Organophosphorus stability

Of no less interest are organophosphorus stabilizers containing the epoxide group and a phosphorus-carbon bond in the molecule simultaneously. As investigations have shown [70], esters of l,2-epoxy-2-propylphosphinic acid ... 

Organophosphorus compounds. Phosphorus-carbon bond fonnation takes place by the reaction of various phosphorus compounds containing a P—H bond with halides or tritlates. Alkylaryl- or alkenylalkylphosphinates are prepared from alkylphosphinate[638]. The optically active isopropyl alkenyl-methylphosphinate 778 is prepared from isopropyl methylphosphinate with retention[639]. The monoaryl and symmetrical and asymmetric diarylphosphi-nates 780, 781, and 782 are prepared by the reaction of the unstable methyl phosphinate 779 with different amounts of aryl iodides. Tnmethyl orthoformate is added to stabilize the methyl phosphinate[640]. 

Organophosphorus Derivatives. Neopentyl glycol treated with pyridine and phosphorus trichloride in anhydrous dioxane yields the cycHc hydrogen phosphite, 5,5-dimethyl-l,3-dioxaphosphorinane 2-oxide (2) (32,33). Compounds of this type maybe useful as flameproofing plasticizers, stabilizers, synthetic lubricants, oil additives, pesticides, or intermediates for the preparation of other organophosphoms compounds (see Flame retardants Phosphorus compounds). 

Primary phosphines (R-PHj) are an important ciass of compounds in organophosphorus chemistry. Aithough discovered over a century ago, their chemistry and appiications have gained prominence in recent years. This review discusses recent deveiopments on synthesis, moiecuiar structure, properties, and appiications of primary phosphines. In particular, discussions on synthesis and properties emphasize recent results from our laboratory on the chemical architecture of amide, thioether, and carboxylate functionalized primary bisphos-phines. The utility of bromo- and aminopropyl phosphines (X(CH2)3PH2 X=Br or NH2) as building blocks to produce designer primary phosphines that display exceptional oxidative stability is described. The review also discusses the utility of carboxylate functionalized primary phosphines for incorporation on to peptides and their potential applications in catalysis and biomedicine. 

Indeed, these reactions proceed at 25 °C in ethanol-aqueous media in the absence of transition metal catalysts. The ease with which P-H bonds in primary phosphines can be converted to P-C bonds, as shown in Schemes 9 and 10, demonstrates the importance of primary phosphines in the design and development of novel organophosphorus compounds. In particular, functionalized hydroxymethyl phosphines have become ubiquitous in the development of water-soluble transition metal/organometallic compounds for potential applications in biphasic aqueous-organic catalysis and also in transition metal based pharmaceutical development [53-62]. Extensive investigations on the coordination chemistry of hydroxymethyl phosphines have demonstrated unique stereospe-cific and kinetic propensity of this class of water-soluble phosphines [53-62]. Representative examples outlined in Fig. 4, depict bidentate and multidentate coordination modes and the unique kinetic propensity to stabilize various oxidation states of metal centers, such as Re( V), Rh(III), Pt(II) and Au(I), in aqueous media [53 - 62]. Therefore, the importance of functionalized primary phosphines in the development of multidentate water-soluble phosphines cannot be overemphasized. 

Schaefer, C.H. and E.F. Dupras, Jr. 1969. The effects of water quality, temperature and light on the stability of organophosphorus larvicide used for mosquito control. Proc. Pap. Annu. Conf. Calif. Mosq. Control Assoc. 37 67-75. 

Certain organophosphorus compounds can be used to melt-stabilize PET. Stabilizers such as 3,5-di-t-butyl-4-hydroxybenzyl diethyl phosphate (Irganox 1222) and triphenylphosphate lead to a reduction in the concentration of terminal carboxyl groups of PET, thus giving improved hydrolytic stability. 

While the consideration of nonflammability and SEI stability favors a high concentration of these organophosphorus compounds in electrolytes, the capacity utilization, rate capabilities, and low-temperature operation require that they be used at minimal concentrations. A compromise would be reached between 15 and 20% TFP or BMP in a binary 1.0 M LiPFe in EC/EMC (1 1) system or at higher than 30% in a ternary 1.0 M LiPFe in PC/EC/EMC (1 1 3) system. Such electrolytes are completely or at least nearly nonflammable. To further alleviate the above tradeoff, Xu et al. suggested that new cosolvents of higher flame retarding ability should be tailor-made. 

Creasey, N.H., Green, A.L. 1959. 2-Hydroxyiminomethyl-N-methyl- pyridinium methanesulphonate (P2S), an antidote to organophosphorus poisoning. Its preparation, estimation, and stability. J. Pharm. Pharmacol. 11 485-490. 

Enzyme Stabilization in Nanostructured Materials, for Use in Organophosphorus Nerve Agent Detoxification and Prophylaxis... 

LeJeune et al. - - investigated this stabilizing effect of immobilization at the expense of activity. They immobilized an organophosphorus hydrolase by emulsifying a solution of the enzyme with a hydrophilic polyurethane prepolymer. They intended to study the enzymatically catalyzed hydrolysis of organophosphate nerve... 

The synthesis of alkenes through the Wittig reaction has generated an impressive understanding of the chemistry of organophosphorus compounds. The generated car-banions stabilized by a phosphoryl moiety can be considered as ylide anions, and the... 

Phosphaalkynes of the type RC=P, featuring a three-valent phosphorus atom with coordination number 1 (X3a -P), represent novel organophosphorus compounds. Their chemistry has been extensively investigated since 1981, when the first synthesis of a kinetically stabilized phosphaalkyne (f-BuC=P) was reported (283). Several reviews on the cycloaddition chemistry of these compounds with diazo compounds have been published (284-286). 

Sulfur-containing organophosphorus compounds are prone to oxidation and degradation, especially in the presence of acids and strong oxidants. Their hydrolytic and thermal stability increase in the order dialkyl dithiophosphoric acids ((RO)2PSSH) < dialkyl dithiophosphinic acids (R2PSSH), due to the absence of the weak ether bridge. 

With oxygen donors like organophosphorus extractants (presence of P = O group) or amide-based molecules (presence of (N)C = O group), the main cleavage occurs in the a-position of the chemical function. The introduction of an O atom into this sensitive a-position was responsible for a lower stability, because the cleavage of an... 

Pesticides are also a major source of concern as water and soil pollutants. Because of their stability and persistence, the most hazardous pesticides are the organochlorine compounds such as DDT, aldrin, dieldrin, and chlordane. Persistent pesticides can accumulate in food chains for example, shrimp and fish can concentrate some pesticides as much as 1000- to 10,000-fold. This bioaccumulation has been well documented with the pesticide DDT, which is now banned in many parts of the world. In contrast to the persistent insecticides, the organophosphorus (OP) pesticides, such as malathion, and the carbamates, such as carbaryl, are short-lived and generally persist for only a few weeks to a few months. Thus these compounds do not usually present as serious a problem as the earlier insecticides. Herbicides, because of the large quantity used, are also of concern as potential toxic pollutants. Pesticides are discussed in more detail in Chapter 5. 

Lacorte, S., N. Ehresmann, and D. Barcelo. 1995. Stability of organophosphorus pesticides on disposable solid-phase extraction precolumns. Environ. Sci. Technol. 29 2834—2841. 

Selected Novel Trivalent Organophosphorus Processing Stabilizers for Polyolefins... 

These derivatives have not only provided new synthetic pathways but have shown improved thermal stability (as in the case of arsenic ylides) and a modified pattern of chemical reactivity. The donor properties of ylides 55, 24), and most of their synthetic applications 103), have been covered in other reviews and articles 3, 26) and are not duplicated here. The general organometallic chemistry of arsenic, antimony, and bismuth is the subject of the invaluable monograph by Doak and Freedman 11). The broad scope of phosphorus ylide and pentaorganophosphorane chemistry was covered in the leading multivolume series on organophosphorus chemistry edited by Kosolapoff and Maier 3, 21). Finally, the recent... 

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