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Aluminium compound

Detailed studies of systems involving aluminium-based Lewis acids and hydrogen halides are scarce. Fontana and Kidder investigated the polymerisation of propene initiated by the pair aluminium bromideTiydrt n bromide. The cocatalytic role of the latter acid was clearly proved since no polymerisation could be detected in its absence. The dependence of the rate of polymerisation upon the cocatalyst concentration and the induction periods observed make this system similar to those in which stannic chloride induces the polymerisation of olefins in the presence of variable quantities of water (see Sect. IV-C-3-b). With relatively large quantities of added hydrogen bromide, addition of this acid to the mcmomer to give fso-propyl bromide must have constituted an important side reaction. [Pg.137]

Kennedy and Squires studied the effect of hydrogen chloride on the course of isobutene polymerisation catalysed by aluminium chloride. They showed that at —78 °C HCl increased the polymer yield if introduced before the catalyst, but had no effect if added to a quiescent mixture obtained by direct initiation giving a limited conversion. These observations are entirely consistent with our interpretation of the phenomenology of direct initiation HCl is a cocatalyst in the presence of free aluminium chloride, i.e. when added at the beginning of the experiment, but is ineffective if the Lewis acid is tied up in conjugation products which, as we have seen, bring the polymerisation to a halt before all the monomer is consumed (cf. Sect. IV-B). [Pg.138]

since in the latter case trimethylaluminium probably complexes with the olefin. The hi er catalytic activity observed with the former procedure stems from the hi er reactivity of the mixed organoaluminium halides compared with that of trialkylalumi-nium compounds. [Pg.138]

Crystal Structure, Mechanical and Thermal Properties Tables 4.1-37-4.1-44. [Pg.610]

Aluminium nitride AIN I ci P6imc hex Wurtzite At nmnal pressure Fig. 4.1-3 [Pg.610]

Aluminium arsenide AlAs n F43m fee Zinc blende Transition to NiAs structure Fig. 4.1-2 [Pg.610]

Aluminium arsenide AlAs a = 0.566139 291K High-resolution X-ray diffraction [Pg.610]


Aluminium tetrahydridoborate is a volatile liquid. It is the most volatile aluminium compound known. It is covalent and does not contain ions but has a hydrogen-bridge structure like that of diborane, i.e. each boron atom is attached to the aluminium by two hydrogen bridges ... [Pg.147]

Many of the uses of boron and aluminium compounds have already been discussed. The elements and a number of other compounds also have important applications. [Pg.157]

Kirk-Othmer Encyclopedia cf Chemical Technology, 4th edn., Vol. 2, Aluminium and aluminium alloys, pp. 184-251 Aluminium compounds, pp. 252-345. Interscience, New York, 1992. [Pg.219]

Aluminium compounds of weak acids are extensively hydrolysed to [A1(H20)3(0H)3] and the corresponding hydride, e.g. AI2S3----->... [Pg.225]

Chemical deposition, gas or vapour plating This is a chemical process whereby the aluminium is deposited when an aluminium compound is pyrolysed. Organo-metallic compounds such as aluminium diethylhydride or tri-(iso) butyl aluminium (TIBA) are introduced into the work chamber after purging with an inert gas such as argon or nitrogen. The hydride... [Pg.467]

K. Ziegler, Organo-Aluminium-Compounds, in Organometallic Chemistry, Hrsg. H. Zeiss, S. 1944ff., Reinhold Publishing Corp., New York 1960. [Pg.60]

Bailey, N. A., P.H. Bird, and M. G. H. Wallbridge Stereochemistry of 1 1 Adducts of Aluminium Compounds Crystal Structure of Aluminium Borohydride Trimethylamine. Chem. Comm. 7 965, 438. [Pg.106]

Organo-Aluminium Compounds Organometallic Chemistry", ACS Monograph No. 147 (Editor H. Zeiss). Reinhold, New York, 1960. [Pg.117]

The major mode of action of such products appears to be depot formation at the site of injection. The antigen is only slowly released from the gel, ensuring its sustained exposure to immune surveillance. The aluminium compounds are also capable of activating complement. This can lead to a local inflammatory response, with consequent attraction of immunocompetent cells to the site of action. [Pg.413]

Zheng, W. J. Roesky, H. W. Alkynyl aluminium compounds bonding modes and stmctures. Dalton Trans. 2002, 2787—2796. [Pg.284]

Brannon and Patrick [129] reported on the transformation and fixation of arsenic V in anaerobic sediment, the long term release of natural and added arsenic, and sediment properties which affected the mobilization of arsenic V, arsenic III and organic arsenic. Arsenic in sediments was determined by extraction with various solvents according to conventional methods. Added arsenic was associated with iron and aluminium compounds. Addition of arsenic V prior to anaerobic incubation resulted in accumulation of arsenic III and organic arsenic in the interstitial water and the exchangeable phases of the anaerobic sediments. Mobilization of... [Pg.353]

In Experiments C7 and C9, the initiator solutions remained clear and colourless throughout the addition of isobutylene. At the end of the experiments the solutions were hydrolysed, and immediately the cloudy precipitate of Al(OH)3 was observed. This showed that under the conditions of the Experiment the initiator solution had not been hydrolysed and that the aluminium was still there, i.e., it had not been distilled out of the conductivity cell as a volatile organo-aluminium compound. [Pg.312]

Alloys with Aluminium compounds Indium compounds ... [Pg.487]

A fourth mechanism for chain transfer involves the transfer of the polymer chain to the large excess of aluminium alkyls present. This has also been observed. Since the reaction rate for this process depends on the concentration of the aluminium compound, the molecular weight distribution now also depends on the latter concentration. For oligomer production this is only relevant when a very large excess of aluminium alkyls is present. [Pg.183]

Most catalysts are based on chromium that has been studied for this purpose since the mid-seventies, probably started by Union Carbide Corporation. Chromium is the metal of the Phillips ethene polymensation catalysts and presumably it was discovered accidentally that under certain conditions 1-hexene was obtained as a substantial by-product. Neither the precise catalytic cycle nor the intermediate complexes or precursors are known. It is generally accepted that an alkyl aluminium compound first reduces the chromium source and that coordination of two molecules of ethene is followed by cyclometallation, giving a chromocyclopentane. During the cyclometallation the valence of chromium goes up by two and thus a starting valence of either one or zero seems reasonable. This cyclic mechanism explains why such high selectivity is obtained [5],... [Pg.184]

The Phillips process uses a threefold excess of 2,5-dimethylpyrrole, a chromium salt, and an excess of an alkyl aluminium compound [6], In Figure 9.9 we have drawn only one ligand per chromium, but we do not know the... [Pg.184]

Scheme 2.20. Stannylation of terminal alkynes with stannylcopper reagents derived from stannylated aluminium compounds. Scheme 2.20. Stannylation of terminal alkynes with stannylcopper reagents derived from stannylated aluminium compounds.
About structures of lithium compounds LisMeFs we have but rare knowledge. Klemm, Brandt and Hoppe (193) report in accordance with Meyers and Cotton (225) that the x-ray-diagrams of the cobalt compound LisCoFe were of a poor quality. The polymorphism that Carton and Wanklyn (108) report of the aluminium compound LisAlFe points to a more complicated situation in this ternary fluoride. The sizes given of the unit cells do not show any simple relation to the cryolite cell. The same may be true of compounds LisMeFa of the transition metals. [Pg.20]

Finally, we believe that theory can play a significant role in the design of new aluminium catalysts. Aluminium compounds are more amenable to high-level calculations than transition metal complexes. Because of the lower coordination numbers involved the catalysts tend to be smaller, which also simplifies calculations. As a result, it is frequently possible to carry out reasonably accurate calculations on a real catalyst , so that theory can at times really guide or at least assist experiment. [Pg.163]

Aluminium compounds tend to be constipating Magnesium compounds tend to be laxative... [Pg.620]

Changes in the form of the alumina, in the pH of the solution, the type of base used (organic or inorganic) and in the proportions of alkali, aluminium compound, and silica lead to the production of different zeolites. [Pg.164]

These reagents demonstrate two important properties of boron and aluminium compounds. Xf you are uncertain of tbe periodic table just check to see where these two elements come. Neutral tervalent B and Al compound are electron deficient ... [Pg.13]

These two properties may be summarised by saying that tervalent boron and aluminium compounds will accept anions from one molecule and transfer them to another. [Pg.13]

Independently of the co-catalyst, the productivity is only low when the ratio of A1 to Zr is small. The productivity increases steeply with an increase in this ratio, to reach a constant level. A further increase of Al/Zr does not further increase the productivity. When organoborate is the co-catalyst, less aluminium compound is required to reach a high productivity, as with MAO. [Pg.532]


See other pages where Aluminium compound is mentioned: [Pg.878]    [Pg.214]    [Pg.218]    [Pg.393]    [Pg.878]    [Pg.514]    [Pg.256]    [Pg.360]    [Pg.576]    [Pg.187]    [Pg.198]    [Pg.59]    [Pg.79]    [Pg.130]    [Pg.202]    [Pg.38]    [Pg.777]    [Pg.14]    [Pg.878]    [Pg.535]   
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Alkyl aluminium compounds

Alkyl aluminium compounds determination

Aluminium Ammonium compounds

Aluminium and Zirconium Compounds

Aluminium and its compounds

Aluminium compounds Quinolones

Aluminium compounds Subject

Aluminium compounds carbonylation

Aluminium compounds properties

Aluminium compounds thermal properties

Aluminium organometallic compounds

Aluminium paste, compound

Aluminium-nitrogen cluster compounds

Amorphous Aluminium Compounds

Band aluminium compounds

Complex Compounds of Aluminium

Density aluminium compounds

Dielectric aluminium compounds

Effective aluminium compounds

Electrical aluminium compounds

Electron aluminium compounds

Electronic aluminium compounds

Energy aluminium compounds

Initiator aluminium compounds

Iron compounds Aluminium hydroxide

Lattice aluminium compounds

Linear aluminium compounds

Lithium compounds Aluminium hydroxide

Melting aluminium compounds

Mixed metal oxides aluminium compounds

Mobility aluminium compounds

Nickel aluminium compounds

Organosilyl Compounds of Boron, Aluminium, Gallium, Indium and Thallium

Other Aluminium Compounds

Phonon aluminium compounds

Polymeric aluminium compounds

Semiconductors aluminium compounds

Spin aluminium compounds

Thermal aluminium compounds

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