Organophosphorus additive

ORGANOPHOSPHORUS ADDITIVE FLAME RETARDANTS 5.4.1 Phosphates and Phosphonates... 

As we proceeded to try to discover other, perhaps more effective, functional additives, several different approaches were considered to prepare such reactive organophosphorus additives. We will now discuss some of the alternate approaches, not all of which became commercial. 

In Section 10.6 of the preceding chapter it was shown that tricresyl phosphate, a widely used organophosphorus additive, left an interaction film of ferrous phosphate on the steel surface that it lubricated. In terms of a mechanism generally applicable to the esters of phosphorus oxyacids, two reaction paths immediately suggest themselves. One is the thermal decomposition of the ester linkage, catalyzed by the activated metal interface ... 

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). 

The addition of isocyanides and azide to aldehyde-derived enamines has led to tetrazoles (533,536). On the other hand the vinylogous amide of acetoacetic ester and related compounds reacted with aldehydes, isocyanides and acids to give a-acylaminoamides (534). Iminopyrrolidones and imino-thiopyrrolidones were obtained from the addition of cyclohexylisocyanide and isocyanates or isothiocyanates to enamines (535). An interesting method for the formation of organophosphorus compounds is found in the reactions of imonium salts with dialkylphosphites (536). 

Polyphosphates are also an important class of organophosphorus polymers. In addition to their flame-retardant characteristics, they possess attractive plasticizing properties and can be used as polymeric additives to other polymers [123-128]. In general, polyphosphates can be prepared by interfacial [119,129], melt [130], or solution polycondensation [131,132a,b]. Kricheldorf and Koziel [133] prepared polyphosphates from silylated bisphenols. 

Neutral organophosphorus chalcogenide-metal salt interactions addition and decomposition products. N. M. Karayannis, C. M. Mikulski and L. L. Pytlewski, Inorg. Chim. Acta, Rev., 1971, 5, 69-105 (479). 

Phosphinidenes [1] are low-valent organophosphorus compounds that have attracted attention since the early 1980s when they were first discovered [2]. They are known in two classifications, one being the six-electron singly substituted phosphorus species (A) and the other in which the phosphorus atom carries an additional ri -stabifizing group, typically, but not necessarily, a transition metal group (B). Much has been learned about the reactivities of the complexed phos-... 

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]. 

In addition to phosphotriesterase from P. diminuta (PTE) discussed above, two other types of enzymes were found to exhibit phosphotriesterase activity. Interestingly, both are peptidases - the enzymes which in nature hydrolyse a peptide bond. The first one - organophosphorus acid anhydrolase (OPAA) from Alteromonas sp. JD6.5 - is a proline dipeptidase its original activity is to cleave a dipepfide bond with a prolyl residue at the carboxy terminus. The second one - aminopeptidase P (AMPP) from Escherichia coli - is a proline-specific peptidase that catalyses hydrolysis of N-terminal peptide bonds containing a proline residue. ° ... 

Brief notes are added on phosphorofluoridates even though their destruction by microbial activity— though clearly possible—is limited by their toxicity to the requisite microorganisms. One of the motivations for their inclusion is the fact that the hydrolytic enzyme(s) responsible for defluorination—organophosphorus acid anhydrase (OPA)—is widespread, and is found in a number of bacteria (Landis and DeFrank 1990). The microbial hydrolysis of organophosphorus pesticides and cholinesterase inhibitors is accomplished by several distinct enzymes, which are collectively termed organophosphorus acid anhydrases (OPAs). These have been reviewed (DeFrank 1991), so that only a few additional comments are necessary. 

Because organophosphorus compounds are important in the chemical industry and in biology, many methods have been developed for their synthesis [1]. This chapter reviews the formation of phosphorus-carbon (P-C) bonds by the metal-catalyzed addition of phosphorus-hydrogen (P-H) bonds to unsaturated substrates, such as alkenes, alkynes, aldehydes, and imines. Section 5.2 covers reactions of P(lll) substrates (hydrophosphination), and Section 5.3 describes P(V) chemistry (hydrophosphorylation, hydrophosphinylation, hydrophosphonylation). Scheme 5-1 shows some examples of these catalytic reactions. 

SFE. SFE has been established as the extraction method of choice for solid samples. The usefulness of SFE for soil samples has been demonstrated for carbamate,organophosphorus and organochlorine pesticides. However, SFE is more effective in extracting nonpolar than polar residues. In order to obtain a greater extraction efficiency for the polar residues of imidacloprid, the addition of 20% methanol as modifier is required. Extraction at 276 bar and 80 °C with a solvent consisting of supercritical carbon dioxide modified with methanol (5%) for 40 min gives a recovery of 97% (RSD = 3.6%, n = 10). It is possible to use process-scale SFE to decontaminate pesticide residues from dust waste. ... 

In addition, studies of the kinetics of equilibria and reactions involving organophosphorus compounds have been reviewed and this appears in section 11 at the end of this chapter. 

Diazaphospholes constitute the most widely investigated class of heterophospholes, the 67t-aromatic phosphorus heterocycles [1,2]. Diazaphospholes are unique in the manner that the five-membered ring incorporates one phosphorus atom. First diazaphosphole representative, i.e. 2//-[l,2,3 diazaphospholc was obtained as early as 1967 [3] and until 1980s the interest of organophosphorus chemists remained in the development of different synthetic routes and in investigating their varied reactivity due to the structural diversity within the class [4], On the basis of the relative positions of the three heteroatoms in the five-membered ring, six monocyclic diazaphosphole systems (A-F) are possible and all of them have been reported (Structure 1). 

In spite of their toxicity, alkyl phosphites have been used extensively as lubricant additives, corrosion inhibitors, and antioxidants. In addition to their use as intermediates in synthesis, organophosphorus compounds are useful for separating heavy metals by solvent extraction. Several insecticides that were formerly in widespread use are derivatives of organic phosphates. Two such compounds are malathion and parathion. 

Used industrially for the manufacture of phosphorus oxychloride, phosphorus pentachlor-ide, phosphites, organophosphorus pesticides, surfactants, gasoline additives, plasticizers, dyestuffs used as a chlorinating agent and catalyst. Used to prepare rubber surfaces for electrodeposition of metal. Used as an ingredient of textile finishing agents. 

Used industrially for the manufacture of organophosphorus compounds (Insecticides, dyes, pharmaceuticals, defoliants) as well as esters for plasticizers, gasoline additives, and hydraulic fluids used in industry as a chlorinating agent, catalyst, dopant for semiconductor grade silicon, fire retarding agent, and solvent in cryoscopy. 

Chlordane interacts with other chemicals to produce additive or more-than-additive toxicity. For example, chlordane increased hepatotoxic effects of carbon tetrachloride in the rat (USEPA 1980 WHO 1984), and in combination with dimethylnitrosamine acts more than additively in producing liver neoplasms in mice (Williams and Numoto 1984). Chlordane in combination with either endrin, methoxychlor, or aldrin is additive or more-than-additive in toxicity to mice (Klaassen et al. 1986). Protein deficiency doubles the acute toxicity of chlordane to rats (WHO 1984). In contrast, chlordane exerts a protective effect against several organophosphorus and carbamate insecticides (WHO 1984), protects mouse embryos against influenza virus infection, and mouse newborns against oxazolone delayed hypersensitivity response (Barnett et al. 1985). More research seems warranted on interactions of chlordane with other agricultural chemicals. 

Several new sections have been added to this Second Edition, and the presentations of the established methods have been updated to emphasize the recent advances in their use. In addition to the survey of the approaches toward carbon-phosphorus bond formation, details of specific preparations are provided as guides for the performance of these reactions without detailed recourse to the original literature. In this way, this work is anticipated to be of particular value to the synthetic organic chemist who is skilled in the general art but not particularly experienced in organophosphorus chemistry. 

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