1,3-Polymerization, olefins isomerization

A number of smaller but nevertheless important apphcations in which activated alumina is used as the catalyst substrate include alcohol dehydration, olefin isomerization, hydrogenation, oxidation, and polymerization (43). 

Zirconium—ally complexes also have catalytic properties. Tetraally zirconium [12090-34-5] on a siUca substrate catalyzes ethylene polymerization (265). Supported on sihca, ZrR (R = allyl or neopentyl) catalyzes olefin isomerization (266). 

The use of base catalysis for various reactions, such as olefin isomerization, cyclohexadiene dehydrogenation, aromatic alkylation, and olefin polymerization, has been demonstrated. In some cases, compounds are formed which are difficult to prepare by other means, and some highly selective reactions have been found. 

Several olefin complexes of the Ru(II) aqua-ion [42-44] and of the other Ru complexes [45, 46] have been synthesized and characterized in the ring opening metathesis polymerization (ROMP) or olefin isomerization reactions. The simplest olefin complexes of Ru were also observed, isolated and characterized under ethy-... 

Benzamido-cinnamic acid, 20, 38, 353 Benzofuran polymerization, 181 Benzoin condensation, 326 Benzomorphans, 37 Benzycinchoninium bromide, 334 Benzycinchoninium chloride, 334, 338 Bifiinctional catalysts, 328 Bifiinctional ketones, enantioselectivity, 66 BINAP allylation, 194 allylic alcohols, 46 axial chirality, 18 complex catalysts, 47 cyclic substrates, 115, 117 double hydrogenation, 72 Heck reaction, 191 hydrogen incorporation, 51 hydrogen shift, 100 hydrogenation, 18, 28, 57, 309 hydrosilylation, 126 inclusion complexes, oxides, 97 ligands, 19, 105 molecular structure, 50, 115 mono- and bis-complexes, 106 NMR spectra, 105 olefin isomerization, 96... 

Numerous side reactions take place in the reaction zone, some of which are beneficial, but many of which are harmful (4). Some catalysts act to promote olefin isomerization to some extent as well as alkylation. In aviation and motor alkylate production, where more highly branched products are desirable, this isomerization reaction is of considerable benefit. This is especially true when the isomerization of butylene-1 to butylene-2 precedes the alkylation reaction. Harmful side reactions include hydrogen transfer and polymerization. The production of propane from propylene and of normal butane from butylene occurs by hydrogen transfer. Polymerization is very harmful because it not only produces the tar which spends the catalyst, but also reduces the yield of valuable products. 

Olefin isomerization, with Claisen rearrangement, 1, 365 Olefin metathesis with alkyllead, 9, 415 in aqueous media, 1, 834 ESI—MS studies, 1, 812 in high-throughput catalyst discovery, 1, 365 in ionic liquids, 1, 869 for polymerization characteristics, 1, 149 Grubbs catalysts, 1, 151 Schrock catalysis, 1, 150... 

The 10-undecenoic acid motif has also been attached to isosorbide in the preparation of a fatty acid-/carbohydrate-based monomer [131]. ADMET polymerization in the presence of C3 and C4 produced fully renewable unsaturated polyesters (Scheme 18). Most importantly, the transesterification of these polyesters with MeOH, and subsequent analysis by GC-MS of the products, allowed for the quantification of double-bond isomerization during ADMET in a very simple manner. This strategy was then extended to fatty acid-based ADMET polyesters synthesized in the presence of indenylidene metathesis catalysts [132]. With these studies, the knowledge on the olefin isomerization in ADMET reactions was widened, and it is now possible to almost completely suppress this undesired side reaction. 

ADMET offers a synthetic route to strictly linear, fimctionalized polyethyl-enes through the polymerization of a,co-dienes followed by exhaustive hydrogenation. Researchers have been able to use metathesis catalysts in conjimction with the functionalized monomers to produce statistical or sequenced copolymers of ethylene with various polar monomers. With the improved tolerance and reactivity of [ Ru], the broadening of ADMET methodology will allow the syntheses of numerous functionalized systems [4]. However, due to the well known olefin isomerization that occurs during the metathesis polymerization with [Ru], monomer sequence control is lost and the methylene run length between functional groups varies widely. 

Good hydrocarbon dispersion in hydrofluoric acid is an impxjrtant factor In producing alkylate rich in trimethylpentanes and thus favors olefin isomerization (to isobutene), isobutene dimerization, and maximizes hydrogen transfer and primary alkylation reactions. Excess olefin polymerization to form residue is suppressed by good dispersion. 

The first example of fully aqueous metal catalysis of olefin isomerization was reported by Grubbs et al. in 1994 [2]. These authors adopted [Ru(H20)6](tos)2 (tos = p-toluenesulfonate) [8] as a catalyst, which is highly active for the ring-opening polymerization of strained cyclic olefin. Both allylic alcohol and allylic ethers undergo isomerization in the presence of [Ru(H20)6](tos)2. 

The fundamental carbonium ion-type reactions of olefins— including double bond and carbon skeleton isomerization, polymerization, isotopic exchange, and hydrogen transfer—have been reviewed earlier (62). The importance of a thorough understanding of the nature of olefin transformations over zeolite catalysts cannot be underestimated. Probably the most important and frequently recurring pattern is the transfer or redistribution of hydrogen that is observed with olefins over acidic crystalline aluminosilicate catalysts. 

The application of Ziegler-Natta catalysts to monomer isomerization polymerization, in which an olefin such as 2-butene is first isomerized to 1-butene and then polymerized, has been described in an extensive series of papers by Endo and Otsu.431 The non-participation of 2-butene in Ziegler-Natta polymerization (taking precautions to exclude the possibility of carbocationic polymerization)432 also allowed the selective polymerization of 1-butene from mixtures of butene isomers.433 It was proposed that isomerization and polymerization took place on Ti(ll) and Ti(lll) species, respectively.434 The relative rates of isomerization and polymerization were dependent on the catalyst system, polymerization being more rapid with TiCl3/AlEt3 than with Ti(OBu)4/AlEt3. 

In olefin isomerization 14.5.1.3. Ziegler-Natta polymerization cocatalyst 14.5.3.2.2. 

The layered hydroxides by themselves are catalytically inactive, probably due to a lack of accessible sites. Upon calcination up to 450°C, materials intercalated with COj or NO3-anions have been found active for aldol condensation ( ), olefin isomerization and 8-propiolactone polymerization (9). Although many elimination reactions have been studied over decomposed double metal hydroxides, the nature of the sites involved is still unclear. 

USE In the manuf of pharmaceutical hydrochlorides, vinyl chloride from acetylene, alkyl chlorides from olefins, and arsenious chloride from arsenious oxide. In the chlorination of rubber, as a gaseous flux for babbitting operations. In Organic reactions involving isomerization, polymerization, and alkylation. For making chlorine where economical. 

OTHER COMMENTS used in the manufacture of pharmaceutical hydrochlorides, alkyl chlorides for olefins, and vinyl chloride from acetylene used in the chlorination of rubber and for making chlorine used in isomerization, polymerization, and alkylation reactions used in the cleaning of membranes in desalination plants. 

In olefin isomerization 16, 14.5.1.3 Ziegler-Natta polymerization co-catalyst 16,... 

Because various important industrial organic processes utilize olefins, convenient methods to convert olefins into various products are vital. Transition metal catalysts with proper ligands have proved most useful in controlling the course of these reactions. Transition metal complexes catalyze skeletal isomerization, double bond isomerization, polymerization, and other processes. Insertion of a terminal olefin into a transition metal hydride bond by 1,2-inserfion or... 

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