Olefins codimerization

Other Dimer Olefins. Olefins for plasticizer alcohols are also produced by the dimerization of isobutene [115-11-7] 4 8 codimerization of isobutene and / -butene [25167-67-3]. These highly branched octenes lead to a highly branched isononyl alcohol [68526-84-1] product. BASE, Ruhrchemie, ICl, Nippon Oxocol, and others have used this source. 

Propjiene (qv) [115-07-1] is the predominant 0x0 process olefin feedstock. Ethylene (qv) [74-85-1J, as well as a wide variety of terminal, internal, and mixed olefin streams, are also hydroformylated commercially. Branched-chain olefins include octenes, nonenes, and dodecenes from fractionation of oligomers of C —C olefins as well as octenes from dimerization and codimerization of isobutylene and 1- and 2-butenes (see Butylenes). 

As in the case of dimerizations, MCP derivatives are known to undergo metal-catalysed [2 + 2] codimerizations with other alkenes in a few cases [2]. The examples are limited to strained olefins, such as norbornadiene (572) (Scheme 79) [152] and cyclobutene (574) (Scheme 80) [153], and to alkyl acrylates (Table 46) [154] and always compete with the alternative [3 + 2] addition of TMM species. 

Included are the dimerization, codimerization, oligomerization, double-bond isomerization, and cyclization of olefins. 

In this codimerization reaction, the predominant complex is 3, which should lead to the ethylene-butadiene codimerization product. If the ethylene in complex 3 is displaced by butadiene to form 7 before the insertion reaction takes place, then a C8 or higher olefin could be formed... 

Ziegler-type catalysts based upon Co, Ni, and Fe and in the presence of aluminum alkyls codimerize butadiene with olefins such as ethylene,... 

Codimerization, 170, 221 iron-catalyzed, 221 olefins, 7 Compactin, 68 Computer simulation, 79 Conglomerates, 279... 

The efforts of synthetic organic chemists over the course of the past two decades have brought about a number of selective asymmetric catalyses (Chapters 2-5). Phosphine-Rh(I) catalyzed hydrogenation of dehydro amino acids (75) and phosphine-Ni-aided olefin codimerization (70, 16) were early milestones on the road to highly enantioselective... 

A tremendous amount of work concerning metal-induced cycloadditions of methylenecyclopropane with olefins and alkynes has been done in recent years since the first reported nickel(0) catalyzed 3+2 cycloaddition of methylenecyclopropanes with electron-poor olefins (equation 352)415 and the analogous palladium(O) codimerization (equation... 

Nickel(0)-catalyzed codimerization of methylenecyclopropanes with electron-deficient olefines are highly regiospedfic, but show a rather poor stereoselectivity. Thus the asymmetric nickel(0)-catalyzed codimerization of methylenecyclopropanes with the chiral bomane derivatives of acrylic acid leads to the optically active 3-methylenecyclopen-... 

However, when a series of electron-deficient rtms-olefins is codimerized with methyl-enecyclopropane a mixture of stereoisomers is obtained, though only the regioisomers where the electron-withdrawing group is far from the exo-methylene group are formed (equation 358)367. 

This principle may also be illustrated by some real cases. In the codimerization of propene and hexene it is important primarily to minimize the dimerization of the reactive propene. In order to favor the codimerization, a stage injection of propene according to the principle in Fig. 1 was therefore performed [2]. A similar process design with distributed additions of chlorine was applied in the chlorination of propene to allyl chloride in order to suppress different side reactions [3]. For liquid-phase processes, a distributed feed to the cascade of stirred reactors was a more natural variant. This was applied in the sulfuric acid alkylation of / obutane, where the olefin feed has to be subdivided due to selectivity reasons and the goal was to reach a desired octane number of the product [4]. 

Ni(0) catalysis is able to induce reactions of methylenecyclopropane with olefins activated by electron-withdrawing groups (equation 193). These cycloadditions work with the utmost efficiency in the case shown, whereas more substituted components might give lower yields due to competing side reactions such as cyclo- and codimerization. These problems could be circumvented by employing new Ni(0) systems with triarylphosphines as cocatalysts (equation 193). Similar conditions lead to the smooth addition of dialkylmethylenecyclopropanes to electron-deficient olefins. ... 

Dimerization and codimerization reactions are widely used on an industrial scale either to provide chemicals of high added value or to upgrade by-product olefinic streams coming from various hydrocarbon cracking processes (steam or catalytic cracking) or hydrocarbon forming processes (Fischer-Tropsch synthesis or methanol condensation) (e. g., according to eq. (1)). 

Using this catalyst norbomene (1) and butadiene codimerize to (2) in yields of about 90 %. Less strained olefins give lower yields of vinylcyclobutane products. 

In a large number of carbene and carbenoid addition reactions to alkenes the thermodynamically less favored syn-isomers are formed 63). The finding that in the above cyclopropanation reaction the anti-isomer is the only product strongly indicates that the intermediates are organonickel species rather than carbenes or carbenoids. Introduction of alkyl groups in the 3-position of the electron-deficient alkene hampers the codimerization and favors isomerization and/or cyclodimerization of the cyclopropenes. Thus, with methyl crotylate and 3,3-diphenylcyclopropene only 16% of the corresponding vinylcyclopropane derivative has been obtained. 2,2-Dimethyl acrylate does not react at all with 3,3-dimethylcyclopropene to afford frons-chrysanthemic add methyl ester. This is in accordance with chemical expectations 69) since in most cases the tendency of alkenes to coordinate to Ni(0) decreases in the order un-, mono-< di- < tri- < tetrasubstituted olefines. 

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