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5-vinylborazine

The copolymers were obtained following this method by exploiting the similarity of 5-vinylborazine and styrene. Several poly(styrene-co-B-vinylborazine) copolymers soluble in ethers were formed in solution at 80°C using AIBN.28... [Pg.173]

The same authors proposed an alternative methods for obtaining soluble poly(/i-vinylborazine) homopolymers and poly(styrene-co-B-vinylborazine) copolymers 28 In fact, gentle polymerization conditions in solution at 80°C using Azobisisobutyronitrile (AIBN) (1.6 mol%) as an initiator provided soluble homopolymers. The polymer displays typical Mw and Mn values of —18,000 and 11,000, respectively, whereas an increase in the AIBN concentration results in a decrease in the molecular weight, contrary to what is usually observed in free-radical polymerization. [Pg.172]

Figure Z Vacuum line used for the transfer of reactants and the purification of borazine or B-vinylborazine. (A, B, C, and D) U-traps (E and F) ports for attaching reaction flasks to the vacuum line. Figure Z Vacuum line used for the transfer of reactants and the purification of borazine or B-vinylborazine. (A, B, C, and D) U-traps (E and F) ports for attaching reaction flasks to the vacuum line.
Although vinyl derivatives of alkylated borazines have been known for some time,15 the methods used for their syntheses cannot be used for the parent B-vinylborazine because of extensive side reactions. The transition metal catalyzed synthetic route described below gives B-alkenyl borazines in high yields.16... [Pg.237]

B-Vinylborazine is an air-sensitive volatile liquid and is soluble in dry aprotic organic solvents. It decomposes rapidly in contact with water and alcohols. [Pg.239]

A 0.056-g sample of AIBN (2,2 -azobisisobutyronitrile) is placed into a one-piece 100-mL flask (such as Chemglass AF-0522-02)t equipped with a Teflon vacuum stopcock and a magnetic stir bar, and the flask is evacuated at — 196°C. A 1.69-g (15.9 mmol) sample of B-vinylborazine (prepared by the procedure described above) is vacuum distilled into the flask. Three freeze-pump-thaw cycles are performed in order to remove any traces of oxygen. The stopcock is closed and the reaction flask is removed to a shielded hood where it is heated in an oil bath at 70°C for about 3 h, at which point the material is sufficiently viscous that the stir bar stops. Then 5 mL of benzene is condensed into the flask and the solution is heated at 70°C for another 9 h. Slow addition of the benzene solution into 40 mL of pentane under inert atmosphere affords the precipitation of 0.73 g (43.2% yield) of poly(B-vinyl-borazine). The polymer is filtered under nitrogen and dried in vacuo for about 5 min. [Pg.240]

Poly(B-vinylborazine) is an air-sensitive white solid. Lightly cross-linked, freshly prepared samples are soluble and thermally stable in most dry aprotic solvents, such as benzene and ethers. If stored as a solid at room temperature, the polymer may become insoluble in several hours, but in benzene or glyme solution it is stable and can be used as a stock solution. The polymer decomposes rapidly in contact with water and alcohols. [Pg.240]


See other pages where 5-vinylborazine is mentioned: [Pg.172]    [Pg.172]    [Pg.232]    [Pg.232]    [Pg.233]    [Pg.235]    [Pg.237]    [Pg.237]    [Pg.238]    [Pg.239]    [Pg.239]    [Pg.239]    [Pg.239]    [Pg.240]    [Pg.241]    [Pg.152]    [Pg.189]    [Pg.189]    [Pg.232]    [Pg.232]    [Pg.233]    [Pg.235]    [Pg.237]    [Pg.237]    [Pg.238]    [Pg.239]    [Pg.239]    [Pg.239]    [Pg.239]    [Pg.239]    [Pg.240]   
See also in sourсe #XX -- [ Pg.155 ]




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