Polydialkoxyphosphazenes with different substituents varying from methoxy up to octoxy which contain only minor amounts (below 0,l mol-%) of various defective units in their macromolecules were synthesized. It was shown that such polyphosphazenes with propoxy, butoxy and pentoxy side groups can exist in the mesomorphic state and that a defect content as low as about 2 mol-% prevents mesophase formation. In spite of high flexibility of the main chain, the polydialkoxyphosphazenes were found to gain the ability to crystallize only if the number of C atoms in the alkoxy substituents is higher than six.

AbstractÜber die im Formelschema angegebenen Reaktionsschritte wird die im Titel genannte Verbindung (IV) erhalten.

Along with the progress of research in the field of polymer-bound phase transfer catalysts and with extending knowledge of the properties of crown-ethers, the formation of solid complexes of alkali metals cations with crown-ether units bound to the polymer was investigated in detail, in view of their use in the activation of anions in the three-phase catalysis of substitution and elimination reactions.'*z Copolymers of styrene and divinylbenzene containing pseudocrownether groupings also possess complex-forming properties3 with respect to anions of complexes of transition metals. Immobilized linear polyethers may even become more active phase-transfer catalysts than similarly bound 18-crown-6-units. ' In view of the high costs of polymer syntheses involving immobilized crown-ether units, polymers containing functional oligo (oxyethy1ene) branchesi-' seem to be very attractive.The effect of a relative participation of catalytic functional groups and polymer matrix on the efficiency of functionalized polymers as catalysts of organic reactions has already been discussed.8*9At the same time, the inert character of the polymer matrix was proved, and thus the catalytic effect of functional groups was documented. The heteroatomic main chains of the polymer carrier need not be catalytically inert. After catalytically functional groups have been introduced into such chains, the heteroatomic backbone may contribute to the catalytic efficiency of the polymer.Polyalkoxyphoephazema are an example of polymers with a heteroatomic main chain. They may be obtained by substitution reactions of highly reactive polydichlorophosphe, either with alcohols in presence of tertiary arnines or with sodiumThe reactions may be conducted to a high degree of transformation of polydichlorophosphazene by applying alkoxides derived from fluomsubstituted alcohols or phenoxides. With an excess of 2,2,2-trifluoroethoxide, products containing less than 0.05% chlorine are obtained." The stability of products of the substitution reactions mentioned above depends just on the content of residual chlorine. If the latter is not sufficiently low, water may bring about hydrolysis on the P-CI bond followed by the formation of various structures which are due to both degradation of the main chain and modinking. Data on reaction of polyethers containing functional hydroxyl .groups with polydichlorophoephazene are still missing.

No abstract

No abstract