Hexacyanocobaltate initiator

In the case of these complex zinc hexacyanocobaltate initiators, the telogen could be a diol such as propylene glycol, a triol such as glycerine, or a higher functionality polyol such as pentaerythritol or sorbitol, and the product could then be a polyol of the type used extensively in making polyurethanes in elastomeric, foam, or... 

Preparation of Poly (propylene ether) Polyols. The polymerization of propylene oxide with zinc hexacyanocobaltate complexes in the presence of proton donors results in the production of low-molecular-weight polymers. Table V shows the variety of types of compounds that have been found to act this way. Since these compounds end up in the polymer chains, it seems reasonable to call them chain initiators. Thus, in essence, each of these compounds is activated by the catalyst to react with propylene oxide to form a hydroxylpropyl derivative. Thereafter, the reaction continues on the same basis, with the proton of the hydroxyl group reacting with further propylene oxide. This sequence is shown here with 1,5-pentanediol as the initiator. The hydroxyl... 

Among new initiators for the polymerization of propylene oxide, ethylene oxide, 1-butene oxide, and isobutylene oxide are zinc hexacyanocobaltate [54] and aluminum porphyrin [55]. 

Kinetic studies. The rate of formation of poly (propylene ether) diol using 1,5-pentanediol as an initiator and the zinc hexacyanocobaltate complex as a catalyst is shown in Figure 2. 

Coordinate initiation routes to principally amorphous polymer have been found that do offer certain advantages, although these routes have been slow to be adopted, probably due to the apparently complicated structures of the initiators. One of these processes employs zinc with a complex anion promoted with a low-molecular-weight polyether such as dioxane or diglyme (109). The initiator system is based on zinc cobalticyanide (hexacyanocobaltate), Zn3[Co(CN)6]2, or zinc ferricyanide (hexacyanoferrate), Zn3[Fe(CN)6]2, (110-113). 

The structure of the zinc hexacyanocobaltate complex in the vicinity of an active initiator site can then be... 

Fluorescent-dye-labeled PPO was synthesized with exactly one fluorophore in the polymer backbone. This was achieved by initiating the polymerization of propylene oxide with the dye 4-diethanolamino-7-nitrobenzofurazan with zinc hexacyanocobaltate as catalyst in tetrahydrofuran. A fraction of this dye-labeled polymer having molecular weight Mff = 33 600 and a narrow molecular weight distribution, = 1.1, was selected by... 

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