Subject organophosphorus

Recently there has been a renewed interest in the extraction of actinides with various neutral bifunctional organophosphorus extractants (1-9). An excellent review on this subject has been published recently by Schulz and Navratil (9). Interest in neutral bifunctional organophosphorus extractants stems largely from the fact that these compounds have the ability to extract tri-... 

This chapter will also deal with compounds containing two or three phosphinous amide units, which, for simpUcity, will be named here as bis(amino-phosphanes) or tris(aminophosphanes) but not with phosphinous amides containing other additional organophosphorus functionaUties as, for instance, the so-called aminophosphine phosphinites (AMMP), which have been the subject of increasing attention in the Uterature dealing with catalytic asymmetric transformations and have been treated in other reviews [2,3]. 

Elemental phosphorus in white or red forms is subject to attack by a variety of nucleophilic reagents. Aqueous bases provide one of the most useful reagent systems for organophosphorus syntheses, although other nucleophiles can also be used for specific synthetic processes. 

Inmost instances, a haloorganic subject to either SN2 displacement reaction or SN1 substitution is heated at reflux with the trivalent phosphorus ester with the concomitant formation of the valence-expanded organophosphorus compound and haloorganic by-product, as illustrated with an example in Equation 3.1. 

As anhydrides, such compounds are subject to spontaneous hydrolysis, which may contribute to detoxification [160]. Thus, soman hydrolysis at pH 7.5 and 37° occurs with a rate constant of 0.003 - 0.004 min-1 and an activation energy of ca. 55 kJ mol 1 [161]. However, most of the published data refer to enzymatic hydrolysis. Enzymes hydrolyzing P-X anhydride bonds are now known as organophosphorus acid anhydrolases (OPA anhydrolases) classified as EC 3.1.8.2 (also known as diisopropyl-fluorophosphatase, DFPase, tabunase, somanase), an activity related to EC 3.1.8.1 (aryldialkyl-phosphatase, paraoxonase, A-esterase) and formerly classified as EC 3.8.2.1 [64] [65] [69], Much public information on these enzymes can be found in [106],... 

Two factors contribute to the safety of oximes in the treatment of acute poisoning by organophosphorus compounds recommended doses are small, compared with doses likely to cause even mild toxic effects in normal subjects and adverse effects of oximes are reduced in the presence of poisoning by an organophosphorus compound. 

Absorption. Absorption of foreign compounds from various sites is dependent on the physiological and physical conditions at these sites. These, of course, may be subject to species variations. Absorption of compounds through the skin shows considerable species variation. Table 5.2 gives an example of this and shows the species differences in toxicity of an organophosphorus compound absorbed percutaneously. Human skin is generally less permeable to chemicals than that of rabbits, mice, and rats, although there is variation. For some compounds, rat skin has similar permeability to human skin and seems to be less permeable than that of the rabbit. 

The Chemistry of Organophosphorus Compounds is a multi-volume work within the well established series of books covering The Chemistry of Functional Groups. It is proposed to cover the extensive subject matter in four volumes. 

The chemistry of the extraction of UO + by mixtures of organophosphoric acids and neutral organophosphorus compounds has been the subject of many studies, and the available information has been widely discussed.75 118 127 131 134 There is no general agreement on the mechanism of the synergistic effect, although an addition process such as... 

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... 

The increased use of derivatisation reactions is evident from the gradual increase in the number of publications dealing with the subject. Figure 1 shows the yearly variation in numbers of publications dealing with derivatisation in pesticide analysis over the period 1963 to 1978. While the interest in derivatisation techniques in organophosphorus insecticide analysis has remained fairly constant and a low level of activity, the OC insecticides underwent an increased period of attention from 1968-1972 which has stablized over the last few years. It is in the insecticidal carbamate and herbicide areas that an overall steady increase in the use of derivatisation reactions for quantitative and con-... 

Theory. Cholinesterase inhibition by organophosphorus insecticides has been the subject of several excellent reviews by O Brien (I, 2) and Heath (3). The basis of toxic action of organophosphates and carbamates in mammals is generally associated with their ability to inhibit cholinesterase in the central and peripheral nervous systems where it plays an important role in the transmission of nerve impulses. 

One of the subjects of our investigations involved the interaction of allenes with the P=E derivatives. This work provided some very interesting, unexpected results that may well be of use in synthetic organophosphorus chemistry. Thus, in attempting to study the (2+2)-cycloadditions of the phosphinimine and the (methylene)phosphine systems with the allenic C=C bond, we established that the reactions take a different and more interesting course — that of an ene" reaction (eq 1). In the first step of the reaction, the electrophilic phosphorus center apparently attacks the nucleophilic central carbon of the allene system. Then, instead of undergoing nucleophilic attack on the incipient carbonium ion, the anionic center (E) abstracts a proton from the terminal C-H bond, leading to the formation of a new double bond in the phosphorus-substituted 1,3-butadiene derivatives (3). 

Aprea C, Sciarra G, Lunghini L. Analytical method for the determination of urinary alkylpho-sphates in subjects occupationally exposed to organophosphorus pesticides and in the general population. J Anal Toxicol 1996 20 559-63. 

This branch of organophosphorus chemistry continues to attract a great deal of effort, although the general pattern of the literature in recent years has been continued. Thus a number of significant theoretical papers have appeared, while experimental studies are clearly being devoted more to mechanistic than purely preparative chemistry. A comprehensive review of the latter aspects of the subject has appeared. ... 

Polypropylene. The six organophosphorus compounds (Figure 1, 0.05 weight %) were each formulated together with AO-1 (0.10%) in Hercules general purpose Profax 6501 polypropylene and were subjected to multiple extrusion in two series, one at 500 F (260°C) and another at 550°F (288°C). Comparison of the test compounds in the presence of AO-1 were made at each temperature by measuring the melt flow rate and color development after the first, third and fifth extrusions (6,7). The results after the fifth extrusion are shown in Table I. 

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