Zinc hexacyanocobaltate

Preparation of Zinc-Hexacyanocobaltate (in) -Based Catalyst. A solution of 88 grams of calcium hexacyanocobaltate(III) (0.265 mole)... 

Shown here are typical compositions of two highly active catalysts, one based on zinc hexacyanoferrate(II, III) and the other on zinc hexacyanocobaltate( III) ... 

Figure 3. Infrared spectra of Nujol mulls of zinc hexacyanocobaltate glyme complexes of different activities...

Table II. Effects of Glyme and Zinc Chloride on Activity of Zinc Hexacyanocobaltate for Bulk Polymerization of Propylene Oxide...

Activities of the catalysts for polymerizing propylene oxide in bulk at 30° C were compared on the basis of the weight of polymer formed per weight of catalyst per unit time. Zinc hexacyanocobaltate itself was a fairly active catalyst, giving 300 grams of polymer per gram of... 

Table III. Bulk Polymerization of Propylene Oxide with Zinc Hexacyanocobaltate-Glyme-Zinc Chloride Catalyst at 30° C...

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]. 

Poly (Propylene Ether) Polyols Prepared With a Zinc Hexacyanocobaltate Complex Catalyst... 

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. 

Having established that the polymerization of propylene oxide by the zinc hexacyanocobaltate complex catalyst proceeds in the absence of a chain termination reaction, it was of interest to study separately the chain propagation reaction. A non-termi-nated polymer "seed" was prepared and its rate of reaction with propylene oxide was studied. The results of a series of these seeded polymerizations carried out at 30°, 40° and 50° are given in Figvire 6, where log [M]o/[M]t is plotted against time. 

Figure 10. Gel permeation chromatogram of commercial poly(propylene ether) diol and diols prepared using zinc hexacyanocobaltate complex...

Figure 11. Effect of monomer addition method on gel permeation chromatogram for poly(propylene ether) trials prepared using zinc hexacyanocobaltate complex catalyst...

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

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... 

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... 

In a highly active catalyst consisting of zinc hexacyanocobaltate, glyme, zinc chloride and water, this absorption is shifted to... 

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