Diene butadiene

Conjugated dienes Butadiene 1,3-cyclohexadiene Piperylene Phenylbutadienes... 

Dienes (butadiene and isoprene) may yield polymers with high 1,4 unit contents 4S 49), when the process is initiated with butyllithium in nonpolar solvents. Small amounts of polar additives suppress steric control6). 

The cycloaddition reactions of the anhydrides (88a-88e) with acyclic dienes (butadiene and 1,4-dimethylbuta-l,3-diene) were conducted at 23 °C in dichlo-... 

As to the first route, we started in 1969 (1) in investigating unconventional transition metal complexes of the 5 and 4f block elements of periodic table, e.g., actinides and lanthanides as catalysts for the polymerization of dienes (butadiene and isoprene) with an extremely high cis content. Even a small increase of cistacticity in the vicinity of 100% has an important effect on crystallization and consequently on elastomer processability and properties (2). The f-block elements have unique electronic and stereochemical characteristics and give the possibility of a participation of the f-electrons in the metal ligand bond. 

The thiophene ring system can be utilized as a synthetic scaffold for the preparation of nonthiophene materials as the sulfur moiety can be removed by reduction (desulfurization) or extrusion (loss of SO2). The extrusion of sulfur dioxide from 3-sulfolenes (2,5-dihydrothiophene 1,1-dioxides) give dienes (butadienes or o-quinodimethanes) that can be utilized to prepare six-membered rings by cycloaddition chemistry. For example, thermolysis of 3-sulfolene 120 provided tricyclic pyrazole 122 via an intramolecular cycloaddition of the o-quinodimethane 121 that results by extrusion of sulfur dioxide <00JOC5760>. Syntheses of 3-sulfolenes 123 and 124 <00S507> have recently been reported. 

This field is still active today numerous recent patents [46, 63-89] and several reports [90-92] have detailed the efficiency of such types of systems for the hydrogenation of unsaturated polymers resulting from the polymerization of dienes (butadiene, isoprene, 1,3-cyclohexadiene) or the co-polymerization of dienes and styrenes (block co-polymers of butadiene and styrene SB, SBS, SBSB polymers). 

The Diels-Alder reaction is the best known and most widely used pericyclic reaction. Two limiting mechanisms are possible (see Fig. 10.11) and have been vigorously debated. In the first, the addition takes place in concerted fashion with two equivalent new bonds forming in the transition state (bottom center, Fig. 10.11), while for the second reaction path the addition occurs stepwise (top row, Fig. 10.11). The stepwise path involves the formation of a single bond between the diene (butadiene in our example) and the dienophile (ethylene) and (most likely) a diradical intermediate, although zwitterion structures have also been proposed. In the last step, ring closure results with the formation of a second new carbon carbon bond. Either step may be rate determining. 

Dienes butadiene, isoprene, piperylene, and 2,3-dimethylbuta-diene. 

Beyond this exclusive lanthanide Ziegler-Natta model, Ziegler-type multicomponent systems ( Mischkatalysatoren ) represent the only class of homogeneous rare-earth metal catalysts of considerable commercial relevance [40-43]. High-czs-1,4-polydienes are industrially produced from 1,3-dienes (butadiene and isoprene) in aliphatic or aromatic hydrocarbons by a number of Mischkatalysatoren based on the transition metals titanium, cobalt, and nickel, and the lanthanide element neodymium [40-47]. The... 

Reactions of 32a with acyclic dienes (butadiene and piperylene) yielded the cyclohexadienes derived from desulfinylation of the resulting adducts, precluding the deduction of any information about the stereochemical course of these reactions [45]. From the results of the reaction of racemic sulfoxide 34 with the acyclic diene 35, Alexandre et al. [48] were able to isolate and characterize bicy-clic adduct 36 as the only adduct because its desulfinylation required 30 min in CH2C12 under reflux (Scheme 17). This result proved that the exo-selectivity of these reactions with acyclic dienes is much higher than that with cyclic dienes. Moreover, this paper shows that the reactivity of 3-sulfinyl acrylates is lower than that of the 2-sulfinyl derivatives, because the former are not able to react with 35. 

The products for which X is an alkyl group [130, 131] can be prepared from the reaction of ligands onto non conjugated dienes (butadiene derivatives). 

Arbuzov and Kataev40 obtained selenophene and its methyl homologs from dienes (butadiene, piperylene, or hexadiene) and metallic selenium at 380°-420°C. 

By use of methylenebisdiethylcarbamate, A-ethoxycarbonyl-3-piperideines have been prepared from the following dienes butadiene,... 

The dimers [ Co(CO)(/ii-CO)(Tj -diene) 2] (56) (diene = butadiene, isoprene, or cyclohexadiene) react with weak oxidants, such as [CPha]", in the presence of PPha to give [Co(CO)3 (PPh3) (i7 -diene)] (n = 1 or 2). Infrared evidence was presented (726) for the intermediacy of the cation radical [ Co(CO)(/x-CO)(T/ -diene) 2] [56]", but cyclic voltammetry on 56 (diene = 2,3-dimethylbutadiene) in CH2CI2 showed a diffusion-controlled, but totally irreversible, one-electron oxidation wave (727). 

Polymers of dienes (hydrocarbons containing two C—C double bonds) have the potential for head-to-tail and head-to-head isomerism and variations in doublebond position as well. The conjugated diene butadiene can polymerize to produce 1,4 and 1.2 products ... 

Photolysis of (n -diene)Cr(CO) (diene - butadiene, trans, frans-hexa-2,4-diene, 2,3-dimethylbutadiene) in a matrix leads to loss of CO auid reaction of the resulting complex with to give (Ti -diene)Cr(C0),(N2). In a CO matrix there is stepwise displacement of the diene ligemd to give (n -cliene)Cr(CO) and... 

The most important oligo-polyol obtained by radical mechanism is hydroxyl terminated poly butadiene. Dienes (butadiene, isoprene), in conditions of radical polymerisation are special monomers because during radical polymerisation, which is a nonstereospecific polymerisation, several types of microstructures are generated in the same chain. Thus, in the particular case of butadiene the following types of microstructures are generated ... 

The conjugated diene butadiene can polymerize to produce 1,4 and 1,2 products (Rudin,... 

Biethylene Bivinyl Butadieen Buta-1,3-dieen Butadien Buta-1,3-dien Butadiene Buta-1,3-diene 1,3-Butadiene a,o-Butadiene Butadiene monomer CCRIS 99 Divinyl EINECS 203-450-8 Erythrene HSDB 181 NCI-C50602 UN 1010 r n Vinylethylene, Monomer for BUNA rubbers. Gas mp = -108,9° bp = -4.4° Lm =... 

EPDM ethylene-propylene-diene butadiene, isoprene, and styrene... 

The objective of this chapter is to examine the basic research on diene (butadiene, isoprene, and piperylene) polymerisation with the LnHalj-nL-AlRj (Ln = lanthanide, Hal = halogen, ligand (L) = tributyl phosphate (TBP), AlRj = triisobutylaluminum and diisobutylaluminum hydride) catalytic system. The chapter will analyse the role of such factors as the electronic and geometric structure of bimetallic active centres, anti-syn and 7t-o-transitions of the terminal units of the growing polymer chains and the nature of the lanthanide, diene, and organoaluminum component in the mechanism of stereoregulation. 

The objective of this part of work was to study the role of the structure of the diene (butadiene, isoprene and piperylene) in the mechanism of regio- and stereoselectivity in polymerisation with the lanthanide catalytic system NdCl3-3TBP-Al(2-C4H9)3. To this... 

From TpRuCl(COD), also the neutral complexes TpRu(f/ -diene)Cl (diene = butadiene, isoprene, 2,4-hexadiene) can be obtained, " where the diene ligand is coordinated in S-trans fashion as proven by X-ray crystallography. In the synthesis, TpRuCl(COD) is heated in xylene in the presence of air. The dark-green paramagnetic (i.e., Ru(III)) complex, tentatively formulated as TpRuCl, thus obtained is redissolved in MeOH. Upon addition of Zn in the presence of the diene, TpRuCl(f/" -diene) is formed (Scheme 13). 

Synonyms Atactic butadiene polymer BR Buta-1,3-diene Butadiene homopoiymer 1,3-Butadiene, homopolymer Butadiene oligomer Butadiene poiymer 1,3-Butadiene, poiymers Butadiene resin Butadiene rubber Poiy-1,3-butadiene cis-Poiybutadiene Polybutadiene latex Polybutadiene resin Polybutadiene rubber ClassiTication Polymer elastomer latex Empirical (C4H6) ... 

On the other hand, irradiation of (2Z,4 )-hexa-2,4-diene (butadiene system) promotes an electron to W3, which then becomes HOMO, and bond formation is possible only through disrotation (Scheme 2.6). 

Olefin o-b-fon [ISV, fr. F gaz) olefiant ethylene, fr. L oleum] (1860) n. ) Any of the class of monounsaturated, aliphatic hydrocarbons of the general formula Cn 2w nd named after the corresponding paraffins by changing their -ane endings to -ene or -ylene. Examples are ethylene (ethene), propylene, and butanes. The class of polymers of olefins is called polyolefins or olefin plastics. (2) The term is sometimes taken to include aliphatics containing more than one double bond in the molecule such as a diolefin or diene. Butadiene is a typical member and an important comonomer for plastics. (3) A... 

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