Search results for "Styrene"
showing 10 items of 561 documents
Studien zum Vorgang der Wasserstoffübertragung, 54. Mechanismus und Grenzen der Clemmensen-Reduktion des Acetophenons und verwandter Verbindungen
1978
Bei der Reduktion von Acetophenon nach Clemmensen entstehen auser Ethylbenzol (1; Vier-Elektronen-Ubergang) in von den Reaktionsbedingungen abhangigen Mengen das Hydrodimerisierungsprodukt 2,3-Diphenyl-2,3-butandiol (2; Ein-Elektronen-Ubergang) und dessen Umlagerungsverbindungen 3 und 4, aber weder 1-Phenylethanol noch Styrol (Zwei-Elektronen-Ubergang). Temperatur, Saurekonzentration, Saureart, Reduktionsmittel (amalgamiertes Zink, Zinkamalgam, Cadmium, Zink-Cadmium-Legierung, Cadmiumamalgam, Magnesiumamalgam, Blei, Zink, Blei-Legierung) bestimmen die Anteile der gebildeten Reduktionsprodukte 1 — 4. 1-Phenylethanol und Styrol konnen unter Clemmensen-Bedingungen partiell in Ethylbenzol (1) u…
LS104, a non-ATP-competitive small-molecule inhibitor of JAK2, is potently inducing apoptosis in JAK2V617F-positive cells
2008
Abstract The activating JAK2V617F mutation has been described in the majority of patients with BCR-ABL-negative myeloproliferative disorders (MPD). In this report, we characterize the small-molecule LS104 as a novel non-ATP-competitive JAK2 inhibitor: Treatment of JAK2V617F-positive cells with LS104 resulted in dose-dependent induction of apoptosis and inhibition of JAK2 autophosphorylation and of downstream targets. Activation of these targets by JAK2 was confirmed in experiments using small interfering RNA. LS104 inhibited JAK2 kinase activity in vitro. This effect was not reversible using elevated ATP concentrations, whereas variation of the kinase substrate peptide led to modulation of …
Dynamic thermal expansivity near the glass transition
2000
Dielectric techniques were used to investigate the thermal expansivity of polystyrene films. Capacitive scanning dilatometry (CSD) employs temperature ramping in order to monitor the non-linear structural relaxation in the glass transformation range and to quantify liquid fragility. In the linear response regime, the complex thermal expansivity is obtained as a function of the temperature cycling frequency and is observed to reflect the structural relaxation.
An automated and self-cleaning nano liquid chromatography mass spectrometry platform featuring an open tubular multi-hole crystal fiber solid phase e…
2017
An open tubular (OT) sample preparation/separation platform was developed. A multi-channel polymer layer open tubular (mPLOT) solid phase extraction (SPE) column was prepared by wall-coating the 126 channels (8μm inner diameter (ID) each) of a crystal fiber capillary with an organic polymer, namely poly(styrene-co-octadecene-co-divinylbenzene) (PS-OD-DVB). The mPLOT SPE was coupled on-line with a 10μm×2m poly(styrene-co-divinylbenzene) (PS-DVB) OT liquid chromatography column with nanospray mass spectrometry (OTLC-MS). Compared to using monolithic/particle-packed SPEs, mPLOT-SPE-OTLC allowed both fast loading and sufficient refocusing on the OT analytical column of small model compounds (su…
Covalently Supported Ionic Liquid Phases: An Advanced Class of Recyclable Catalytic Systems
2016
In this review, the most recent advances in the synthesis and catalytic applications of covalently supported ionic liquid (IL) phases will be discussed. This class of recyclable catalytic materials is based on the covalent attachment of several types of ammonium salts, usually imidazolium, but also thiazolium, triazolium, and pyrrolidinium salts, on the surface of different supports, for example, silica, periodic mesoporous organosilica, polystyrene, magnetic-based materials, carbon nanotubes (NTs), halloysite NTs, polyhedral oligomeric silsesquioxane (POSS), and fullerenes. Moreover, poly(ionic liquid) materials, in which the IL-based structure also acts as a support, will be considered. T…
A system for rapid radiochemical separations from aqueous solutions
1969
Abstract For the study of short-lived fission products, an automatic system has been developed that allows to irradiate aqueous solutions sealed in polystyrene capsules, to separate chemically the radioactive products formed, and to start counting, all within a few seconds. Irradiations are performed in a pneumatic tube system installed in a horizontal beam hole of a reactor. The capsule is projected into a separation apparatus where it breaks by impact. Its content is then sucked through a thin reactive layer that takes up the desired product. The whole sequence of irradiation, transportation, chemical separation, and counting is controlled by automatic timers. The adaption of this techniq…
From Spherical Mesopores to Worm-Shaped Mesopores : Morphology Transition in Titania–Polystyrene-b-poly(ethylene oxide) Composite Films with Increasi…
2013
A morphology transition from spherical mesopores to worm-shaped mesopores within titania block copolymer composite thin films has been observed by varying the sol–gel reaction time from 40 min to 48 h in the four-component templating system of polystyrene-$\mathit{b}$-poly(ethylene oxide) (PS-$\mathit{b}$-PEO), 1,4-dioxane, concentrated HCl, and titanium tetraisopropoxide (TTIP) with a PS-$\mathit{b}$-PEO mass concentration of 0.25 wt.-%. The impact of the sol–gel reaction time on the local structure, long-range lateral structure, and vertical structure of the as-prepared, calcined, and UV-degraded thin films as well as the structural changes in solution have been systematically investigate…
Kinetics of styrene biodegradation by Pseudomonas sp. E-93486
2011
The research into kinetics of styrene biodegradation by bacterial strain Pseudomonas sp. E-93486 coming from VTT Culture Collection (Finland) was presented in this work. Microbial growth tests in the presence of styrene as the sole carbon and energy source were performed both in batch and continuous cultures. Batch experiments were conducted for initial concentration of styrene in the liquid phase changed in the range of 5–90 g m−3. The Haldane model was found to be the best to fit the kinetic data, and the estimated constants of the equation were: μm = 0.1188 h−1, KS = 5.984 mg l−1, and Ki = 156.6 mg l−1. The yield coefficient mean value \documentclass[12pt]{minimal} \usepackage{amsmath} \…
Size Dependence of Tracer Diffusion in Supercooled Liquids
1996
We have determined by forced Rayleigh scattering the diffusion coefficients D of several photochromic tracers with van der Waals radii between 0.38 and 8 nm (the largest ones being photolabeled polystyrene micronetworks) in 10 glass-forming liquids at temperatures between the glass temperature Tg and ∼1.2Tg. The results were analyzed in terms of power law plots, D(T) ∝ T/η(T)ξ, where η is the solvent shear viscosity, and temperature shifts, D(T) ∝ T/η(T + ΔT). The shift ΔT was related with the width of the rotational correlation time distribution via the time−temperature superposition principle.
A theoretical study of the electronic spectrum of styrene
1999
Abstract The electronic spectrum of styrene has been studied by using multiconfigurational second-order perturbation theory (CASPT2). The study includes geometry optimization of the ground state, the lowest triplet state, and the lowest singlet excited state. The covalent 2 1 A ′ state placed vertically at 4.34 eV is assigned to the first band. The 1 1 A ′→3 1 A ′ transition located at 4.97 eV is responsible for the second band. The most intense feature involves the 5 1 A ′ state, which is calculated to lie 6.19 eV above the ground state. The lowest singlet–singlet Rydberg transition (3s) is predicted to occur at 5.85 eV.