Search results for "Aluminium"

Aluminum complexes of sterically hindered tetradentate Schiff bases: Synthesis, structure, and reactivity toward ɛ-caprolactone

1997

Abstract The sterically hindered Schiff bases tbmSalenH2 [tbmSalen = N,N′-1,2-ethylenebis(3-tert-butyl-5-methylsalicylideneimine)] and tbmSalcenH2 [tbmSalcen = N,N′-trans-1,2-cyclohexanediyl-bis(3-tert-butyl-5-methylsalicylideneimine)] afforded a series of aluminum complexes of the general formulae [Al(tbmSalen)X] and [Al(tbmSalcen)X] (X = Cl, Me, Et). The molecular structure of [Al(tbmSalcen)Cl] was determined by single-crystal X-ray structural analysis which revealed a five-coordinate aluminum center with a distorted square pyramidal geometry. The alkyl complexes were found to oligomerize ɛ-caprolactone.

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.

Reversible, room-temperature C—C bond activation of benzene by an isolable metal complex

2019

The activation of C-C bonds is of fundamental interest in the construction of complex molecules from petrochemical feedstocks. In the case of the archetypal aromatic hydrocarbon benzene, C-C cleavage is thermodynamically disfavored, and is brought about only by transient highly reactive species generated in situ. Here we show that the oxidative addition of the C-C bond in benzene by an isolated metal complex is not only possible, but occurs at room temperature and reversibly at a single aluminium center in [(NON)Al]- (where NON = 4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene). Selectivity over C-H bond activation is achieved kinetically and allows for the generation…

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…

Alkylumlagerungen und acidolyse der ethylidenbrücken bei der synthese von ethylidendiphenolen

1990

For the synthesis of symmetrical and unsymmetrical ethylidenediphenols the corresponding hydroxyphenylethanols (1a–c) were prepared by hydrogenation of hydroxyphenyl methyl ketones with hydrogen/Raney nickle or with lithium aluminium hydride. Condensations of the hydroxyphenylethanols with different phenols under the usual acidic conditions gave products formally resulting form transalkylations. Only the reaction of 1-(3-bromo-2-hydroxy-5-methylphenyl)ethanol (1c) with p-cresol gave the expected product 2d with 82% yield. Experiments with ethylidenediphenols showed that with acids in presence or absence of phenols cleavage and recondensations take place leading to products of formal transal…

Spectroscopic and chromatographic study of the interaction of nonionic micelles with the aluminum-morin complex

1989

Abstract The interaction of the aluminum-morin system with different nonionic surfactants has been studied spectrophotometrically and by high-performance liquid chromatography. It has been found that ethylene oxide-propylene oxide condensate surfactants sensitize the spectrophotometric determination of aluminum with morin more than ethylene oxide condensate surfactants. Binding ratio parameters for the different surfactants with free morin have been also estimated from the analysis of chromatographic vacant peaks.

Selective oxidation of propane and ethane on diluted Mo–V–Nb–Te mixed-oxide catalysts

2007

Abstract Te-free and Te-containing Mo–V–Nb mixed oxide catalysts were diluted with several metal oxides (SiO 2 , γ -Al 2 O 3 , α -Al 2 O 3 , Nb 2 O 5 , or ZrO 2 ), characterized, and tested in the oxidation of ethane and propane. Bulk and diluted Mo–V–Nb–Te catalysts exhibited high selectivity to ethylene (up to 96%) at ethane conversions 10 % , whereas the corresponding Te-free catalysts exhibited lower selectivity to ethylene. The selectivity to ethylene decreased with the ethane conversion, with this effect depending strongly on the diluter and the catalyst composition. For propane oxidation, the presence of diluter exerted a negative effect on catalytic performance (decreasing the forma…

Protection of iron-based alloys likely to be exposed to corrosive atmospheres

1998

Summary This study examines the influence of temperature on oxidation kinetics of the alloys Z2CT 17 and Z4CN 18-09. A thin layer of aluminium oxide was laid down on these, using chemical, vapor deposition, in order to give improved protection.

Computer Simulation of Molten and Glassy Silica and its Mixtures with Sodium Oxide and Aluminium Oxide

2007

Structure and mechanical properties of Al–B composite powder

1997

Abstract Al-B composite powder has been obtained by crushing pieces of composite material presenting industrial waste. Structural peculiarities and microhardness of separate powder particles (d∼1 mm) have been investigated. Original design of high precision microhardness tester made it possible to detect the properties of powder both in near-surface layer and below it. The powder represents a new structurally non-homogenous material with the increased microhardness (1.5 GPa) which grows up to 4 GPa in near-surface layers. Stable oxide compounds are formed on internal surfaces and defects of the aluminium alloy. Powder compacts were obtained. Adhesion on Al–B and Al–Al interfaces at various …