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Hazards
Published in Rick Houghton, William Bennett, Emergency Characterization of Unknown Materials, 2020
Rick Houghton, William Bennett
The researchers excluded from their definition water-reactive substances that produce flammable gases that do not otherwise pose a toxic hazard. Examples would include hydrogen gas from wet calcium hydride and acetylene gas from wet calcium carbide.
Synthesis and thermo-responsive properties of poly(N-vinyl caprolactam)/polyether segmented networks
Published in Y. Yagci, M.K. Mishra, O. Nuyken, K. Ito, G. Wnek, Tailored Polymers & Applications, 2020
Natalya A. Yanul, Yury E. Kirsh, Sam Verbrugghe, Eric J. Goethals, Filip E. Du Prez
Tetrahydrofuran (Acros 99%) was dried for 24h over calcium hydride and then refluxed over sodium wire until the addition of benzophenone generated a blue color. The dry THF was distilled into the reaction vessel under nitrogen prior to use. 2,2,6,6-Tetramethylpiperidine (Across 98%), trifluoromethane sulfonic anhydride (triflic anhydride) (Aldrich 98%), triethylamine (Aldrich 99%), methacryloyl chloride (Acros 99%), acrylic acid (Acros 99%) and N-vinyl caprolactam (Aldrich 98%) were purified by vacuum distillation before use. Poly(ethylene glycol) (Aldrich, Mn = 600, 2000, 3400 and 4600) was dried by azeotropic distillation in toluene and by further drying under vacuum during six hours at 80°C. Isopropyl alcohol (Aldrich, HPLC-grade), 2,2′-azobisiso-butyronitrile (AIBN) (Aldrich) and tetra(ethylene glycol) dimethacrylate (Aldrich) were used without further purification.
Mathematical Modelling of the Mechanism of Some Aromatic Amine Inhibitors
Published in Richard A. Pethrick, Gennadi E. Zaikov, Teiji Tsuruta, Naoyuki Koide, Polymer Yearbook 13, 2019
V.V. Kharitonov, B.L. Psikha, G.E. Zaikov
n-Hexadecane (HD) was purified by shaking with alkaline potassium permanganate, sulphuric acid, oleum, and washed after each operation with distilled water. HD, was then dried above sodium sulphate, and then calcium hydride and distilled with the aid of an argon gas leak in vacuum. After purification HD contained not more than 10−4 mole/1 of hydroperoxides and 10−5 mole/1 of double bonds. Cumyl peroxide recrystallized twice from ethanol was used as initiator.
Evaluation of the resistance to bacterial growth of star-shaped poly(ε-caprolactone)-co-poly(ethylene glycol) grafted onto functionalized carbon nanotubes nanocomposites
Published in Journal of Biomaterials Science, Polymer Edition, 2019
L. R. Cajero-Zul, F. A. López-Dellamary, S. Gómez-Salazar, M. Vázquez-Lepe, R. Vera-Graziano, M. R. Torres-Vitela, M. A. Olea-Rodríguez, S. M. Nuño-Donlucas
Poly(ethylene glycol) (Mw = 1000 g mol−1), ε-caprolactone (ε-CL) (97%), pentaerythritol (PTOL) (>99%), tin (II) 2-ethyl hexanoate (stannous octoate, SnOct2) (92.5%), oxalyl chloride (OxCl) (98%), calcium hydride (>90%), triethylamine (Et3N) (99%), dichloromethane (ACS reagent), toluene (ACS reagent), tetrahydrofuran (THF) (ACS grade), methanol (ACS reagent), petroleum ether (ACS reagent) (distillation range: 30–60 °C), lithium aluminum hydride powder (reagent grade 95%) were purchased from Sigma-Aldrich. Absolute alcohol (99.9%) was provided from J. T. Baker. Fe(NO3)3·9H2O (98.2%) was acquired from Golden Bell. Alumina boats were purchased from Alfa Aeser. Argon (99.998%) was acquired from PRAXAIR, México. Also, deionized and bi-distilled water was used. The mentioned chemical reagents were used without further purification with the exception of PTOL wich was purified via soxhlet using toluene as solvent and the ε-CL, which was purified by drying it with calcium hydride for 48 h. After this time, the flask containing the e-CL/calcium hydride mixture was connected to a Schlenkline, where an exhausting-refilling process was repeated two times to separate the wet calcium hydride. The product ε-CL purified was kept in a container under a N2 atmosphere before use.
Phenyl-functionalized diiron propanediselenolato complexes containing the chelated or bridged 1,3-bis(diphenylphosphine)propane ligand
Published in Journal of Coordination Chemistry, 2018
Zhi-Fen Meng, Hui-Ling Gao, Jiu-Xia Wang, Jing-Yan Shang, Chang-Gong Li
All reactions and operations were carried out under an atmosphere of purified argon using standard Schlenk and vacuum line techniques. Dichloromethane and acetonitrile were distilled over calcium hydride, while n-hexane and xylene were distilled over sodium under argon. Diphosphine ligand 1,3-bis(diphenylphosphine)propane (dppp) was commercially available from J&K Scientific Ltd (Beijing, China). and used as received without further purification. Complexes 1 and 2 have the formulas of Fe2(CO)4(κ2-dppp)[(μ-SeCH2)2CHC6H5] and {Fe2(CO)5[(μ-SeCH2)2CHC6H5]}2(μ,κ1,κ1-dppp), named as (μ-2-phenyl-1,3-propanediselenolato)(κ2-1,3-bis(diphenylphosphine)propane) tetracarbonyl diiron (I) and bis[(μ-2-phenyl-1,3-propanediselenolato)][μ,κ1,κ1-1,3-bis(diphenylphosphine)propane]bis[pentacarbonyl diiron (I)]. Precursor A was prepared according to literature methods [31–33]. Preparative thin-layer chromatography (TLC) was carried out on glass plates (25 cm × 20 cm × 0.25 cm) coated with silica gel G (10–40 μm). IR spectra were recorded on a Bruker TENSOR 27 FTIR spectrometer. 1H and 31P NMR spectra were obtained on a Bruker Avance 400 MHz spectrometer. Elemental analyses were performed on an Elementar Vario EL analyzer.
Highly enantioselective asymmetric reduction of aromatic ketimines promoted by chiral enantiomerically pure sulfoxides as organocatalysts
Published in Journal of Sulfur Chemistry, 2018
Zuzanna Wujkowska, Stanisław Leśniak, Piotr Kiełbasiński, Michał Rachwalski
Unless otherwise specified, all reagents were purchased from commercial suppliers and used without further purification. Dichloromethane was distilled from calcium hydride. 1H NMR spectra were recorded on a Bruker instrument at 600 MHz with CDCl3 as the solvent and relative to TMS as an internal standard. Data are reported as s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br = broad. Optical rotations were measured on a Perkin-Elmer 241 MC polarimeter with a sodium lamp at room temperature (c = 1). Column chromatography was carried out using Merck 60 silica gel. TLC was performed on Merck 60 F254 silica gel plates. Visualization was accomplished with UV light (254 nm). The enantiomeric excess (ee) values were determined by chiral HPLC (Knauer, Chiralcel OD-H or AD-H). Chiral hetero-organic catalysts 1a–d were synthesized using the procedures described previously [18].