Zinc hexacyanocobaltate complex catalyst

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... 

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

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