Search results for "Aluminium chloride"
showing 10 items of 10 documents
27Al NMR Study of the pH Dependent Hydrolysis Products of Al2(SO4)3 in Different Physiological Media
2018
Soluble inorganic aluminium compounds like aluminium sulfate or aluminium chloride have been challenged by the European Chemical Agency to induce germ cell mutagenicity. Before conducting mutagenicity tests, the hydrolysis products in water and in physiological solutions should be determined as a function of the concentration and pH. We used different 27Al NMR spectroscopic techniques (heteronuclear Overhauser effect spectroscopy (HOESY), exchange spectroscopy (EXSY), diffusion ordered (DOSY)) in this work to gain the information to study the aluminium species in solutions with Al2(SO4)3 concentrations of 50.0, 5.0, and 0.5 g/L and their pH and time dependent transformation. At low pH, thre…
Luting of ceramic crowns with a self-adhesive cement: Effect of contamination on marginal adaptation and fracture strength
2012
Objectives: This study evaluated the percentages of continuous margins (%CM) and fracture strength (FS) of crowns made out from blocs of leucite-reinforced ceramic (IPS Empress CAD) and luted with a representative self-adhesive cement (RelyX Unicem) under four contaminating agents: saliva, water, blood, a haemostatic solution containing aluminium chloride (pH= 0.8) and a control group with no contamination. Study Design: %CM at both tooth-cement (TC) and cement-crown (CC) interfaces were determined before and after a fatigue test consisting of 600’000 chewing loads and 1’500 temperature cycles changing from 5º C to 50º C. Load to fracture was recorded on fatigued specimens. Kruskal-Wallis t…
Propyl substituted 4-arylimino-1,2,3-trihydroacridylnickel complexes: Their synthesis, characterization and catalytic behavior toward ethylene
2015
Propyl substituted 4-arylimino-1,2,3-trihydroacridylnickel dihalide complexes were designed and prepared by metal-induced template reaction with NiCl2 center dot 6H(2)O or (DME)NiBr2. They were characterized by infrared spectroscopy and elemental analysis. Single crystal X-ray crystallography of representative complex Ni3 revealed a distorted trigonal bipyramidal geometry around nickel. The catalytic activities of the title nickel complexes were negatively affected by propyl substituent on their backbone when comparing with the results by unsubstituted ones. With the activation of diethylaluminium chloride, all nickel complexes exhibited moderate activity (up to 5.10 x 10(5) g mol(-1)(Ni) h…
Vanadium-based Ziegler-Natta catalyst supported on MgCl2(THF)2 for ethylene polymerization
1996
A supported magnesium‐vanadium‐aluminium catalyst was prepared by depositing –with the use of a milling technique–VOCl3 on the MgCl2(THF)2 support and subsequent activation with diethylaluminium chloride. Catalytic activity of the obtained system for ethylene polymerization was evaluated as a function of Mg/V and Al/V ratios as well as catalyst ageing time and polymerization temperature. High concentrations of THF in the catalytic system and considerable excess of an organoaluminium co‐catalyst were found to have no deactivating action on vanadium active sites. The catalyst obtained is stable and its activity for ethylene polymerization is high. It yields polyethylene with higher molecular …
ChemInform Abstract: LEAD TETRAACETATE OXIDATION OF PHENYLHYDRAZONES OF 3-BENZOYLAZOLES. SYNTHESIS OF AZOACETATES AND THEIR CONVERSION INTO INDAZOLES
1985
Lead tetraacetate (LTA) oxidation of (E)- and (Z)-phenylhydrazones of 3-benzoyl-5-phenyl-1,2,4-oxadiazole, 3-benzoyl-5-phenylisoxazole, and 3-benzoyl-4-methyl-1,2,5-oxadiazole has been studied. Conversion of azoacetate products into 3-(azol-3-yl)-substituted indazoles has been achieved by reacting them with aluminium chloride in benzene at room temperature.
Zur herstellung molekulareinheitlicher, über schwefelhaltige brücken verbundener, phenolischer zweikernverbindungen
1963
Phenole lassen sich mit Thionylchlorid mittels Aluminiumchlorid in hohen Ausbeuten zu molekulareinheitlichen Sulfoxyden kondensieren, die sich im praparativen Masstab einerseits zu Sulfiden reduzieren und andererseits zu Sulfonen oxydieren lassen. Die Sulfone konnen auch in guten Ausbeuten mittels Aluminiumchlorid durch Kondensation von Phenolathersulfochloriden mit Phenolathern und durch FRIESsche Verschiebung entsprechender Sulfonsaureester erhalten werden. Phenols can be condensed with thionylchloride using aluminium chloride as catalyst in good yields to molecularly defined sulfoxides, which can be preparatively reduced to sulphides or oxidised to sulphones. The sulphones were also obta…
Achieving branched polyethylene waxes by aryliminocycloocta[b]pyridylnickel precatalysts: Synthesis, characterization, and ethylene polymerization
2017
Cycloocta[b]pyridin-10-one was prepared to form the corresponding imino derivatives, which then reacted with (DME)NiBr2 to form 10-aryliminocycloocta[b]pyridylnickel bromides (Ni1–Ni5). The new compounds were characterized by means of FT-IR spectroscopy as well as elemental analysis and the organic ligands were also analyzed by the NMR measurements. Furthermore, the molecular structure of a representative complex Ni3 was determined by the single crystal X-ray diffraction, indicating the distorted tetrahedral geometry around the nickel atom. Upon the activation with either methylaluminoxane (MAO) or diethylaluminium chloride (Et2AlCl), the title nickel complexes exhibited high activity in et…
Haemostatic agents on the shear bond strength of self-adhesive resin
2015
Background Dentin surface contaminated with haemostatic agents can interfere with the bonding of self-adhesive resin cement. Therefore the purpose of this study was to evaluate the effect of various haemostatic agents such as Aluminium chloride, Ferric sulphate and Tannic acid on the shear bond strength of self-adhesive resin luting agent. Material and Methods The buccal surfaces of extracted premolars were flattened to expose the dentine. The teeth were then randomly divided into four groups. In Group I Aluminium Chloride was applied on the flattened dentinal surface, in Group II Ferric Sulphate was applied to exposed dentin surface, in Group III tannic acid was applied on to the dentinal …
Mechanism of anionic polymerization of (meth)acrylates in the presence of aluminium alkyls, 1. 13C NMR studies of model compounds in toluene
1994
The bimetallic ate complex [(CH 3 ) 2 C=C(OEt)(O - AlR 3 )]Li + is regarded to be the model of the active centre of the polymerization of methyl methacrylate in the presence of aluminium alkyls. This complex is detectable by 13 C NMR up to 273 K. At ambient temperature irreversible decomposition takes place. Apart from the formation of the ate complex, excess aluminium chloride coordinates to the ester carbonyl groups of both the monomer and the polymer chain
Photochemical versus aluminium chloride-catalyzed fries rearrangement of aryl hydrogen succinates. synthesis of 2(3H)-furanones
1989
The photochemical and aluminium chloride-catalyzed Fries rearrangement of a series of aryl hydrogen succinates3 a–f to the corresponding 4-oxoacids1 a–f are compared. Both approaches are complementary: the photochemical process is more general and becomes the method of choice for the succinoylation of phenols supporting alkoxy or hydroxy substituents, while the classical rearrangement is superior in the presence of alkyl or halogen substituents. These results are applied to the preparation of the 2(3H)-furanones2 a–f.