of tetracosane, tetracosane and sulfuric acid, and dioctyl sebacate and sulfuric acid. These compositions were chosen because they roughly simulate the composition of nanoparticles found in Diesel exhaust. The TD method produced semi-volatile particle artifacts due to the incomplete removal of evaporated compounds that nucleated and formed particles and solid particle artifacts that formed during treatment of the aerosol by the TD. Our results suggest that the differences in these methods will lead to different conclusions regarding the presence or absence, size, and concentration of solid particles in Diesel exhaust.

Optimization of tramadol–PVC membrane electrodes using miscellaneous plasticizers and ion-pair complexes

Effect of the ISE membrane composition on the characteristics of the tramadol–PVC-electrodes has been investigated. The parameters studied include the effect of the plasticizer and the effect of the ion-pair complex. The plasticizers used were 2-nitrophenyl octyl ether (2-NPOE), dioctyl phthalate (DOP), dibutyl phthalate (DBP), tris(2-ethylhexyl) phosphate (TEPh), dioctyl sebacate (DOS), tributyl phosphate (TBPh) and dibutyl butyl phosphonate (DBBPh) and the ion-pair complexes were tramadolium–silicotungstate (TD–ST), silicomolybdate (TD–SM). These electrodes were fully characterized in terms of composition, life span, usable pH range and working concentration range. The results showed that the best combination was TD–ST as the ion-pair complex and DBP as the plasticizer that produced the electrode with favorable characteristics. Another electrode using TD–SM was tested and produced close results. The present electrodes show clear discrimination of tramadol hydrochloride from several inorganic, organic ions, sugars and some common drug excipients. The sensors were applied for determination of tramadol hydrochloride in urine, milk and pharmaceutical preparations using potentiometric determination, standard addition and the calibration curve methods. The results obtained were satisfactory with excellent percentage recovery comparable and sometimes better than those obtained by other routine methods for the assay.

Corrosion inhibition with different protective layers in tinplate cans for food preservation

In this work the influence of essential onion oil (EOO) on the protection of tinplates was compared with dioctyl sebacate oil (DOS) and epoxy phenolic lacquers, which are frequently used in the food canning industry. When EOO as the protective layer instead of DOS oil was used, tinplate porosity, measured electrochemically (7.58 ± 1.97 µA cm(-2) and 23.0 ± 1.3 µA cm(-2), respectively), and iron coating mass, calculated from AAS data (1.52 ± 0.15 mg m(-2) and 3.14 ± 0.42, respectively), was much lower indicating better corrosion protection. At higher storing temperature (36 °C) the addition of EOO to canned tomato purée enhanced the formation of hydrogen with time. The increasing volume fraction of H(2) (from 34.0 to 90.9% for cans without nitrates, and from 33.8 to 89.2% for cans with nitrates) is an indicator that corrosion takes place. As the use of EOO improves the protection of tinplate compared with DOS oil, and is almost as effective as epoxy phenolic lacquer, the addition of EOO can be recommended due to lower cost of canned food production and enhanced organoleptic properties, but the storage temperature has to be lower then 36 °C.

Determination of the ratio of diffusion charging-based surface area to geometric surface area for spherical particles in the size range of 100–900 nm

Diffusion charging-based surface area for spherical particles was measured and compared with geometric surface area in the submicrometer size ranging from 100 to 900 nm. Spherical aerosol particles (polystyrene latex particles (PSL) and droplets of diethylhexyl sebacate (DEHS)) were generated by electrosprays for 100–600 nm particles and by a condensation generator for 700–900 nm particles. Two commercially available diffusion chargers (DCs) (DC2000CE, Ecochem, USA; LQ1-DC, Matter Engineering, Switzerland) were challenged with monodisperse uncharged spherical aerosols. Results showed that the surface areas measured by the two DCs were proportional to mobility diameter to power 1.22 and 1.38, respectively, in the size range from 100 to 900 nm. Comparison of the DC-based surface area with theoretical active surface area resulted in reasonable agreement within ±30%, indicating that the DCs underestimate geometric surface area of particles. The deviation of the DC-based surface area from the geometric surface area was quantitatively measured and was found to be up to 94% in the size range studied. Three types of aerosol particles were used to validate the correction of the DC deviation from the geometric surface area for particles larger than 100 nm based on the fit obtained for spherical particles in this study: spherical silver particles, carbon nanofibers, and titanium dioxide agglomerates. Comparison of the corrected DC-based surface area to Brunauer–Emmett–Teller (BET)-measured surface area indicated that the DC surface area reasonably agrees with the BET value for the particles tested except carbon nanofibers with 300 nm modal diameter.

Properties of ibuprofen ion-selective electrodes based on the ion pair complex of tetraoctylammonium cation

Abstract Ibuprofen membrane electrodes based on different plasticizers: diisobutyl phthalate (DIBP), o-nitrophenyloctyl ether (o-NPOE), dioctyl sebacate (DOS) and tetraoctylammonium 2-(4-isobutylphenyl)propionate were prepared. All electrodes show: a near Nernstian slope of characteristic (58.3–60.9 mV decade−1) in the measurement range (10−4–10−1 mol L−1), limit of detection (5.0×10−5 mol L−1), really long lifetime (12 months), dependence of the electrode potential on pH (5.5–9.0), reproducibility of potential (0.6–1.2 mV) and selectivity coefficients in relation to some organic and inorganic anions. The electrodes were applied for the determination of ibuprofen in tablets by the calibration curve method and the standard addition method.

Method for High-Temperature Particle Sampling in Tar-Rich Gases from the Thermochemical Conversion of Biomass

The thermochemical conversion of biomass produces compounds in both gas and particle phases that may be regarded as contaminants. These contaminants include both particulate matter (e.g., fly ash, soot, and fragmented nonvolatilized material) and volatilized metals and tars that condense and form particulate matter during cooling. In this study a method for high-temperature particle sampling in tar-rich gases from the thermochemical conversion of biomass was developed and tested. Both a bed of granular activated carbon and a denuder were used for tar adsorption. First, the transport efficiency of particles was determined both theoretically and experimentally using a K2SO4 reference aerosol, and the losses were found to be smaller in the denuder than in the bed of granular activated carbon. The adsorption capacity was then tested using a model aerosol of K2SO4 and diethyl-hexyl-sebacate (DEHS). The adsorption capacity of the bed of granular activated carbon was found to be higher than that of the denuder. ...

Investigation of laminated fabric cages used in rolling bearings by ToF-SIMS

Properties of textile-laminated phenolic composition cages were studied by ToF-SIMS: (i) by monitoring the di- octyl- sebacate (DOS) content of the lubricant film within the elastohydrodynamic (EHD) contact region of the inner and outer rings of tested high-speed rolling element bearings, and (ii) by the investigation of boundary layers of cages in the region of the cage–ball-contact. Portions of the DOS amount stored in the cage by the bearing conservation process are released vs. the operation time via the cage surfaces into the EHD contact regions. It was revealed that the amount of the diester DOS separated from the cage into lubricating film of the raceway, is influenced by the lubricant additive formulations used in the tribological tests via their attributes concerning the acting tribological system processes like wear, boundary layer formation, adsorption, etc. ToF-SIMS research [1,2] of both the lubricant surface and the boundary layer in the EHD contact region showed that the primary antioxidants used as additives do not only act as oxidation inhibitors, but that they also do influence the wear processes of the counteracting bodies and the formation processes of boundary layers on rolling bearing steel SAE 52100. With the amounts of DOS, found in dependence on six different lubricant additive formulations A–F investigated, also an influence on the boundary layer formation processes is detected for the surface of the textile-laminated phenolic composition cage. ToF-SIMS imaging and depth profiling of cage boundary layers prove this dependence of the boundary layer formation process. The secondary ion (SI) intensities of DOS correspond with the lubricant dependence of the 56 Fe + / C 4 H 8 + ratios obtained from the used lubricant films in the EHD contact regions [1,3] as well as with the ratios 56 Fe + / C 4 H 8 + of the boundary layers in the raceways and of the cages [3]. Both the 56 Fe + / C 4 H 8 + ratios and the DOS intensity values show an indirect dependence to the lubricant service life of the lubricants A–F.

A comparative study of chromium(III) ion-selective electrodes based on N,N-bis(salicylidene)-o-phenylenediaminatechromium(III)

A comparative study was made between three types of Cr(III) ion-selective electrodes: PVC membrane electrode, silver coated electrode and modified carbon paste electrode based on N,N-bis(salicylidene)-o-phenylenediaminatechromium(III) complex (Crsalophen). As anticipated, electrodes with a solid contact, rather than a traditional liquid inner contact, give lower detection limits because of diminished ion fluxes. Often, however, ill-defined solid contact gives rise to instabilities and interferences by oxygen gas. The carbon paste electrode provides a more sensitive and stable device than that afforded by PVC and coated electrodes. The best performance was obtained by an electrode based on the paste containing 3.5 wt% Cr-complex, 48.5% graphite plasticized with a mixture of 24.0 wt% tris(2-ethylhexyl) phosphate (DOPh) + 24.0 wt% dioctyl sebacate (DOS). The sensor has a linear dynamic range of 7.5 × 10-6 to 1.0 × 10-2 M, with a Nernstian slope of 20.1 ± 0.6 mV decade-1, and a detection limit of 1.8 × 10-6. It has a short response time of a bout 8 s and is applicable in a pH range of 4.5-7.7. It was successfully used as an indicator electrode in potentiometric titration of Cr(III) with EDTA and in determination of Cr(III) in water samples and chromium in (Crsalophen).

Real‐Time Measurement of the Size Distribution of Diesel Exhaust Particles using a Portable 4‐stage Electrical Low Pressure Impactor

AbstractFor this study, a 4 stage electrical low pressure impactor was designed to measure the real‐time size distribution of diesel particulate matter (DPM). For the performance evaluation, sodium chloride (NaCl) particles and dioctyl sebacate (DOS) particles were used. After evaluating the collection efficiency of each stage of the impactor, the size distributions of test particles were estimated using electrical current data and their inversion algorithm, and this was found to agree with the results obtained by a scanning mobility particle sizer (SMPS). For measurement of DPM, a common‐rail direct injection (CRDI) diesel engine, for engine speeds of 1,200 rpm and 1,500 rpm at 2.7 kgf·m, was used.Therefore, it was found that the size distribution of the DPM could be easily obtained, with the currents measured by the impactor and the data inversion algorithm, in less than 5 seconds. Furthermore, the effective density of the DPM could be obtained using the calculated results and the SMPS data.

Corrosion behaviour of tinplate cans in contact with tomato purée and protective (inhibiting) substances

The dissolution of iron and tin from tinplate cans filled with tomato purée (pH 4.34) and dioctyl sebacate oil (DOS), essential onion oil (EOO) or potassium nitrate was studied using atomic absorption spectroscopy (AAS), while nitrate was determined using high-performance liquid chromatography (HPLC). The maximum values found in cans were up to 284 mg kg−1 for tin and 513 mg kg−1 for iron at elevated storage temperature. Results indicated that the addition of EOO to tomato purée prevents the corrosion process in the case of tin, where concentrations were lowered from 223 to 28 mg kg−1 for cans with DOS oil and EOO at 20°C, respectively (inhibition rate of 87%). On the other hand, the presence of EOO enhanced the corrosion process for iron increasing the concentration from 15 to 46 mg kg−1 during 7 months of storage, although this value did not exceed maximum permitted value (50 mg kg−1). In cans with tomato purée and potassium nitrate, dissolution of tin started after 30 (36°C) and 60 (20°C) days of storage as a consequence of nitrate action, which act as a corrosion accelerator. Since the addition of EOO improves the taste of canned tomato purée, its potential use as a corrosion inhibitor would be of interest.

Determination of Activity Coefficients of Semi-Volatile Organic Aerosols Using the Integrated Volume Method

We demonstrate the use of the Integrated Volume Method (IVM) to estimate activity coefficients of semi-volatile organic compounds pertinent to ambient/atmospheric aerosols in binary mixtures. We generate binary solution aerosols with different mole fractions of individual components; for each mixture, we measure total change in aerosol volume upon heating from 25 ○ C to 35 ○ C, with the aerosols being at equilibrium in both states. The change in aerosol volume, or in other words, the partitioning between the particle phase and the gas phase, is used to determine activity coefficients of the compounds as a function of their mole fraction in the mixture. We demonstrate this method using the following four model systems. System 1: adipic acid–pimelic acid, which illustrates polar organic–polar organic interactions. Non-ideal behavior was observed with activity coefficients around three at infinite dilution. System 2: adipic acid–dioctyl sebacate, which illustrates polar organic–non-polar organic interactions...

Effect of particle spatial distribution on particle deposition in ventilation rooms

We used simulations and experimental tests to investigate indoor particle deposition during four commonly used ventilation modes, including ceiling supply, side-up supply, side-down supply and bottom supply. We used a condensation monodisperse aerosol generator to generate fine diethylhexyl sebacate (DEHS) particles of different sizes along with two optical particle counters that measured particle concentration at the exhaust opening and inside a three-dimensional ventilated test room. We then simulated particle deposition using the same ventilation modes with computational fluid dynamics (CFD) method. Our simulated results indicate that mean deposition velocity/rate for particles 0.5–10 μm (aerodynamic diameter) is not affected by different ventilation modes. However, both our experimental and simulated results indicate that the deposition loss factor, a parameter defined based on mass balance principle to reflect the influence of particle distribution on deposited particle quantity, differ significantly by ventilation mode. This indicates that ventilation plays an important role in determining particle deposition due to the apparent differences in the spatial distribution of particles. The particle loss factor during ventilation modes characterized by upward air flow in the room is smaller than that of mixing ventilation; however this trend was strongly influenced by the relative location of the inlets, outlets and aerosol source.

Influence of essential onion oil on tin and chromium dissolution from tinplate

During food and beverage packaging in tinplate cans the dissolution of tin and chromium into food content may occur. To protect metallic surface different corrosion inhibitors are recommended, nowadays particularly a new group of natural products is of interest. In this work the influence of essential onion oil (EOO) on metals dissolution (tin and chromium) from tinplate sheets before food canning was investigated. The analyses were performed by galvanostatic method and atomic absorption spectroscopy. The values of tin obtained for the internal surface of tinplate covered with EOO (7.31–9.76 g m −2) are lower than the values when dioctyl sebacate oil (DOS), as a protective tinplate surface layer for food caning, was used (9.24–11.03 g m −2). Obviously, the presence of EOO diminished more efficiently then DOS oil the dissolution of tin in electrolyte during galvanostatic analyses. The efficiency of EOO as corrosion inhibitor was even more pronounced in the case of chromium where the dissolution from 1.8–2.5 mg m −2 (DOS oil) was lowered to 1.0–1.3 mg m −2 (EOO). Correlation of results obtained with two different physico-chemical methods was satisfying.

Molecular Dynamics Simulation on Compatibility of Hydroxyl-Terminated Polybutadiene/Plasticizer Blends

It has been found that the mechanical properties of solid propellants and plastic bonded explosives (PBX) depend heavily on the compatibility of the polymer binder and plasticizer used in their formulation. Two systems, one miscible and the other immiscible, were simulated by molecular dynamics (MD) simulations to test the usefulness of this molecular simulation technique. Density, cohesive energy density, and solubility parameters of hydroxyl-terminated polybutadiene (HTPB), dioctyl sebacate(DOS), nitroglycerine (NG), HTPB/DOS blend and HTPB/NG blend were calculated by MD simulations with the COMPASS force field for the prediction of polymer binder and plasticizer compatibility. Results show that HTPB/DOS is a miscible system but HTPB/NG is not miscible by comparing the difference in the solubility parameter value (△δ), pair correlation function and the change of density. The predictions agreed well with experimental observations. By calculating the pair correlation function the HTPB/plasticizer interaction was clarified. Therefore, the method used in this work is a useful tool to provide information on miscibility and other properties of a given polymer/plasticizer blend. In addition, it is a promising technique to help to design formulations for screening solid propellants and PBX before experimental tests.

High-Throughput Phase-Distribution Method to Determine Drug-Cyclodextrin Binding Constants

A high-throughput method has been developed to measure drug-cyclodextrin binding constants. It measures the distribution ratio of a drug between a polymer film [polyvinyl chloride (PVC) with 67% (w/w) dioctyl sebacate (DOS)] and a cyclodextrin-containing buffer in a 96-well format. Measurements of distribution ratios at several cyclodextrin concentrations lead to binding constants. Binding constants for econazole with six CDs have been determined in one 96-well microplate with four replications of each condition in 10h. The K1:1/103 M−1 values are 3.98 ± 0.13, 3.90 ± 0.22, 29.3 ± 2.2, 0.66 ± 0.04, 1.78 ± 0.30, 4.08 ± 0.50, with (2-hydroxyethyl)-β-cyclodextrin, (2-hydroxypropyl)-β-cyclodextrin, 2,6-di-O-methyl-β-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin, α-cyclodextrin, β-cyclodextrin, respectively. It is likely that 1:2 complexes are also formed in some cases. This method has also been applied to study the binding behavior as a function of the drug concentration and pH. Binding weakens at higher drug concentration which may be due to the self-association of the drug. An acidic environment decreases the binding constant of CD with the basic econazole. The formation of the 1:2 complexes is completely suppressed in acid as well. This protocol is faster than the phase-solubility method. Moreover, the material requirement is up to four orders of magnitude lower. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:229–238, 2009

A hybrid chip based on aerodynamics and electrostatics for the size-dependent classification of ultrafine and nano particles

Conventional virtual impactors experience a large pressure drop when they classify particles according to size, in particular ultrafine particles smaller than 100 nm in diameter. Therefore, most virtual impactors have been used to classify particles larger than 100 nm. Their cut-off diameters are also fixed by the geometry of their flow channels. In the proposed virtual impactor, particles smaller than 100 nm are accelerated by applying DC potentials to an integrated electrode pair. By the electrical acceleration, the large pressure drop could be significantly decreased and new cut-off diameters smaller than 100 nm could be successfully added. The geometric cut-off diameter (GCD) of the proposed virtual impactor was designed to be 1.0 microm. Performances including the GCD and wall loss were examined by classifying dioctyl sebacate of 100 to 600 nm in size and carbon particles of 0.6 to 10 microm in size. The GCD was measured to be 0.95 microm, and the wall loss was highest at 1.1 microm. To add new cut-off diameters, monodisperse NaCl particles ranging from 15 to 70 nm were classified using the proposed virtual impactor with applying a DC potential of 0.25 to 3.0 kV. In this range of the potential, the new cut-off diameters ranging from 15 to 35 nm was added.

The simulator for icy world interiors: A 700 MPa pressure system for impulsive stimulated scattering and other optical measurements, with thermal control from −20 to 100 °C

The simulator for icy world interiors (SIWI) was developed for sound velocity measurements in simulated extraterrestrial ocean materials by the method of impulsive stimulated scattering (ISS). The design and operation of SIWI are described. Optical measurements at low temperature in corrosive solution were enabled by enclosing sample fluid in a stoppered spectrophotometric cuvette. To maintain minimum optical density it was necessary to limit contact of the dioctyl sebacate hydraulic fluid with nitrile o-rings, which caused discoloring enhanced absorption of the 532 nm ISS probe pulses. Dilution of hydraulic fluid with kerosene in the amount of 5% by volume prevented clouding at high pressures and at low temperatures. Pure kerosene was found to attenuate the ISS signal, and so was deemed unsatisfactory at low temperatures where the lower thermal expansion of water leads to weaker density contrasts between heated and unheated regions in the sample fluid. When 50 cS silicone oil was used as a hydraulic medium, clouding was observed at pressures above 400 MPa when temperatures were raised above approximately 50 degrees C and lowered to less than approximately 10 degrees C. To our knowledge, such clouding has not been reported previously for dioctyl sebacate, nor for silicone at such low pressures.