Investigation of thermal hazard during the hydrosilylation of 1,6-divinyl(perfluorohexane) with trichlorosilane

In this study, we examined the reaction hazard during the hydrosilylation reaction between trichlorosilane (TCS) and 1,6-divinyl(perfluorohexane) (FDV) in the presence of a butanol solution of chloroplatinic acid (Pt-Cat) as the catalyst. Assuming the three industrial risks of excessive addition of Pt-Cat, contamination by iron rust and mixing with cooling water, we observed the temperature and pressure change of TCS/FDV with an excessive amount of Pt-Cat, TCS/FDV/Pt-Cat with Fe₂O₃ and TCS/FDV/Pt-Cat with distilled water, using an accelerating rate calorimeter (ARC). The temperature and pressure greatly increased, especially in the sample with Fe₂O₃. For instance, in TCS/FDV/Pt-Cat with 1.5 wt.% Fe₂O₃, the heat release rate exceeded 624 K · min^?1 and the pressure rose above 25 MPa during the exothermic reaction.     

An LC method for quantifying bepridil in human plasma using 1-naphthol as the internal standard

A modified method for the quantitative determination of bepridil hydrochloride in human plasma is described. This method is unrelated to chemical methods currently in use. The mobile phase is 50 mM phosphate buffer (pH3.0)-methanol-acetonitrile-triethylamine (57:3:40:1, v/v), and the samples are fractionated on a C8-3 column (150 × 4.6 mm, 5 μm) using a flow rate of 0.9 mL/min. Bepridil was detected by UV spectroscopy at 254 nm. The retention times of bepridil and 1-naphthol were 12.6 min and 7.5 min, respectively; there was no interference originating from human plasma. We confirmed that the bepridil and 1-naphthol peaks were not influenced by the presence of 32 commercial medicines frequently co-administered with bepridil. Additionally, the concentration of bepridil in the plasma of five patients treated with bepridil for atrial fibrillation was measured. These samples were collected just before each dosage of bepridil. Their rhythm and rate control were well maintained. Trough concentrations ranged from 233.9 to 347.4 ng/mL, similar to previously reported values.     

$${\varvec{teaspoon}}$$ : solving the curriculum-based course timetabling problems with answer set programming

Annals of Operations Research - Answer Set Programming (ASP) is an approach to declarative problem solving, combining a rich yet simple modeling language with high performance solving capacities....     

Determination of elemental and ionic compositions for diesel exhaust particles by particle induced X-ray emission and ion chromatography analysis.

The purpose of this study is to clarify the chemical characterization of PM2.5 and PM10 in diesel exhaust particles (DEP). Sampling of PM2.5 and PM10 in DEP was carried out in November 1999 using an automobile exhaust testing system at the National Traffic Safety and Environment Laboratory, with a diesel truck (engine type: direct injection, displacement: 7,961 cc, carrying weight: 2,020 kg, equivalent inertia weight: 5,600 kg) placed on a chassis dynamometer. Sampling conditions included idling, constant speed of 40 km/h, M-15 test pattern and 60%-revolution/40%-load of maximum power. Samples were collected on a polycarbonate membrane filter (Nuclepore, pore size: 0.8 microm) using a MiniVol Portable Air Sampler (Airmetrics Co., Inc.). The concentrations of several elemental and ionic species in the PM2.5 and PM10 samples were determined by particle induced X-ray emission (PIXE) and ion chromatography analysis. PIXE analysis of the PM2.5 and PM10 samples revealed 15 elements, of which Na, Mg, Si, S, Cl, Ca, Fe and Zn were found to be the major components. Ionic species were Cl-, NO2-, NO3-, SO4(2-), Na+, NH4+, K+ and Ca2+. Concentrations of elements and ionic species under the sampling condition of 60%-revolution/40%-load were highest in comparison with those of the other sampling conditions. The elemental and ionic species data were compared for PM2.5 and PM10; PM2.5 concentrations were 70% or more of PM10 concentrations for the majority of elements, and concentrations of ionic species in PM2.5 and PM10 were almost identical.     

Semiconductor-catalyzed photooxygenation of aromatic olefins

Irradiation of semiconductors (TiO₂ and CdS) suspended in organic solvents containing 1,1-diphenylethylene and its derivatives under oxygen afforded the corresponding epoxides and benzophenone. A possible mechanism is discussed.     

Interfacial adsorption phenomena at a weakly first-order phase transition

We study the interfacial adsorption phenomena of the ferromagnetic five-state Potts model on the square lattice, whose transition is of weakly first-order, by using Monte Carlo simulations and finite-size scaling theory. It is shown that the net-adsorption has a finite-size effect according to the first-order phase transition even for systems much smaller than the bulk correlation length.     

Photoelectron spectroscopic study of simple hydrogen-bonded dimers. I. Supersonic nozzle beam photoelectron spectrometer and the formic-acid dimer

In this paper we describe several characteristics of our supersonic nozzle beam photoelectron spectrometer recently constructed for studying hydrogen-bonded dimers in the gas phase by HeI (58.4 nm) radiation. Using this photoelectron apparatus, we have reinvestigated the HeI photoelectron spectrum of the formic-acid dimer (HCOOH)₂ which is well known as a fairly strong doubly hydrogen-bonded dimer. It was found that the (HCOOH)₂ spectrum deduced here from the spectrum of the monomer—dimer mixture considerably differs from that reported by Carnovale et al. in the region beyond 16.5 eV. New spectral assignments are given for four ionization bands beyond 16.5 eV. It is also indicated that the lower bound of the dissociation energy of (HCOOH)₂⁺ is estimated to be 1.0 ± 0.1 eV from the threshold of the dimer band (11.0 eV) obtained in this experiment. This value is considerably smaller than the value of 1.7 ± 0.2 eV recently reported for the water dimer cation (H₂O)₂⁺.     

Photoelectron spectra and sum rule consideration: Effect of chlorine substitution on ionization energies for chloroethanes,chloroacetaldehydes and chloroacetyl chlorides

He(I) photoelectron spectra are reported for various series of chlorine-substituted compounds: (a) CH₃CH_3?mCl_m, (b) CH_3?mCl_mCCl₃, (c) CH_3?mCl_mCHO and (d) CH_3?mCl_mCOCl, where m = 1, 2 and 3. In each series it is shown that the total sum of vertical ionization energies over all p-type localized molecular orbitals (LO's) has an excellent linear relationship to the number of substituted chlorine atoms. The differences in the total orbital energy sum by successive chlorine substitutions are found to be 26.7 eV for series a and b and 27.2 eV for series c and d, yielding the corresponding experimental σ_CCl, energies useful for sum rule considerations. The photoelectron spectra of the chloro compounds studied are interpreted with the help of the sum rule as well as CNDO/2 calculations. Orbital correlation diagrams have been constructed for these compounds.