Alkylphosphonates

Gao W, Dickinson L, Grozinger C, Morin F G and Reven L 1996 Self-assembled monolayers of alkylphosphonic acids on metal oxides Langmuir M 6429-35... 

Triethyl phosphite is a colourless mobile liquid, insoluble in water. Trialkyl phosphites are valuable intermediates in the preparation of many organophosphorus compounds they readily form dialkyl esters of alkylphosphonic acids by the Arbusov reaction (p. 311). 

If R = R, the reaction appears to be catalytic as a small quantity of R Cl will suffice to convert a considerable quantity of the trialkyl phosphite into the dialkyl alkylphosphonate (I). As little as o-i mol. of the alkyl iodide will suffice to isomerise the trialkyl phosphite. 

Detergents are metal salts of organic acids used primarily in crankcase lubricants. Alkylbenzenesulfonic acids, alkylphenols, sulfur- and methjiene-coupled alkyl phenols, carboxyUc acids, and alkylphosphonic acids are commonly used as their calcium, sodium, and magnesium salts. Calcium sulfonates, overbased with excess calcium hydroxide or calcium carbonate to neutralize acidic combustion and oxidation products, constitute 65% of the total detergent market. These are followed by calcium phenates at 31% (22). 

The reaction proceeds through an intermediate phosphonium salt which can be isolated in some instances. The Michaehs-Arbusov reaction is especially useful for converting trialkyl phosphites, (RO) P, to alkylphosphonic esters, and to esters of phosphonocarboxyhc acids. 

Phosphonic acid is an intermediate in the production of alkylphosphonates that are used as herbicides and as water treatment chemicals for sequestration, scale inhibition, deflocculation, and ion-control agents in oil weUs, cooling tower waters, and boiler feed waters. For example, aqueous phosphonic acid reacts with formaldehyde and ammonium chloride in the presence of hydrochloric acid to yield aminotri(methylenephosphonic acid) [6419-19-8]. 

Trialkyl esters of phosphonic acid exist ia two structurally isomeric forms. The trialkylphosphites, P(OR)2, are isomers of the more stable phosphonates, 0=PR(0R)2, and the former may be rearranged to resemble the latter with catalytic quantities of alkylating agent. The dialkyl alkylphosphonates are used as flame retardants, plasticizers, and iatermediates. The MichaeUs-Arbusov reaction may be used for a variety of compound types, including mono- and diphosphites having aryl as weU as alkyl substituents (22). Triaryl phosphites do not readily undergo the MichaeUs-Arbusov reaction, although there are a few special cases. 

Phosphoms trichloride may also be used directly ia the production of trialkyl phosphites, dialkyl phosphonates, and dialkyl alkylphosphonates ... 

The recent development and comparative application of modern separation techniques with regard to determination of alkylphosphonic acids and lewisite derivatives have been demonstrated. This report highlights advantages and shortcomings of GC equipped with mass spectrometry detector and HPLC as well as CE with UV-Vis detector. The comparison was made from the sampling point of view and separation/detection ability. The derivatization procedure for GC of main degradation products of nerve agents to determine in water samples was applied. Direct determination of lewisite derivatives by HPLC-UV was shown. Also optimization of indirect determination of alkylphosphonic acids in CE-UV was developed. Finally, the new instrumental development and future trends will be discussed. 

Far less than the stoichiometric amount of sequestrants precipitation of insoluble salts from water hardness can be prevented by slowing down the formation of crystals and crystal growth. This process is called the threshold effect. It has long been used in the preparation of boiler feeding water, e.g., steam vessels of railroad engines. Originally sodium pyrophosphate was used for this task, but alkylphosphonic acids and derivatives thereof are superior in their effect. 

Compounds with a P-C bond can be observed to a large extent in the field of bi- and poly functional phosphorus-containing surfactants. Alkylphosphonic... 

Alkylphosphonates are surface-active agents. But the main use of these substances lies in their ability to form stable complexes with bi- or polyvalent cations. Thus, besides the identification of the P-C bond and the determination of the amount of phosphorus in the molecule by one of the previously mentioned methods, measurement of their sequestering ability is carried out. 

The strained hydrocarbon [1,1,1] propellane is of special interest because of the thermodynamic and kinetic ease of addition of free radicals (R ) to it. The resulting R-substituted [ 1.1.1]pent-1-yl radicals (Eq. 3, Scheme 26) have attracted attention because of their highly pyramidal structure and consequent potentially increased reactivity. R-substituted [1.1.1]pent-1-yl radicals have a propensity to bond to three-coordinate phosphorus that is greater than that of a primary alkyl radical and similar to that of phenyl radicals. They can add irreversibly to phosphines or alkylphosphinites to afford new alkylphosphonites or alkylphosphonates via radical chain processes (Scheme 26) [63]. The high propensity of a R-substituted [1.1.1] pent-1-yl radical to react with three-coordinate phosphorus molecules reflects its highly pyramidal structure, which is accompanied by the increased s-character of its SOMO orbital and the strength of the P-C bond in the intermediate phosphoranyl radical. 

During the last decade, Bentrude et al. [65] has shown that the triplet-sensitized photorearrangement of allylphosphites and analogs (Scheme 28) is a powerful method for preparation of alkylphosphonates from phosphites. Moderate to high yields were observed when triphenylene was used as photosensitizer [66,67]. 

G.l.c. studies of tributylphosphine, dialkyl phosphites, and dialkyl alkylphosphonates are reported. Tributyl phosphate in nitric acid can be estimated by g.l.c. if a glass column is used. Tetraethyl pyrophosphate has been directly determined on a nanogram scale by g.l.c., whereas it was found most convenient to first convert the tetra-aryl pyrophosphates by methanolysis to diarylmethyl phosphates. Phosphorochloridates were converted by t-butyl alcohol into t-butyl chloride before analysis. G.l.c. studies of pesticides have been reported and the isomeric thiophosphates (138a) and (138b) have quite different retention times. ... 

Chen C-M, Q-Z Zhuang, Z Zhu, BL Wanner, CT Walsh (1990) Molecuar biology of carbon-phosphorus bond cleavage Cloning and sequencing of the phn (psiD) genes involved in alkylphosphonate uptake and C-P lyase activity in Escherichia coli. J Biol Chem 265 4461-4471. 

Olefination Reactions Involving Phosphonate Anions. An important complement to the Wittig reaction involves the reaction of phosphonate carbanions with carbonyl compounds 253 The alkylphosphonic acid esters are made by the reaction of an alkyl halide, preferably primary, with a phosphite ester. Phosphonate carbanions are generated by treating alkylphosphonate esters with a base such as sodium hydride, n-butyllithium, or sodium ethoxide. Alumina coated with KF or KOH has also found use as the base.254... 

Mixed phosphonate acid esters can also be prepared from alkylphosphonate monoesters, although here the activation is believed occur at the alcohol.57... 

Purdon JG, Pagotto JG, Miller RK. 1989. Preparation, stability, and quantitative analysis by gas chromatography and gas chromatography-electron impact mass spectrometry of tert-butyldimethylsilyl derivatives of some alkylphosphonic and alkyl methylphosphonic acids. J Chromatogr 475 261-272. 

Reactions and Properties of Phosphonic and Phosphinic Acids and their Derivatives.-A free radical mechanism has been proposed to account for the cleavage of the phosphorus-carbon bond in the alkylphosphonic acids (155) by E coli to give a mixture of alkane (methane only, from methylphosphonic acid) and terminal alkene. 

Danesi, P. R. Reichley-Yinger, L. Mason, G. Kaplan, L. Horwitz, E. P. Diamond, H. Selectivity structure trends in the extraction of cobalt(II) and nickel(II) by dialkyl phosphoric, alkyl alkylphosphonic, and dialkylphosphinic acids. Solvent Extr. Ion Exch. 1985, 3, 435 152. 

Shpaisman FI, Salomon E, Nesher G, Vilan A, Cohen H, Kahn A, Cahen D (2009) Electrical transport and photoemission experiments of alkylphosphonate monolayers on GaAs. J Phys ChemC 113 3313-3321... 

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