Trialkylphosphine oxide

B. By Hydrolysis Reactions.—Details have appeared of the synthesis of dibenzophosphorin oxides (15) from 5-alkyldibenzophospholes, by reaction with methyl propiolate in the presence of water, and of confirmatory syntheses from phosphinic acid chlorides, as shown below. Evidence for the suggested mechanism of the ring-expansion reaction is presented. The hydrolysis of enamine phosphine oxides is an efficient, although somewhat indirect, method for the preparation of j8-ketoalkylphosphine oxides (16) [see Section 3(iii), for the preparation of enamine oxides]. Reasonable yields (48—66%) of trialkylphosphine oxides (17) have been obtained by the alkaline hydrolysis of the products from the pyrolysis at 220 °C of red phosphorus with alkyl halides, in the presence of iodine. 

Trialkylphosphine oxides and tris(dimethylamino)phosphine oxide are undergoing this reaction as well (62). 

Acyclic phosphoranes. - A number of difluorotris(perfluoro-alkyl)phosphoranes (7) have been prepared by electrochemical fluor-ination of trialkylphosphine oxides (6) in anhydrous HF17. The phosphoranes are conveniently converted into the perfluoroalkyl-phosphine oxides (8) by reaction with hexamethyldisiloxane and the phosphoranes are regenerated by treatment of (8) with HF. 

Bis(trialkylphosphine oxide) complexes [NiBr2(0=PR3)2] reversibly bind S02 to give species formulated as (259).734... 

For example, direct treatment of red phosphorus with potassium hydroxide in a mixture of dioxane and water with a phase-transfer catalyst (benzyltriethylammonium chloride) allows direct reaction with primary haloalkanes to form the trialkylphosphine oxide in moderate (60-65%) yield.1415 Allylic and benzylic halides are similarly reported to generate the corresponding tertiary phosphine oxides. When the reaction is performed with a,(o-dihalides, cyclic products are generated only with four- and five-carbon chains the third site... 

Permittivity measurements have been used to study hydrogen bonding of phenol or carboxylic acids with trialkylphosphine oxides (154). The results can be explained in terms of a simple electrostatic model. The properties of trimethylphosphine oxide were different from the general properties of the series.189... 

Compared with the variety of existing carbon or nitrogen nucleophiles that were subjected to nucleophilic addition to there are few examples for phosphorus nucleophiles. Neutral trialkylphosphines turn out to be to less reactive for an effective addihon to Cjq even at elevated temperatures [114], Trialkylphosphine oxides show an increased reactivity. They form stable fullerene-substituted phosphine oxides [115] it is not yet clear if the reaction proceeds via a nucleophilic mechanism or a cycloaddition mechanism. Phosphine oxide addition takes place in refluxing toluene [115], At room temperature the charge-transfer complexes of with phosphine oxides such as tri-n-octylphosphine oxide or tri-n-butylphosphine oxide are verifiable and stable in soluhon [116],... 

Isocyanate formation through multiple bond metathesis of C02 with carbodiimide has been also demonstrated [112]. This transformation can be promoted by titanium isopropoxide, at 383 K, in THF as solvent. It is worth noting that the reverse process, which opens an entry into carbodiimide synthesis, is a well-known process that is catalyzed by several other systems, including trialkylphosphine oxides [113] or vanadium-oxo or -imido complexes [114]. 

TRPO Trialkylphosphine oxide R R j.R, = hexyl, heptyl, octyl (1 5 4)... 

Zhang, P, Song, C.L., Liang, J.F., Xin, R.X. 2001. Extraction and retention of plutonium with y-irradiated 30% trialkylphosphine oxide-kerosene solution. Solvent Extr. Ion Exch. 19 (1) 79-89. 

Solution phase chemical synthesis is a convenient way for making surfactant coated magnetic nanoparticles, as described in various reviews [12-18]. Monodisperse Co nanoparticles with standard deviation less than 10% are synthesized by decomposition of Co2(CO)8 [19-22] or Co(rj3-C8Hi3X n4-C8Hi2) [23] and reduction of cobalt salt [24,25] in the presence of oleic acid and trialkylphosphine, or trialkylphosphine oxide, or alkylamine. Monodisperse iron nanoparticles are normally prepared from decomposition of Fe(CO)5 [26-28]. However, metallic iron-based particles from this decomposition procedure are difficult to characterize due to the chemical instability. A recent synthesis using decomposition of Fe[NSiMe3)2]2 offers a promising approach to monodisperse Fe nanocrystals [29]. 

While tetraalkylphosphonium salts may be generated by the reaction of elemental phosphorus (white or red see Section 3.2) with haloalkanes, the reaction is complicated by the concomitant formation of trialkylphosphine dihalides. The resultant mixtme is generally converted to the corresponding trialkylphosphine oxide by treatment with ethanol under... 

R3P=0 Phosphine oxide (trialkylphosphine oxide) Phosphan Oxid... 

Polyfunctional phosphinopyridine VV,P-dioxides, (phosphinomethyl)pyridine A,P-dioxides and bis(phosphinomethyl)pyridine VV,P,P-trioxides have been prepared, and selected coordination chemistry with actinide ions has been explored. The phosphinopyridine A,P-dioxides form bidentate chelates with uranyl and Th , and in the solid state these complexes display six-membered chelate rings that appear to be relatively sterically congested." " The solvent extraction properties of these ligands are not unique since they resemble the performance of trialkylphosphine oxides." ... 

The suggested mechanism involves an attack of the nucleophilic phosphorus reagent on the anomeric oxygen to afford an anomeric phosphonium ion and a thiolate counterion, which then attacks in a Sn2 reaction the anomeric position to give the thioglycoside and triafkyl phosphate or trialkylphosphine oxide. 

The claim that trialkylphosphine oxides are obtained by treating elementary phosphorus with sodium and alkyl halide during heating at 400 °C in an organic solvent is surprising... 

Neutral-Species Extractants. Ketones, ethers, linear poly-ethers, and more recently, macrocyclic or "crown ethers all have useful properties as extractants if they are sufficiently water insoluble. Sulfoxides, the trialkyl phosphates, the trialkylphosphine oxides, and the carbamoylmethylphosphonates are among the stronger coordinators classified as neutral species extractants. These compounds usually coordinate directly with the metal ion and supply coordination that would be suppli by water in the aqueous phase. 

HoUow-fiber SLMs have been used in the removal of phenol from aqueous matrices. Kujawski et al. [142, 143] studied polypropylene membranes impregnated with methyl-terbutyl ether, cumene, and/or a mixture of hydrocarbons. With Cyanex 923 (a mixture of trialkylphosphine oxides), the recoveries of phenol reached of 98% into the stripping phase from the 0.2 mol.dm solution of caustic soda [144, 145]. Carriers for phenol removal from wastewaters have included hnear monoalkyl cyclohexane [146], N,N-di(l-methyl heptyl) acetamide [147], dibenzo-18-crown-6 [148], dodecane [149], trioctylamine [150], and N-octanoylpyr-rolidine [151]. Many diluents and carriers are of synthetic origin, and so their application carries with issues of flammabUity, volatility, toxicity, and potential detrimental effects to the environment and the health of the human population [152]. 

More important is the alkylation of red phosphorus in the presence of catalytic amounts of iodine or diphosphorus tetraiodide, which after hydrolytic working up leads to trialkylphosphine oxides, sometimes in high yield. Lower alkyl iodides are treated at 200-220° in a sealed tube or an autoclave,184 higher-boiling iodides at atmospheric pressure.185,186... 

Recently it has been shown188 that red phosphorus can combine directly with iodine and higher alcohols, yielding about 50% of the alkylphosphonic acid and 25-30% of the trialkylphosphine oxide. 

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