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Linear aluminium compounds

Table b.1-ir2 Linear thermal expansion coefficient a of aluminium compounds... [Pg.611]

Ethene oligomerisation. In view of the above limitations there is a demand for a process that selectively makes linear 1-alkenes. Three processes are available, two based on aluminium alkyl compounds or catalysts and one on nickel catalysts. The aluminium processes use aluminium in a stoichiometric fashion and they produce a narrow molecular weight distribution (a Poisson distribution, vide infra). [Pg.176]

Often Lewis acids are added to the system as a cocatalyst. It could be envisaged that Lewis acids enhance the cationic nature of the nickel species and increase the rate of reductive elimination. Indeed, the Lewis acidity mainly determines the activity of the catalyst. It may influence the regioselectivity of the catalyst in such a way as to give more linear product, but this seems not to be the case. Lewis acids are particularly important in the addition of the second molecule of HCN to molecules 2 and 4. Stoichiometrically, Lewis acids (boron compounds, triethyl aluminium) accelerate reductive elimination of RCN (R=CH2Si(CH3)3) from palladium complexes P2Pd(R)(CN) (P2= e g. dppp) [7], This may involve complexation of the Lewis acid to the cyanide anion, thus decreasing the electron density at the metal and accelerating the reductive elimination. [Pg.232]

Lithium aluminates. The compounds Li0H-2Al(0H)3-mH20 and LiCl-2Al(0H)3-mH20 (here m = 0.5 1.0 2.0) are easily synthesized under very low mechanical loading (blade mixer) in stoichiometric Al(0H)3+Li0H H20 and Al(0H)3+LiCl H20 mixtures [1,2]. It was stated that the dispersion of the initial aluminium hydroxide strongly influenced on the kinetics of mechanochemical interaction. The interaction rate increases linearly with the specific surface of the initial hydroxide. Fig. 6.1 shows the data on reactivity of initial hydroxide with different specific surface area (6 and 2 mVg, respectively). [Pg.79]

No monomeric alkali metal alkyls or aryls are known, as those crystal structures which have been determined indicate electron-deficient, e.g. (MeLi), or ionic (K Me ) constitutions. The dialkyls of the lighter second group metals are mostly electron-deficient dimers or polymers, but those of zinc, cadmium and mercury are monomers with a linear structure as expected from participation of one (metal) s and one p orbital (with or without dji participation). In the third group the pattern is more complex. Whereas the trialkylboranes are monomeric, boron hydrides (and alkyl hydrides) and polyboron compounds form electron-deficient structures. Aluminium alkyls and alkyl hydrides are normally electron-deficient dimers or trimers gallium trialkyls are monomeric though the trivinyl is a dimer trimethylindium is a weakly associated tetramer in the solid state, otherwise all indium and thallium trialkyls appear to be monomers. [Pg.37]

Prior to 1965, alkylbenzene production was synthesized from petroleum tetrapropylene reacted with an aluminium chloride or hydrogen fluoride catalyst and benzene. The resultant alkylate was a hard branched-chain compound that was considered slowly biodegradable. A straight-chain alkylate, termed LAB (linear alkylbenzene), has been produced since 1965 in the United States. Extensive research has demonstrated biodegradation effectiveness in sewage treatment plants in excess of 95 percent. ... [Pg.1032]

Aluminium forms solid trihalides when it is heated with the halogens or hydrogen halides. Unlike the boron trihalides, these substances do not contain discrete MX3 molecules at room temperature. Thus, AIF3 melts at 1 290 °C and has a three-dimensional structure, characteristic of an ionic compound, in which each aluminium atom is surrounded by six fluorines, and each fluorine atom is nearly linearly coordinated to two aluminiums. AICI3, however, has a layer structure (Figure 9.20), which resembles that of MgCl2. [Pg.122]


See other pages where Linear aluminium compounds is mentioned: [Pg.115]    [Pg.62]    [Pg.242]    [Pg.179]    [Pg.38]    [Pg.152]    [Pg.230]    [Pg.314]    [Pg.129]    [Pg.73]    [Pg.71]    [Pg.89]    [Pg.188]    [Pg.133]    [Pg.504]    [Pg.70]    [Pg.699]    [Pg.43]    [Pg.1514]    [Pg.32]    [Pg.13]    [Pg.109]    [Pg.65]    [Pg.91]    [Pg.164]   
See also in sourсe #XX -- [ Pg.611 ]

See also in sourсe #XX -- [ Pg.611 ]




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Aluminium compounds

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