Carbonates, olefination

Alkaline earth metal alkoxides decompose to carbonates, olefins, hydrogen, and methane calcium alkoxides give ketones (65). For aluminum alkoxides, thermal stability decreases as follows primary > secondary > tertiary the respective decomposition temperatures are ca 320°C, 250°C, and 140°C. Decomposition products are ethers, alcohols, and olefins. 

In refining, the polymerization process is utilized to produce high-octane gasoline components from three- and four-carbon olefins. It can also be used for the production of certain alcohols and aromatic compounds. Cumene and ethyl benzene can be produced through catalytic polymerization. 

The photolysis of cyclobutanone in the presence of 20- to 50-fold excess of ethylene has been reported (17). In this instance various five-carbon olefins but not cyclopentane are said to be observed among the products. The hydrocarbons are believed to be formed by a reaction between a tri-... 

Additions to functionalized three-carbon olefins have been studied extensively. We have used methyl acrylate as a standard olefin since it always reacts only at the terminal carbon and the a,/3-double bond in the product is always trans. The stereospecificity of its reactions with vinylic halides varies with structure. The simple 1-halo-l-alkenes with methyl acrylate under normal conditions give mixtures of E,Z- and E,E-dienoates. The reaction is more selective with the bromides than with the iodides and the stereoselectivity increases with increasing triphenylphosphine concentration. This occurs because the excess phosphine displaces the hydridopalladium halide group from the diene 7r-complex before readdition to form the ir-allylic species occurs (see Equation 6). The disubstituted vinylic bromides react stereospecifically with methyl acrylate (4). 

A very useful three-carbon olefin is acrolein dimethyl acetal (5). Acrolein itself cannot be used because it polymerizes and/or reacts with amines under the normal reaction conditions. With piperidine or morpholine as the base, acrolein acetals react in good yield with a wide variety of vinylic bromides to give dienal acetals and/or ami-noenal acetals. These product mixtures, after being treated with excess aqueous oxalic acid and being steam distilled, yield E,E-conjugated dienals, usually in good yields. Methacrolein acetals and 3-buten-2-one ethylene ketal also react well, but the crotonaldehyde acetals do not. 

Both gold(I) and gold(III) form cr-bonds to carbon. Olefin, carbene, and carbonyl complexes are also known. 

Percent Saturate Carbon Percent Aromatic Carbon Olefins... 

The crystal structure shows the expected E geometry of the double bond. The length of the silicon-potassium bond (3.45 A) lies within the range observed for similar anionic compounds [3]. The length of the carbon-carbon olefinic bond is not significantly affected by the adjacent anionic silicon atom, in contrast to the spectroscopic behavior of this bond (see below). 

Loss of a proton back to the catalyst surface again releases a molecule of 2,4,4-trimethylpentene-l, a branched Cs olefin, from the catalyst surface. Processes analogous to this can occur not only between two branched four-carbon olefins but also between straight chain olefins, propylene and C4 olefins, and two propylene molecules. The carbonium ion formed by coupling of any two of these olefin units may also, occasionally, add a third olefin. The composite result of all of these processes is that a stream of C, Cy, and Cg olefins, plus much still unreacted material, is obtained from the predominantly C3 plus C4 feed stream (Eq. 18.24). 

For the preparation of aliphatic nitriles, mainly acetonitrile, 2-4 carbon olefins have been reacted over a supported vanadium oxide catalyst in a... 

The kinetics of low-carbon olefins, ethylene [21] and propylene [22], in aqueous systems was reported and different rate models proposed. Wachsen et al. [13] proved that aqueous biphasic hydroformylation of propylene took place at the interfacial region, in contrast to two preliminary kinetic models that incorporate mass transport. 

Another method of producing a nonyl alcohol, which has gained predominance in the past few years, is by the dimerization process. In this process n-butylenes react to form an octene. Then through hydroformylation the 8-carbon olefin is converted to a nonyl alcohol (eq. 6). This alcohol has specific branching and some linearity that provides the corresponding ester with improved properties over esters made from isononyl alcohol. 

---