N. P. Tarasova

Influence of Media on Processes of Radiation-Induced Polymerization of White Phosphorus

Radiation-induced polymerization of elemental phosphorus in the presence of ionic liquids(IL) was investigated. Composition, structure, and properties of the products-phosphorus-containing polymers (PCPs)-were examined by the methods of physicochemical analysis. It was found that the structure of ionic liquid and its concentration in the media has a significant influence on the polymerization rate. Some kinetic properties of the radiation-induced polymerization process of the elemental phosphorus in the presence of ionic liquids in the mixed solvent “dimethylsulfate (DMSO)/benzene” were determined (reaction rate, effective rate constant, reaction orders).

Effect of the Polarity of the Medium on the Ionic Radiation-Induced Polymerization of Elemental (White) Phosphorus

In recent years, inorganic polymers (red phosphorus, polymeric sulfur and arsenic, compositions based on them, etc.) have been the objects of intensive theoretical and applied studies [1, 2] because elucidation of fundamental characteristics would help to identify the optimal ways of synthesis of these polymers and would contribute to the solution of the general problem of the molecular structure‐inorganic material structure‐material physicochemical properties relationship. Within the framework of the research topic of radiation-induced chemical synthesis of inorganic phosphorus polymers and materials with specified properties based on them, we studied the radiation-induced polymerization of white phosphorus in nonpolar media (benzene, halohydrocarbons, and hexane) [3]. The process was shown to follow a radical mechanism.

Synthesis of Polymeric Forms of Phosphorus

White phosphorus is an interesting element, which polymerises in solution to give the so-called red phosphorus. The latter has been widely used in industry, and for many defence-related purposes. Though the polymerisation process itself is well known (Figure 1), the intermediates formed during the polymerisation of white phosphorus (or its reaction with a substrate in solution, a case under current investigation), as well as the structure and the properties of different modifications of red phosphorus, are not well understood.

Reactions of Elemental Phosphorus and Phosphines with Electrophiles in Superbasic Systems: XIII. Phosphorylation of Phenylacetylene with Active Modifications of Elemental Phosphorus

Phosphorylation of phenylacetylene with white or activated red phosphorus (prepared from white phosphorus under the action of ionizing radiation) occurs in KOH-DMSO or KOH-HMPA systems with heat evolution and stereoselective formation of Z isomers of tristyrylphosphine and -phosphine oxide in yields of 48-49% and 10-15%, respectively. Under the comparable conditions the commercial red phosphorus is considerably less reactive toward phenylacetylene: The total yield of the above-mentioned products is 5%.

REACTION OF VINYLPYRIDINES WITH ACTIVE MODIFICATIONS OF ELEMENTAL PHOSPHORUS IN KOH/DMSO

The phosphorylation of 2-vinyl- and 4-vinylpyridines by white phosphorus and active modifications of red phosphorus (obtained by thermal polymerization of white phosphorus in the presence of graphite or the action of ionizing radiation in benzene) in the KOH/DMSO superbase system at room temperature leads to the formation of tris[2-(2-pyridyl)ethyl]- and tris[2-(4-pyridyl)ethyl]phosphine oxides in 58-72% yield. These oxides are promising ligands for design of metal complex catalysts. These vinylpyridines react less efficiently with ordinary red phosphorus and the yield of the corresponding tris(2-pyridylethyl)phosphine oxides does not exceed 10%.

Reaction of Activated Red Phosphorus with Allyl Bromide under Phase-Transfer Catalysis

Common red phosphorus (Pn) reacts with allyl halides (bromide and chloride) on heating (45 75 C) under phase-transfer catalysis to form mixtures of tertiary unsaturated phosphine oxides (total yield up to 23%), among which products of prototrophic isomerizations of tri(propen-2-yl)phosphine oxide (I) prevail. These are di(propen-2-yl)[(E)-propen-1-yl]-, di(propen-2-yl)[(Z)-propen-1-yl]-, (propen-2-yl)[(E)propen-1-yl][(Z)-propen-1-yl]-, di[(E)-propen-1-yl](propen-2-yl)-, di[(Z)-propen-1-yl](propen-2-yl)-, tri[(E)-propen-1-yl]-, and di[(E)-propen-1-yl][(Z)-propen1-yl]phosphine oxides [1]. At room temperature this reaction gives mainly the kinetically controlled product, phosphine oxide I, in a yield less than 2% (in this case, the phosphorus conversion is 18%) [1].

Radiation chemical synthesis of modified phosphorus-containing polymers

Currently, considerable effort is directed to the search for new environmentally friendly processes needed for successful and sustainable development of industrial chemistry. The organophosphorus chemis� try tends to switch from the use of elemental (white) phosphorus as the phosphorylating agent to less toxic polymeric phosphorus forms with controllable prop� erties. The radiation chemical synthesis of phosphorus� containing polymers (PCP) from white phosphorus in the presence of modifying additives (TiO2, Al(OH)3, CaCl2, talcum Mg3(OH)2[Si4O10], graphite, I2, indus� trial red phosphorus (IRP) etc.) developed in our pre� vious works [1–3] made it possible to solve a number of problems related, in particular, to stabilization of

Biographical radiation-induced defect formation as a method for the activation of red phosphorus in reactions with arylalkenes

In recent years, it has been reported that the modifica tion of the chemical properties of red phosphorus (both in inorganic1—2 and organic3—6 processes) can be regulated by controlled defect formation in its structure. New data on the effect of biographical defects on the reactivity of elementary phosphorus were obtained in di rect phosphorylation of arylalkenes in a KOH—DMSO system. Red phosphorus *Pn synthesized by radiation induced polymerization of white phosphorus in benzene (with 60Co as the radiation source) and containing P— P—R type defects (R is a benzene fragment)5 reacts with styrene at room temperature to give diphenethylphosphine oxide (1) and phenethylphosphinic acid (2) in a total yield of 15%. With commercial red phosphorus Pn pro duced by thermal polymerization of white phosphorus, the total yield of organophosphorus compounds 1 and 2 did not exceed 2%. Under similar conditions, white phos phorus P4 is more reactive: the total yield of compounds 1 and 2 is 30%. In phosphorylation of 2 vinylnaphthalene (90—96 °C), defective *Pn is superior to both Pn and P4 to give tris[2 (2 naphthyl)ethyl]phosphine oxide (3), 2 (2 naph thyl)ethylphosphinic acid (4), and bis[2 (2 naph thyl)ethyl]phosphine oxide (5) as the major reaction prod ucts in a total yield of 73% (product ratio 1.6 : 1.2 : 1). Under comparable conditions, phosphorylation of 2 vinylnaphthalene with P4 or Pn is less efficient but more selective (phosphine oxide 3 is formed in 58 and 44% yield, respectively). In addition, the above reaction with Pn affords acid 4 in 11% yield. The formation of oxygen containing compounds 1—5 seems to be in accord with the proposed mechanism.7 Compounds 1—5 were isolated and identified by com paring their 1H and 31P NMR spectra (Bruker DPX 400; 400 and 161.98 MHz, respectively; CDCl3) with spectro scopic data for authentic samples.8,9

Reaction of Activated Red Phosphorus with Phenylacetylene in the KOH-HMPA System

Crude (commercial) red phosphorus reacts with phenylacetylene upon heating (60365oC) in a system the KOH3HMPA3H2O to yield 50% of tris[(Z)-styryl)phosphine and small amounts of the corresponding tris[(Z)-styryl)phosphine oxide [1]. Phosphorylation of phenylacetylene with phosphine generated separately from crude red phosphorus and KOH in water3dioxane medium proceeds under milder conditions (553 57oC), yielding 70% of phosphine I [2].

Radiation-Chemical Synthesis of Phosphorus- and Sulfur-Containing Polymers

Phosphorus- and sulfur-containing polymers were obtained by radiation-chemical synthesis from elementary phosphorus and sulfur in benzene. The structure and composition of the products were studied by solid-phase 31P NMR spectroscopy, MALDI mass spectroscopy, and other physicochemical analytical methods. The reactivity ratios of inorganic monomers, phosphorus and sulfur, were determined.