Alkoxy cyclophosphazene

B. Alkoxy- and Aryloxy-derivatives.—The preparation and physical properties of a series of thermally stable monoalkoxy (or aryloxy) fiuoro-cyclophosphazenes have been reported ... 

Mention has already been made of the application of alkoxycyclophos-phazenes, [NP(OR)2] , as flame retardants in rayon. Although the methoxy-derivatives, with their high phosphorus content, were expected to be most efficient in this respect, their water solubility proved a major shortcoming. However, the n-propoxy series, [NP(OPr )2] ( mainly 3—6), were found to impart excellent flame resistance and were well retained by rayon. The cyclophosphazene alkoxides were obtained by the addition of sodium-n-propoxide to the chloride homologues, (NPCl2)n, and were added to the viscose dope before the rayon was spun. The flame resistance imparted by various amino- and thioalkoxy-derivatives was also tested, but found to be inferior to the results obtained with alkoxy-deriva-tives. Several patent applications have resulted from work on this topic. ... 

Alcohols and phenols react with halocyclophosphazenes in the presence of a base to give alkoxy/aryloxy cyclophosphazenes (Eq. 22) [1-3]. 

Proton NMR has been extremely valuable in the structural elucidation of cyclophosphazene derivatives containing alkylamino, alkoxy or simple alkyl substituents [287]. 

Both colourless and deeply coloured compounds are found among the common unsaturated heterocyclic inorganic systems. For example, borazine B3N3H6 (see Section 4.1.2.1), like benzene, is a colourless liquid which exhibits a strong absorption band in the UV region. Similarly, cyclophosphazenes (NPX2) ( = 3-6 X = halogen, alkyl, aryl, alkoxy, dialkylamino) are also... 

An alternative, and more recent, approach is shown in reaction (42).9091 Here, a cyclophosphazene is synthesized with two non-geminal alkoxy chains that bear terminal olefinic groups. Treatment of these compounds with an organometallic ADMET catalyst causes loss of ethylene and formation of a cyclolinear polymer. The chain lengths achieved by this method are generally longer than those produced by the dehydrohalo-genation technique. 

The 19F NMR spectroscopic data for trifluoroethoxy derivatives, N3P3R6 n(OCH2CF3)n (R = alkylamino, dialkylamino, alkoxy) can be used as an indirect method of establishing the structures of the chloro-cyclophosphazene precursors, N3P3R6 C1 (63, 139), but this technique has received very little attention. 

The chioro-triazadiphosphinines are readily soluble in a variety of solvents, such as dichloromethane or toluene. Compared to (NPCl2)3 they are more sensitive to moisture. At high temperature (—250°) they decompose, losing nitrile and forming a polymeric phosphazene. This decomposition may in certain cases be used to initiate the polymerization of a cyclophosphazene. Nucleophilic substitution converts the chioro-triazadiphosphinines to partially or completely amino-, alkoxy-, or aroxysubstituted derivatives. " ... 

In contrast to the amino-substituted cyclophosphazenes, many papers have appeared concerning alkoxy and aryloxy substituted phosphazenes. A one-pot procedure based on phase-transfer catalysis has been developed for the preparation of N3P3 0C6H4[C(0)H-4] 6 and N3P3 0C6H4[C(0)Me-4] 6. ... 

Syntheses of alkoxy and aryloxy substituted cyclophosphazenes still forms an important research item, in particular as the knowledge thus obtained can be used for the preparation of the corresponding polymers. 

Alkoxy- and Aryloxy-derivatives.—The cyclophosphazene (90) undergoes the reactions with alcohols and with sodium alkoxides that are shown in Scheme 9. The... 

More unusual alkoxy-derivatives of N3P3CI6 are formed in the reactions with sodium salts of cellulose, which obey second-order kinetics, and in copolymers derived from arabinose, the latter being hydrolysed by alkaline phosphatase. By contrast, (95) is not hydrolysed by this phosphatase. Relative basicity measurements,obtained from the i.r. spectra of cyclophosphazenes mixed with phenol, show that fluoroalkoxy-derivatives N3P3(ORp)6 are more basic than NaPaClg. 

Similar rearrangements have been observed for alkoxy (in particular methoxy) derivatives of (NPCl2)3 and 4- ° The composition of the products depends on the technique used for the rearrangements (solution or melt). The mechanism involves autocatalysis, whereas intermolecular OR exchanges occur. In some instances, cyclophosphazenes with partial phosphazane character have been isolated. ... 

In addition to certain of the articles cited above, numerous new applications of cyclophosphazenes have been described, almost exclusively in the patent literature. The ever popular flame retardancy property of phosphazenes is again an important area. The use of amidophosphazenes [(NH2)2PN] (n>3) for cellulose fibers is noted, - including an approach which allows the use of the amidophosphazene without previous removal of the difficult to separate NH Cf. Alkoxy (Et,Pr,Bu) phosphazenes combined with siloxanes have also been used in cellulosic fibers. Triallyl-phenoxytriphenoxycyclotriphosphazene is an additive in the production of flame retardant poly (siloxanes). ... 

Cyclophosphazene based lubricating fluids are also of interest. Alkoxy and aryloxy trimers and tetramers are proposed as lubricating oils for metal working and fluoroalkoxy... 

Strained cyclophosphazenes such as o -gew-N3P3F4(r -C5H4-Fe-ri -C5H4) and even the alkoxy derivative N3P3(OCH2CF3)4(Ti -C5H4-Fe-Ti -C5H4) can be polymerized by ROP to the linear polymers. 

The use of cyclophosphazene in the formulation of flame retardant materials has generated numerous patents. " Various known cyclo-matrices based on phosphazene bismaleimide or triazine and, especially, the styrene polymer (159) having cyclo-alkoxy or aryloxy-phosphazenes as pendant groups, have been found to be resistant to atomic oxygen, probably by the formation of a protecting layer of phosphate. " ... 

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