1.3- Butadienes vinylic coupling

Table V. Coupling Constants for HO-Adduct Radicals of Butadiene, Vinyl Fluoride, and Vinyl Chloride...

Uses Emulsifier, coupling agent for industrial formulations emulsifier for min. oils emulsifier, dispersant for universal colorants emulsifier for acrylic, vinyl acrylic, styrene acrylic, ethylene vinyl acelate, polyvinyl acetate, styrene butadiene, vinyl veova... 

Vinylic halides can be coupled to give 1,3-butadienes by treatment with activated copper powder in a reaction analogous to the Ullmann reaction (13-14). " This reaction is stereospecific, with retention of configuration at both carbons. 

To probe the possibility that rrfl/wo/d-2-metalla-l,3-butadiene species (like 47) would spontaneously rearrange to 17-allyl products (like 48) via interligand C—C coupling, the Fe-vinyl complex 50 was treated first with methyllithium and then with benzoyl chloride [Eq. (14)] (57). Attack by... 

Mikami and co-workers16-19 have done extensive work for developing catalysts for the asymmetric carbonyl-ene reaction. Excellent enantioselectivites are accessible with the binol-titanium catalyst 17 (Equation (10)) for the condensation of 2-methyl butadiene (R1 = vinyl) and glyoxalates (binol = l,T-binaphthalene-2,2 -diol).16 The products were further manipulated toward the total synthesis of (i )-(-)-ipsdienol. The oxo-titanium species 18 also provides excellent enantioselectivity in the coupling of a-methyl styrene with methyl glyoxalate.17 Reasonable yields and good enantioselectivites are also obtained when the catalyst 19 is formed in situ from titanium isopropoxide and the binol and biphenol derivatives.18... 

Bauer et al. describe the use of a noncontact probe coupled by fiber optics to an FT-Raman system to measure the percentage of dry extractibles and styrene monomer in a styrene/butadiene latex emulsion polymerization reaction using PLS models [201]. Elizalde et al. have examined the use of Raman spectroscopy to monitor the emulsion polymerization of n-butyl acrylate with methyl methacrylate under starved, or low monomer [202], and with high soUds-content [203] conditions. In both cases, models could be built to predict multiple properties, including solids content, residual monomer, and cumulative copolymer composition. Another study compared reaction calorimetry and Raman spectroscopy for monitoring n-butyl acrylate/methyl methacrylate and for vinyl acetate/butyl acrylate, under conditions of normal and instantaneous conversion [204], Both techniques performed well for normal conversion conditions and for overall conversion estimate, but Raman spectroscopy was better at estimating free monomer concentration and instantaneous conversion rate. However, the authors also point out that in certain situations, alternative techniques such as calorimetry can be cheaper, faster, and often easier to maintain accurate models for than Raman spectroscopy, hi a subsequent article, Elizalde et al. found that updating calibration models after... 

Wang S, Huang Y, Cong G (1997) Study on nitrile-butadiene rubber/poly(propylene carbonate) elastomer as coupling agent of poly(vinyl chloride)/poly(propylene carbonate) blends I. Effect on mechanical properties of blends. J Appl Polym Sci 63 1107-1 111... 

The copolymer of vinyl ferrocene (VF) and butadiene has also been reported in the literature for use as a binder for composite propellants. It does not require any burn-rate (BR) accelerator because of the presence of iron (Fe) in vinyl ferrocene which is converted to finely divided Fe203 (a well-known BR accelerator) during combustion. A few groups of scientists have also studied fluorocarbon polymers as binders for composite propellants because of their excellent compatibility with oxidizers and fuels coupled with high density. Accordingly, Kel-F elastomer (a copolymer of vinylidene fluoride and chlorotrifluoroethylene, trade name of 3M, USA) and Viton-A (copolymer of hexafluoropropylene and vinylidene fluoride, trade name of Du Pont, USA) have also been reported for this purpose. The structures of Kel-F 800 [Structure (4.13)] and Viton-A [Structure (4.14)] are ... 

Reductive Coupling. Only one example of this interesting reaction has been disclosed (46). This is the coupling of vinyl chloride to butadiene (Reaction 14). 

As discussed in connection with olefin-coupling reactions and shown in Fig. 4, the coupling of vinyl Grignard reagents is stereospecific and dependent upon the transition metal catalyst used (32, 33). The dimerization of ethylene, shown in Fig. 6, was also shown to produce primarily the terminal olefin 1-butene (35). The size of the metal has also been shown to influence the course of the catalyzed oligomerization reactions of butadiene. When bis-(ir-allyl) metal complexes are used as... 

Here n is the average refractive index, k is Boltzman s constant, and T is absolute temperature (13). If a polyblend were to form a homogeneous network, the stress would be distributed equally between network chains of different composition. Assuming that the size of the statistical segments of the component polymers remains unaffected by the mixing process, the stress-optical coefficient would simply be additive by composition. Since the stress-optical coefficient of butadiene-styrene copolymers, at constant vinyl content, is a linear function of composition (Figure 9), a homogeneous blend of such polymers would be expected to exhibit the same stress-optical coefficient as a copolymer of the same styrene content. Actually, all blends examined show an elevation of Ka which increases with the breadth of the composition distribution (Table III). Such an elevation can be justified if the blends have a two- or multiphase domain structure in which the phases differ in modulus. If we consider the domains to be coupled either in series or in parallel (the true situation will be intermediate), then it is easily shown that... 

Thiele and Beckhaus reacted zirconocene dichloride with two molar equivalents of vinyl lithium. The expected divinylzirconocene product proved not to be stable under the applied reaction conditions. It was initially not even observed as an intermediate but reacted further by cr-ligand coupling to give a good yield of the stable (butadiene)zirconocene (see Scheme 23).72 This coupling reaction was actually used synthetically to... 

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