Ion quaternary phosphonium

It can be seen from these data that permanganate can easily be transfered from an aqueous phase into methylene chloride solutions. Quaternary phosphonium ions and polyethers (both cyclic and linear) also exhibit large Ke values (30,32). 

Polystyrene-supported quaternary phosphonium ions with spacer chains between the active site and the aromatic ring (5, 4, 17-19% RS)... 

Polymer-supported multi-site phase-transfer catalysis seems to require the use of less material in order to provide activity comparable to others253 (Table 27). Quaternary phosphonium ions on polystyrene latices, the particles of which are two orders of magnitude smaller than usual, were shown to be capable of higher activity coagulation of the catalysts under reaction conditions was minimized by specific treatment904. The spacers may also contain ether linkages. 

These compounds, which are often called phosphine ylides, are prepared by deprotonation of a quaternary phosphonium ion, namely,... 

The rate constant of the ion-trapping reaction, kz, is much larger than the propagation rate constant, at least in cyclic ether and acetal polymerizations. The ratio kz [pRii/yw] is large and termination is instantaneous compared with growth [136], In this way, the number of centres can be determined at any moment during polymerization. The chemical shifts of some quaternary phosphonium ions (of structure corresponding to terminated polyheterocyclic chains) are summarized in Table 2. 

UV spectroscopy shows that quaternary phosphonium ions are present but, of course, does not prove that they are joined to polymer chains. The authors fractionated their polymers with a THF/water solvent-non solvent combination. They had found that the model compound described above could be quantitatively separated from phosphorus free poly(methylenemalonie ester). After fractionation the phosphorus content fell, but when the molecular weight was determined by vapour pressure osmometry, it was found that there was approximately one phosphonium group per chain. The absorption coefficient of the model compound was used to calculate the phosphorus content of the product. 

It has recently been shownthat the growing macrocations react rapidly with triaryl- or trialkylphosphines. This process, called ion trapping by analogy with radical trailing, gives stable quaternary phosphonium ions, e.g. ... 

A problem in interpreting the effect of different counterions on the mechanical properties of ionic polymers is the difficulty in evaluating how cation-anion interactions are changing from counterion to counterion. For example, metal counterions differ in ionicity as well as in size and valence, and they can have a partially covalent character. In contrast, quaternary phosphonium ions have a number of desirable characteristics that make them particularly attractive as model systems for the study of counterion effects. They have an essentially full positive charge on the heteroatom so partially covalent interactions, fractional charge transfer between the counterion and anion, and hydrogen bonding do not come into play. Furthermore, with quaternary ions there is no possibility of the tautomerism that can occur with nonquatemary ammonium or phosphonium counterions. 

Table I. Tensile Properties at 100°C of a Sulfonated EPDMa Neutralized with Quaternary Phosphonium Ions...

Table II. Physical Properties of a Sulfonated EPDM° Neutralized with Various Quaternary Phosphonium Ions...

Table V. Effect of Water Uptake on a Sulfonated EPDM° Neutralized with a Quaternary Phosphonium Ion...

Ionic Liquids with different unsymmetrical cations. The most important classes are Ionic Liquids having as cation either imidazolium derivatives or quaternary ammonium ions pyrrolidimium-, piperidimium-, or morpholinium-based derivatives or quaternary phosphonium ions [23]. As counterions, simple halogenides are possible or more hydrophobic ions such as PFg or bis ((trifluoromethyl) sulfonyl) amide (N(S02CF3)2). ... 

Continuous flow phase-transfer-catalyzed reactions of 1-bromooctane in o-dichlorobenzene with aqueous KI have been performed in packed beds of PS beads bearing lipophilic quaternary phosphonium ions. Activity was as high as 0.4 times that attained with the same catalyst in a stirred reaction mixture. Poly(tetrafluoroethylene) membrane reactors have been used for phase-transfer-catalyzed reactions of 1-bromooctane in chlorobenzene with aqueous potassium iodide using tetra-n-butylammonium bromide as catalyst. ... 

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