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Dimerization and oligomerization reactions

In dimerization and oligomerization reactions, ionic liquids have already proven to be a highly promising solvent class for the transfer of established catalytic systems into biphasic catalysis. [Pg.244]

Biphasic catalysis is not a new concept for oligomerization chemistry. On the contrary, the oligomerization of ethylene was the first commercialized example of a biphasic, catalytic reaction. The process is known under the name Shell Higher Olefins Process (SHOP) , and the first patents originate from as early as the late 1%0 s. [Pg.244]

One technically important example of an oligomerization that could not be carried out in a liquid-liquid biphasic mode with polar organic solvents or water is the [Pg.244]

As early as 1990, Chauvin and his co-workers from IFP published their first results on the biphasic, Ni-catalyzed dimerization of propene in ionic liquids of the [BMIM]Cl/AlCl3/AlEtCl2 type [4]. In the following years the nickel-catalyzed oligomerization of short-chain alkenes in chloroaluminate melts became one of the most intensively investigated applications of transition metal catalysts in ionic liquids to date. [Pg.245]

Because of its significance, some basic principles of the Ni-catalyzed dimerization of propene in chloroaluminate ionic liquids should be presented here. Table 5.2-2 displays some reported examples, selected to explain the most important aspects of oligomerization chemistry in chloroaluminate ionic liquids [97]. [Pg.245]

Ni-catalyzed dimerization of propene and/or butenes, which was intensively studied in the 1960 s [96] and later commercialized as the Dimersol process by the Institut Franjais du Petrole (IFF). The active catalytic species is formed in situ through the reaction between a Ni(ll) source and an alkylaluminium co-catalyst. [Pg.245]


A similar reaction occurs with fatty acids (such as stearic acid) or methyl stearate, which undergo isomerization, cracking, dimerization, and oligomerization reactions. This has been used to convert solid stearic acid into the more valuable liquid isostearic acid [102] (Scheme 5.1-70). The isomerization and dimerization of oleic acid and methyl oleate have also been found to occur in chloroaluminate(III) ionic liquids [103]. [Pg.210]

Dimerization and Oligomerization Reactions. Besides Diels-Alder-type dimerization reactions, butadiene undergoes a number of other dimerization or oligomerization reactions to produce cyclic or linear products. With the proper catalysts these reactions proceed quite selectivity. Noncatalyzed or photocatalyzed dimerizations produce compounds like divinylcyclobutanes and have been studied in detail (137,138). [Pg.344]

Ionic liquids can be used as replacements for many volatile conventional solvents in chemical processes see Table A-14 in the Appendix. Because of their extraordinary properties, room temperature ionic liquids have already found application as solvents for many synthetic and catalytic reactions, for example nucleophilic substitution reactions [899], Diels-Alder cycloaddition reactions [900, 901], Friedel-Crafts alkylation and acylation reactions [902, 903], as well as palladium-catalyzed Heck vinylations of haloarenes [904]. They are also solvents of choice for homogeneous transition metal complex catalyzed hydrogenation, isomerization, and hydroformylation [905], as well as dimerization and oligomerization reactions of alkenes [906, 907]. The ions of liquid salts are often poorly coordinating, which prevents deactivation of the catalysts. [Pg.323]

Olefin additions to bridging alkylidenes yield dimetallacyclopentanes . These reactions also provide a mechanism for olefin metathesis, a topic not discussed here. Although addition of an olefin to a metal carbone, a 2n + In addition, would be symmetry forbidden in organic chemistry, ab initio calculations " of the conversion of a metal carbene-alkene to a metallocyclobutane show it to be a barrierless reaction. Metal d orbitals relax the symmetry restrictions for the In + 2n addition. The mechanism of reaction (p) has not been widely considered for the olefin polymerization, but it may be relevant to olefin dimerization and oligomerization—reaction (s), for example ... [Pg.659]

Purified laccase oxidizes various phenolic compounds via hydrogen abstraction. The resulting phenoxy radical undergoes various dimerization and oligomerization reactions. Even though the synthetic potential of such reactions has to be considered as moderate, in some cases interesting products (such as complex coumaran type compounds) can be obtained in reasonable yields from simple phenols1151. [Pg.1174]


See other pages where Dimerization and oligomerization reactions is mentioned: [Pg.344]    [Pg.244]    [Pg.274]    [Pg.257]    [Pg.244]    [Pg.258]    [Pg.274]    [Pg.244]    [Pg.430]    [Pg.547]    [Pg.408]   


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Dimerization reactions

Oligomerization reactions

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